FINAL REPORT 

Zeolite Coating System for Corrosion Control to Eliminate 

Hexavalent Chromium from DoD Applications 

SERDP Project WP-1342 

AUGUST 2009

Yushan Yan 

University of California, Riverside, CA 
This report was prepared under contract to the Department of Defense Strategic 

Environmental Research and Development Program (SERDP). The publication of this 

report does not indicate endorsement by the Department of Defense, nor should the 

contents be construed as reflecting the official policy or position of the Department of 

Defense. Reference herein to any specific commercial product, process, or service by 

trade name, trademark, manufacturer, or otherwise, does not necessarily constitute or 

imply its endorsement, recommendation, or favoring by the Department of Defense. 
SERDP PP1342: Zeolite Coating System 

University of California, Riverside, CE‐CERT   2 

Contents

1. PERFORMING ORGANIZATIONS....................................................................3

2. PROJECT BACKGROUND ...............................................................................4

3. OBJECTIVES ..................................................................................................8

4. TECHNICAL APPROACH.................................................................................9

5. PROJECT ACCOMPLISHMENTS ....................................................................15

TASK 1‐1: EXTENSION OF ZSM‐5 COATING TO OTHER DOD ALLOYS ...................................16

TASK 1‐2: SCALE UP THE DEPOSITION PROCESS TO 3X6” PANELS FROM 2X3 CM COUPONS.......18

TASK 1‐3 & 1‐4: ALTERNATIVE ZEOLITE AND DEPOSITION PROCESS.....................................21

TASK 2.  ZEOLITE/TOPCOAT SYSTEMS ........................................................................... 33

TASK 3.1: LASER SCANNING CONFOCAL MICROSCOPY (LSCM) CHARACTERIZATION OF COATING

SURFACES ............................................................................................................... 35

TASK 3.2: INSTRUMENTAL ANALYSIS OF COATING DEGRADATION ........................................39

TASK 3‐3: QUANTITATIVE/QUALITATIVE ADHESION TESTING OF COATING TO AL & STEEL

SUBSTRATES............................................................................................................ 42

TASK 3‐4: CONDUCT ACCELERATED SERVICE SIMULATION TESTING ......................................48

TASK 3‐5: EXAMINE SUBSTRATE DEGRADATION AND CORROSION INHIBITION – EIS TEST..........66

TASK 3‐6: MARINE ATMOSPHERE TEST/COATING DEGRADATION STUDIES.............................68

TASK 4: TECHNOLOGY TRANSITION.............................................................................. 82

APPENDIX .........................................................................................................83

REFERENCE .......................................................................................................86

 
SERDP PP1342: Zeolite Coating System 

University of California, Riverside, CE‐CERT   3 

1. Performing Organizations

 

Dr. Y. Yan

Dr. Y. Yan Dr. P. Zarras Mr. S. Smith Dr. M. Tsapatsis 

Mr. D. Beving 

Dr. Y. Kim 

Dr. R. Cai 

Mr. R. Munoz 

Mr. C. O’Neill 

Ms. N. Anderson 

Ms. C. Webber 

Dr. A. Guenthner 

Mr. M. Fleszar 

Ms. Aisha Bishop 

Dr. Gay Kendall 

Dr. Z. P. Lai 

Dr. S. Ghosh 

Mr. M. Boretz 

Ms. L. Arth 

Ms. C. Howard 

Zeolite coating 

In-situ crystallization 

Basic and standard 

characterization 

Standard (Mil-spec) 

characterization 

Polymer coating 

Formulation/deposition 

Basic coa ting 

characterization 

Standard (Mil-Spec) 

characterization 

Zeolite coating 

Alternative deposition 

Basic coa ting 

characterization 

Materials engineering/Chemical engineering /Inorganic chemistry/Polymer chemistry/Polymer physics/Physics 

Mr. D. Harmston, NADEP 
SERDP PP1342: Zeolite Coating System 

University of California, Riverside, CE‐CERT   4 

2. Project Background

Corrosion control coa ting systems for DoD applications. Corrosion costs associated with 

corrosion prevention and correction of corrosion-generated failures account for approximately 

25% of the armed services’ annual maintenance budgets, or more than $1 billion a year1. A 

majority of these costs is associated with compliance with new environmental regulations 

regarding worker safety and hazardous waste disposal. These costs have risen dramatically over 

the past several years – as high as 20% in some DoD facilities. This increase is responsible for a 

significant portion of noncompliance with new environmental regulations, systems downtime, 

and failure of mission readiness. 

Current effective corrosion control coating systems for alloys and especially aluminum alloys 

used in DoD applications rely on extensive use of hexavalent chromium (Cr+6) in conversion 

coatings and primers. Table 2-1 shows several current military coating systems used for 

corrosion inhibition on aluminum alloys. All coatings contain hexavalent chromium. As a 

surface pretreatment, chromium conversion coatings (CCC) were first introduced during the 

1950s2-5. Since this time, they have found widespread use in both military and commercial 

applications. Within the DoD community, the CCC process is extensively used to enhance paint 

adhesion and corrosion inhibition. CCC has been used to effectively treat numerous metals such 

as aluminum, copper, cadmium, manganese and zinc. Hexavalent chromium is also widely used 

in the primers for corrosion control (Table 2-1). Unfortunately, Cr+6 is toxic and carcinogenic6. 

Therefore, regulations regarding its use and disposal have become increasingly stringent. The 

current Permissible Exposure Limits (PEL) (50 μg/m3) of Cr+6 have been recommended to be 

reduced to 1.0 μg/m3 by OSHA in order to meet the required low level of risk. Additionally, 

painting and depainting operations continue to be a significant source of hazardous waste for the 

DoD7. Hazardous waste generation and disposal from such operations are a significant source of 

painting operation costs. The National Emission Standards for Hazardous Air Pollutant 

(NESHAP)/Environmental Protection Agency (EPA) regulations are implementing new 

regulations for reducing chromate exposure for workers and will eventually eliminate its use 

altogether in the near future. Therefore, a new chromium-free coating system is critically needed 

to meet corrosion protection performance requirements in all DoD applications. 

Table 2-1 Military coatings specifications (All coatings systems listed below contain chromates) 

MIL-Spec Description 

TT-2756 solvent-based polyurethane self-priming topcoat 

TT-P-2760 solvent-based polyurethane flexible primer 

MIL-P-53022 solvent-based epoxy primer 

MIL-P-53030 water-reducible epoxy primer 

MIL-PRF-85582 water-reducible epoxy primer 

MIL-PRF-23377 solvent-based epoxy primer 

DOD-P-15328 wash pretreatment (primer) 

DOD-P-5541 chromate conversion coating 
SERDP PP1342: Zeolite Coating System 

University of California, Riverside, CE‐CERT   5 

Corrosion resistant zeolite coatings. Zeolites are crystalline inorganic polymers with a reduced 

molecular formula mSiO2-AlO3 (1 ≤ m ≤∞)

8

. At the atomic level, zeolites are constructed from 

TO4 tetrahedra (T = tetrahedral atom, e.g., Si, Al); each apical oxygen atom is shared between 

two adjacent tetrahedra. Aluminum atoms usually are uniformly distributed within the polymer 

structure. According to Si/Al ratio, zeolite can be classified into two groups – high-silica (i.e., 

high Si/Al) and low-silica (i.e., low Si/Al). Zeolites, and especially high-silica zeolites are known 

for their thermal stability. Many zeolites are stable to 900 °C and some high-silica zeolites are 

stable up to 1400 °C without losing their crystalline structure9. All zeolites are stable to organic 

solvents and high-silica zeolites are stable to most mineral acids and react only with hydrofluoric 

acids10. Zeolites are inexpensive. Zeolites are non-toxic. Although not a high-volume 

application, zeolites are used in personal hygiene products such as odor removal gels and baby 

diapers. Very recently FDA has approved a medical application, which involves using zeolites as 

an oral contrast agent for magnetic resonance imaging11.

Thus far, zeolite materials are most commonly used in particle form as catalysts (e.g., catalytic 

cracking for petroleum refining) and gas separation media (e.g., air separation into nitrogen and 

oxygen). Recently zeolite films have been prepared as membranes for separation applications12. 

All of these applications take advantage of the uniform microporosity of zeolites (3-13Å). In 

other words, zeolites are used in these applications as molecular sieves – sieving molecules 

according to their size with precision of a fraction of an angstrom. UCR has recently 

demonstrated for the first time that as-synthesized high-silica zeolite ZSM-5 coatings can be 

extremely corrosion resistant (Figure 2-1, Figure 2-2) 13, 14. Syntheses of high-silica zeolites 

usually involve using an organic template (or structure-directing-agent) to crystallize the desired 

structure. These template molecules (e.g., tetrapropylammonium) are bulky and eventually 

trapped inside the zeolite structure. To free up the pore spaces for catalysis and separation 

applications, these trapped molecules are usually burned-out by high temperature calcinations 

(e.g., 500 oC) in air or oxygen overnight. Therefore, as-synthesized zeolite coatings (without 

going through calcinations) can be non-porous (Figure 2-1c). 

High-silica zeolite ZSM-5 coatings on aluminum alloy 2024-T3 (AA-2024-T3) have been shown 

to offer remarkably better corrosion resistance than chromate conversion coating and anodization 

coating in strong acids (Figure 2-2 a&b), bases (0.5 M NaOH, not shown), and pitting aggressive 

environments (Figure 2-2 c&d)13, 14. For example, there is no decrease of corrosion resistance 

after the zeolite coated AA-2024-T3 sample is immersed in 0.5 M H2SO4 for 10 days (Figure 2-2 

b). The zeolite coating is chemically bonded to the aluminum alloys or other metals through 

condensation of surface hydroxyl groups12. Zeolite coating also has good thermal stability (e.g., 

240 oC) and thermal shock stability (e.g., fast thermal cycling between 240 oC and – 70 oC) and 

good adhesion under mechanical stresses (cutting, impact, and bending). Preliminary results have 

shown that the zeolite coatings have good paint compatibility and is compatible to polyurethane 

type paints13. They also have better abrasion resistance than anodization coatings. The coating 

thickness can be readily controlled between 0.5 to 50 μm according to specific needs. 
SERDP PP1342: Zeolite Coating System 

University of California, Riverside, CE‐CERT   6 

Figure 2-1 Scanning electron microscope (SEM) 

micrographs of an as-synthesized zeolite coating on 

Al-2024-T3, (a) top view and (b) cross-sectional 

view, (c) schematic of ZSM-5 pore system and 

location of the trapped template – tetrapropylammonium (TPA) molecule. Open circle for 

nitrogen atom and solid circle for carbon atom, and 

hydrogen atoms were not shown. Ref.13. 

Figure 2-2 DC polarization curves of several 

coatings in different corrosive media. (1) zeolite 

coating on Al-2024-T3, (2) anodization coating on 

Al-5005 (sulfuric acid anodized and sealed by hot 

water, 18 μm thick, provided by Southern 

Aluminum Finishing, Atlanta, GA), (3) bare Al2024-T3, (4) chromate conversion coating on Al2024-T3 (submicron thick provided by Triple AAA 

plating, Inc. Bells, Texas); (a) 0.5 mol/L H2SO4

after immersion for 2 hours, (b) 0.5 mol/L H2SO4

after immersion for 10 days, (c) 0.5 mol/L 

NaCl/HCl (pH=1) after immersion for 2 hours, (d) 

0.5 mol/L NaCl + 0.26 g/L CuCl2 + HAc (pH=3) 

after immersion for 1 day. All tests at 25 °C with 

sweep rate of 1 mV/s, saturated calomel electrode 

and Solartron 1287 potentiostat. . Ref.13. 

Zeolite coating (line 1) provides better corrosion 

protection than chromate conversion coating and 

anodization coating in strong acid (a) and (b), 

strong base (0.5 M NaOH, not shown), and pitting 

aggressive solutions (c and d). 

Zeolite coating by in-situ crystallization. The high-silica ZSM-5 coatings discussed above were 

prepared by in-situ crystallization process. In-situ crystallization here refers to a coating process 

in which the zeolite crystals making up the eventual polycrystalline coating are crystallized 

directly at the solid-liquid interface from a synthesis solution during the coating formation 

process(Figure 2-4)12. The synthesis solution used is a clear, dilute aqueous solution containing 

primarily molecular species of silicon and aluminum. The term “in-situ crystallization” 

originates from the fact that there are no preformed zeolite particles in the synthesis solution. The 
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SERDP PP1342: Zeolite Coating System 

University of California, Riverside, CE‐CERT   8 

3. Objectives

The overall objective of the proposed project is to develop a new environmentally friendly 

zeolite coating system for corrosion control to eliminate hexavalent chromium in DoD 

applications without sacrificing performance. The specific goals of the project are as follows. 

1) Development of zeolite coatings (see Tasks for details). 

2) Demonstrate compatibility with current Military water-dispersible polyurethane topcoats. 

3) Basic characterization and standard testing of zeolite and zeolite/topcoat systems and 

provide performance benchmarking with current chromium-containing DoD coating 

systems. 

4) Fast technology transition. 

 
SERDP PP1342: Zeolite Coating System 

University of California, Riverside, CE‐CERT   9 

4. Technical approach

This SERDP project will have four major thrusts: (1) development of zeolite coatings on DoD 

relevant alloys; (2) demonstrate compatibility of zeolite coatings with current Military waterdispersible polyurethane topcoats; (3) basic characterization and standard testing of 

zeolite/topcoat systems with benchmarking obtained from performance of current chromiumcoating coating systems; (4) technology transition. Specifically, the following tasks will be 

carried out by the research team consisting of UCR, UMN, NAWCWD (China Lake), Army 

Benet Labs, and NADEP (North Island). 

Task 1: Zeolite coatings 

Task 1-1: Extension of in-situ crystallization coating deposition process from AA-2024-T3 to 

other DOD relevant alloys such as AA-6061-T6, and AA-7075-T6, and steels (S1008, S4130, 

SS304) 

With support from US EPA, UCR has so far focused on 2x3 cm coupons to demonstrate that 

high-silica-zeolite (PSZ) coatings can be successfully deposited on AA-2024-T3, and the assynthesized coatings are corrosion-resistant in strong acid, base, and pitting aggressive 

environments, and have good thermal and thermal shock stability, and good adhesion under 

mechanical stresses (cut, bending, and impact). For the proposed effort, it is important to show 

that the in-situ crystallization coating process can be extended to other DoD relevant alloys such 

as AA-6061-T6, AA-7075-T6, and cold rolled steel S-1008. 

Task 1-2: Scale-up in-situ crystallization coating deposition process from current 2x3 cm 

coupons to larger panels such as 3x6 inches 

With US EPA support, UCR’s effort up to today has focused on 2x3 cm coupons because they 

are convenient to produce and adequate for the current research needs. By using small coupons, 

the amount of chemicals used can also be minimized. In the proposed effort, it is critical to 

demonstrate that the process can be scaled up. Large 3x6 inch panels are also needed for 

standard tests (e.g., ASTM and Mil-Spec as described in Task 4). 

Task 1-3&1-4: Develop alternative coating and coating deposition method 

The goal of this task is to develop alternative zeolite coatings (i.e., other than ZSM-5) and 

deposition process. The central requirements are ambient pressure, low temperature, and short 

deposition time. The process should also be convenient for repair should the original coating 

damaged. Two different deposition methods are being developed. The first one is a layer-bylayer deposition process using MCM-22 developed by UMN. The precursor of zeolite MCM-22, 

namely MCM-22(P), is a layered aluminosilicate. Layers in the as-synthesized MCM-22-(P) are 

weakly linked together with organic structure directing agents, Hexamethyuleneimine (HMI), 

along the [001] direction. Two-dimensional large channels are running in-plane of the MCM-22-

(P) layers. However, the limiting apertures for transport perpendicular to the layers (along [001] 

direction) are 6MR’s, i.e. defined by six interconnected SiO4 tetrahedra. Thus, molecules like 

water and O2 cannot penetrate along the c-axis. Upon calcination, MCM-22(P) condenses to 

MCM-22. On the other hand, layers in MCM-22(P) can be delaminated. After calcination, it 
SERDP PP1342: Zeolite Coating System 

University of California, Riverside, CE‐CERT   10 

forms another material called ITQ-2. Either MCM-22(P) or MCM-22 particles are plate-like. 

Delaminated layers will be even thinner. We use these materials as building blocks to assemble a 

thin film by a chemical interaction based Layer-by-Layer method for corrosion protection. The 

second one is microwave-assisted ambient pressure ionothermal synthesis method using SAPO11. In this method, ionic liquid was used instead of water, making it possible for zeolite synthesis 

at ambient pressure even at temperatures higher than 100 o

C since ionic liquid has negligible 

vapor pressure. Microwave radiation can accelerate the deposition process to fulfill the 

requirement of short deposition time.

Task 2: Application of primer/topcoat or topcoat to zeolite coatings 

The U.S. Army has developed a water dispersible polyurethane (U. S. Patent #5,691,410), which 

is currently being used by DoD for tactical and related support equipment. The water-dispersible 

(WD) chemical agent resistant coating (CARC) utilizes hydroxyl-functional polyurethane 

dispersions and water dispersible polyisocyanates. The U.S. Air Force has similarly developed a 

water dispersible polyurethane topcoat. Both Army and Air Force polyurethane topcoats will be 

applied to the zeolite coated alloys to demonstrate compatibility with these systems. 

Primers and primer/topcoat systems currently in use by the military will also be applied to the 

zeolite coatings to demonstrate compatibility of the zeolite coating with existing systems. The 

different primers and topcoats and combinations to be tested are shown below. 

 Primer Topcoat 

 Mil-P-23377 I (chromated) Mil-PRF-85285 

 Mil-P-23377 I (non-chromated) Mil-PRF-85285 

 Mil-P-85582 (non-chromated) Mil-PRF-85285 

 Mil-P-23377 I (chromated) none 

 Mil-P-23377 I (non-chromated) none 

 Mil-P-85582 (non-chromated) none 

 TT-P-2756 A (self-priming topcoat) none 

Task 3: Laboratory characterization and standard tests

Task 3-1: Characterization of coating surfaces. Quantitative surface characterization will be 

performed by Laser Scanning Confocal Microscopy (LSCM) and Atomic Force Microscopy 

(AFM). These methods provide non-destructive 2- and 3-dimensional imaging with no a priori

surface preparation. Surface characterization of individual proposed layers will provide insights 

to total coating system performance (e.g., enhanced adhesion of topcoat to zeolite due to 

significant surface area available for bonding). LSCM and AFM will be used to obtain a 

quantitative measure of surface area, complexity (roughness, fractal dimension), and quality 
SERDP PP1342: Zeolite Coating System 

University of California, Riverside, CE‐CERT   11 

(frequency/size of defects) of the following systems, having been applied to Al and steel 

substrates: (i) zeolite coating, (ii) zeolite/polyurethane topcoat system. 

Surface characterization by LSCM and AFM will be repeated following sequential accelerated 

weathering exposures (see Task 3-4) of systems (ii) to quantitatively describe coating system 

degradation. Results will be benchmarked with current Army & Air Force 

pretreatment/primer/topcoat systems. 

Task 3-2: Instrumental analyses of coating degradation. Several analytical techniques will be 

used to examine the degradation due to accelerated environmental weathering of zeolite/topcoat 

systems on aluminum alloy and steel substrates. These tests include thermal gravimetric analysis 

(TGA), Fourier transform infrared spectrometry (FTIR), thermal mechanical analysis (TMA), 

scratch tests and wear tests. In all cases, these tests will be conducted before, during and after 

accelerated service simulation testing. TGA is a technique which measures the weight of a 

sample as a function of temperature. TGA can effectively measure moisture, solvent, additive or 

plasticizer loss and the rate of thermal decomposition. FTIR can provide valuable information 

regarding the chemical nature and molecular structure of the material. This technique can 

provide information regarding the effects of drying and weathering on paints. TMA techniques 

can measure the coefficient of thermal expansion, stress relaxation, penetration, softening and 

glass transition temperature of thin films such as paint coatings, which will provide degradation 

profiles. 

Task 3-3: Quantitative/qualitative adhesion testing of coatings to substrates. Current standard 

techniques for adhesion testing will be performed using ASTM qualitative adhesion testing such 

as the wet tape adhesion (FED-STD –141 method 6301) and dry tape adhesion (ASTM D3359). 

Benet Laboratories will apply semi-quantitative assessments of coating adhesion. They will use 

several techniques pioneered in their laboratories16. Adhesion Peel Testing (APT) and Dynamic 

Mechanical Analysis (DMA) will be utilized to evaluate the effects of surface pretreatments and 

coating process parameters on interfacial adhesion. Tests will be performed on zeolite and 

zeolite/topcoat systems. 

Task 3-4: Conduct accelerated service simulation testing. Accelerated testing of all panels 

using novel zeolite and zeolite/topcoat systems and current military coatings as controls will be 

carried out using an Accelerated Corrosion Test Chamber. This chamber will provide precision 

testing such as 2000-hour salt-fog (ASTM B117) tests. If test panels meet this initial 

requirement, further testing will include acetic acid/salt spray (ASTM B287), copper accelerated 

salt spray (ASTM B368), corrodkote (ASTM B380), sulfur dioxide (ASTM B605) and GM 9540 

tests. UV exposure tests will be performed on coated coupons following ASTM test 53-96 

guidelines for 32 weeks. 

Task 3-5: Examine substrate degradation and corrosion inhibition. The evaluation of the 

substrate corrosion, pitting, etc., will be evaluated using such techniques as eddy current, 

electrochemical impedance spectroscopy (EIS) and DC Polarization. Nondestructive eddy 
SERDP PP1342: Zeolite Coating System 

University of California, Riverside, CE‐CERT   12 

current techniques will be used to measure electrical resistivity of the component structure to 

determine if corrosion has occurred. Eddy currents have been extensively used to measure the 

electrical resistivity of metals and have been very successful at determining cracks and 

corrosion17. EIS is a very sensitive technique to measure the corrosion barrier performance of a 

coating by measuring its electrical impedance. The charge transfer resistance obtained from this 

experiment provides an excellent indicator of the integrity of the coating and successfully 

predicts long-term corrosion behavior. This technique can effectively measure coating defects, 

water uptake, coating degradation and substrate corrosion. The technique measures various 

degradation processes in the coating, which causes absorption of electrical energy at different 

frequencies. This causes a time lag between the time-dependent excitation and response signals. 

These processes can be simulated by equivalent electrical networks. The frequency response 

generated from the EIS test is analyzed using a Bode plot, which can discriminate between 

different electrochemical processes. These plots provide detailed information about coating 

stability and degradation. They do not require any accelerating factors for testing and can be 

conducted in-situ. 

Task 3-6: Marine atmosphere tests. Zeolite and zeolite/topcoat systems will be field-tested in 

marine environment, and subsequently evaluated by all the relevant laboratory tests listed 

previously including adhesion. The coated coupons will be exposed to a marine environment 

both continuous and intermittent. The intermittent exposure tests will be performed at the 

NADEP located near coastal waters. If the panels pass this initial phase of testing, they will be 

subject to continuous exposure mounted on a navy vessel. Both these tests will provide initial 

verification of the robustness of the proposed coatings systems. Further studies for extensive 

field-testing will be developed as part of the transition study (Task 4).

Task 3-7: Toxicology studies. Initial toxicology studies will focus on the Extraction Procedure 

(EP) Toxicity Test Method (EPTOX) (Method 1310A) and Toxicity Characteristic Leaching 

Procedure (TCLP) (Method 1311) for the analysis of potential byproducts from the zeoliteconductive polymer coatings. These tests are EPA approved to determine the leachates obtained 

from solid materials (Index to EPA Methods, ed. Peg Nelson, updated December 2001, SW-846 

Manual, Chap 8.4-Methods for Determining Characteristics, April 1998), such as any potential 

small molecules that can be leached out of the coating into the environment. 

Task 4: Transition study of proposed technology 

After successful completion of Task 3, a transition plan will be implemented. This plan will 

document all data from all laboratory tests. Once all technical data is assembled, it will provide a 

basis for a new MIL-spec for control of corrosion and elimination of hexavalent chromium. The 

cost-effectiveness data will also be documented and provided for fleet-wide study. This will 

allow an easy transition and dispersion of the data to other applications and maintenance sites for 

NAVAIR, AF and Army systems. 

 
SERDP PP1342: Zeolite Coating System 

University of California, Riverside, CE‐CERT   13 

Milestones and milestone owners 

The following milestones are built according to the federal fiscal year cycles. Milestone owners 

and the deadline are in parenthesis. In case of multi-institutions as milestone owners, the first 

one is the lead institution. 

Task 1-1: Extension of in-situ crystallization from AA-2024-T3 to AA-6061-T6, AA-7075-T6, 

S-1008

(1) Production of 2x3 cm ZSM-5 on AA-2024-T3, AA-6061-T6, AA-7075-T6, and S-1008. 

(UCR 10/1/03) Æ COMPLETED

Task 1-2: Scale-up in-situ crystallization from 1x3 coupons to 3x6 panels

(2) Production of 3x6 ZSM-5 on AA-2024-T3 (UCR 10/1/03) Æ COMPLETED

(3) Production of 3x6 ZSM-5 on AA-5052-H32, AA-6065-T6, AA-7075-T6 and S1008, 

(UCR 10/1/04) Æ COMPLETED and expanded to include ZSM-5 on S4130 and SS304-

2b 

Task 1-3 and 1-4: Develop alternative zeolite and alternative deposition method (MCM-22)

(4) Production of 2x3 cm MCM-22 on AA-2024-T3 (UM 10/1/03) Æ COMPLETED

(5) Production of 3x6 inches MCM-22 on AA-2024-T3 (UM 10/1/05) Æ COMPLETED

(6) Production of 2x3 cm SAPO-11 on AA-2024-T3 (UCR 1/31/08) Æ THIS WAS AN 

ADDED TASK WITH SERDP PERMISSION AND COMPLETED

Task 2: Application of primer/topcoat or topcoat to zeolite coatings

(7) Production of 3x6” ZSM-5/CARC Topcoat(Mil-PRF-64159) (UCR, Benet, 

NAWCWD 10/1/05) Æ COMPLETED

(8) Production of 3x6” ZSM-5/topcoat [VOC-free topcoat (Deft product #55W-002, Deft, 

Irvine CA) and Self-Priming topcoat (TT-P-2756A from Deft, Irvine, CA)] (UCR, 

NAWCWD 10/1/05) Æ COMPLETED

(9) Production of 3x6” ZSM-5/topcoat and ZSM-5/primer/topcoat (UCR, NAWCW D

10/1/06) Æ COMPLETED

Task 3-1: Characterization of coating surfaces.

(10) Quantitative Surface Imaging by LSCM (Benet 10/1/05) Æ COMPLETED

(11) RMS Roughness (Benet 10/1/05) Æ COMPLETED

(12) Scaling Analysis & Optimized Filtering for LSCM Images (Benet 10/1/05) Æ

COMPLETED

Task 3-2: Instrumental analyses of coating degradation. 

(13) Dynamic mechanical analysis (Benet 10/1/05) Æ COMPLETED

(14) Quality Control testing method by DC Polarization on 3x6 inch zeolite coatings on 

AAs(2024-T3, 5052-H32, 6061-T6, 7075-T6) and steels (SS304, S4130, S1008)(UCR

10/1/06) Æ COMPLETED

(15) 3x6 ZSM-5 on AA-6061-T6, AA-7075-T6, and S-1008 (Benet, NAWCWD, UCR 

10/1/03) Æ COMPLETED 

(16) 2x3 cm MCM-22 on AA-2024-T3 (UM, UCR 10/1/03) Æ COMPELTED 

(17) 3x6 MCM-22 on AA-2024-T3 (UM, UCR 10/1/05) Æ DROPPED 
SERDP PP1342: Zeolite Coating System 

University of California, Riverside, CE‐CERT   14 

(18) 3x6” ZSM-5/topcoat system on AA-2024-T3 (Benet, NAWCWD, UCR 10/1/05 ) Æ

DELAYED BUT LATER COMPLETED 

Task 3-3: Quantitative/qualitative adhesion testing of coatings to substrates 

(19) ASTM D3359-2 adhesion test of ZSM-5 on AAs (2024-T3, 5052-H32, 6061-T6, 7075-

T6) (UCR 10/1/04) Æ COMPLETED

(20) Mechanical cutting test of ZSM-5 on AAs (UCR 10/1/04) Æ COMPLETED

(21) Mechanical hole punching of ZSM-5 on AA-2024-T3(UCR 10/1/04) Æ COMPLETED

(22) ASTM D-2794-93 impact test (UCR 10/1/05) Æ COMPLETED

(23) ASTM D- 522-93a bending test (UCR 10/1/05) Æ COMPLETED

(24) ASTM G154-00a UV exposure (UCR, Benet 10/1/06) Æ COMPLETED

Task 3-4: Conduct accelerated service simulation testing

(25) ASTM B117 Salt-fog testing on bare zeolite coating (0.5 -2 um thick) on AA2024-T3 

(3x6 inch) (NAWCWD, 4/1/04) Æ COMPLETED

(26) ASTM B117 Salt-fog testing on 3x6” ZSM-5/CARC Topcoat(Mil-PRF-64159) 

(NAWCWD 10/1/05) Æ COMPLETED

(27) ASTM B117 Salt-fog testing on bare zeolite coating (7.5 um thick, no QC) on 

AA2024-T3 (3x6 inch) (NAWCWD, 4/1/05) Æ COMPLETED

(28) ASTM B117 Salt-fog testing on bare zeolite coating (7.5 um thick, with QC) on 

AA2024-T3 (3x6 inch) (NAWCWD, 4/1/06) Æ COMPLETED

(29) ASTM B117 Salt-fog testing on ZSM-5/topcoat [VOC-free topcoat (Deft product 

#55W-002, Deft, Irvine CA) and Self-Priming topcoat (TT-P-2756A from Deft, Irvine, 

CA)] (NAWCWD 10/1/05) Æ COMPLETED

(30) ASTM B117 Salt-fog testing on machine scribed bare zeolite coating (7.5 um thick, 

with QC) on AA2024-T3 (3x6 inch) (NAWCWD, 4/1/06) Æ COMPLETED

(31) ASTM B117 Salt-fog testing on ZSM-5/topcoat and ZSM-5/primer/topcoat 

(NAWCWD 10/1/06) Æ COMPLETED

(32) ASTM B117 Salt-fog testing on bare zeolite coating (4-5 um thick, with minimal QC) 

on 3x6 inch steels (SS304,S4130,S1008) (NAWCWD, 10/1/06) Æ COMPLETED

(33) ASTM B117 Salt-fog testing on machine scribed bare zeolite coating (4-5 μm thick, 

with minimal QC) on 3x6 inch steels (SS304 and S4130) (NAWCWD, 6/20/08 ) Æ

COMPLETED

Task 3-5: Examine substrate degradation and corrosion inhibition. (UCR, NAWCWD, 4/1/07) 

Æ COMPLETED

Task 3-6: Marine atmosphere tests/EIS measurements/coating degradation studies. (UCR, 

NAWCWD, 4/1/07) Æ In progress

Task 3-7: Toxicology Studies (UCR, NAWCWD, 4/1/07) Æ DROPPED WITH PERMISSION 

FROM SERDP

Task 4: Transition Study of Proposed Technology (NAWCWD, NADEP, Benet, UCR, 4/1/07) 

ÆConsidered finished for the project but will still be pursued

 
SERDP PP1342: Zeolite Coating System 

University of California, Riverside, CE‐CERT   15 

5. Project Accomplishments

This is a final report for a project with duration of 5/2003 – 7/1/2008. We will follow the order of 

tasks. We use a simplified section heading for each task in most cases to save space, and for the 

details of each milestone please see section 4. 

 
SERDP PP1342: Zeolite Coating System 

University of California, Riverside, CE‐CERT   16 

Task 1­1: Extension of ZSM­5 coating to other DoD alloys

UCR has successfully extended ZSM-5 

coating from AA 2024-T3 to AA-6061-T6, 

AA7075-T6 and steel SS1008 using 2x3 cm 

coupons. A universal solution composition 

and a universal deposition procedure were 

developed that produce high quality 

coatings on all of the aluminum alloys 

tested (2000, 5000, 6000, and 7000 series). 

Universal solution and deposition 

procedures are important as this eliminates 

the need to adjust the solution composition 

and deposition procedure to suit an 

individual alloy, and this means significant 

cost savings. The molar composition of the 

synthesis solution is TPAOH/0.16 : 

NaOH/0.64 : TEOS/1 : H2O/92 : Al/0.0018. 

Here TPAOH is for tetrapropylammonium 

hydroxide and TEOS for 

tetraethylorthosilicate. This is a fairly dilute 

aqueous solution and the deposition process 

produces uniform coating on the substrate 

with little bulk crystallization. The 

deposition was carried out in convection 

oven at 175 °C for 12-16 hours. 

Figure 5-1 shows the scanning electron 

micrographs of ZSM-5 coatings on AA-2024-T3, AA-5052-H32 (not required by the project), 

AA-6061-T4, and AA-7075-T6. The coatings are polycrystalline, continuous, and well adhered 

to the substrate. Thickness varies from 7-10 um. 

The corrosion resistance of the ZSM-5 coatings on these aluminum alloys are measured in acid, 

base and pitting aggressive media and their polarization curves are shown in Figure 5-2. Clearly, 

good corrosion resistance was obtained on all of these coatings and in all of the media tested. 

 

20 um

a

b

10 um

d

10 um

c

a

10 um

b 10 um

c

10 um

d 10 um

20 um

20 um

a

b

10 um

d

10 um

c

a

10 um

b 10 um

c

10 um

d 10 um

20 um

a

b

10 um

d

10 um

c

a

10 um

b 10 um

c

10 um

d 10 um

20 um

Figure 5-1. SEM images of ZSM-5 coatings on 

aluminum alloys (a)AA-2024-T3, (b)AA-5052-H32, 

(c)AA-6061-T4, and (d)AA-7075-T6.
SERDP PP1342: Zeolite Coating System 

University of California, Riverside, CE‐CERT   17 

Figure 5-2 Polarization curves of ZSM-5 coatings on AA2024-T3, AA-5052-H32, AA-6061-T4, and 

AA-7075-T6 in acid (H2SO4), base (NaOH) and NaCl solutions. 

 

DC Polarization Curves 

and Corrosion Profiles

0.5M NaOH immersion 2 min

0.5M NaCl/HCl (pH=3) immersion 30 min

0.5M H2SO4 immersion 30 min

2024 - T3

5052 - H32

6061- T4

7075 - T6

Al Alloys

10-1210-1110-1010-910-810-710-610-510-410-310-210-1 -2

-1

0

1

2

.

.

ZSM-5 coated

alloys Bare alloys

E (Volts)

I (Amps/cm2)

NaOH

10-1210-1110-1010-910-810-710-610-510-410-310-210-1 -2

-1

0

1

2

.

.

ZSM-5 coated

alloys Bare alloys

E (Volts)

I (Amps/cm2)

NaOH

10-1210-1110-1010-910-810-710-610-510-410-310-210-1100 -1.0

-0.5

0.0

0.5

1.0

1.5

.

.

I (Amps/cm2)

E (Volts)

ZSM-5 coated

alloys

Bare alloys

NaCl/HCl

10-1210-1110-1010-910-810-710-610-510-410-310-210-1100 -1.0

-0.5

0.0

0.5

1.0

1.5

.

.

I (Amps/cm2)

E (Volts)

ZSM-5 coated

alloys

Bare alloys

10-1210-1110-1010-910-810-710-610-510-410-310-210-1100 -1.0

-0.5

0.0

0.5

1.0

1.5

.

.

I (Amps/cm2)

E (Volts)

ZSM-5 coated

alloys

Bare alloys

NaCl/HCl

10-1310-1210-1110-1010-910-810-710-610-510-410-310-2 -1.0

-0.5

0.0

0.5

1.0

1.5

.

.

ZSM-5 coated Bare alloys

alloys

I (Amps/cm2)

E (Volts)

H2SO4

10-1310-1210-1110-1010-910-810-710-610-510-410-310-2 -1.0

-0.5

0.0

0.5

1.0

1.5

.

.

ZSM-5 coated Bare alloys

alloys

I (Amps/cm2)

E (Volts)

H2SO4
SERDP PP1342: Zeolite Coating System 

University of California, Riverside, CE‐CERT   18 

Task 1­2: Scale up the deposition process to 3x6” panels from 2x3 cm coupons

UCR successfully scaled up the coating process from 2x3cm coupons to 3x6" panels (ZSM-5 on 

AA-2024-T3) in October 2003. This allows the performance of many ASTM and Mil-spec 

testing. The same chemical solution (TPAOH/0.16 : NaOH/0.64 : TEOS/1 : H2O/92 : 

Al/0.0018) was used on the large 3x6” panels as for the small 2x3cm” coupons. And the 

deposition was also carried out in a convection oven at 175 °C for 12-24 hours. The reactor used 

was a simple standard steel autoclave with a Teflon liner from Parr Instruments. The substrate 

was suspended from a Teflon bridge at the top of the liner (Figure 5-3a). The scale up had little 

impact on deposition chemistry. The coatings are extremely uniform (Figure 5-3b) and have 

excellent adhesion. The coatings are very flexible. 

Figure 5-3 (a) A commercial Parr autoclave was used as the reactor; with white Teflon liner, (b) Optical 

images of bare AA-2024-T3 (right) and ZSM-5 coated AA-2024-T3 (left). 

We have gone through three evolutions of zeolite coating syntheses on the 3” x 6” AA-2024-T3 

coupons (Figure 5-4). Each generation of zeolite coating was salt fog tested by ASTM B117 

(results shown later in this report). 

By adjusting the solution to surface area ratio and crystallization time, we can produce uniformly 

coated 3x6”panels of variable but controlled thicknesses. We have investigated the coating 

corrosion properties at several thicknesses (0.5, 2, 4.5, 7.5, 11, and 13 um thick). Salt fog tests 

(ASTM B117) were performed on zeolite coated AA-2024-T3 (0.5 um [Generation – 1] and 7.5 

um thick [Generation - 2 & 3]) and on scribed coatings (7.5 um thick [Generation – 3]) (see 

testing results in later sections). 
SERDP PP1342: Zeolite Coating System 

University of California, Riverside, CE‐CERT   19 

Figure 5-4 Evolution of zeolite coatings on metal alloys. 

The scale up and application of Generation - 3 zeolite coatings was successfully expanded to 

other DoD aluminum alloys (AA-5052-H32, AA-6061-T6, and 7075-T6) and to several steels 

(SS304-2b, S4130, and C1008). These have all been tested by DC Polarization in 5 wt% NaCl, 

showing excellent corrosion resistance (results and details shown later in this report). 

Figure 5-5 shows the scanning electron micrographs of Generation – 3 ZSM-5 coatings on 

S1008, S4130 and SS304-2b (S4130 and SS304-2b not required by the project). The coatings are 

polycrystalline, continuous, and well adhered to the substrate. Thickness varies slightly from 4 - 

5 um. 

Five zeolite coated panels of each steel (SS30-2b, S4130, and C1008) with zeolite thickness of 

about 5 um salt fog tested (ASTM B117) at China Lake (results and details shown later in this 

report). 

Key features and milestones of zeolite coating technology: 

• Simple alkaline detergent solution pretreatment adequate for all metals 

• Immerse metal in 3 grams Alconox® per 400 ml de-ionized H2O at 60o

C for 30 minutes 

• Single zeolite chemical formulation adequate for all metals 

• TPAOH/0.16 : NaOH/0.64 : TEOS/1 : H2O/92 : Al/0.0018 

Evolution of zeolite coatings on metal alloys

Evolution of zeolite coatings on AA-2024-T3 (and other AAs)

Generation – 1

–0.5 um thick (no optimization and no QC)

–Poor salt-fog performance of bare zeolite on AA-2024-T3

–Actions

•Developed protocols for producing coatings of various thickness (e.g., 0.5, 2.0, 4.5, 11, 13 um)

•Decided to use 7.5 um as the new benchmark (Generation-2 and -3 coatings)

Generation – 2

–7.5 um thick (no optimization)

–Inconsistent salt-fog performance of bare zeolite on AA-2024-T3

–Actions

•Optimize zeolite coating synthesis

•Implement QC testing on zeolite coatings (DC Polarization in 5 wt% NaCl)

Generation – 3

–7.5 um thick (limited optimization – aging time and DC Polarization in 5 wt% NaCl testing for QC)

–Excellent DC Polarization performance in 5 wt% NaCl

–Consistently excellent salt-fog performance of bare zeolite on AA-2024-T3

Evolution of zeolite coatings on steels (SS-304-2b, S4130, S1008)

Generation – 3 (same synthesis methods as Generation – 3 for zeolite on AAs)

–4-6 um thick (no optimization specific for zeolite on steels and no routine QC testing)

–Excellent DC Polarization performance in 5 wt% NaCl

–Good to excellent salt-fog performance of bare zeolite on steels
SERDP PP1342: Zeolite Coating System 

University of California, Riverside, CE‐CERT   20 

Figure 5-5 SEM images of ZSM-5 coatings (4 - 5 um thick) on steels. SS304-2b (a, b); S1008 (c, d); 

S4130 (e, f) 
SERDP PP1342: Zeolite Coating System 

University of California, Riverside, CE‐CERT   21 

Task 1­3 & 1­4: Alternative zeolite and deposition process

The central goal of this task is to develop a coating process that is low pressure, low temperature, 

and short deposition time. 

Layer by layer deposition of MCM‐22

MCM-22 and its precursor MCM-22(P) are microporous aluminum silicates reported by Mobil 

researchers18. In MCM-22(P), the structure directing agent, hexamethyleneimine, is located 

between layers. By special treatments, MCM-22(P) can be delaminated leading to a new 

aluminosilicate, ITQ-219. The delaminated material was reported to be stable at high 

temperatures (in excess of 500°C). On the other hand, by calcination the silicate layers in MCM22(P) condense to form MCM-22 (structure code MWW). Based on their framework structures, 

the limiting apertures for transport perpendicular to the layers (along [001] direction) are 6MR’s, 

i.e. defined by six interconnected SiO4 tetrahedra. Molecules like water and O2 cannot penetrate 

along the c-axis. Therefore, the primary idea of this project is to prepare a dense c-oriented 

MCM-22 film which is practically impermeable and thus suitable for the corrosion protection 

purpose. 

Synthesis of MCM­22(P)

Layered MCM-22(P) precursor was prepared using hexamethylenimine (HMI, Aldrich), silica 

(Aerosil 200, Degussa), sodium aluminate (56% Al2O3, 37% Na2O Carlo Erba), sodium 

hydroxide (98% Prolabo), and deionized water18. More specifically a sample with Si/Al = 50 was 

prepared as follows: 0.239g of sodium aluminate and 0.826g of NaOH were dissolved in 

103.498g of H2O by magnetic stirring for few minutes, then 6.373g of HMI were added slowly 

leading to a yellowish solution, and finally 7.86g of SiO2 were added very slowly under 

continuous stirring. After 30 minutes of vigorous stirring, the very viscous final gel was poured 

into a 60-ml Teflon lined stainless-steel autoclave and treated at 408K for 11 days, rotating at 60 

rpm. After cooling down the autoclaves quickly, the samples were centrifuged at 10,000 rpm and 

washed with water until pH < 9. Typical particle morphology of as-synthesized MCM-22(P) is 

shown in Figure 5-6. Most particles are plate-like with dimensions of about 1μm in width and 

length and less than 100nm in thickness. Some particles curl. The x-ray diffraction pattern on the 

right verifies that the synthesized materials are MCM-22(P). 

Figure 5-6 MCM-22(P) as made for 11 days at 135oC, before calcination or swelling. 

 
SERDP PP1342: Zeolite Coating System 

University of California, Riverside, CE‐CERT   22 

Condensation of MCM­22(P) to MCM­22 and avoidance of agglomeration

To ensure good dispersion and to avoid agglomeration during calcination, MCM-22(P) particles 

were first filtered and then calcined in a way analog to that reported in ref20. First, 5g of MCM22(P) wet cake was well-dispersed into 20ml DI water by stirring for one hour followed by 

ultrasonication for another one hour. The suspension was filtered by high-density polyethylene 

filter tips (POREX) with particle retention size of 5μm, and then diluted to a total volume of 

100ml. The solution was stirred at room temperature for another one hour before 10g of 

acrylamide (AM, Aldrich) and 0.1g of N, N’-methylenebisacrylamide (MBAM, Aldrich) were 

added inside. The mixture was further stirred for about 30 minutes until all the water-soluble 

organic monomers completely dissolved. Then 0.25g of (NH4)2S2O8 was added to the solution 

under stirring. Finally the solution was placed in an ultrasonicator for one hour. During 

sonication the solution will become warm and the organic monomers will be polymerized to 

form a white hydrogel with the MCM-22(P) particles trapping inside. The hydrogel was dried at 

90°C overnight before it was carbonized under nitrogen (150cc/min) at 540°C for 2 hours 

(heating rate 2°C /min) and then calcined at 540°C for 3 hours under air (150cc/min). 

Figure 5-7 shows the SEM image and the x-ray diffraction pattern of particles after calcination. 

Most crystals have the plate-like shape with similar dimensions to the as-synthesized MCM22(P) crystals. The x-ray diffraction pattern confirms that the MCM-22(P) crystals condensed to 

MCM-22 during calcination. 

Figure 5-7 MCM-22 crystals. A) SEM image of particles after calcination at 540oC in air for 3 hours; 

B) X-ray diffraction pattern.

 
SERDP PP1342: Zeolite Coating System 

University of California, Riverside, CE‐CERT   23 

Exfoliation of MCM­22(P) to ITQ­2

The exfoliation procedure involves two steps, that is, swelling under the interaction of 

surfactants followed by exfoliation provoked by ultrasonication. After compared the swelling 

procedures in ref.21 and ref.22, we adopted the following procedure. First, 3.05g 

cetyltrimethylammonium bromide (CTAB surfactant, Aldrich), 4.16g deionized water and 6.60g 

tetrapropylammonium hydroxide (TPAOH, 1M in water, Aldrich) were mixed together and 

stirred for 1 hour to form a slurry. Then 1.00g MCM-22(P) cake was added to the slurry under 

stirring. Swelling was processed by refluxing the mixture at 80°C for 20 hours. The excess 

surfactant was dissolved by adding about 10 drops of concentrated hydrochloric acid until the pH 

of the mixture was less than 2. The mixture was stirred for another 1 hour before the remained 

powder was collected by filtration. The collected powder was dried at 90°C overnight. XRD 

pattern of the powder was taken at this point. Exfoliation of the dry powder was carried out by 

first re-disperse the powder (~1g) into 40g of deionized water. The solution was then 

ultrasonicated for 2 hours. Powder was collected from the solution by centrifuging at the speed 

of 15000rpm. 

XRD patterns of the MCM-22(P) powder before swelling, after swelling and after exfoliation are 

shown in Figure 5-8, respectively. As pointed out in ref.22, a successful swelling can be roughly 

determined from changes in the XRD patterns according to the following criteria. 

1) General hkl reflections shift to lower 2θ

angles or disappear altogether. 

2) hk0 reflections remain invariant. 

3) A prominent 001 peak emerges around 5.0-

5.5nm d-spacing, possibly accompanied by 

higher order peaks at appropriate positions. 

As can be seen from Figure 5-8, the XRD pattern 

before swelling is the typical pattern for MCM22(P)19. After swelling, the [001] peak moves to a 

lower 2θ angle with d-spacing of about 4.5nm. The 

[002], [101] and [102] peaks disappear, while the 

[100] peak remains. All of these changes roughly 

obey the rules as stated above, thus suggesting a 

successful swelling. After ultrasonication, all 

reflections disappear. Considering the exfoliation 

process is carried out in a chemically mild condition, we think the layers are exfoliated instead of 

completely destructed. If this is true, the exfoliated layers will also be out of the detection limit 

of SEM. Other techniques, such as Small Angle X-ray Scattering, AFM or TEM, are necessary 

and going to be used in future studies. 

 

Figure 5-8 XRD patterns of MCM-22(P) 

powder before swelling, after swelling and 

after exfoliation.
SERDP PP1342: Zeolite Coating System 

University of California, Riverside, CE‐CERT   24 

Layer­By­Layer deposition

The deposition procedure is mainly based on a chemical-interaction method which is originally 

developed by Ha and coworkers23. We extended this method in our previous work to make a boriented silicalite-1 seed monolayer on α-alumina supports and satisfactory results were 

obtained23. The procedure can be easily adapted here for the purpose of depositing MCM-22 

particles to aluminum alloy surface for corrosion protection. In this method, first a mesoporous 

silica layer is coated on top of the support to provide a smooth and common functional surface. 

Then a silane coupling agent, 3-chloropropyltrimethoxylsilane, was used to covalently link the 

plate-like MCM-22 particles to the silica surface. The silane coupling agent has two functional 

groups, i.e., chloro and methoxyl, with one reacting to the silica surface and the other reacting to 

the MCM-22 particle surface. Extra MCM-22 particles can be removed by sonication, and 

therefore after each coating, an almost close-packed monolayer can be obtained. The procedure 

can be repeated to make the films with two layers, three layers and so on to increase coverage. 

An image of the mesoporous silica layer is shown in Figure 5-9A, which shows that shallow 

dents in the original substrate surface can be leveled off by the mesoporous layer and the entire 

surface is much smoother than before. However, the corrosion results showed this mesoporous 

silica layer was rather detrimental than beneficial for corrosion protection. Since XPS results 

show that there is an oxide layer on the aluminum alloy surface which can also provide enough 

functional groups for deposition, therefore this mesoporous layer can be eliminated. 

Figure 5-9B shows a SEM image of the MCM-22 layer after one deposition. The deposit is 

almost a close-packed monolayer. Most crystals retain their plate-like shape without breakage or 

Figure 5-9 A) SEM image of the mesoporous layer; B) SEM image of the MCM-22 layer after one time 

deposition; C) SEM image of the MCM-22 film after three times deposition; D) Cross view of the MCM-22 film 

after three times deposition.
SERDP PP1342: Zeolite Coating System 

University of California, Riverside, CE‐CERT   25 

curling, and attach to the substrate surface with their flat surfaces and therefore the obtained film 

is c-oriented. After adopting the special treatment during calcination, the film is much smoother 

with few agglomerates bigger than 10μm. Figure 5-9C shows the MCM-22 film after 3 

depositions and Figure 5-9D the corresponding cross view. Film coverage improves substantially 

without loss in orientation by repeating the deposition process. The film is very smooth. From 

the cross view, the film thickness is less than 100 nm even after 3 depositions. 

We have demonstrated our successful efforts on the synthesis of MCM-22(P) and MCM-22 

particles with the desired plate-like shapes. The particle size is about 1 μm in diameter and less 

than 100 nm in thickness. Significant progress was also made regarding the exfoliation of MCM22(P) to ITQ-2 and the elimination of big agglomerates during the calcination process. The film 

after one-time deposition is almost a close-packed and c-oriented monolayer. Without loss of the 

film orientation, the coverage of the film increases substantially by repeating the deposition 

process. The thickness of the film after three-time deposition is still less than 100nm. Therefore, 

the goal to make a thin, compact, and c-oriented MCM-22 film is very close, although the 

compactness of the film and the reproducibility of the procedure still need to be improved. 

 To improve the compactness of the film, we will use uncalcined MCM-22(P) crystals or ITQ-2 

crystals instead of MCM-22 crystals to make the film. The film will then be condensed by 

calcination to eliminate gaps between layers and thus to improve the compactness of the film. 

Significant corrosion protection is demonstrated by coating a substrate with alternating layers of 

zeolite particles and mesostructured surfactant-templated silica. The UMN team developed and 

optimized a coating process that involves deposition of plate-like particles of zeolite MCM-22 on 

a substrate by chemical attachment under sonication. DC-Polarization tests, conducted in acid 

(H2SO4) as well as in salt (NaCl) solution at UC Riverside, show consistent and reproducible 

results of polarization current density of the level achieved by use of chromate conversion 

coatings. Figure 5-10 shows an overview of the layer-by layer deposition process and Figure

5-11 shows a typical MCM-22 film with silica aerosol coating. 

The sequence of processes19-24 to prepare the samples for DC polarization test is described on the 

left side of Figure 5-11. MCM-22 particles were deposited using chemical attachment under 

sonication21, 22 on the polished aluminum plates following experimental protocol (1). The 

deposition of MCM-22 was followed by deposition of surfactant-silica composite by aerosol 

coating using the experimental protocol (2). Samples MN107, 108, prepared using these steps, 

were tested for corrosion protection. Other samples were subjected to additional coating cycles. 

The substrate was calcined at 300oC (experimental protocol (3)) in order to generate enough 

hydroxyl groups for the reaction based deposition of MCM-22 particles. Another deposition of 

MCM-22 particles, this time without sonication, was performed following experimental protocol 

(4), followed by coating with surfactant silica composite layer using procedure (2). At this stage 

samples MN 122, 123, 124, 125 were tested for corrosion protection. Other samples were 

calcined at 300 oC using procedure (3) for an additional deposition cycle yielding samples MN 

126, 127, 128, 129. 
SERDP PP1342: Zeolite Coating System 

University of California, Riverside, CE‐CERT   26 

Figure 5-10 Overview of the Layer-by-Layer deposition process. 

Figure 5-11 MCM-22 film with silica aerosol coating 

DC polarization test results performed in 0.5 M H2SO4 are shown on the right side (top) of 

Figure 5-12. Sample MN 108 with one layer of MCM-22 and one layer of surfactant-silica 

composite shows corrosion protection action. The corrosion protection performance improved 

progressively with additional layer of MCM-22 as observed in samples MN 122 and MN 124 
SERDP PP1342: Zeolite Coating System 

University of California, Riverside, CE‐CERT   27 

(both with two coatings of MCM-22 and surfactant-silica composite) and samples MN 127 and 

MN 129 (both with three coatings). Our findings demonstrate that as the number of deposited 

layers increases, the level of corrosion protection is enhanced considerably. 

DC polarization tests in 0.1M NaCl solution were also performed for the samples prepared in the 

same manner as described above and shown in Figure 5-12 (right side – bottom). Samples MN 

123 and MN 125 (with two MCM-22 layers and two aerosol coatings) show comparable or 

higher degree of corrosion protection as compared to the samples MN 126 and MN 128 which 

have an additional layer of MCM-22 and silica. Therefore, in contrast to the measurements in 

H2SO4, it appears that for NaCl there is an optimum corrosion protection action exhibited by 

films with two layers of MCM-22. 

 

Figure 5-12 Preparation procedure and DC-Polarization Tests in 0.5M H2SO4 and 0.1M NaCl 

 
SERDP PP1342: Zeolite Coating System 

University of California, Riverside, CE‐CERT   28 

Experimental Section

 Procedure (1): Deposition of MCM-22 particles by chemical attachment under sonication 

Prior to seed deposition the polished supports were dried at 120 °C overnight in a drying oven, 

apparatus required during the experiments were dried at 80 °C at least overnight prior to the 

experiments. The substrate which was supported by a Teflon holder was loaded vertically into a 

specially designed glass reactor which was under continuous purge with argon. First, 30 mL of 

dry toluene and then 3 mL of 3-chloropropyltrimethoxysilane were quickly transferred to the 

reactor from argon-purged containers. The reactor was then closed and connected to a watercooled condenser (15 °C). The solution was refluxed for 3 h at 110oC under a gentle argon 

stream. After this, the support was taken out, washed in fresh toluene and dried for about 15 min 

at 120 °C. 

In a separate step 20 mg of precalcined MCM-22 seeds and 50 mL of dry toluene were charged 

into a dry reactor under argon flow. The suspension was sonicated for 1hour (seed dispersion) 

after which the functionalized support was then quickly introduced into this suspension under 

argon purge. The support was positioned vertically sandwiched between two cover glasses using 

a combed shaped Teflon holder. The reactor was then closed and placed in a sonicator (Branson 

1210, 50/60 Hz) for 4 minutes sonication. Subsequently the seeded support was removed from 

the seed suspension, and placed horizontally. Further this was sonicated for 2 minutes. Finally, 

the supports were taken out of the reactor and rinsed in fresh toluene in order to remove 

multilayered crystals. 

Procedure (2): Deposition of surfactant silica composite by aerosol coating 

30ml dry Toluene + 3ml 3CP-TMS

+

Support (dried at 120o

C overnight)

Place support

vertically

Purge argon

Functionalizedsupport

20mg Calcined MCM-22

powder

+

Sonicate 1

Sonicate 4

Rinse with dry toluene

Dry at 120oC 15 min

MCM-22Film

Sonicate 2

Sandwich the support with two cover

Place support vertically Place support horizontally
SERDP PP1342: Zeolite Coating System 

University of California, Riverside, CE‐CERT   29 

A sol was freshly prepared each time aerosol coating was carried out 

as follows. 14.24 g. Brij-56 was mixed with 308.64 g water, 31.66 g 

TEOS and 12.77 g 0.07 M HNO3 in a capped Pyrex bottle. The 

mixture was sonicated (Branson 1210, 50/60 Hz) for 3 h resulting in 

a turbid but homogeneous sol. This sol was aged for about 1 h and 

then charged into a humidifier (kaz). 

The supports were placed horizontally onto wire gauze (polished side 

up) and exposed to an aerosol cloud generated by the underlying 

humidifier into an enclosed space that housed the gauze and 

supports. This allowed heavy aerosol droplets to settle on the support 

surfaces. After the coatings, the supports were left to dry overnight. 

Procedure (3): Calcination at 300°C 

The films were calcined in air at 300°C for 4 hours with a 0.5°C/min ramp rate. 

Procedure (4): Deposition of MCM-22 particles by chemical attachment 

Prior to seed deposition the polished supports were dried at 120 °C overnight in a drying oven, 

apparatus required during the experiments were dried at 80 °C at least overnight prior to the 

experiments. The substrate which was supported by a Teflon holder was loaded vertically into a 

specially designed glass reactor which was under continuous purge with argon. First 30 mL of 

dry toluene and then 3 mL of 3-chloropropyltrimethoxysilane were quickly transferred to the 

reactor from argon-purged containers. The reactor was then closed and connected to a watercooled condenser (15 °C). The solution was refluxed for 3 h at 110 °C under a gentle argon 

stream. After this the support was taken out, washed in fresh toluene and dried for about 15 min 

at 120 °C. 

In a separate step 15 mg of precalcined MCM-22 seeds and 40 mL of dry toluene were charged 

into a dry reactor under argon flow. The suspension was sonicated for 1hour (seed dispersion) 

after which the functionalized support was then quickly introduced into this suspension under 

argon purge. The support was positioned horizontally using a Teflon holder with the 

functionalized silica layer facing upwards. The mixture was refluxed for 5 h at 110 °C. The 

reactor was then closed and placed in a sonicator (Branson 1210, 50/60 Hz) for 1 min sonication 

to get a substrate with MCM-22 deposit. 

14.24g Brij 56 + 308.64g H2O +

31.66g TEOS + 12.77g HNO3

(0.07M)

Sonicate 3 hrs

Age 1 hr

Coating Sol

Coat 1 min

Dry

Aerosol coating
SERDP PP1342: Zeolite Coating System 

University of California, Riverside, CE‐CERT   30 

Microwave‐assisted ionothermal synthesis of SAPO‐11

Ionothermal synthesis uses ionic liquid instead of water as the solvent. An ionic liquid is a 

substance that only consists of ions and has a melting temperature below 100 o

C. The most 

significant advantage of this method is that the whole process can be carried out in an open 

vessel rather than in a sealed Teflon®-lined autoclave; consequently, the syntheses occur at 

ambient pressure due to the negligible vapor pressure of ionic liquid even at an elevated 

temperature. SAPO-11 is one of the first successful example for zeolite ionothermal synthesis25, 

which was prepared under ambient pressure in a convection oven for 68 h at 150 oC using 1-

methyl 3-ethyl imidazolium bromide ([emim]Br) as both solvent and template. This recipe is also 

successful under microwave heating where only one hour was needed for the crystallization due 

to the rapid microwave absorption of ionic liquids26. The primary idea of this project is to 

prepared a SAPO-11 coating on AA 2024-T3 using ionothermal synthesis and microwave 

radiation, which presents a short time, ambient pressure deposition process for zeolite.

Synthesis of SAPO­11 coating on AA 2024­T3

A synthesis mixture with molar composition: 32[emim]Br:1Al(OC3H7)3:0.25tetraethyl 

orthosilicate (TEOS):3H3PO4:0.8HF was prepared and then stirred for 4 h at 100 o

C. AA 2024-

T3 substrates were pretreated by an Alconox detergent solution. The substrate was then fixed 

vertically inside the synthesis mixture in the Teflon vessel designed for MARS5 (CEM Co.) 

microwave reaction system. The unsealed vessel was then quickly heated to 150 o

C and held at 

the temperature for 2 h under microwave radiation. After the synthesis, the coated sample was 

thoroughly washed with DI water and acetone and dried with compressed air. The synthesis 

procedure was repeated once or twice with fresh synthesis solution. SAPO-11 coatings on AA 

2024-T3 are confirmed by the X-ray diffraction (XRD) (Fig.5-13c). No other by-products are 

found. The preferred orientation is evident for the SAPO-11 coatings. AEL consists of a 10-

30ml dry Toluene

+

3ml 3CP-TMS

+

Support (dried at 120oC overnight)

Support placed

vertically

Purge argon

FunctionalizedSupport

15mg Calcined MCM-22 powder

+

40ml dry toluene

Sonicate 1 hour

Support placed horizontally, coating side upward

Purge argon

Reflux at 110oC 5 hours

CoatedSupport

Rinse with dry toluene

Dried at 120oC 15 min

Sonicate 1 min in fresh toluene

MCM-22
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University of California, Riverside, CE‐CERT   31 

membered ring (0.40 ×0.65 nm) channel parallel to the c-axis of the crystal. The strong (002) 

reflection peak in the SAPO-11 XRD pattern indicates that the one-dimensional channels are 

perpendicular to the Al alloy surface. 

Figure 5-13 SEM pictures and XRD pattern of SAPO11 on AA 2024-T3 

BTSM­MEL coatings

It can be seen from the cross-sectional SEM picture of SAPO-11 coating (Figure 5-13b) that the 

film consists of two major components: the dense barrier layer adjoining the metal and a porous 

layer extending from the barrier layer to the outer surface of the film, which is similar to the 

anodized film of Al alloys. This kind of structure has the advantage of being able to be dyed. In 

order to obtain the maximum corrosion resistance, the porous coating must be sealed. A nanozeolite filled silane was used as the sealing agent. Several aspects were considered for choosing 

it: (1) silane has very good adhesion properties, which can act as a binder layer between zeolite 

coating and the polymer topcoat; (2) silane film itself has good corrosion resistance for Al 

alloys;27 (3) nano-particle filled silane films offer better mechanical properties and MEL 

nanocrystal filled silane films also improve the corrosion resistance. 

A dilute 1,2-bis(triethoxysilyl)methane (BTSM) solution was prepared by adding silane to a DI 

water and ethanol mixture. The volume ratio of BTSM:DI water:Ethanol was 1:1:20. Acetic acid 

was then added to adjust the pH of the solution in the range of 4.5~5. The solution was then 

stirred at room temperature for aging at least 24 hours before a MEL gel was added. MEL 

concentration in the solution was about 20 ppm. The SAPO-11 coated sample was polished on a 

Buehler, Ecomet 3 grinder-polisher using 0.05 μm silica slurry and thoroughly cleaned with DI 

water and acetone under sonication. Then the nanoparticle suspension was spun on it at room 

temperature on a Laurell spin coater. Afterward, the sample was heated at 80 o

C overnight and 

then 200 oC for 30 min. 
SERDP PP1342: Zeolite Coating System 

University of California, Riverside, CE‐CERT   32 

DC polarization test

DC polarization testing was 

carried out with Solartron 

potentiostat SI 1287 in a threeelectrode Flat Cell (Princeton 

Applied Research Model K0235) 

with a Pt counter electrode and a 

saturated calomel electrode 

(SCE) as the reference electrode. 

The corrosive medium was 0.1 

mol/L NaCl aqueous solution. 

The samples were immersed in 

the corrosive medium for 30 min 

prior to the DC polarization test 

with a sweep rate of 1 mV/s. 

Figure 5-14 shows that bare AA 

2024-T3 pits at its open circuit 

potential (OCP) (ca. -0.5 VSCE). 

That is, the pitting corrosion 

occurs once the metal is 

immersed in the corrosive media. 

This OCP corrosion is related with the intermetallics of Cu in Al matrix and the presence of Clin the electrolyte. OCP of SAPO-11 (ca. -0.65 VSCE) coated samples are more negative than bare 

AA 2024-T3, which means the AEL coatings inhibit the OCP corrosion of the samples. The 

corrosion current density of SAPO-11 coated samples is about two orders of magnitude smaller 

than that of the bare Al alloy. The pitting potential is slightly higher than the OCP of AA 2024-

T3, which means the favored sites for pit initiation, mostly the copper intermetallics, are at least 

partially covered by the SAPO-11 coatings. The BTSM-MEL modified SAPO-11 coating has 

very good corrosion resistance. The OCP is more negative than -0.9 V and the corrosion current 

is less than 10-8 mA/cm2. The pitting potential also increases to -0.4 V, even higher than the pure 

Al at similar conditions28. The DC polarization behavior of BTSM-MEL spin-on coating directly 

on bare AA 2024-T3 is also tested. It does show good corrosion resistance but the combination 

of SAPO-11 coating and BTSM-MEL sealing shows the best anticorrosion performance in this 

work. 

 

Figure 5-14 DC polarization curves for bare and coated AA 

2024-T3 in 0.1mol/L NaCl at room temperature: (a) Bare AA 

2024-T3, (b) SAPO-11 coated, (c) SAPO-11with spin-on BTSMMEL coated, (d) spin-on BTSM-MEL coated. 
SERDP PP1342: Zeolite Coating System 

University of California, Riverside, CE‐CERT   33 

Task 2.  Zeolite/topcoat systems  

We have gone through three evolutions of zeolite coating syntheses on AA-2024-T3 (see Task 1-

2, Figure 5-4). The primer and/or topcoat systems applied to the zeolite coatings is organized 

based on the different zeolite generation on which the primer and/or topcoat was applied. 

Much of the poor adhesion of the CARC topcoat (MIL-PRF-64159) to Generation-1 zeolite 

coatings has been contributed to the fact of no QC for the synthesis and the thinness of the 

zeolite coatings (0.5-2 um thick). The first Generation-3 zeolite coatings (7.5 um thick) were 

painted with a VOC-free topcoat (5 samples) or a self-priming topcoat (5 samples) and had 

extremely non-uniform topcoat application and blistering occurred after 168 hours of salt-fog 

exposure. The VOC-free and self-priming topcoats were applied at Deft (Irvine, CA) in a trial 

run (The visit by UCR to Deft was primarily aimed to observe and learn the deposition 

technique) and ASTM standards were not followed. Our latest testing of zeolite (Generation – 3) 

coatings with primer and/or topcoat applications showed that coating systems with chromated 

primers with and without topcoat had no delamination from the zeolite surface after 3100 hours 

of salt-fog exposure. 

Zeolite (Generation - 1) 

CARC topcoat (Mil-PRF-64159)

Five aluminum 2024-T3 panels were coated with zeolite of 0.5-2 um thick at UCR and delivered 

to China Lake. The panels were then sent to the Army Research Laboratory (ARL) to be coated 

with CARC topcoat. The panels were coated on one side with the CARC topcoat (Mil-PRF64159) and coated with primer on the other side to keep corrosion from contaminating the salt 

fog chamber. These panels were then scribed and tested in salt-fog (ASTM B117, see Task 3.4 

for details). 

Results: No adherence of the CARC topcoat to zeolite. 

Zeolite (Generation - 2) 

No zeolite/topcoat or zeolite/primer/topcoat system was tested for the Generation – 2 zeolite 

coatings. Salt fog testing of the bare zeolite coatings (Generation – 2) was performed (see results 

in Task 3.4). 

Zeolite (Generation - 3) 

VOC-free topcoat (Deft product #55W-002, Deft, Irvine CA) and Self-Priming topcoat (TT-P2756A from Deft, Irvine, CA)

Once the 7.5 um thick ZSM-5 coating samples were developed and chosen as the benchmark, 

they were applied with topcoats at Deft (Irvine CA) in a trial run (The visit by UCR was 

primarily aimed to learn the deposition technique). Five panels were applied with VOC-free 

topcoat and five panels were applied with self-priming topcoats. These panels were then sent to 

China Lake for salt-fog testing (ASTM B117). The results showed blistering of topcoats after 

168 hours salt-fog exposure (See Task 3.4 for details). 
SERDP PP1342: Zeolite Coating System 

University of California, Riverside, CE‐CERT   34 

Zeolite/Primer, Zeolite/Primer/Topcoat and Zeolite/Topcoat 

Forty nine (49) zeolite (Generation – 3) coated AA-2024-T3 panels were prepared and painted 

by Deft (Irvine, CA), following ASTM guidelines. Figure 5-15 shows the matrix of primers and 

topcoats applied to the zeolite coating. 

Figure 5-15 Primers and topcoats applied to zeolite coatings following ASTM and MIL specs. 

Salt-fog (ASTM B117) and adhesion (wet and dry) testing were performed at NAWC, China 

Lake (See Task 3.4 for details). 

 
SERDP PP1342: Zeolite Coating System 

University of California, Riverside, CE‐CERT   35 

Task 3.1: Laser Scanning Confocal Microscopy (LSCM) characterization of coating

surfaces

• Quantitative Surface Imaging by LSCM 

UCR initially provided six samples of the high-silica ZSM-5 zeolite coating on 2024-T3 Al 

substrates with the following nomenclature: M, Q, P, 8, H, and K. Three samples each of the 

high-silica ZSM-5 zeolite coating on 2x3 cm of 2024-T3 Al, 6061-T6 Al, and 7075-T6 Al 

substrates with the following nomenclature: A, B, and C for each system were later received for 

further analysis. All samples were imaged using the LSCM under 2000x magnification. Figure

5-16 and Figure 5-17depict the optical and height mappings and surface profiles of systems 8 

and P. Figure 5-18 depicts regions of the surface on coating H where there is an “over-growth” 

of the zeolite coating. Figure 5-19 and Figure 5-20 depict the optical, height mappings, and 

filtered surface profiles of the zeolite coating system on 6061-T6 Al and 7075-T6 Al substrates. 

Figure 5-16 LCSM Optical (a), Height Mapping (b), and Surface Profile (c) of Coating 8 

Figure 5-17 LCSM Optical (a), Height Mapping (b), and Surface Profile(c) of Coating P 

Surface profiles in Figure 5-18c, Figure 5-19c and Figure 5-20c suggest that there is an effect of 

the Al substrates on the surface morphology of the zeolite coating. 

 
SERDP PP1342: Zeolite Coating System 

University of California, Riverside, CE‐CERT   36 

Figure 5-18 Mapping (a), Surface Profile (b), and 3-dimensional Images (c) of coating H 

Figure 5-19 (a)LCSM Optical, (b)Height Mapping, and (c) Surface Profile of Zeolite Coating on 6061-

T6 Al 

Figure 5-20(a)LCSM Optical, (b) Height Mapping, and (c) Surface Profile of Zeolite Coating on 7075-

T6 Al 
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University of California, Riverside, CE‐CERT   37 

RMS Roughness 

Coating roughness measurements were calculated to obtain information on coating surface 

structure. Analysis of RMS roughness suggests that there is a difference in surface roughness 

between the three Zeolite coatings systems. Table 5-1 lists RMS roughness values for each 

coating system. 

Table 5-1 Surface Roughness for ZSM-5 on different Al alloy substrates 

 2024-T3 6061-T6 7075-T6 

A 1.15±0.01 0.80±0.03 1.17±0.05 

B 1.59±0.01 0.92±0.34 0.92±0.06 

C 2.73±0.10 1.29±0.07 1.05±0.06 

On large scale, the ZSM-5 coating on 2024-T3 Al has the largest structural fluctuations (1-3 

μm

2

), which yield higher roughness values. Moreover, these results suggest that the ZSM-5 

coating on 6061-T6 Al and 7075-T6 Al substrates have similar structural morphologies. 

• Scaling Analysis & Optimized Filtering for LSCM Images

The scaling analysis technique employed for this analysis was developed to obtain measures of 

changes in surface morphology to gain insight into small-scale surface structural changes. The 

roughness of the coating surface was characterized in terms of scaling exponents to obtain 

power- law correlations. 

 The roughness (w, the average RMS deviation 

in surface heights from a center plane) is 

measured for increasing areas of l 2 where the 

dependence of the roughness on l gives rise to 

a power law relation characterized by the 

roughness exponent α at time t: 

wL (l,t) ~ l α

α is obtained from the scaling dependence of 

the local width on l: 

[ ] x L l txhtxhtlw2 2 −≡ ),(),(),(

h(x,t) is the height of a single-valued surface at 

location x, hl(x,t) is the average height of the local data at time t, t is the exposure time, and l is 

the size of local surface patches. 

 

Figure 5-21 shows the results of local scaling analysis applied to LSCM data collected from 

ZSM-5 coated 2024-T3, 6061-T6 and 7075-T6 Al samples. As with all analyses in this study, the 

results represent averages of three different scans for each sample. Results show that there is not 

Figure 5-21 Local scaling for LSCM filtered 

images (α value shown inside) 
SERDP PP1342: Zeolite Coating System 

University of California, Riverside, CE‐CERT   38 

a significant difference in complexity (fractal dimension) between the three zeolite-substrate 

systems, however there is a large deviation between the three in surface roughnesses. The 

zeolite coating on the 2024-T3 Al substrates have the highest roughness values, which suggests 

that this coating would perform the best as an adhesive pre-coat for CARC coatings. 

The roughness exponent α represents the coating’s small-scale structural changes (denoted by the 

linear region in Figure 5-21). These fluctuations occur within a 1 μm scaling region. Outside of 

this region there is no longer a correlation between independent surface structures and largescale surface changes are measured (RMS roughness). 

Atomic Force Microscopy (AFM) was not employed in this study due to limitation in height 

deviations of the microscope. The surface area that can be imaged using AFM is limited to 100 

μm

2

 with at most a 7 μm variation in heights. The variation in heights of the surfaces used in 

this study are >6 μm. Previous work has shown that a 5x5 median filter of the LSCM image can 

be used to mimic the resolution of the AFM. However in this study, a 3x3 median filter is 

sufficient to remove artifacts on the surface structure. A more rigorous filter may result in a loss 

of information. 

 
SERDP PP1342: Zeolite Coating System 

University of California, Riverside, CE‐CERT   39 

Task 3.2: Instrumental analysis of coating degradation

• Dynamic mechanical analysis 

Dynamic Mechanical Analysis employs the application of thermal analytical techniques to 

measure physical properties such as modulus, heat capacity and linear coefficient of thermal 

expansion of the zeolite coatings. It is believed that this data will lend some insight into the 

adhesion of the coating to the substrate. 

The coated specimens will be analyzed in two ways. The first set of experiments will apply a 

static stress scan, where the applied load will increase at a constant rate over time. The second 

set of experiments will apply a constant or increasing force at a constant frequency; this testing 

will occur at various frequencies. All experiments will be completed with both 3 point bending 

and single cantilever methods. The idea is to see if the composite or combined modulus of the 

coated samples shows any effect due to varying adhesion at the interface between the samples, 

when compared to independent modulus of the bare substrate and of the bare coating and if there 

any effect on the modulus resulting from changes in interface adhesion of the coating. 

Figure 5-22 shows results from DMA analysis of the zeolite coating on 2024 Al vs. bare 2024 

Al. Both have been tested in static stress. The modulus has been measured but has to be 

correlated against the zeolite coating without the Al substrate. Moreover, the effect of varying 

coating thickness has to be addressed. 

Figure 5-22 Stress/Strain curves for Zeolite on 2024-T3 Al & Bare 2024-T3 Al 

 
SERDP PP1342: Zeolite Coating System 

University of California, Riverside, CE‐CERT   40 

• DC Polarization quality control testing development 

For small 2x3 cm coupons we had been using epoxy to seal off the edges before electrochemical 

testing (Figure 5-23). This has been effective for coupons, but this means the large panel has to 

be cut into small pieces for electrochemical tests. 

To preserve the zeolite coated panels and to be able to 

characterize the same panel with both DC Polarization and EIS, 

as well as other tests such as salt-fog and UV exposure, we are 

using a test procedure which only requires a small scratch on one 

side of the panel for electrical contact for the DC Polarization and 

EIS tests (Figure 5-24). This small cut can be easily sealed and 

put on the back side in the salt-fog tests. This allows us to 

correlate the DC Polarization and EIS results with salt-fog or UV 

exposure results. We can also use this quick and almost nondestructive method as quality control for the coatings. We can 

also use this setup to check the uniformity of the coating by 

testing several spots on the same panel. Thus far it has been 

shown that our panels have uniform corrosion resistance. We 

have found that coatings synthesized together in the same reactor 

perform almost identically under electrochemical and mechanical 

testing. As a result, we routinely only perform quality control on 

one of the synthesis pair prior to additional sample testing (i.e. salt fog and UV exposure). 

Figure 5-24 Left: Corrosion test cell that can test a 3x6” panel without sacrificing the panel. Right: 

Zeolite coated panel with scratch on one side for electrical connection.

DC Polarization testing procedure for quality control of zeolite coated samples

A small area of bare metal substrate is exposed on one side of the zeolite coated panel for 

electrical connection with copper conducting tape when panel is used as working electrode. A 

standard corrosion test cell is used as shown in Figure 5-24 Left. Three 1 cm2

 locations are 

tested on the same side of electrical connection: 1” from top of panel (top), 3” from top of panel 

(middle) and 5” from top of panel (bottom). The corrosion media used is 5 wt% NaCl (0.856M 

NaCl), test areas were in contact with corrosion media 5 minutes prior to testing. 

Figure 5-23 2x3 cm coupon 

sealed by epoxy before 

electrochemical tests. 
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University of California, Riverside, CE‐CERT   41 

Figure 5-25 Representative DC Polarization profiles of the 15 zeolite coated panels sent to China Lake 

for salt fog testing. S1 – actual DC polarization profile of S series, sample 1; B1 – actual DC polarization 

profile of B series, sample 1; B3 – actual DC polarization profile of B series, sample 3. 

We sent 15 zeolite coated panels to China Lake 

with 5 of them DC polarization tested on the back 

and shown to have excellent corrosion resistance (S 

series) (Figure 5-25, S1), 5 samples that were not 

tested but synthesis twins of S samples (A series), 

and 5 samples (B series) whose twins were tested 

by DC Polarization and shown to have medium 

(Figure 5-25,B1) to low corrosion current (10-3.5

A/cm2) (Figure 5-25, B3). All 15 panels passed 

2205 hours of salt fog testing (salt fog results 

shown later in this report). 

To date we have synthesized hundreds of zeolite 

coated panels, greater than 99% of the coatings 

exhibit polarization profiles similar those in Figure

5-25. Specifically, greater than 93% have 

polarization profiles similar to S1 and less than 7% 

demonstrate polarization profiles within the range 

of B1 and B3 from Figure 5-25. 

DC Polarization testing in 5 wt% NaCl as a quality 

control measure prior to salt fog testing appears to 

be an excellent predictor of salt fog performance for 

zeolite coated panels. It is likely that as long as 

there is not a complete loss of passivation during 

the DC Polarization testing the panels will pass 

2000 hours exposure to salt fog. 

DC Polarization testing in 5 wt% NaCl was also 

Figure 5-26 Representative DC Polarization 

profiles in 0.856 M NaCl of aluminum alloys 

and steels. 
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University of California, Riverside, CE‐CERT   42 

performed on zeolite coatings (7.5 um thick) on other aluminum alloys (AA-5052-H32, AA6061-T6, AA-7075-T6) and zeolite coatings (4-5 um thick) on 3 different steels (S1008, S4130 

and SS304-2b) Figure 5-26. 

Task 3­3: Quantitative/qualitative adhesion testing of coating to Al & steel substrates

• ASTM D3359-02 adhesion test

UCR has carried out adhesion test 

according to ASTM D3395-02 on ZSM-5 

coating on AA-2024-T3, AA-5052-H32, 

AA-6061-T4, and AA-7075-T6. This is a 

dry adhesion test involving cross-cutting 

through the coating to the substrate with a 

multi-blade knife followed by adhesive 

taping and peeling. Then the cut areas 

were examined using a low magnification 

glass (x6). The test kit and the rating 

protocol according to the damages are 

shown in Figure 5-27. 5B is the highest 

rating under this protocol. ZSM-5 

coatings on all of the aluminum alloys 

tested received a rating of 5B (Table in 

Figure 5-28). Although the ASTM 

D3395-02 protocol does not require a 

high magnification microscope, we 

examined the cuts under high 

magnification microscope (x2000), and 

extremely clean cuts were revealed. 

There were no chipping and cracking into 

the coating after the cutting operation. 

This is a clear indication that the coatings 

are strongly adhered to the substrate. 

High temperature calcination was also 

performed to see if the coating would 

behave differently. 5B rating was retained for all of the samples after calcination at 400 °C for 2 

hours. 

• Mechanical cutting tests

To test the properties of the zeolite coating under mechanical stress, zeolite coated panels were 

cut using a standard lab shear (Figure 5-29a). The cut area was examined by SEM (Figure

5-29b& c). It can be seen that the cut was very clean, having no clack formation and propagation 

into the coating. 

Figure 5-27 ASTM D3359-02 test kit (left) and the 

rating protocol (right)

Figure 5-28 Adhesion rating on ZSM-5 coatings on 

aluminum alloys and a representative optical image of 

the ZSM-5 coating on AA-6061 after adhesion test. 
SERDP PP1342: Zeolite Coating System 

University of California, Riverside, CE‐CERT   43 

Figure 5-29(a) Lab shear for cutting metal sheets, (b) SEM of the cut of ZSM-5 coating on AA-2024-T3 

at low magnification, (c) SEM of the cut of ZSM-5 coating on AA-2024-T3 at high magnification. 

• Mechanical hole punching 

The ZSM-5 coated AA-2024-T3 3x6” 

panels were punched using standard punch 

in a machine shop. Very clean holes were 

generated (Figure 5-30). Similar results 

were obtained on ZSM-5 coating on 

carbon steel S-1008. The edge of the hole 

was examined by SEM, and was found 

that no crack was formed along the cutting 

edge, showing excellent adhesion and 

mechanical properties of zeolite coating. 

• ASTM D-2794-93 impact test 

Impact tests according to ASTM D-2794-

93 were performed on ZSM-5 coated AA2024-T3 panels. Tests were performed on 

2 um and 7.5 um thick coatings showing 

no crack formation or delamination of the 

zeolite coating. Photos of the experimental apparatus and the impacted area are shown in Figure

5-31. Clearly, when the impact is not enough to break the panel, it generates a dent that shows no 

Figure 5-30 Photograph of a ZSM-5 coated AA2024-T3 panel with punched holes 

Figure 5-31 Photographs of the ASTM D-2794-93 

impact setup from Gardner (a and b), impacted area of 

the 2 um thick ZSM-coated AA-2024 panel (c and d for 

each side, and left mark for impact from 1 ft and right 

mark for impact from 2 ft) and impacted area of the 7.5 

um thick ZSM-coated AA-2024 panel (e and f for each 

side, and left mark for impact from 1 ft and right mark 

for impact from 2 ft) 
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cracking of zeolite coatings. Once the impact is large enough, then both the coating and the panel 

were broken. 

• ASTM D 522-93a bending test

To examine the flexibility and adhesion of the zeolite coating, ZSM-5 coated AA-2024-T3 

panels were tested according to ASTM D 522-93a. Basically the zeolite coated panels were bent 

around a metal cone and the coating experiences different degrees of bending at different heights 

along the cone. Tests were performed on 2 um and 7.5 um thick zeolite coatings. For both the 2 

um and 7.5 um thick coatings, no cracking of the coating was observed along the whole height of 

the cone (Figure 5-32) 

Figure 5-32 Photos of the apparatus for ASTM D 522-93a bending test (a); bent 2.0 um thick ZSM-5 

coated AA-2024-T3 (b); bent 7.5 um thick ZSM-5 coated AA-2024-T3 (c). 

• ASTM G154-00a UV exposure 

Ten panels of 7.5 um thick zeolite coated AA-2024-T3 were sent to Benet Labs for UV testing 

following ASTM G154-00a. Five panels were continuously exposed for 32 weeks and then 

tested by DC Polarization in 5 wt% NaCl (Figure 5-34). Another 5 panels were removed from 

UV exposure at 7.23, 16, and 32 week intervals for DC Polarization testing in 5 wt% NaCl at 

UCR (Figure 5-35). Each of the 10 panels was tested by DC Polarization (Figure 5-33) prior to 

be being shipped to Benet Labs. The DC Polarization testing procedure was described 

previously and the test setup is shown in Figure 5-24. 

The legend for the line designations for Figure 5-33, Figure 5-34, and Figure 5-35 is shown in 

Figure 5-35 (bottom panel). In each Figure, one of the DC Polarization test sets has the line 

designations labeled. Figure 5-34 shows the DC Polarization in 5 wt% NaCl profiles of the five 

zeolite coated AA-2024-T3 coupons after 32 weeks of continuous UV exposure compared to the 

DC Polarization profiles prior to UV exposure. There was no decrease in corrosion resistance 

after 32 weeks continuous UV exposure. In all cases the polarization profiles after UV exposure 

for 32 weeks showed improved corrosion resistance, reflected in a decrease in current density 

and more vertical traces for anodic passivity as compared to the polarization profiles before UV 

exposure. The DC Polarization profiles of sample 3-21-05 (Figure 5-34) before and after UV 

exposure exemplifies the improved corrosion resistance following UV exposure. Five zeolite 

coated AA-2024-T3 panels were tested by DC Polarization in 5 wt% NaCl after incremental UV 

exposure (7.23, 16, 32 weeks) and their polarization profiles compared with those taken before 

UV exposure (Figure 5-35). The purpose of the incremental UV exposure and DC Polarization 

testing at each interval is to monitor the effects of UV exposure on corrosion resistance at 

different exposure times. Increased corrosion resistance was observed after 7.23 weeks UV 
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exposure for all five samples and continued to improve with longer UV exposure times. Sample 

3-16-05 (Figure 5-35) was only UV exposed for a total of 16 weeks to provide a sample at a 

shorter UV exposure time for future comparative analyses. 
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Figure 5-33 DC Polarization profiles of each zeolite coated AA-2024-T3 prior to UV exposure. See 

Figure 37 (bottom panel) for line designation legend 

Figure 5-34 DC Polarization profiles of zeolite coated AA-2024-T3 prior to and after 32 weeks 

continuous UV exposure. See Figure 37 (bottom panel) for line designation legend 
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Figure 5-35 DC Polarization profiles of zeolite coated AA-2024-T3 prior to and after 7.23, 16, and 32 

weeks UV exposure. 

 
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Task 3­4: Conduct accelerated service simulation testing

ASTM B117 Salt‐fog testing on bare zeolite coating

Initial salt fog testing on thin (0.5 um to 2 um thick) (Generation-1) zeolite coatings and coatings 

generated from differentially aged synthesis solutions during our coating optimization phase had 

inconsistent results, yielding many non-passing samples. During that process we optimized our 

synthesis process where we can reproducibly generate uniform zeolite coatings of variable, but 

controlled, thickness (0.5 um to greater than 13 um). Coating performance is virtually identical 

between panels that are coated simultaneously in the same reactor. We have developed a quick, 

minimally invasive DC Polarization testing regimen (described previously in section 3.2) for 

quality control monitoring of zeolite coatings prior to salt fog testing. Currently, greater than 

99% of zeolite coatings (7.5 um thick) produced will pass a very demanding DC Polarization 

quality control test in 5 wt% NaCl. 

Following our optimized zeolite synthesis process, zeolite coatings (7.5 um thick) on AA-2024-

T3 samples were salt fog tested for over 2000 hrs at China Lake with all samples passing. Salt 

fog testing (1000 hours) of machine scribed zeolite coatings (7.5 um thick) demonstrated that 

rust, if present, was confined to the scribed area and there was no delamination of the zeolite. 

Generation­1 coatings (0.5 – 2.0 um thick) on AA­2024­T3:

 

Five zeolite coated panels (0.5 um thick) were tested for corrosion performance as a pretreatment 

according to Mil-C-81706, which requires the coating to be free from corrosion after 336 hours 

(2 weeks) of salt fog exposure. Figure 5-36 were taken of the zeolite panels after 336 hours of 

exposure. 

Figure 5-36 Zeolite coated panels after 336 hours of salt fog exposure

Three (Group 2) of the five panels have a significant number of corrosion spots while two 

(Group 1) of the panels show very few corrosion spots. Based on these results new panels with a 

thicker zeolite coating were decided to be tested. 

 
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Generation­2 coating (7.5 um thick)

 

Five zeolite-coated aluminum 2024-T3 panels with 7.5 um thickness (with 3 different aging 

times of the deposition solution) were sent to China Lake for testing under neutral salt fog 

conditions, according to ASTM B-117. We thought 7.5 um would be a good thickness to start 

and likely to strike a balance between corrosion resistance and mechanical properties. The panels 

were in three different bundles, each with a different date, their preparation date. The dates 

indicated on the packages were 2-25-04 (two panels), 2-27-04 (two panels) and 3-1-04 (one 

panel). The panels w ith the same date w ere pr oduced in the same reactor. Thus the 

consistency of perfo rmance amo ng 2-25 and 2-27 w ill show that the coat ing depositio n 

procedure is very reproducible. The panels were labeled with permanent ink on one side (used 

as the back side) with the corresponding dates that were on the packaging. The packages that 

contained two panels with the same date were given “a” and “b” designations. 

The panels were placed in a salt fog chamber on May 11 at 10:30 a.m. At intervals of 168 hours 

and 336 hours of exposure, the panels were rinsed with deionized water, dried, examined and 

photographed. 

With one exception, all of the panels had a uniform appearance before exposure testing began. 

Panel 2-27-04b had a small streak that was grey in appearance but was slightly more reflective or 

shiny than the rest of the coating. See Figure 5-37 and Figure 5-38. 

Figure 5-37 Panels 2-27-04a, 2-27-04b, and 3-1-04 before 

exposure

Figure 5-38 Close up of non-uniform 

coating section on panel 2-27-04b before 

exposure.

The streak or non-uniformity did not adversely affect the coating performance during the test. 

The sole criterion by which a conversion coating is determined to “pass” the salt fog test is that 

there are to be no visible signs of corrosion whatsoever for a specific duration of exposure. Two 

critical times of inspection are 168 hours (1 week) and 336 hours (2 weeks). Many military 

systems require 336 hours of corrosion resistance but some systems require only 168 hours. Of 

the five panels tested, four passed the 168 hour inspection with no signs of corrosion while one 

panel designated as 3-1-04, was severely pitted (Figure 5-39). 
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. 

After one week of salt fog exposure, another difference was 

observed on panel 2-27-04b (other than the streak in the coating). 

Immediately after removing panels from the salt fog, they were 

rinsed with DI water. A significant portion of panel 2-27-04b 

had surface property differences; specifically it did not wet 

evenly. There were other very small areas on other panels that 

would not wet evenly but they were significantly smaller than 

the sections on panel 2-27-04b. Darker sections seen in Figure

5-40, down the left side, are the areas that had differences in 

surface wetting from the rest of the coating. 

The panels were returned to the salt fog chamber and evaluated 

after 1000 hrs of exposure. Panels 2-27-04a and 2-27-04b 

(Figure 5-41) are still passing and show no signs of corrosion. 

Although panels 2-25-04a (Figure 5-43) and 2-25-04b (Figure

5-44) had some pitting corrosion on the surface after 336 hours 

of exposure, they were tested further to determine if the pitting 

corrosion would worsen and delaminate the coating. The number 

of areas of pitting did not significantly increase on the surface 

and the coating around these areas remained intact. There is no sign of filiform corrosion, 

blistering or delamination. (Figure 5-42) 

The zeolite coating shows great promise as a viable conversion coating. It appears that although 

a pit can form within the coating, the corrosion does not undercut, delaminate or cause blistering 

in the surrounding coating; instead the corrosion area is limited in size. 

Coating resistance and performance are virtually identical between panels that are coated 

simultaneously in the same reactor. 

Figure 5-39 Pitting corrosion visible on panel 3-1-04 after 168 hours of exposure.

Figure 5-40 Photo of panel 2-

27-04b after being rinsed with 

DI water after 168 hours of 

exposure 
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Figure 5-41 Panels 2-27-04a and 2-27-04b after 

1000 hours of exposure 

Figure 5-42 Panels 2-25-04a and 2-25-04b after 

1000 hours of exposure 

Figure 5-43 Panel 2-25-04a and 2-25-04b after 

336 hours of exposure. 

Figure 5-44 Close up of panel 2-25-04a after 336 

hours of exposure 

Generation­3 coatings

Based on the previous testing results, it appears that 7.5 um thick coating has sufficient corrosion 

resistance. Therefore we decided to focus on 7.5 um coatings. We produced 25 zeolite coated 

panels with 15 of them without topcoat and 10 with topcoats. The topcoats were applied by Deft 

in a trial run in their facility. The S series have been examined on the back by DC Polarization 

using the almost non destructive method described in Task 3-2 and shown to have excellent 

corrosion resistance. Series B are the non-tested (by DC Polarization) twins of the S samples. 

Series A are the non tested twins of 5 panels that showed medium corrosion resistance (sulfuric 

acid, 10-4 A/cm2

). 

• Generation-3 coatings (7.5 um thick) on AA-2024-T3

ASTM B117 on zeolite coated AA2024-T3 panels: 

Based on the previous testing results, it appears that 7.5 um thick coating has sufficient corrosion 

resistance. Therefore we decided to focus on 7.5 um coatings. 15 zeolite coated panels were 
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sent to China Lake for neutral salt fog testing (ASTM B117). The S series have been examined 

on the back by DC Polarization in 5 wt% NaCl using the almost non destructive method 

described in Task 3-2 and shown to have excellent corrosion resistance (Figure 5-25, S1). Series 

A are the non-tested (by DC Polarization) twins of the S samples. Series B are the non tested 

twins of 5 panels that showed medium corrosion resistance by DC Polarization (Figure 5-25, B1 

& B3). All 15 zeolite panels passed 2205 hours of salt spray exposure. Figure 5-45, Figure 5-46 

and Figure 5-47 are of the three sets of zeolite panels after 1000 hours salt fog exposure and 

Figure 5-48, Figure 5-49 and Figure 5-50 are of the three sets of panels after 2205 hours salt fog 

exposure. Discoloration can be seen on the bottom corners of several panels which are due to 

color transfer of the wood that is used to hold the panels at the required 6° angle. 
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Figure 5-45 Panels A1-A5 after 1000 hours of salt fog exposure. Panel surfaces are alternating smooth 

and rough from A1 to A5 

Figure 5-46 Panels B1-B5 after 1000 hours of salt fog exposure. Panel surfaces are alternating smooth 

and rough from B1 to B5. 

Figure 5-47 Panels S1-S5 after 1000 hours of salt fog exposure. Panel surfaces are alternating rough and 

smooth from S1 to S5. 

After the zeolite panels were inspected and photographed after 1000 hours they were returned to 

the chamber for further exposure, for a total of 2205 hours. 
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Figure 5-48 Panels A1-A5 after 2205 hours of salt fog exposure. Panel surfaces are alternating rough 

and smooth from A1 to A5 

Figure 5-49 Panels B1-B5 after 2205 hours of salt fog exposure. Panel surfaces are alternating smooth 

and rough from B1 to B5 

Figure 5-50 Panels S1-S5 after 2205 hours of salt fog exposure. Panel surfaces are alternating rough and 

smooth from S1 to S5. 

After 2200 hours of exposure, the only visible signs of corrosion were small areas along the 

outer edges of the panels designated S1-S5. 
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The beginnings of corrosion along the outside edges of the 

panels, “edge effects”, are neglected within 0.25” when rating a 

coating according to pass/fail criteria. After 2205 hours of 

exposure the most significant corrosion, seen in Figure 5-51, is 

neglected and the coating meets passing criteria. All of the 

zeolite coatings were 

considered passing 

after the removal from 

the chamber after 2205 

hours of exposure. 

The edge effects were 

only observed on the S 

series. These samples 

had a small area of 

zeolite removed on the 

back side, exposing 

the metal substrate. None of the back sides of the 

samples being salt fog tested were sealed. Figure

5-52(left) shows the back side of sample S2 after 2205 

hours of testing. The right panel shows a similar zeolite 

sample with a small area of zeolite removed, exposing 

the bare metal prior to salt fog testing. The severe 

corrosion on the bare metal observed after the salt fog test and the fact that only those samples 

that had zeolite removed to expose bare metal demonstrated edge effects suggests that the edge 

effects may be caused by the bare metal corroding. If the backs of samples that have had bare 

metal exposed for quality control testing are sealed prior to salt fog testing, the edge effects 

observed may be eliminated. 

ASTM B117 testing on scribed zeolite coated AA-2024-T3 panels: 

Five (5) zeolite coated panels were machine scribed at Deft (Irvine, CA), and then exposed to 

neutral salt fog testing for 1000 hours. Figure 5-53 shows that the only visible corrosion was 

within the scribe and that there was no delamination or pealing of the coating. 

Figure 5-51 Visible corrosion 

along the edge of panel S2 after 

2205 hours of exposure 

Figure 5-52 Back side of sample S2 

from S series after 2205 hours salt fog 

testing (left panel), Non-salt fog tested 

zeolite panel with small area of zeolite 

removed, exposing bare metal (right 

panel). 
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Figure 5-53 Machine scribed Panels after 1000 hours of salt fog exposure 

• ASTM B117 testing of zeolite coated steels (2006) 

Fifteen (15) zeolite coated samples (5 each of 

SS304-2b, S4130, and C1008) with a coating 

thickness of about 5 um were given to China 

Lake on November 18, 2005 for salt fog testing 

(ASTM B117). We are testing a thinner 

zeolite coating of 5 um instead of our previous 

7.5 um thick zeolite coatings for two reasons. 

The first reason is that the zeolite coated steel 

panels or their twins have undergone DC 

Polarization quality control testing in 5 wt% 

NaCl, demonstrating excellent corrosion 

resistance (Figure 5-54). Secondly, we want to 

determine the thinnest coating that can match 

the excellent corrosion protection throughout 

2205 hours of salt fog testing of the 7.5 um 

thick coatings on AA-2024-T3. 

The criteria used to determine coating failure 

on steel panels was that visible edge corrosion 

could have no more than 1/8 inch of creep 

from the edge of the coating and no more than 

5 pits within the coating. After 168 hours of 

exposure, all of the steel samples were passing 

with the exception of 1 of the 5 1008 steel 

panels. After 336 hours of salt fog exposure, 

all of the samples were passing with the 

exception of 2 of the 5 1008 steel panels. After 

552 hours of exposure, multiple failures 

became evident within the 4130 steel panel set 

Figure 5-54 Representative DC Polarization 

quality control curves of 5 um think coatings on 

steels in 5 wt% NaCl . The far left black curve in 

each panel is an internal lab standard used for 

comparative purposes 
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as well as the 1008 steel panel set. The 304 stainless steel set began to fail after 3000 hours of 

exposure. Table 5-2 is a summary of the bare zeolite on steel panel performance data. 

Table 5-2 Salt fog testing (ASTM B117) results for zeolite coatings on steels (2006) 

Alloy Coating Results

S1008 Zeolite only 

0 failures at 48 hours 

2/5 failures at 168 hours 

3/5 failures at 672 hour 

3/5 failures at 1056 hours 

5/5 failures at 1584 hours 

S4130 Zeolite only 

0 failures at 168 hours 

1/4 failures at 336 hours 

1/4 failures at 672 hours 

4/4 failures at 1056 hours 

SS304 Zeolite only 0 failures at 1584 hours

2/5 failures at 3100 hours 

Carbon steel S1008:

The 1008 steel panels in Figure 5-55 had good protection overall after 168 hours of exposure. 

Two of the 3 panels had small pits resulting in visible red rust. The panels tested for over 1000 

hours to look for zeolite coating delamination and further pit formation. The same panels are 

seen in Figure 5-56 after 1056 hours of exposure. Once a pit had formed, the corrosion 

increased, as expected, but the zeolite did not delaminate from the panel. It is clear from these 

photos that the zeolite was still protecting the majority of the surface area on 3 of the 5 panels 

after 1000 hours. 

High-strength steel S4130:

Figure 5-55 Zeolite coated 1008 steel after 168 hours of exposure 

Figure 5-56 Zeolite coated 1008 steel after 1056 hours of exposure 
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The 4130 steel panels seen in Figure 5-57 had no failures after 168 hours of exposure. After 672 

hours only one of the panels had pitting. Although the surfaces of the majority of the panels 

were corrosion free after 1056 hours of exposure, there were at least 5 corrosion pits present on 

each panel (Figure 5-58). 

Figure 5-57 Zeolite coated 4130 steel after 168 

hours of exposure 

Figure 5-58 Zeolite coated 4130 steel after 1056 

hours of exposure 

Stainless steel SS304-2b:

The 304 stainless steel panels just began to show sign of corrosion geminating from the edge of 

the hole in the panel after 3100 hours of exposure (Figure 5-59). 

The protection of steel panels under salt fog conditions exceeds most military requirements. An 

increase in zeolite coating thickness may increase protection times even further by reducing 

corrosion pit formation. 

Figure 5-59 Zeolite coated 304 SS after 3100 hours of exposure 

 
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• ASTM B117 testing of zeolite coated steels (2008) 

Another fifteen zeolite coated samples (5 each of SS304-2b, S4130, and C1008) with a coating 

thickness of about 5 um were tested by China Lake on March 12, 2008. Three different controls 

were used. The C1008 steel was Zn phosphate coated with MIL-DTL-11195. The SS304-2b 

received a nitric acid passivation and the S4130 was Cd plated. 

The C1008 sets were scribed. The zeolite coated samples failed by 24 hours of salt fog (Figure 

5-60). The controls failed as well (Figure 5-61). Three out of the five zeolite coated SS304-2b 

samples passed 2376 hours of salt fog (Figure 5-62). All of the nitric acid passivated controls 

passed 2376 hours test (Figure 5-63). The zeolite coated S4310 samples failed after 500 hours of 

salt fog (Figure 5-64), while the Cd plated counterpart passed (Figure 5-65). The results were 

summarized in Table 5-3. 

Table 5-3 Salt fog testing (ASTM B117) results for zeolite coatings on steels (2008) 

Steel Coating Results 

C1008 Zeolite (Scribed) Failed by 24 h 

C1008 Zn phosphate and coated with MIL-DTL-11195(Scribed) Failed by 24 h 

SS304-2b Zeolite 3/5 passed 2376 h 

SS304-2b Nitric acid passivation 5/5 passed 2376 h 

S4130 Zeolite Failed by 504 h 

S4130 Cd plated Passed by 504 h 
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Figure 5-60 Scribed Zeolite coated C1008 after 24 

hours of exposure 

Figure 5-61 Scribed C1008 (Zn phosphate 

coated with MIL-DTL-11195) after 24 hours of 

exposure 

Figure 5-62 Zeolite coated SS304-2b after 2376 hours 

of exposure 

Figure 5-63 Nitric acid passivated SS304-2b 

after 2376 hours of exposure 

Figure 5-64 Zeolite coated S4130 after 504 hours 

of exposure 

Figure 5-65 Cd plated S4130 after 504 hours of 

exposure 
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ASTM B117 Salt‐fog testing on zeolite coating systems

Generation­1 coating (0.5 – 1.0 um thick):

Aluminum 2024-T3 panels were 

coated with zeolite of 0.5-2 um 

thick at UCR and delivered to 

China Lake. The panels were then 

sent to the Army Research 

Laboratory (ARL) to be coated 

with CARC topcoat. The panels 

were coated on one side with the 

CARC topcoat (Mil-PRF-64159) 

and coated with primer on the 

other side to keep corrosion from 

contaminating the salt fog 

chamber. 

 The painted panels were scribed in 

an “X” configuration and placed 

into the chamber while held at 15° from vertical. The unpainted panels were placed in the 

chamber 6° from vertical. The panels were exposed to a salt fog according to ASTM B-117. 

Unpainted zeolite panels were also 

used to test the zeolite 

performance as a pretreatment. 

All panels were first inspected 

after 19 hours of exposure. Upon 

initial inspection, it was evident 

that the CARC coating did not 

adhere to the zeolite (Figure 5-66). 

Although the CARC topcoat did 

not appear to be compatible with 

the zeolite directly, the primer 

adhered to the test panels and there 

were no signs of delamination 

between the primer and zeolite. Another test using primer and topcoat may show that the zeolite 

coating performs well in a coating system. Because the topcoat came off of the panels very 

cleanly, the excess paint was trimmed away and the panels were allowed to remain in the salt fog 

chamber to test effects on the zeolite coating alone. After 524 hours of exposure, the bulk zeolite 

coating showed almost no corrosion except where the coating had been scribed (See Figure

5-67). Another interesting and positive aspect of the coating is that the corrosion that can be seen 

within the scribed areas did not migrate and damage the bulk coating. 

Figure 5-66 Aluminum panels coated with zeolite and CARC 

topcoat after 19 hours of salt fog exposure 

Figure 5-67 Exposed zeolite surface after 524 hours of 

exposure after CARC removal. 
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Generation­3 coating (7.5 um thick)

VOC-free topcoat (Deft product #55W-002, Deft, Irvine CA) and Self-Priming topcoat (TT-P2756A from Deft, Irvine, CA)

Based on the previous testing results, it appears that 7.5 um thick coating has sufficient corrosion 

resistance. Therefore we decided to focus on 7.5 um coatings. We produced 25 zeolite coated 

panels with 15 of them without topcoat and 10 with topcoats. The topcoats were applied by Deft 

in a trial run in their facility. Five panels were applied with VOC-free topcoat (Deft product 

#55W-002, Deft, Irvine CA) and five panels were applied with self-priming topcoat (TT-P2756A from Deft, Irvine, CA). Three of each of the topcoated panels were then sent to China 

Lake for salt-fog testing (ASTM B117). The S series have been examined on the back by DC 

Polarization using the almost non destructive method described in Task 3-2 and shown to have 

excellent corrosion resistance. Series B are the non-tested (by DC Polarization) twins of the S 

samples. Series A are the non tested twins of 5 panels that showed medium corrosion resistance 

(5 wt% NaCl, 10-4 A/cm2

). 

From initial observation of the panels painted with the VOC-free formulation, there were 

significant differences between the surfaces of the paint. Two of the panels had a smooth 

appearance while one had a rough “orange peel” look (Figure 5-68a&b). During the scribing 

process, one coating peeled away from the scribed area. (Figure 5-68c) 

Figure 5-68 Zeolite panels 6-5-04, 6-10-04a and 6-10-04b with VOC-free self-priming topcoat before 

scribing (a) and after scribing (b). (c) close up view of zeolite panel 6-5-04 with topcoat 

Three panels with designations 8-1-04, 10-16-04a and 10-16-04b were painted with a solventbased self-priming topcoat. The panels 

had a uniform appearance and showed no 

peeling or delamination during the 

scribing process. 

All painted panels were placed in the 

chamber at an angle of 15° from vertical. 

After 168 hours (1 week) of exposure all 

painted panels had some degree of 

blistering between the zeolite and the 

paint along the scribe and significant 

blistering on the outer edges of some 

panels. Although blistering is a 

Figure 5-69 Panel 10-16-04b coated with (a) a VOCfree topcoat and (b) a solvent-based topcoat after 168 

hours of salt fog exposure 
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performance failure for this test, the panels remained in the chamber for a total of 336 hours. 

The severity of the blistering increased and the panels were removed from the test. Figure 5-69 

are photos of blistering areas after 168 hours of exposure of the VOC-free topcoat and the 

solvent-based topcoat, respectively. 

The poor performance of these topcoats is contributed in part to their application to the zeolite 

coatings. Neither ASTM nor MIL specs were followed during the topcoat application; they were 

applied as part of a demonstration of the topcoat application process. Based on these results, 

MIL specs will be adhered to during future primer and/or topcoat application. 

Zeolite/Primer, Zeolite/Primer/Topcoat and Zeolite/Topcoat 

Forty nine (49) zeolite coated AA-2024-T3 panels were prepared and painted by Deft (Irvine, 

CA), following ASTM guidelines. Figure 5-15 shows the matrix of primers and topcoats applied 

to the zeolite coating following MIL specs. 

Aluminum 2024-T3 panels, coated with zeolite, were painted and tested in a salt fog 

environment according to ASTM B-117. Panels were tested with primers alone, primers and 

topcoat, and one set was tested with a self-priming topcoat. The primers include Mil-PRF-23377 

Type I Class C (control), Mil-PRF-23377 Type I Class N and Mil-PRF-85582 Type I Class N. 

The topcoat applied over the primers was a Mil-PRF-85282 and the self-priming topcoat was a 

TT-P-2756A. 

Primed and painted panels were scribed with a 4-inch “X” which exposed bare metal before 

being placed into the test chamber. The panels were inspected at various time intervals, 

including 168 hours, 336, hours, 552 hours, 672 hours, 1056 hours, 1584 and 3100 hours. It 

should be noted that during the first two weeks of the test, a city-wide power failure caused the 

chamber to lose power for approximately 4 days. Once power was restored, the chamber was 

calibrated and the test resumed. 

Coating delamination and corrosion was evident on some samples in the early stages of the test. 

The corrosion is thought to be due to flexing of the aluminum panels causing coating breaches. 

The samples that were provided were less than 0.032 in thickness. While handling, it was 

obvious that the panels were flexing. Possible cracking of the zeolite coating may have lead to 

corrosion within the bulk of some of the samples. 

Table 5-4 summarizes the performance data of the tested coating systems. It should be noted 

that the test was stopped after 3100 hours. 

Figure 5-70 are of the panel sets that had the chromated Mil-PRF-23377 Type I primers applied. 

After 3100 hours of exposure, the scribed areas were free of corrosion and the coating did not 

show signs of delamination from the zeolite surface. 

Corrosion is evident within the scribed areas of the panel sets in Figure 5-71. The panels had the 

non-chromated Mil-PRF-23377 Type I primer. These panels failed after 336 hours of exposure.
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Table 5-4 Summary of performance and exposure time 

Alloy Primer Topcoat Result 

Al 2024-T3 Mil-PRF-23377 Type I Class C Mil-PRF-85285 Passing at 3100 hours 

Al 2024-T3 Mil-PRF-23377 Type I Class N Mil-PRF-85285 Partial failure at 168 hours 

Complete Failure at 336 hours 

Al 2024-T3 Mil-P-85582 Type I Class N Mil-PRF-85285 Failure at 168 hours due to delamination 

Al 2024-T3 Mil-PRF-23377 Type I Class C None Passing at 3100 hours 

Al 2024-T3 Mil-PRF-23377 Type I Class N None Partial failure at 168 hours 

Complete Failure at 336 hours 

Al 2024-T3 Mil-P-85582 Type I Class N None Failure at 500 hours 

Al 2024-T3 ---------- TT-P-2756A Failure at 168 hours due to delamination 

Figure 5-70 Zeolite coated 2024-T3 aluminum with Mil-PRF-23377 Type I Class C primer (a) without 

and (b) with Mil-PRF-85285 topcoat after 3100 hours of exposure. 

Figure 5-71 Zeolite coated 2024-T3 aluminum with Mil-PRF-23377 Type I Class N primer (a) without 

and (b) with Mil-PRF-85285 topcoat after 336 hours of exposure. 
SERDP PP1342: Zeolite Coating System 

University of California, Riverside, CE‐CERT   65 

 In Figure 5-72, corrosion is evident within 

the scribe on the 3-25-05A panel after 336 

hours of corrosion. Failure was observed 

after 500 hours of exposure. 

Delamination between the coating system 

and the zeolite is evident in the scribed 

areas of the panels that contained the MilPRF-85582 Type I Class N primer and MilPRF-85285 topcoat (Figure 5-73). The 

adhesion of the primer to the zeolite surface 

was affected by the addition of the topcoat. 

The self-priming topcoat was delaminating 

from the zeolite surface and there was 

corrosion present within the scribes after 168 hours of exposure to the salt fog (Figure 5-74).

Figure 5-73 Zeolite coated aluminum 2024-T3 

panels with Mil-PRF-85582 Type I Class N primer 

and Mil-PRF-85285 topcoat after 168 hours of 

exposure 

Figure 5-74 Zeolite coated 2024-T3 aluminum 

with self-priming topcoat TT-P-2756A after 168 

hours of exposure 

Summary  

The bare zeolite coating offers excellent corrosion protection on 2024-T3 aluminum in the 

accelerated weathering tests. The reproducibility of the zeolite deposition process is excellent. A 

simple alkaline detergent solution pretreatment is used for all aluminum alloys and steels. A 

single chemical formulation is used for generating zeolite coating on all metals. If the coating is 

breached, corrosion remains localized to the damaged area. The zeolite does not blister or 

delaminate from any damaged areas. It appears from the most recent test results that a consistent 

zeolite application has been achieved. After 2205 hours of salt fog exposure there is no visual 

difference between a rough or smooth zeolite surfaces. 

A complete zeolite coating system passing 3100 hours of salt-fog exposure (ASTM B117) has 

been achieved. The chromated primer (Mil-PRF-23377) both with and without topcoat (MilFigure 5-72 Zeolite coated aluminum 2024-T3 with 

Mil-PRF-85582 Type I Class N primer after 336 

hours of exposure 
SERDP PP1342: Zeolite Coating System 

University of California, Riverside, CE‐CERT   66 

PRF-85285) showed no delamination of the primer or topcoat from the zeolite and there was no 

rust observed in the scribed areas after 3100 hours salt-fog exposure. 

Task 3­5: Examine substrate degradation and corrosion inhibition – EIS test

EIS testing procedure 

EIS testing was carried out at room temperature 

with Solartron potentiostat SI 1287 and Solartron 

impedance/gain-phase analyzer SI1260 in a threeelectrode Cell (Gamry PTC1 Paint Test Cell) with 

a graphite rod counter electrode and a saturated 

calomel electrode (SCE) as the reference electrode 

(Figure 5-75). A ZSM-5 coated AA 2024-T3 was 

used as the working electrode with an exposed 

area of 15 cm2

. A small area of bare metal 

substrate is exposed on one side of the coated 

panel for electrical connection with copper 

conducting tape (as shown in Figure 5-24, right). 

The corrosive medium was 0.5 mol/L NaCl 

aqueous solution. The impedance measurements 

were performed at an open circuit potential with 

applied 10 mV sinusoidal perturbations in the 

frequency range of 10-2 -2*105

 Hz with 10 steps 

per decades. 

EIS measurement results

To date, a ten-day EIS test was measured. During this period, the spectra don’t change much 

(Figure 5-76). The bode plot for the ZSM-5 coated AA 2024 has two distinguishable timedependent processes. The time constant at high frequencies (103

~105 Hz) is related to the 

capacitance of zeolite coating. The resistive plateau at 100

~103 Hz represents the pore resistance 

of the zeolite film. The time constant at low frequencies (10-2~100 Hz) is attributed to the 

capacitance of an intermediate layer present at the AA/ZSM-5 interface. An intermediate layer 

was also reported for sol-gel coating29 and chromate conversion coating30, although the 

composition is not clear. It is believed that the intermediate layer is very important for the 

corrosion resistant coating since it is the last barrier for the corrosive species. 

A three layer model (Figure 5-77) was used to fit the data and explain the protective and 

degradation mechanism of ZSM-5 coating. One simulation example was given in Figure 5-77, 

which shows perfect fitting results. Since a 10-day EIS test is not enough to show the 

degradation of ZSM-5 coatings, no further explanation was given here. A long-term EIS test is 

under investigation. 

Figure 5-75 EIS test cell 
SERDP PP1342: Zeolite Coating System 

University of California, Riverside, CE‐CERT   67 

Figure 5-76 Impedance spectra during immersion in 0.5 mol/L NaCl solution. (a) Nyquist plot and (b) Bode plot 

Figure 5-77 EIS model and fitting result 
Universi

Task 3­6

Six zeoli

by the U

condition

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B

C

D

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The NAS

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processin

monitor c

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University of

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owing evalua

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C) Color in C

D) Gloss (AS

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SA Beach C

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CIE Lab form

STM D 523) 

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Corrosion Te

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Figure

PP1342: Z

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de (UCR). 

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STM D714)

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f the sample

(Figure 5-78

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has the capa

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A Beach Corr

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bare aluminu

The sample

ASA Beach

s: 

ASTM D 610

s. 

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ability to pro

conditions.

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ystem 

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posure site, 

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nished 

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ess to 
SERDP PP1342: Zeolite Coating System 

University of California, Riverside, CE‐CERT   69 

Six zeolite coated 2024-T3 coupons and five uncoated 2024-T3 samples were labeled as shown 

in Table 5-5 Zeolite samples and bare AA 2024-T3 from UCR. The numbering sequence, 

provided in Table 5-5, is used throughout this report. 

Table 5-5 Zeolite samples and bare AA 2024-T3 from UCR 

UCR Zeolite Samples UCR AA 2024-T3 Samples 

080619B 

080620A 

080620B 

080621A 

080621B 

080626A 

2024 T3-1 

2024 T3-2 

2024 T3-3 

2024 T3-4 

2024 T3-5 

All samples were mounted on corrosion racks at the NASA Beach Corrosion Test Site, and 

remained in place for 12 months. Each rack was oriented so the face of each coupon was in 

direct exposure with the coastal marine atmospheric environment from the Atlantic Ocean 

(Figure 5-79 NAVAIR Panels at the NASA Beach Corrosion Test Site). 

Figure 5-79 NAVAIR Panels at the NASA Beach Corrosion Test Site

Coating performance parameters, with respect to corrosion control, were ascertained using the 

following methodologies: 

• ASTM D1654 - Standard Test Method for Evaluation of Painted or Coated Specimens 

Subjected to Corrosive Environments 

• ASTM D610 - Standard Test Method for Evaluating Degree of Rusting on Painted 

Surfaces 

• ASTM D714 - Standard Test Method for Evaluating Degree of Blistering of Paints 
SERDP PP1342: Zeolite Coating System 

University of California, Riverside, CE‐CERT   70 

Gloss and color measurements were performed to determine aesthetic and technical parameters 

related to the coating systems. 

ASTM D610 Standard Test Method for Evaluating Degree of Rusting on Painted Surfaces

All coupons were rated according to ASTM D 610 “Standard Test Method for Evaluating 

Degree of Rusting on Painted Surfaces”. ASTM D 610 rates the degree of rusting on painted 

steel surfaces on a scale in which each rating number correlates to the area of a coupon that is 

corroded (Table 5-6 ASTM D 610 Rating Scale). 

Table 5-6 ASTM D 610 Rating Scale 

To determine the degree of corrosion emanating from the unscribed metal surface, a series of 

pictorial examples from ASTM D 610 were used as a reference. These reference diagrams are 

shown in Figure 5-80 Pictorial examples of rust type and grade (7-9) from ASTM D 610.Figure 

5-81, and Figure 5-82. In accord with these illustrations, the type of corrosion is reported as 

spot, general, pinpoint or hybrid; and the extent of corrosion is reported on a scale from 0-10 

(worst-best). 

A summary of the evaluations, according to ASTM D 610, is shown in Table 5-7 Summary of 

ASTM D 610 Ratings – Degree of Rusting on Painted SurfaceThe coating performance is color 

coded according to the extent of corrosion away from the scribe or edges of the samples. A 

perfect rating of 10 was color coded in green. A rating number from 7 to 10 (non inclusive of 

10) was color coded in yellow. Finally, a rating below 7 was color coded in red. 

Table 5-7 Summary of ASTM D 610 Ratings – Degree of Rusting on Painted Surface 

Description Rating

No rusting or less than 0.01% of surface rusted. 10

Minute rusting, less than 0.03% of surface rusted. 9

Few isolated rust spots, less than 0.1% of surface rusted. 8

Less than 0.3% of surface rusted. 7

Extensive rust spots, but less than 1% of surface rusted. 6

Rusting to the extent of 3% of surface rusted. 5

Rusting to the extent of 10% of surface rusted. 4

Approximately 1/6 of the surface rusted. 3

Approximately 1/3 of the surface rusted. 2

Approximately 1/2 of surface rusted. 1

Approximately 100% of surface rusted. 0

Substrate / Code Conversion Coat Primer Topcoat Panel ID #s 4 Month 6 Month 9 Month 12 Month

2024 UC Zeolite None None 080619B 6 5 5 2

2024 UC Zeolite None None 080620A 10 10 10 8

2024 UC Zeolite None None 080620B 10 8 8 7

2024 UC Zeolite None None 080621A 7 7 6 6

2024 UC Zeolite None None 080621B 7 7 6 6

2024 UC Zeolite None None 080626A 6 5 5 5
SERDP PP1342: Zeolite Coating System 

University of California, Riverside, CE‐CERT   71 

The summary in Table 5-7 proves useful to show the degree of protection afforded by the different zeolite 

coated samples. All ratings that deviated from a perfect condition (10) were classified as pinpoint. It 

should be noted that neither a primer, nor a topcoat was used on the 2024-T3 zeolite samples. 

Figure 5-80 Pictorial examples of rust type and grade (7-9) from ASTM D 610. 
SERDP PP1342: Zeolite Coating System 

University of California, Riverside, CE‐CERT   72 

Figure 5-81 Pictorial examples of rust type and grade (4-6) from ASTM D 160 
SERDP PP1342: Zeolite Coating System 

University of California, Riverside, CE‐CERT   73 

Figure 5-82 Pictorial examples of rust type and grade (1-3) from ASTM D 610 

ASTM D714 Standard Test Method for Evaluating Degree of Blistering of Paints

ASTM D714 is a test method that uses photographic reference standards to evaluate the degree 

of blistering that may develop underneath a coating. The ratings are based upon the size of the 

blister, as well as the distribution of anomalies. Figure 5-83 ASTM D714-02 Blister Reference 

Photographs shows the template that was used to evaluate the size and distribution of blistering. 
SERDP PP1342: Zeolite Coating System 

University of California, Riverside, CE‐CERT   74 

Figure 5-83 ASTM D714-02 Blister Reference Photographs 

A summary of the ASTM D 714 blister ratings (by coating type) is shown in Table 5-8. A 

perfect rating value of 10 (indicating no blisters) was color coded in green. A system that 

exhibited blisters was color coded in red. Yellow indicates that the coating had previously 

blistered. 

No blistering was evident on any of the zeolite coated aluminum substrates throughout the 

duration of exposure. 
SERDP PP1342: Zeolite Coating System 

University of California, Riverside, CE‐CERT   75 

Table 5-9. Summary of ASTM D 714 Ratings – Degree of Blistering 

ASTM D2244 Color Measurements

Color can be a key aesthetic and technical consideration for a coating system. Color 

measurements were recorded on a ColorTec-PCM handheld portable color meter using the CIE 

L*a*b* format, D-65 illuminant, and a 10° observer. 

Briefly, a color’s "lightness" (L*) runs from light (white) to dark (black). A more reddish color 

will give a positive a* value and conversely, a more greenish color will give a negative a* value. 

As with the a* values, the more bluish color will give a positive b* value, and a more yellowish 

color will give a negative b* value.

A single number indicator of overall color change (delta E) was calculated by taking the square 

root of the sum of the squares of the lightness and color difference according to the following 

equation: 

delta E= ( ) ( ) ( ) fi fi fi − + − + − bbaaLL 2 2 2 

 Where: 

L i = initial Lightness value a i = initial Red/Green value 

L f = final Lightness value a f = final Red/Green value 

b i = initial Blue/Yellow value b f = final Blue/Yellow value 

As a general rule, a “delta E” value of 1 is discernable by the human eye in a side-by-side 

comparison. However, in less than ideal lighting, a delta E value of 2 or 3 can still be considered 

the same color. Delta E values were calculated from the initial, and time dependent 

measurements after each exposure period. 

The delta E change in color for each coating type and duration of exposure is shown in 

Table 5-10. Color values for individual coupons are reported in Tables 11-14. Each value was 

based upon the average of three measurements for each sample. 

As expected, significant changes in color were exhibited from white corrosion products that 

formed on the uncoated 2024-T3 aluminum substrates. Significant changes in color were not 

seen (compared to the unprotected aluminum) for the zeolite coated specimens. 

System Substrate / Code Conversion Coat Primer Topcoat Panel ID #s 4 Month 6 Month 9 Month 12 Month

UC 2024 UC Zeolite None None 080619B

2024 UC Zeolite None None 080620A

2024 UC Zeolite None None 080620B

2024 UC Zeolite None None 080621A

2024 UC Zeolite None None 080621B

2024 UC Zeolite None None 080626A

Color Code

No Blisters

Previously Blistered

Blisters
SERDP PP1342: Zeolite Coating System 

University of California, Riverside, CE‐CERT   76 

Since a topcoat was not used in conjunction with the zeolite pretreatment, color values may be 

irrelevant for the zeolite coated product when used in the field. 

Table 5-10. Average Delta E Color Calculations by Coating Type. 

Table 5-11. Four Month Color Ratings 

Table 5-12. Six Month Color Ratings 

Sample 4 Month Delta E 6 Month Delta E 9 Month Delta E 12 Month Delta E

2024 T3 24.26 23.89 31.09 22.36

080619B 5.92 5.69 5.34 5.78

080620A 6.74 6.87 6.43 6.37

080620B 6.16 6.04 5.81 5.75

080621A 3.31 3.30 3.45 3.40

080621B 3.39 3.27 3.16 3.07

080626A 5.18 5.26 6.04 5.76

Average Delta E Calculations by Group

Sample

4 Month 

Delta E Initial L Intial a Initial b

4 month 

L

4 month 

a

4 month 

b

2024 T3-1 22.441 51.84 -3.59 8.34 73.72 1.12 6.70

2024 T3-2 23.528 56.03 11.27 -7.51 72.08 0.97 6.27

2024 T3-3 34.792 51.43 11.09 -20.77 70.65 1.00 6.42

2024 T3-4 12.815 55.43 -0.60 2.70 67.94 0.80 5.10

2024 T3-5 27.711 53.89 -12.85 18.68 74.82 1.14 7.10

080619B 5.916 74.93 6.42 -2.93 75.45 2.12 1.10

080620A 6.743 74.44 6.16 -6.22 76.27 2.56 -0.82

080620B 6.162 74.76 6.34 -4.91 76.56 3.22 0.09

080621A 3.314 75.65 4.31 -3.26 75.57 2.27 -0.65

080621B 3.392 77.71 4.27 -2.52 78.17 2.49 0.33

080626A 5.182 68.44 3.02 1.08 71.51 0.70 4.55

Sample Delta E Initial L Intial a Initial b

6 month 

L

6 month 

a

6 month 

b

2024 T3-1 21.860 51.84 -3.59 8.34 73.14 0.90 6.34

2024 T3-2 22.728 56.03 11.27 -7.51 70.93 0.88 6.15

2024 T3-3 35.297 51.43 11.09 -20.77 71.54 0.93 6.40

2024 T3-4 12.602 55.43 -0.60 2.70 67.74 0.63 5.10

2024 T3-5 26.977 53.89 -12.85 18.68 73.66 0.96 6.59

080619B 5.687 74.93 6.42 -2.93 75.64 2.16 0.77

080620A 6.873 74.44 6.16 -6.22 76.50 2.47 -0.80

080620B 6.041 74.76 6.34 -4.91 76.49 3.12 -0.10

080621A 3.304 75.65 4.31 -3.26 75.61 2.15 -0.76

080621B 3.269 77.71 4.27 -2.52 78.22 2.41 0.12

080626A 5.256 68.44 3.02 1.08 71.66 0.72 4.54
SERDP PP1342: Zeolite Coating System 

University of California, Riverside, CE‐CERT   77 

Table 5-13. Nine Month Color Ratings 

Table 5-14. Twelve Month Color Ratings 

ASTM D523 Gloss Measurements

Gloss can be a key aesthetic and technical consideration for a coating system. The gloss meter 

records the amount of reflective illuminated light at specified angles of 20°, 60°, or 85°; and 

gives a value in gloss units (GU). The 60° geometry is used for most specimens, and is the 

initial angle used to determine whether the 20° or 85° angles may be more applicable. The 20° 

angle is used when the 60° angle gloss values are higher than 70 GU’s, while the 85° angle is 

used when the 60° angle gloss values are less than 10 GU’s. 

Gloss measurements were recorded using a calibrated BYK Gardner Tri-Gloss portable gloss 

meter. Measurements were recorded in three locations on the face of each coupon, and the 

average of those three measurements is reported in Table 5-15. 

The gloss measurements for the bare aluminum substrates were heavily influenced by the 

corrosion products that formed on the face of the unprotected samples. This phenomenon is as 

expected, and provides a control that might be used to form a comparison with the zeolite coated 

samples. 

Sample Delta E Initial L Intial a Initial b

9 month 

L

9 month 

a

9 month 

b

2024 T3-1 20.655 51.84 -3.59 8.34 71.89 0.92 6.27

2024 T3-2 43.190 56.03 11.27 -7.51 95.81 -1.26 3.71

2024 T3-3 52.367 51.43 11.09 -20.77 96.04 -1.26 3.72

2024 T3-4 12.742 55.43 -0.60 2.70 67.77 0.76 5.57

2024 T3-5 26.482 53.89 -12.85 18.68 73.00 0.95 6.61

080619B 5.342 74.93 6.42 -2.93 76.88 1.88 -0.90

080620A 6.433 74.44 6.16 -6.22 75.39 2.67 -0.90

080620B 5.813 74.76 6.34 -4.91 75.56 3.30 -0.02

080621A 3.445 75.65 4.31 -3.26 75.47 2.14 -0.59

080621B 3.158 77.71 4.27 -2.52 77.55 2.47 0.07

080626A 6.041 68.44 3.02 1.08 72.46 0.69 4.94

Sample Delta E Initial L Intial a Initial b

12 month 

L

12 month 

a

12 month 

b

2024 T3-1 19.168 51.84 -3.59 8.34 70.27 0.98 5.72

2024 T3-2 21.435 56.03 11.27 -7.51 69.15 1.06 6.02

2024 T3-3 32.962 51.43 11.09 -20.77 68.59 0.89 5.46

2024 T3-4 12.481 55.43 -0.60 2.70 67.65 0.81 4.81

2024 T3-5 25.737 53.89 -12.85 18.68 71.48 1.05 6.04

080619B 5.780 74.93 6.42 -2.93 77.12 2.04 0.14

080620A 6.371 74.44 6.16 -6.22 74.98 2.65 -0.93

080620B 5.748 74.76 6.34 -4.91 75.01 3.25 -0.07

080621A 3.402 75.65 4.31 -3.26 75.04 2.19 -0.67

080621B 3.067 77.71 4.27 -2.52 77.27 2.52 -0.04

080626A 5.760 68.44 3.02 1.08 72.13 0.69 4.84
SERDP PP1342: Zeolite Coating System 

University of California, Riverside, CE‐CERT   78 

Table 5-15. Gloss Measurements by Sample 

Figure 5-84~5-89 show the digital pictures of those zeolite coated and bare AA2024-T3 samples 

exposed at marine atmosphere on the rack up to 12 month (each sample’s position is labeled in 

Figure 5-84 ). 

Initial Gloss 4 mo. Gloss 6 mo. Gloss 9 mo. Gloss 12 mo. Gloss

2024 T3-1 98.2 9.3 3.9 2.5 1.8

2024 T3-2 51.2 3.4 1.8 1.6 1.3

2024 T3-3 109.0 4.4 3.1 2.0 1.5

2024 T3-4 145.0 1.9 1.5 1.1 1.0

2024 T3-5 105.0 7.8 4.8 3.4 2.3

080619B 9.4 7.8 6.6 8.1 8.2

080620A 13.1 13.8 11.6 13.6 12.9

080620B 10.2 13.7 12.8 14.5 13.2

080621A 2.6 3.3 3.8 3.9 2.8

080621B 40.8 37.8 28.3 32.6 22.2

080626A 10.7 8.7 7.1 7.2 5.9

Gloss Measurements
SERDP PP1342: Zeolite Coating System 

University of California, Riverside, CE‐CERT   79 

Figure 5-84 Sample position on rack 

Figure 5-85 Initial photo documentation 

 
SERDP PP1342: Zeolite Coating System 

University of California, Riverside, CE‐CERT   80 

Figure 5-86 Four month exposure Figure 5-87 Six month exposure 
SERDP PP1342: Zeolite Coating System 

University of California, Riverside, CE‐CERT   81 

Figure 5-88 Nine month exposure Figure 5-89 Twelve month exposure 
SERDP PP1342: Zeolite Coating System 

University of California, Riverside, CE‐CERT   82 

Task 4: Technology Transition

The corrosion resistant zeolite coating is protected by an issued US patent and one invention 

disclosure for the ionothermal synthesis process has been filed. There have been regular 

enquiries from companies about the technology (e.g., Metalast, VestaScience, UTEK 

Corporation, etc.). We have also submitted a demonstration pre-proposal lead by Navy China 

Lake to the ESTCP program. And now a full proposal is requested. We have recently 

demonstrated that zeolite could be possible replacement for hard chrome and cadmium. Since 

here mostly small parts are involved the pressured vessel is expected to be of less concern. This 

may open up more commercialization prospects. 
SERDP PP1342: Zeolite Coating System 

University of California, Riverside, CE‐CERT   83 

Appendix

Publications

1) Cheng, X.L., Z.B. Wang, and Y.S. Yan, Corrosion-resistant zeolite coatings by in situ 

crystallization. Electrochemical and Solid State Letters, 2001. 4(5): p. B23-B26. 

2) Wang, Z.B., et al., Pure silica zeolite films as low-k dielectrics by spin-on of nanoparticle 

suspensions. Advanced Materials, 2001. 13(19): p. 1463. 

3) Wang, Z.B. and Y.S. Yan, Oriented zeolite MFI monolayer films on metal substrates by in 

situ crystallization. Microporous and Mesoporous Materials, 2001. 48(1-3): p. 229-238. 

4) Mitra, A., et al., Synthesis and corrosion resistance of high-silica zeolite MTW, BEA, and 

MFI coatings on steel and aluminum. Journal of the Electrochemical Society, 2002. 

149(10): p. B472-B478. 

5) Lai, Z.P., et al., Microstructural optimization of a zeolite membrane for organic vapor 

separation. Science, 2003. 300(5618): p. 456-460. 

6) Li, S., et al., Micropatterned oriented zeolite monolayer films by direct in situ 

crystallization. Chemistry of materials, 2003. 15(14): p. 2687-2689. 

7) Li, S., Z.J. Li, and Y.S. Yan, Ultra-low-k pure-silica zeolite MFI films using cyclodextrin as 

porogen. Advanced Materials, 2003. 15(18): p. 1528. 

8) Yan, Y., S. Li, and Z. Li, Pure-Silica-Zeolite Low Dielectric Constant Films: Present and 

the Future. Zeolite News letters, 2003. 20: p. 110-119. 

9) Li, S., et al., TEM investigation of formation mechanism of monocrystal-thick b-oriented 

pure silica zeolite MFI film. Journal of the American Chemical Society, 2004. 126(34): p. 

10732-10737. 

10) Li, S., et al., Evaluation of pore structure in pure silica zeolite MFI low-k thin films using 

positronium annihilation lifetime spectroscopy. Journal of Physical Chemistry B, 2004. 

108(31): p. 11689-11692. 

11) Li, S., et al., Molecular sieving in a nanoporous b-oriented pure-silica-zeolite MFI 

monocrystal film. Journal of the American Chemical Society, 2004. 126(13): p. 4122-4123. 

12) Li, Z.J., et al., Effects of crystallinity in spin-on pure-silica-zeolite MFI low-dielectricconstant films. Advanced Functional Materials, 2004. 14(10): p. 1019-1024. 

13) Mitra, A., et al., Synthesis and evaluation of pure-silica-zeolite BEA as low dielectric 

constant material for microprocessors. Industrial & Engineering Chemistry Research, 2004. 

43(12): p. 2946-2949. 

14) Yan, Y.S. and H. Wang, Nanostructured Zeolite Films, in Encyclopedia of nanoscience and 

nanotechnology, H.S. Nalwa, Editor. 2004, American Scientific Publishers: Stevenson 

Ranch. p. 1-19. 

15) Li, Z.J., et al., Pure-silica-zeolite MEL low-k films from nanoparticle suspensions. Journal 

of Physical Chemistry B, 2005. 109(18): p. 8652-8658. 

16) McDonnell, A.M.P., et al., Hydrophilic and antimicrobial zeolite coatings for gravityindependent water separation. Advanced Functional Materials, 2005. 15(2): p. 336-340. 

17) Munoz, R.A., D. Beving, and Y.S. Yan, Hydrophilic zeolite coatings for improved heat 

transfer. Industrial & Engineering Chemistry Research, 2005. 44(12): p. 4310-4315. 

18) Beving, D.E., et al., Corrosion resistant high-silica-zeolite MFI coating - One general 

solution formulation for aluminum alloy AA-2024-T3, AA-5052-H32, AA-6061-T4, and AA7075-T6. Journal of the Electrochemical Society, 2006. 153(8): p. B325-B329. 

19) Hu, L.L., et al., Interfacial adhesion of nanoporous zeolite thin films. Journal of Materials 

Research, 2006. 21(2): p. 505-511. 
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University of California, Riverside, CE‐CERT   84 

20) Li, Y.S., et al., Microwave synthesis of LTA zeolite membranes without seeding. Journal of 

Membrane Science, 2006. 277(1-2): p. 230-239. 

21) Li, Y.S., J. Liu, and W.S. Yang, Formation mechanism of microwave synthesized LTA 

zeolite membranes. Journal of Membrane Science, 2006. 281(1-2): p. 646-657. 

22) Li, Z.J., et al., Mechanical and dielectric properties of pure-silica-zeolite low-k materials.

Angewandte Chemie-International Edition, 2006. 45(38): p. 6329-6332. 

23) O'Neill, C., et al., Durability of hydrophilic and antimicrobial zeolite coatings under water 

immersion. Aiche Journal, 2006. 52(3): p. 1157-1161. 

24) Johnson, M., et al., Mechanical characterization of zeolite low dielectric constant thin films 

by nanoindentation. Thin Solid Films, 2007. 515(6): p. 3164-3170. 

25) Cai, R., et al., Ionothermal synthesis of oriented zeolite AEL films and their application as 

corrosion-resistant coatings. Angewandte Chemie-International Edition, 2008. 47(3): p. 

525-528. 

26) Cai, R. and Y. Yan, Corrosion-resistant zeolite coatings. Corrosion, 2008. 64(3): p. 271-

278. 

Presentations

1) Beving D.; Yan Y. 2003. Corrosion Resistant Zeolite Coatings: A General Coating for 

Aluminum Alloys. The American Institute of Chemical Engineers National Meeting, 

November 3-8, San Francisco, California. 

2) Beving D.; McDonnell A.: Yan Y. 2004, Corrosion Resistant Zeolite Coatings: A General 

Coating for Aluminum Alloys, American Chemical Society 227th National Meeting, March 

28- April1, 2004, Anaheim, California. 

3) Beving D.; McDonnell A.: Yan Y. 2004, Corrosion Resistant Zeolite Coatings: A General 

Coating for Aluminum Alloys, The American Institute of Chemical Engineers National 

Meeting, November 7-12, Austin, Texas. 

4) McDonnell A. M. P.; Beving D.; Wang A.; Chen W.; Yan Y. 2005. Hydrophilic and 

antimicrobial zeolite coatings for gravity-independent water separation, Adv. Functional 

Materials, 15:336-339. 

5) O’Neill C.; Beving D.; McDonnell A.; Chen W.; Yushan Y. 2005, Hydrophilic and 

Antimicrobial Zeolite Coatings, The American Institute of Chemical Engineers National 

Meeting, October 30 - November 4, Cincinnati, Ohio. 

6) O’Neill C.; Beving D.; McDonnell A.; Chen W.; Yushan Y. 2005, Zeolite-A Coatings for 

Use in Condensing Heat Exchangers Onboard Manned Spacecraft, The American Institute 

of Chemical Engineers National Meeting, October 30 - November 4, Cincinnati, Ohio. 

7) Mao Y.; Beving D.; Munoz R.; Yushan Y. 2005, Hydrothermal Synthesis and Corrosion 

Resistance of Vanadium ZSM-5 Films, The American Institute of Chemical Engineers 

National Meeting, October 30 - November 4, Cincinnati, Ohio. 

8) Mao Y.; Beving D.; Munoz R.; Yushan Y. 2005, Hydrothermal Synthesis of Inorganic and 

Organic Nanocomposite ZSM-5 Films from Recycled Solution, The American Institute of 

Chemical Engineers National Meeting, October 30 - November 4, Cincinnati, Ohio. 

9) Munoz R.; Beving D.; Mao Y.; Yushan Y. 2005, Zeolite Y Coatings on Al-2024-T3 

Substrate by a Novel Three-Step Synthesis Method, The American Institute of Chemical 

Engineers National Meeting, October 30 - November 4, Cincinnati, Ohio. 
SERDP PP1342: Zeolite Coating System 

University of California, Riverside, CE‐CERT   85 

10) Lai Z.; Tsapatsis M.; Beving D.; Yan Y. 2005, Fabrication of Zeolite Films Using Layerby-Layer Depositions, The American Institute of Chemical Engineers National Meeting, 

October 30 - November 4, Cincinnati, Ohio. 

11) Beving D.; Anderson N.; O’Neill C.; Yan Y. 2005, Corrosion Resistant Zeolite Coatings: 

A General Coating for Aluminum Alloys, The National Association of Corrosion Engineers 

Tri-Service Corrosion Conference, November 14-18, Orlando, Florida. 

12) Beving D.; Anderson N.; O’Neill C.; Yan Y. 2005, Corrosion Resistant Zeolite Coatings: 

A General Coating for Aluminum Alloys, The Electrochemical Society National Meeting, 

October 16-21, Los Angeles, California. 

13) Beving D.; Anderson N.; O’Neill C.; Yan Y. 2006, Salt Fog Accelerated Weathering 

Testing of High-Silica-Zeolite MFI Coatings on Aluminum Alloy 2024-T3, The 

Electrochemical Society Transactions, 1(9):65-72. 

14) Guthrie S.; Beving D.; Yan Y. 2006, Zeolite Hybrid Coatings on Metal Alloys for 

Chemical Resistance, Hydrophilicity and Microbiocidal Activity, The American Institute of 

Chemical Engineers National Meeting, November 12 - 17, San Francisco, CA. 

15) O’Neill C.; Beving D.; Flores D.; Chen W.; Yan Y. 2006, Durability of Hydrophilic and 

Antimicrobial Zeolite Coatings, The American Institute of Chemical Engineers National 

Meeting, November 12 - 17, San Francisco, CA. 

16) O’Neill C.; Beving D.; Chen W.; Yan Y. 2006, Zeolite A/ZSM-5 Hybrid Coating, The 

American Institute of Chemical Engineers National Meeting, November 12 - 17, San 

Francisco, CA. 

17) O’Neill C.; Beving D.; Chen W.; Yan Y. 2006, Antimicrobial and Hydrophilic Zeolite 

Coating, The American Institute of Chemical Engineers National Meeting, November 12 - 

17, San Francisco, CA. 

18) R. Munoz, Y. Kim, D. Beving, Y. Yan 2006. High Silica Zeolite (ZSM-5) Coated 

Aluminum (Al-20204-T3): Micro-Structural Characterization by Laser Confocal 

Microscopy and Electrochemical Studies, Oral Presentation at 210th Meeting of The 

Electrochemical Society, October 29 – November 3, Cancun, Mexico. 

19) R Munoz, J Liu, G Aguilar, Y Yan 2006. Corrosion Resistant Hydrophilic Zeolite Coatings 

for Improved Heat Transfer, Poster Presentation at 210th Meeting of The Electrochemical 

Society, October 29 – November 3, Cancun, Mexico. 

20) R Cai, M Sun, Z Chen, D Beving, Y Yan, New synthesis route for corrosion resistant zeolite 

coatings, Poster Presentation at 212th ECS Meeting, October 7-12, 2007, Washington, DC, 

USA. 

21) D Beving, C O’Neill, N. Anderson, Y. Yan, Salt Fog Testing of Zeolite, Zeolite-Primer, and 

Zeolite-Primer-Topcoat Systems on AA-2024-T3, Oral Presentation at 212th ECS Meeting, 

October 7-12, 2007, Washington, DC, USA. 

22) R Beti, D Beving, Y Yan, Electronically Conductive Corrosion Resistant Zeolite Coatings 

by in-situ Crystallization, Poster Presentation at 213th ECS Meeting, May 18-22, 2008, 

Phoenix, Arizona, USA. 

 
SERDP PP1342: Zeolite Coating System 

University of California, Riverside, CE‐CERT   86 

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