## SUPPLEMENTAL REPORT



# O PTIMIZ ED 

# D EPOSITION 

# P ARAMETERS 

# & C OATING



# P ROPERTIES OF 

# C OBALT 

# P HOSPHORUS 

# A LLOY



# E LECTROP LATING FOR 

# T ECHNOLOGY 

# I NSERTION 

# R ISK



# R EDUCTION

( ESTCP Project WP

- 0411 )

Ruben Prado & John Benfer

Naval Air Systems Command

Diana Fa cchini

Integran Technologies, Inc.

Keith Legg

Rowan Technology Group



## October 2010

Final Version

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Standard Form 298 (Re . 8-98) v

Prescribed by ANSI Std. Z39.18WP-0411 Supplemental Report2August2009 

### Table of Contents

1.0 Introduction

................................ ................................ ................................ ............ 1

1.1 Background

................................ ................................ ................................ ........ 1

1.2 Objectives

................................ ................................ ................................ .......... 1

2.0 Process Window

................................ ................................ ................................ .... 2

2. 1 Methods

................................ ................................ ................................ ............. 2

2.2 Results

– Exploratory DOE

................................ ................................ ................ 6

2.3 Results

– Optimization DOE

................................ ................................ ............. 11

3.0 Data acquisition

................................ ................................ ................................ ... 17

3.1 Methods

................................ ................................ ................................ ........... 17

3.2 Results

................................ ................................ ................................ ............. 18

3.3 Summary and discussion

................................ ................................ ................. 24

4.0 Producibility

................................ ................................ ................................ ......... 25

4.1 Inner Diameter plating demonstration

................................ .............................. 25

4.2 Outer Diameter plating demonstration

................................ ............................. 28

5.0 Cost Benefit Analysis

................................ ................................ ........................... 31

5.1 Background

................................ ................................ ................................ ...... 31

5.2 Assumptions

................................ ................................ ................................ ..... 31

5.3 Cost

- Benefit Analysis for FRC

- SE

................................ ................................ .... 36

5.4 Opt imum Method of Adoption

................................ ................................ ........... 41

6.0 Conclusion

................................ ................................ ................................ ........... 42

7.0 Summary

................................ ................................ ................................ ............. 43

8.0 Appendix: Rod & Seal Test

................................ ................................ ................. 46

8.1 Hydraulic Seal and Piston Rod Coating Evaluation of nCoP

............................ 46WP

- 0411 Supplemental Report 1 October 2010WP-0411 Supplemental Report1August2009 

### 1.0 INTRODUCTION

1.1 BACKGROUND

At the conclusion of SERDP program ( PP

- 1 152 ) to develop Nanocrystalline Cobalt

Phosphoru s Alloy Plating ( nCo

- P ) as an alternative to hard chrome plating for IDs, the

coating exhibited good wear and corrosion resistance, with no hydrogen embrittlement

(even without heat treating) and a fatigue de bit similar to that of hard chrom ium

electroplate (EHC)

.

At the beginning of the ESTCP program (WP

- 0411) the deposition conditions were

adjusted to make the coating coverage more uniform between the edges and center of

flat specimens (i.e. more uniform as a function of current density). After a considerable

amount of development and testing both at Integran Technologies Inc. and at NAVAIR

Jacksonville , the team had resolved most of the se issues

.

Subsequent hydrogen embrittlement testing of samples perfor med with new deposition

conditions resulted in a coating that was embrittling to high strength steel substrates

with or without embrittlement relief baking . Furthermore, the fatigue data set generated

with the above deposition conditions was rejected due t o invalid failure locations in the

samples.

1.2 OBJECTIVES

The goals of this study were to define and optimize the process window for producing a

high quality non

- embrittling coating and to also perform a rapid fatigue analysis

screening via rotating beam te st protocol. In pursuit of these objectives, the following

tasks were performed :

**•** Process W indow D efinition and plating parameter optimization using a design of

experiments approach

**•** Data A cquisition using the optimized plating parameters

**•** Producibility Ev aluation using the optimized plating parameters

**•** Cost Benefit Analysis using the optimized plating parametersWP

- 0411 Supplemental Report 2 October 2010WP-0411 Supplemental Report2August2009 

### 2.0 PROCESS WINDOW

2.1 METHODS

2.1.1 Design of Experiments

The process window was determined using a standard Design of Experiment ( DOE )

approach. Input vari ables were current density, pulse frequency and duty cycle. The

plating bath was operated as specified by the Technical Data Sheet by Integran

Technologies Inc. which includes optimized ranges for plating parameters and resulting

material properties. Two e xperiments were conducted:

1. Exploratory DOE: The exploratory DOE was designed to define the initial

operating window and the effects of operating variables on deposit properties.

Here, a 2 3 full factorial design with a centerpoint was used , as shown in **Table 1** 

. (high=1, low=

- 1, center pt=0)

2. Optimized DOE: Following the exploratory DOE, the optimized DOE was

designed to downselect the final plating parameters for data acquisition,

producibility and cost

- benefit task s

. Here, a L8 m ixed 2

- 4 level design was used,

as shown in **Table 2** 

. (For CD: low=1, mid

- low=2, mid

- high=3, high=4. For Frequency: low=0, high=1.

For Duty Cycle: high=0, low=1)

**TABLE 1** 

**EXPLO RATORY DOE INPUT VAR**  **IABLES**

**. Coded Variables** 

Current

Density Frequency Duty Cycle

1 1 1

1 1

- 1

1

- 1 1

1

- 1

- 1

- 1 1 1

- 1 1

- 1

- 1

- 1 1

- 1

- 1

- 1

0 0 0WP

- 0411 Supplemental Report 3 October 2010WP-0411 Supplemental Report3August2009 **TABLE 2** 

**OPTIMIZED DOE INPUT VARIABLES** 

**. Coded Variables** 

Current

Density Frequency Duty Cycle

1 0 0

2 0 0

3 0 0

4 0 0

1 1 1

2 1 1

3 1 1

4 1 1

The output varia bles are described in detail below. They included appearance,

composition and microstructure, adhesion, current efficiency

, thickness, hardness,

internal stress , and hydrogen embrittlement. Experimental design and data analysis was

performed with the aid of Minitab statistical software.

2.1.2 Sample Preparation

Three types of coupons were prepared using the plating conditions defined in **Table 1**  &

**Table 2**  for use in subsequent tests

. **Figure 1**  illustrates coupon types as described

below:

a) Flat Coupons: 1”x4” ASTM A36 ( similar to AISI 1018/ mild s teel) c oupons coated

on one side with 0.010” in thickness nCo

- P

.

b) Stress S trips: thin copper strips with two legs that are epoxy coated on opposing

sides. When opposing sides of legs are plated, the legs deflect under the stress

of the coating.

c) Hydrogen embrittlement bars: ASTM F519, Type 1a1 bars, coated on a 1”

section centered on the gage (i

. e. 0.5” above/below gage) with 0.003” in

thickness nCo

- P. Four bars per plating condition. Hydrogen relief baking was not

performed on the Exploratory DOE samples. F or the Optimized DOE samples, a

hydrogen relief bake at 375oF for 24 h r was applied within 1 h r of plating

.WP

- 0411 Supplemental Report 4 October 2010WP-0411 Supplemental Report4August2009

(a ) (b) (c)

**FIGURE 1** 

**. IMAGES OF TEST COUPO**  **NS, INCLUDING (A) FL AT COUPONS** 

**, (B)** 

**STRESS STRIPS AND (C ) HYDRO**  **GEN EMBRITTLEMENT BA RS.** 

2.1.3 Appearance

Flat coupons were visually examined for coating uniformity, nodules, dendrites, pits,

pores, cracks and other defects.

2.1.4 Composition and Microstructure

Composition and microstructure evaluations were conducted on the fl at coupons. The

composition of the deposits was determined using Energy Dispersion Spectroscopy

(EDS). The crystal structure and grain size of the coatings was characterized using X

ray diffraction (XRD) techniques

. A specific coating composition was not t argeted.

Rather, the composition was monitored to verify that there were no detrimental effects

due to the changes in the operating conditions.

2.1.5 Adhesion

Adhesion testing was conducted on the flat coupons per ASTM B571 (“Standard

Practice for Qualitative Adhesion Testing of Metallic Coatings”). C oupons were bent

repeatedly, back and forth, through an angle of 180° until failure of the basis metal

occurred. The fractured region was then examined at low magnification for separation or

peeling of the coating. Attempts were then made to pry the coating with a sharp blade to

assess whether there was any lift off of the coating which would indicate unsatisfactory

adhesion.

2.1.6 Current Efficiency and Thickness

Plating efficiency and thickness were evaluated on the f lat coupons. The plating

efficiency was calculated for each of the samples by recording the mass of the sample

before and after plating to obtain the total mass of the coating. T he theoretical mass

, m t , was calculated using Faraday’s Law:WP

- 0411 Supplemental Report 5 October 2010WP-0411 Supplemental Report5August2009

F t i A

n M

m Co

t **⋅ ⋅**  **⋅**

**=** (1)

where:

M Co is the atomic mass of cobalt

n is the valence of cobalt

A is the plating area

i is the current density

t is the plating time

F is Faraday’s constant

The cathode current efficiency, CCE, was then calculated by:

t a

m m CCE

**=** (2)

where:

m a is the measured coating mass

Coating thickness was determined by calculating the difference in thickness of the flat

coupons before and after plating, as measured with a micrometer.

Throwing power was not explicitly evaluated as part of the DOE, however

, it was

assessed as part of the producibility evaluation using the down selected plating

parameters.

2.1.7 Hardness

Hardness was evaluated on metallographically prepared cross

- sections of the flat

coupons. The microhardness of the co atings was determined using a Vickers Indenter

with a 100 g load.

2.1.8 Internal Stress

Internal stress was evaluated on the stress strips. The deflection of the strips was

measured using a deposit stress analyzer. This was t hen used to calculate the internal

stress , S, according to :

K

W UD S

3 **=** (3)

w here:

U is the measured deflection of the strips

D is the coating density

W is the coating weight

K is the strip calibration constantWP

- 0411 Supplemental Report 6 October 2010WP-0411 Supplemental Report6August2009 2.1.9 Hydrogen embrittlement

Hydrogen embrittlement testing was conducted in accordance with ASTM F519

(“Standard Test Method for Mechanical Hydrogen Embrittlement Evaluation of

Plating/Coating Processes and Service Environments”)

. H ydrogen embrittlement bars

were subjected to a sustained tensile load of 75% of the no tch fracture strength (NFS)

until (a) failure or (b) 200 h r had elapsed

. For the Exploratory DOE only, s amples

sustaining 200 h r loading were then step

- loaded in increments of 5% NFS per hour until

failure. Results were therefore expressed in time to failu re or % NFS

.

The exploratory DOE for hydrogen embrittlement testing was utilized as a screening tool

to identify near

- optimized plating ranges. Step

- load increases were performed on

coupon sets that passed the hydrogen embrittlement criteria to increase the fidelity of

the obtained data. The hydrogen embrittlement testing conducted as a part of the

follow

- on optimization DOE was intended to confirm that the selected optimized plating

conditions satisfied HE pass/fail criteria

.

2.2 RESULTS

– EXPLORATORY DOE

2.2.1 Appearance

Results of the appearance evaluations are summarized in **Table 3**  . Uniformly smooth

and shiny deposits were produced at all plating conditions tested. However, the

severity of edge dendrites varied with plating conditions. **Table 3**  ranks the samples in

order of the severity of edge dendrites observed. The current density was found to

have the most significant effects on edge dendrites, followed by duty cycle, then

frequency. The most severe edge dendrites were produced with high current density,

low duty cycle and low frequency.WP

- 0411 Supplemental Report 6 October 2010WP-0411 Supplemental Report6August2009 **TABLE 3** 

**RESULTS OF APPEARANC E EVALUATIONS** 

**. Factors**  **Responses**

Current

Density Frequency Duty

Cycle Rank 1 Ima ges

1

- 1

- 1 1

1 1

- 1 2

1

- 1 1 3

1 1 1 4

0 0 0 5WP

- 0411 Supplemental Report 7 October 2010WP-0411 Supplemental Report7August2009 **TABLE 3** ( continued )

RESULTS OF APPEARANCE EVALUATIONS

1 Rank: most severe edge dendrites to least severe edge dendrites

. **Factors Responses** 

Current

Density Frequency Duty

Cycle Rank 1 Images

- 1

- 1

- 1 6

- 1 1

- 1 7

- 1

- 1 1 8

- 1 1 1 9WP

- 0411 Supplemental Report 8 October 2010WP-0411 Supplemental Report8August2009 2.2.2 Composition and Microstructure

The results of the composition and microstructure testing are summarized in **Table 4** 

. Statistical eva luations of the data indicate that the deposit phosphorus content

increases with decreasing current density, but does not vary with frequency or duty

cycle in the ranges evaluated.

All deposits were found to be nanocrystalline, with a hexagonally close p acked grain

structure. Neither the grain size nor the microstructure was found to vary with current

density, frequency or duty cycle in the ranges evaluated.

**TABLE 4** 

**RESULTS OF COMPOSITI ON AND MICROSTRUCTUR**  **E EVALUATIONS**

**. Factors**  **Responses**

Current

Density Frequency Duty

Cycle Composition

(wt%P) Grain

size

(nm) Microstructure

1 1 1 1.2 ±0.1 6 Nanocrystalline

1 1

- 1 1.1 ±0.2 5 Nanocrystalline

1

- 1 1 1.1 ±0.1 5 Nanocrystalline

1

- 1

- 1 1.1 ±0.1 5 Nanocrystalline

- 1 1 1 1.4 ±0.1 8 N anocrystalline

- 1 1

- 1 1.5 ±0.1 8 Nanocrystalline

- 1

- 1 1 1.3 ±0.1 8 Nanocrystalline

- 1

- 1

- 1 1.4 ±0.1 8 Nanocrystalline

0 0 0 1.2 ±0.1 6 Nanocrystalline

2.2.3 Adhesion

The results of the adhesion testing are summarized in **Table 5**  . Two failures were

observed, however these did not correlate with any of the operating conditions.

Therefore, it is suspected that activation process rather than the plating process was

responsible for the adhesion failures. The activation p rocess is an immersion for 3

minutes in an acid dip. It is susceptible to contamination

.WP

- 0411 Supplemental Report 9 October 2010WP-0411 Supplemental Report9August2009 **TABLE 5** 

**RESULTS OF ADHESION EVALUATION** 

**. Factors**  **Responses**

Current

Density Frequency Duty

Cycle Adhesion

(Pass/Fail)

1 1 1 Pass

1 1

- 1 Pa ss

1

- 1 1 Pass

1

- 1

- 1 Fail

- 1 1 1 Pass

- 1 1

- 1 Pass

- 1

- 1 1 Fail

- 1

- 1

- 1 Pass

0 0 0 Pass

2.2.4 Current Efficiency and Thickness

The results of the current efficiency and thickness testing are summarized in **Tab le**  **6**

. Statistical evaluations of the data indicate that current efficiency does not vary with

current density, frequency or duty cycle in the ranges evaluated. Thickness was found

to decrease with decreasing current density (for the same plating time) but did not vary

with frequency or duty cycle in the ranges evaluated. The thickness distribution was

found to vary with duty cycle, with lower duty cycles resulting in increased edge buildup.

**TABLE 6** 

**RESULTS OF CURRENT E FFICIENCY A**  **ND THICKNESS EVALUAT IONS** 

**. Factors**  **Responses**

Current

Density Frequency Duty

Cycle Thickness

(thou) Current

Efficiency

(%)

1 1 1 11.4 80

1 1

- 1 7.2 73

1

- 1 1 12.4 90

1

- 1

- 1 7.2 85

- 1 1 1 8.0 81

- 1 1

- 1 8.6 83

- 1

- 1 1 9.1 86

- 1

- 1

- 1 7.4 77

0 0 0 12.2 84WP

- 0411 Supplemental Report 10 October 2010WP-0411 Supplemental Report10August2009 2.2.5 Hardness

The results of the hardness testing are summarized in **Table 7**  . Statistical evaluations of

the data indicate that hardness increases with decreasing current density, but does not

vary with fr equency or duty cycle in the ranges evaluated.

**TABLE 7** 

**RESULTS OF HARDNESS EVALUATION** 

**. Factors**  **Responses**

Current

Density Frequency Duty

Cycle Hardness

(VHN)

1 1 1 506

1 1

- 1 499

1

- 1 1 515

1

- 1

- 1 528

- 1 1 1 534

- 1 1

- 1 537

- 1

- 1 1 536

- 1

- 1

- 1 546

0 0 0 515

2.2.6 Internal Stress

The results of the internal stress testing are summarized in **Table 8** 

**.** A tensile residual

stress was observed for all plating conditions evaluated. Statistic al evaluations of the

data indicate that residual stress does not vary with current density, frequency or duty

cycle in the ranges evaluated.

**TABLE 8** 

**RESULTS OF RESIDUAL STRESS EVALUATIO**  **N**

**. Factors**  **Responses**

Current

Density Frequ ency Duty

Cycle Residual

stress

(ksi)

1 1 1 13.6

1 1

- 1 13.5

1

- 1 1 13.3

1

- 1

- 1 12.0

- 1 1 1 14.6

- 1 1

- 1 12.2

- 1

- 1 1 15.2

- 1

- 1

- 1 13.8

0 0 0 14.2WP

- 0411 Supplemental Report 11 October 2010WP-0411 Supplemental Report11August2009 2.2.7 Hydrogen embrittlement

The results of the hydrogen embrittlement testing are summarized in **Table 9**  . Results

are shown as time to failure (hours) for bars that failed prior to the 200 h r threshold, or

as %NFS at failure for bars that surpassed the 200 h r threshold and were subsequently

step

- loaded.

Despite having not been baked for hydrogen embrittlement relief after the coating was

applied, over 50% of the samples tested were able to sustain the 75% NFS load for 200

h r

. Statistical evaluations of the data indicate that hydrogen embrittlement does not vary

w ith current density, frequency or duty cycle in the ranges evaluated.

**TABLE 9** 

**RESULTS OF HYDROGEN EMBRITTLEMENT EVALUA**  **TION**

**. Factors**  **Responses**

Current

Density Frequency Duty

Cycle Hydrogen Embrittlement

(hours to failure or % NF S)

Bar 1 Bar 2 Bar 3 Bar 4

1 1 1 40 121 193 193.1

1 1

- 1 85% 100% 100% 100%

1

- 1 1 49 57 58 80%

1

- 1

- 1 85% 90% 90% 100%

- 1 1 1 136 193 200 80%

- 1 1

- 1 80 80 121 193

- 1

- 1 1 85% 100% 100% 100%

- 1

- 1

- 1 85% 90% 100% 100%

0 0 0 80 123 137 80%

2.2.8 Summary and Conclusions

Several properties were found to be independent of the plating parameters, including:

current efficiency, hydrogen embrittlement, internal stress, adhesion and microstructure.

Composition and hardness were found to vary with curren t density. Severity of edge

dendrites were found to vary with all parameters evaluated.

For further evaluation in the optimization DOE, four current densities were selected with

two pulsing conditions as input variables. The output variables remained unc hanged.

2.3 RESULTS

– O PTIMIZATION DOE

2.3.1 Appearance

Results of the appearance evaluation are shown in **Table 10** 

. Deposits were found to be

generally uniform ly smooth and shiny , however s urface nodules formed at low cur rent

density for both pulse conditions . These were found to be l ess severe at the lower duty

cycle. As was previously observed, the severity of the e dge dendrites increased with

increasing current density . The edge dendrites were the most severe for the low dutyWP

- 0411 Supplemental Report 12 October 2010WP-0411 Supplemental Report12August2009 cycle/high frequency condition. These results are consistent with those previously

obtained for the Exploratory DOE.

**TABLE 10** 

**RESULTS OF THE APPEA RANCE EVALUATION** 

**. Current** 

**Density Pulse Condition** 

0 1

1

2

3

4

2.3.2 Composition and Microstructure

The results of the composition and microstructure testing are summarized in **Table 11** 

. Statistical analysis of the results indicate that the deposit phosphorus content in creases

with decreasing current density, but does not vary with pulse conditions.

All samples were found to be nanocrystalline , with a hexagonally close

- packed

microstructure. Statistical analysis of the results indicates that the grain size and

microstr ucture do not vary with current density or pulse conditions. Results obtained

here for the composition and microstructure are consistent with the trends observed for

the Exploratory DOE.WP

- 0411 Supplemental Report 13 October 2010WP-0411 Supplemental Report13August2009 **TABLE 11** 

**RESULTS OF THE COMPO SITION AND M**  **ICROSTRUCTURE EVALUA TIONS** 

**. Factors**  **Responses**

Current

Density Frequency Duty

Cycle Composition

(wt%P) Grain

size

(nm) Microstructure

1 0 0 1.9 ±0.1 15 Nanocrystalline

2 0 0 1.9 ±0.1 11 Nanocrystalline

3 0 0 1.9 ±0.2 8 Nanocrystalline

4 0 0 1.6 ±0.1 8 Nanoc rystalline

1 1 1 2.1 ±0.1 12 Nanocrystalline

2 1 1 1.9 ±0.1 11 Nanocrystalline

3 1 1 1.9 ±0.2 10 Nanocrystalline

4 1 1 1.8 ±0.1 8 Nanocrystalline

2.3.3 Adhesion

The results of the adhesion testing are summarized in **Tab le**  **12**

. Two failures were

observed, however these did not correlate with any of the operating conditions.

Therefore, it is suspected that the activation process (i

. e. inadequate surface

preparation due to operator error) rather than the plating process was responsible for

the adhesion failures.

**TABLE 12** 

**RESULTS OF THE ADHES ION EVALUATION** 

**. Factors**  **Responses**

Current

Density Frequency Duty

Cycle Adhesion

(pass/fail)

1 0 0 Fail

2 0 0 Pass

3 0 0 Pass

4 0 0 Fail

1 1 1 Pass

2 1 1 P ass

3 1 1 Pass

4 1 1 Pass

2.3.4 Current Efficiency and Thickness

The results of the current efficiency and thickness testing are summarized in **Table 13** 

. Statistical evaluations of the data indicate that current eff iciency does not vary with

current density, frequency or duty cycle in the ranges evaluated. Thickness was found

to decrease with decreasing current density (for the same plating time) but did not vary

with frequency or duty cycle in the ranges evaluated. These results are consistent with

the trends observed for the Exploratory DOE.WP

- 0411 Supplemental Report 14 October 2010WP-0411 Supplemental Report14August2009 **TABLE 13** 

**RESULTS OF THE CURRE NT EFFICIENCY AND TH**  **ICKNESS EVALUATIONS**

**.**

**Factors Responses** 

Current Density Frequency Duty

Cycle Thickness

(thou) Current

Efficiency

(%)

1 0 0 10.6 90

2 0 0 9.2 89

3 0 0 9.7 90

4 0 0 10.2 87

1 1 1 12.1 89

2 1 1 9.0 89

3 1 1 10.9 86

4 1 1 10.0 90

2.3.5 Hardness

The results of the hardness testing are summarized in **Table 14**  . Stat istical analysis of

the results indicates that the hardness increases with decreasing current density, but

does not vary with pulse conditions. These results are consistent with the trends

observed for the Exploratory DOE.

**TABLE 14** 

**RESULTS OF THE HARDN ESS EVALUATION** 

**. Factors**  **Responses**

Current Density Frequency Duty

Cycle Hardness

(VHN)

1 0 0 591

2 0 0 574

3 0 0 560

4 0 0 547

1 1 1 586

2 1 1 567

3 1 1 557

4 1 1 549

2.3.6 Hydrogen Embrittlement

Property evaluations revealed t hat only the edge dendrite severity varied with the

pulsing conditions, and that the low duty cycle condition was preferred to minimize their

severity. Mid

- range current densities were preferred to increase the hardness and

maintain a uniformly smooth and shiny appearance.WP

- 0411 Supplemental Report 15 October 2010WP-0411 Supplemental Report15August2009 As a final screening, hydrogen embrittlement testing was conducted on samples

produced using the low duty cycle condition at current densities of mid

- low, mid

- high

and high

. Within 1 h r of plating, test samples were baked at 375oF for 2 4 h r

. Hydrogen

embrittlement testing was then conducted per the methods described in Section 2.1.9

. All samples were found to sustain the 75% NFS load for 200 h r , indicating that the

coating s passe d hydrogen em brittlement testing.

2.3.7 Summary and C onclusion s

The final downselected plating parameters were a duty cycle and frequency of low and

a current density of mid

- high

.WP

- 0411 Supplement al Report 17 October 2010WP-0411 Supplemental Report17August2009 

### 3.0 DATA ACQUISITION

Once the process window had been established , additional data were obt ained with the

new optimized deposition conditions.

3.1 METHODS

3.1.1 Microstructure and stress

Microstructure and stress were evaluated per the methods described in Section 2.1.4

and Section 2.1.8 , respectively.

3.1.2 Adhesion

Adhesion was evaluated per the methods described in Section 2.1.5

.

3.1.3 Porosity Test

Flat coupons were cross

- sectioned and examined using optical and scanning ele ctron

microscopes for signs of voids and porosity.

3.1.4 Hydrogen Embrittlement

Hydrogen embrittlement testing was conducted per the methods described in Section

2.1.9 . Within 1 h r of plating, test samples were bak ed at 375oF for 24 h r

. In an industrial

setting, baking could occur up to 4 hrs prior to plating, provided the part is not subjected

to stresses.

3.1.5 Corrosion

Corrosion testing was conducted in accordance with ASTM B117 (“Standard Practice

for Operating Sal t Spray (Fog) Apparatus”). Two m ild steel coupons ( 4”x4” ) were coated

on one side with 0.003” nCo

- P at Integran Technologies Inc. and two mild steel coupons

(4”x4”) were coated with 0.003” EHC at FRC

- SE. The backs and sides of the coupons

were masked to p revent uncoated steel from being exposed to the test. Samples were

left in the as deposit condition and subject ed to salt spray testing for 165 hrs. Following

testing, samples were visually examined for signs of red rust. The surface composition

of the sa mples was also evaluated by μ

- EDXRF for the presence of iron.

3.1.6 Fatigue

Fatigue testing consisted of r otating beam fatigue in lieu of axial fatigue testing as

defined the whitepaper proposal to minimize cost and to improve the turnaround time of

the fatig ue data. Fatigue testing was conducted on bare, nCo

- P

- coated and EHC

coated test samples. Test samples were 4340 steel (260

- 280 ksi) hourglass bars as

shown in **Figure 2** 

, and their surfaces were unpeened. The unpe ened condition wasWP

- 0411 Supplement al Report 18 October 2010WP-0411 Supplemental Report18August2009 motivated in order to meet NAVAIR approval requirements and to better understand the

fatigue sensitivity of the coating without introducing additional external variables

. Twenty

specimens were coated with 0.006” nCo

- P at Integran Technol ogies Inc. , twenty were

coated with 0.006” EHC at FRC

- SE, and twenty remained bare. Coatings were ground

to 0.003” using low

- stress grinding techniques, and were longitudinally polished to a 16

μinch Ra finish.

**FIGURE 2** 

**. ROTATI**  **NG BEAM FATIGUE BAR GEOMETRY.** 

Rotating beam fatigue testing was conducted in laboratory air at ambient temperature.

Loads were spread between 85% of tensile yield strength ( Fty ) and the runout load (10 7

cycles), with no more than four points per load. L oad and cycles to failure were used to

generate S

- N curves for bare, nCo

- P

- coated and EHC

- coated specimens.

3.1.7 Immersion testing

Fluid compatibility wa s not expected to change significantly, as the deposit

microstructure and composition has not changed sign ificantly. The optional fluid

immersion testing w as therefore not conducted in this study. It was expected to be

revisited during the next stage of the program

.

3.1.8 Wear and hardness testing

Hardness was evaluated per the methods described in Section 2.1.7

.

Abrasive wear resistance s of the nCo

- P and EHC baseline were evaluated by Taber

wear testing in accordance with ASTM D 4060 (“Standard Test Method for Abrasion

Resistance of Organic Coatings by the Taber Abraser ”)

. Flat mild steel coupons (4”x4”)

were coated with 0.002” nCo

- P at Integran Technologies Inc. or 0.002” at FRC

- SE.

Testing was conducted using CS

- 17 wheels at FRC

- SE.

3.2 RESULTS

3.2.1 Microstructure and stress

**Figure 3**  shows a portion of the X

- ray diffraction pattern for the nCo

- P deposit. The

d eposit was found to be nanocrystalline, with the HCP crystal structure typically found in

cobalt, and an average grain size of 8 nm

.WP

- 0411 Supplement al Report 19 October 2010WP-0411 Supplemental Report19August2009

**FIGURE 3** 

**. PORT**  **ION OF THE X**

**- RAY DIFFRACTION PATT**  **ERN FOR NCO**

**- P** 

**DEPOSIT PRODUCED WIT H THE OPTIMIZED PLAT**  **ING CONDITIONS.**

Deposit stress was found to be 10

- 15ksi tensile

.

3.2.2 Adhesion

As shown in **Figure 4.** , e xamination of the fracture d surface revealed n o signs of

coating delamination or flaking, indicating that the sample passes adhesion testing.

**FIGURE 4** 

**. IMAGE OF THE FRACTUR**  **E SURFACE FOLLOWING BENDING.** 

3.2.3 Porosity Test

As shown in **Figure 5**  examination of the coating cross

- section revealed n o sign s of

cracks pores or voids , indicating that the sa mple is free of gross porosity. This is in

contrast to EHC, which exhibits microcracking.WP

- 0411 Supplement al Report 20 October 2010WP-0411 Supplemental Report20August2009

**FIGURE 5** 

**. OPTICAL MICROGRAPH O**  **F THE CROSS**

**- SECTION OF THE NCO** 

**- P** 

**DEPOSIT USING**  **NITAL ETCHANT.**

3.2.4 Hydrogen Embrittlement

No failures were noted after 200 h at the sustained load of 75% NFS, indicating that the

coating passes hydrogen embrittlement. This behavi or is similar to that of EHC, which is

known to pass hydrogen embrittlement testing when a similar bakeout is performed

following plating.

3.2.5 Corrosion

As shown in **Figure 6**  **a** , examination of the EHC

- coated panels fol lowing 165 h salt fog

exposure reveals an orange/brown discoloration across the entire panel. Surface

composition analysis reveals the presence of iron and chromium, as shown by the μ

EDXRF spectra in **Figure 6**  **a** in dicating that red rust has formed. By contrast, the

nCoP

- coated panels following salt fog exposure exhibit a golden brown discoloration.

Surface composition analysis reveals the presence of cobalt, but with no iron as shown

by the μ

- EDXRF spectra in **Figure 6**  **b** in dicating the absence of red rust but likely a

surface oxide. These results indicate that nCo

- P exhibits superior corrosion resistance

to EHC. nCo

- P SubstrateWP

- 0411 Supplement al Report 21 October 2010WP-0411 Supplemental Report21August2009

(a)

(b)

**FIGURE 6** 

**. IMAGES AND**  **μ**

**- EDXRF SPECTRA FOR TH**  **E SURFACES OF (**  **A**

**)**

**EHC**

**- COATED AND (B) NCO** 

**- P** 

**- COATED MILD STEEL FO**  **LLOWING 165H**

**SALT FOG EXPOSURE.**

3.2.6 Fatigue

As shown in **Figure 7**  below, fatigue data shows a signifi cant fatigue debit for EHC

coating compared to bare material. In comparison, the nCo

- P coating shows a fatigue

life similar to the bare material at lower loads

. At lower applied loads there appears to

be a debit compared to bare, however, this is not nea rly as severe as the debit exhibited

by the EHC coated material. Therefore, nCo

- P exhibits significantly enhanced fatigue

performance compared to EHC. Substrate

Corrosion

Coating

OxidationWP

- 0411 Supplement al Report 22 October 2010WP-0411 Supplemental Report22August2009

**FIGURE 7** 

**. ROTATING BEAM FATIGU**  **E RESULTS SHOWN AS AN**  **S**

**- N CURVE.** 

3.2.7 Wear and ha rdness testing

The mic r oh ardness was found to be 560 VHN as

- deposited

. The results indicate that

nCo

- P has lower hardness than EHC.

The results of the Taber Wear test are shown in **Table 15**  . The Taber Wear Index w as

found to be 17 .23 mg/10 0 0 cycles for nCoP, and 4 .15 mg/1000 cycles for EHC,

indicating that EHC has super ior abrasive wear performance to nCo

- P.WP

- 0411 Supplement al Report 23 October 2010WP-0411 Supplemental Report23August2009 **TABLE 15** 

**TABER WEAR TEST RESU LTS FOR NCO** 

**- P & EHC COUPONS.** 

**Cycles Weight (g)** 

**nCo**

**- P Coupon** 

**#3RZ2057 nCo** 

**- P Coupon** 

**#4LZ2056 Cr Coupon** 

**#3L Cr Coupon** 

**#4R**

0 128.7596 131.1900 118.1269 121.4091

1000 128.7399 131.1713 118.1206 121.4052

2000 128.7218 131.1539 118.1167 121.3975

3000 128.7047 131.1367 118.1143 121.3938

4000 128.6855 131.1 219 118.1068 121.3906

5000 128.6684 131.1034 118.1051 121.3869

6000 128.6525 131.0859 118.1015 121.3819

7000 128.6346 131.0704 118.0977 121.3777

8000 128.6175 131.0545 118.0951 121.3727

9000 128.6016 131.0378 118.0873 121.3726

10000 128.5850 131.0200 118.0865 121.3666

Total Wt Loss

(mg/1000 cycles) 17.46 17.0 4.04 4.25WP

- 0411 Supplement al Report 24 October 2010WP-0411 Supplemental Report24August2009

3.3 S UMMARY AND DISCUSSIO N

**Type of**

**Performance**

**Objective Primary** 

**Performance**

**Criteria Expected Performance** 

**(Metric) Result**  **Actual**

**Performance**

**Objective Met?**

Quantitative Internal Str ess No specific requirement. 10

- 15 ksi

-

Quantitative Microstructure Microstructure includes items such as

grain size and crystal structure. For

nCo

- P coatings, grain size shall be

less than 100 nm and crystal structure

shall be HCP. Nanocrystalline

(8 n m grain

size), hexagonal

close

- packed

structure Yes

Quantitative Microhardness Microhardness of as

- deposited

coatings shall be no less than 650

VHN. Microhardness shall be capable

of being controlled through heat

treatment up to 800 VHN. 560 VHN (as

depo sited) No

Qualitative Porosity Coatings shall be free of pits, pores

and microcracks when observed

microscopically. No cracks,

pores or voids Yes

Quantitative Fatigue Low

- cycle and high

- cycle rotating

beam fatigue testing shall be

conducted for nCo

- P coa tings of

0.003” thickness on 4340 steel

substrates heat treated to 260

- 280 ksi.

Cycles

- to

- failure at different stress

levels shall be determined and

standard S/N curves shall be

generated. The S/N curves for the

nCo

- P coatings shall lie on or above

those for EHC coatings. Credit vs. EHC.

Comparable to

bare at LCF,

debit compared

to bare at HCF. Yes

Quantitative Wear Abrasive wear tests shall be conducted

using the Taber wear test apparatus in

accordance with ASTM D4060 using a

CS

- 17 wheel . The wear rat e of the

nCo

- P coating shall be less than or

equal to EHC. 17.23 mg/1000

cycles No

Quantitative Corrosion In salt

- fog corrosion tests, time until

observing corrosion product for nCo

- P

coatings should be less or equal to

time for EHC coatings (ASTM B117). No red rust after

165 h Yes

Quantitative Hydrogen

embrittlement A coating thickness of 0.003” of nCo

- P

shall be deposited onto ultra

- high

strength steel Type 1a1 ASTM F519

specimens. Specimens loaded to 75%

of notch tensile stress must pass 200

hour test (after a hydrogen bake) Passed 200 h

sustained load Yes

Qualitative Adhesion No spalling or delamination of the

coating from the substrate when tested

in accordance with ASTM B571. No delamination

or flaking YesWP

- 0411 Supplement al Report 25 October 2010WP-0411 Supplemental Report25August2009 

### 4.0 PRODUCIBILITY

Producibility testing was conducted by Integran Technologies Inc. using the optimized

plating conditions due to hardware failures at FRC

- SE

. Components were provided by

FRC

- SE. The coating was applied to both internal diameter sections and outer diameter

sections as described bel ow.

4.1 I NNER D IAMETER PLATING DEMONSTRATIO N

4.1.1 Component Description

The d emonstration piece for internal diameter plating was a J52 coupling, as shown in

**Figure 8**  . This part was 4340 steel and required plating on a small 1” wide band on t he

inner diameter of the part.

**FIGURE 8** 

**. J52 COUPLING USED FO**  **R THE INNER DIAMETER PLATING** 

**DEMONSTRATION.**

4.1.2 Methods/Setup

A process flow chart shown in **Figure 9**  s ummarizes the operations completed in

preparing the demonstration part for plating. The demonstration part as

- received did

not require stripping of previous coatings on the desired plating area.

In order to mask the part for plating, several methods of m asking were employed. First,

the plating area was covered using generic black tape. Next

, holes found on the bottom

of the part were plugged with plastic plugs. Plugs were trimmed in order to facilitate

application of maskants. Electroplating tape was u sed to mask the remaining holes on

the surface. Enthone Stop

- Off #1 was then applied by brushing and dipping and allowed

to cure. Once the part was sufficiently masked, the plating area was uncovered by

removing the black tape.WP

- 0411 Supplement al Report 26 October 2010WP-0411 Supplemental Report26August2009 The area to be plated was t hen alconox scrubbed using a Scotch Brite pad. Use of

higher mesh pads is recommended in order to reduce appearance of scratches in the

final deposit. Next the part was attached to the plating rack. After checking for

electrical continuity, the part was then immersed in the alkaline cleaning solution. It was

then electrocleaned for 3 minutes at a current density of 50 mA/cm 2 followed by a

rinsing step

. The part was then activated using a mineral acid (5% HF/30% Sulfuric

Acid) for 1 minute at an anodic current density of 300 mA/cm 2 (live entry)

. Following

activation, the part was rinsed , and then plated with nCoP with the optimized pulse

condition identified in Section 2.0

. A flow eductor was attached in orde r to facilitate flow

at the plating area. Following plating, t he part was removed and rinsed. The part was

then de

- racked, and manually de

- masked.

**FIGURE 9** 

**. PROCESS FLOW CHART F**  **OR J52 SHA FT ID PLATING** 

**.**WP

- 0411 Supplement al Report 27 October 2010WP-0411 Supplemental Report27August2009 4.1.3 Results

The as

- deposit ed electroplate on the J52 coupling was smooth and shiny. No pits or

cracks we re observed . A few isolated nodules including some small dendrites were

present along the plated edge of the ID which is not uncommon in areas where higher

current densitie s are expected . Some imperfections were noted, consistent with how the

part was rece ived. The average as

- deposit thickness was 0.011”± 0.00076”. Following

plating, the part was machine ground to a surface finish of 16 microinches Ra or better.

The aim of grinding the plated part was to evaluate machinability characteristics. A

runout of t he edges was not performed as this was not required for the evaluation.

**J52 COUPLING FOLLOWI NG FRC** 

**- SE MACHINING OF ID P**  **LATED AREA**WP

- 0411 Supplement al Report 28 October 2010WP-0411 Supplemental Report28August2009

4.2 O UTER D IAMETER PLATING DEMONSTRATIO N

4.2.1 Component Description

The demonstration piece for outer diameter plating was a J52 shaft (section), as shown

in **Figure 10** 

. This part was 4340 steel and required plating on a small 2” wide band on

t he outer diameter of the part.

**FIGURE 10** 

**. J52 SHAFT (SECTION)**  **USED FOR THE OUTER D IAMETER PLATING** 

**DEMONSTRATION**

**.**

4.2.2 Methods/Setu p

A process flow chart shown in **Figure 11**  summarizes the operations completed in

preparing the demonstration part for plating. The demonstration part as received had a

corroded surface where it was previously plat ed. In order to prepare the part for plating,

the substrate was abrasively blasted using aluminum oxide media with a mesh size of

120. Upon inspecting the part, there was a pit present along the outline of the

plated/non

- plated interface

.

In order to ma sk the part for plating, several methods of masking were employed. First,

l ead tape was adhered along the border of the area to be plated

. Next

, generic masking

tape was applied to the area to be plated. This helped to prevent any maskant from

covering t he plating surface. The rack , consisting of two threaded rods and two hose

clamps , was then connected to the part to allow for electrical contact. Then, using

Electroplater’s tape

, the remaining uncovered areas were masked

. Enthone Mask

- off

No.1 was then applied on top of the tape. The area to be plated was then uncovered by

removing generic masking tape.

The area to be plated was scrubbed with a cleaning pad. Use of higher mesh pads is

recommended in order to reduce appearance of scratches in the final deposit. Next theWP

- 0411 Supplement al Report 29 October 2010WP-0411 Supplemental Report29August2009 part was immersed in the alkaline cleaning solution. It was electrocleaned for 3 minutes

at a current density of 50 mA/cm 2

. The part was rinsed and then attached to a rotator

assembly. The part was activated using a mineral acid (5% H F/30% Sulfuric Acid) for 1

minute at an anodic current density of 300 mA/cm 2 (live entry). The part was rinsed and

then plated with nCo

- P with the optimized pulse condition Section 2.0 . A flow eductor is

attach ed in order to facilitate flow at the plating area. Once plating was compl ete, the

rotation was stopped, the part was removed and was rinsed. Finally, the part was de

racked and manually de

- masked.

**FIGURE 11** 

**. PROCESS FLOW CHART F**  **OR J52 SHAFT OD PLAT ING.** WP

- 0411 Supplement al Report 30 October 2010WP-0411 Supplemental Report30August2009 4.2.3 Results

Many small nodules were scattered along t he surface of the plated J52 Shaft. This is

consistent with electroplating of thick coatings. Some small dendrites were seen along

the plated edges which is typical in high current density areas. Some imperfections

were noted, consistent with how the part was received. The average deposit thickness

prior to machining was 0.014”± 0.0001”. Following plating, the part was machine ground

to a surface finish of 16 microinches Ra or better. The aim of grinding the plated part

was to evaluate machniability chara cteristics. A runout of the edges was not performed

as this was not required for the evaluation.

**J52 SHAFT SECTION FO LLOWING FRC** 

**- SE MACHINING OF OD P**  **LATED AREA**WP

- 0411 Supplement al Report 31 October 2010WP-0411 Supplemental Report31August2009 

### 5.0 COST BENEFIT ANALYSIS

5.1 BACKGROUND

This section contains a Cost Benefit Analysis carried out using the C

- MAT (Calculation

for Material Alternative Techno logies) Decision Tool, whose development was funded

by SERDP/ESTCP. Cost data has been reviewed to reflect new processing conditions

(including current density, hence plating speed).

5.2 ASSUMPTIONS

1. The plating workload is based on the actual number of parts processed, taken

from shop records, and an estimate of the average part size. Most calculations

in the present analysis (except environmental costs) therefore reflect the cost per

sq uare f oo t plated.

2. The workload is based on JAX chrome plating data for 2 006 (see Table 16

- 18)

. Note that current OD plating approved for HVOF is being migrated

. The nCoP

coating is being considered for both ID & OD workload. Only the ID workload (all

of which is J52 engine parts) for JAX chrome plating operations will be in c luded

as a worst

- case scenario.

3. The calculations assume plating tank sizes of 1000 gals for each of the stripping,

activation, and plating operations in both the Cr and nCo

- P process lines. The

masking tanks (wax for Cr, peel coat for nCo

- P) are assumed to be smaller at

700 gals, and the Co anode tank for nCo

- P only 10 gals.

4. It is assumed that the plating tanks are dummy plated once a month for Cr and

once a week for nCo

- P, and that each dummying requires 1 hr of labor.

5. 24/7 operation is assumed for:

**•** Pla ting tank heating (by steam) for both Cr and nCo

- P plating

**•** Total water usage (makeup + rinse water)

**•** The Cr 6+ scrubber, and also EPA NESHAP monitoring of Cr 6+ (monitoring

actually required only when Cr plating operations occur)

6. Power required for the activa tion step is ignored in both cases, because it is

small.

7. For nCo

- P plating, it is assumed that the anodes will be Ti rods, Co plated in a

special Co anode tank (rather than electrolytic Co squares in a basket). The rods

will be plated to a thickness of 20 mils, enabling 10 ID parts to be plated from

each anode rod in 1

- 2 runs.

8. Hazardous waste:WP

- 0411 Supplement al Report 32 October 2010WP-0411 Supplemental Report32August2009 **•** At JAX, Cr 6+ waste from all Cr stripping and chromating operations is

combined with waste from the Cr plating line. But the Cr 6+ waste numbers

used in this analysis , including the $53,625 annual cost of scrubber energy

and maintenance, are estimates for plating operations only.

**•** The quantity of Cr 6+ solid waste is based on 2006 data. (This number has

been decreasing annually as more Cr plating work is migrated to HVOF .)

9. EPA NESHAP non

- compliance fines are not included in the environmental costs

for Cr plating, since such fines have never been levied on JAX. However, the

penalties are substantial resulting in $32,500 per day per violation.

10. OSHA monitoring costs for Cr plating are not included in the cost model either.

This is because it has been found that the exposure level of plating personnel to

Cr 6+ under typical plating conditions barely registers on the monitoring

equipment, so that ongoing monitoring is not requi red. However, a n annual s kin

test is carried out

.WP

- 0411 Supplement al Report 33 October 2010WP-0411 Supplemental Report33August2009 **TABLE 16** 

**FRC**

**- SE GENERAL COST DATA** 

**.** Cost item Quantity Unit Source/Comments

Workload

# ID parts Cr plated per year 85 NAVAIR FRCSE Product ion, 4/18/07

Average ID part plated area 0.4 sq ft NAVAIR FRCSE Production, 4/18/07

ID plating workload 34 sq ft Same workload assumed for nCo

- P plating

OD plating workload 144 sq ft NAVAIR FRCSE Production, 4/18/07

Total (ID + OD) workload 178 sq f t

ID area ratio 19%

OD area ratio 81% OD workload gradually being migrated to HVOF

Average ID plating process time 8.43 hr ISSC JAX Materials Engineering, 3/28/07

– includes 0.30

hr for baking step (both Cr and nCo

- P)

Actual process time de pends on part configuration

Rates

Labor rate

- direct $65.00 $/hr NADEP JAX, 2005*

– generic burdened rate

Material

- indirect 1.74% of direct

Water utility rate $0.00 $/gal NADEP JAX, 2005*

– rate used for rinse and makeup

water

Electricity uti lity rate $0.07 $/kWh ISSC JAX Environmental Logistics, 3/6/07

– rate used

for plating power

Steam utility rate $ 1

– 1.50 $/hr ISSC JAX Environmental Logistics, 3/28/07

– rate used

for plating tank heater power (Cr

– nCoP)

Inflation rate 0%

Discoun t rate 3 %

Depreciable life of equipment 15 yr

Salvage value 10%

Hazardous waste disposal

Cr 6+ solid waste $1.03 $/lb NADEP JAX, 2005*

– hazardous waste rate

Cr 6+ rinsewater $0.85 $/gal NADEP JAX, 2005*

– 2% of EHC rinsewater treated

nCo

- P solid waste $0.03 $/lb NADEP JAX, 2005*

– solid waste rate

nCo

- P rinsewater $0.85 $/gal NADEP JAX, 2005*

– 0.2% of nCo

- P rinsewater

assumed treated

* Data from “ Infrared Reflectance Imaging Technique (IRRIT), Baseline and Alternative Cost Data, Engine ering Estimates,

and Assumptions ”WP

- 0411 Supplement al Report 34 October 2010WP-0411 Supplemental Report34August2009 **TABLE 17** 

**FRC**

**- SE EHC COST DATA.** 

Cost item Quantity Unit Ann fixed Unit Ann

Cost

EHC adoption

Initial stripping & plating chemicals $4,800 $

Total adoption $4,800 $

EHC Summary co sts

Direct production labor $265 $/sq ft $47,190

Indirect production labor $1.91 $/sq ft $340

Direct materials $26 $/sq ft $4,690

Indirect materials $0.46 $/sq ft $82

Utilities $86 $/sq ft $15,385

Environmental $560 $/s q ft $99,611

Total $940 $/sq ft $167,298

EHC breakdown

Water use: rinse + makeup 87,600 gal/yr $209

Water use /sq ft $1.18 $/sq ft 492 gal/sq ft

Plating power /sq ft $23.74 $/sq ft 323 kWh/sq ft $4,226

Tank heater power (steam) $61.52 $/sq ft 8,760 hr/yr $10,950

Utilities total $86.43 $/sq ft

Scrubber energy cost $280.90 $/sq ft $50,000 $/yr

Scrubber maintenance cost $20.37 $/sq ft $3,625 $/yr

Stack testing, inspection $44.83 $/sq ft $7,980 $/yr

NESHAP monitoring $158.89 $/sq ft 432 hr/yr $28,283

NESHAP reporting, training $3.68 $/sq ft 10 hr/yr $655

Haz waste management $4.97 $/sq ft 13.5 hr/yr $884

Haz waste disposal 6,500 lb/yr $6,695

Haz waste disposal /sq ft $37.61 $/sq ft 37 lb/sq ft

Wastewater treatment 1,752 gal/yr $1,489

Wastewater treatment /sq ft $8.37 $/sq ft 10 gal/sq ft

Environmental total $559.61 $/sq ft $99,611 $/yrWP

- 0411 Supplement al Report 35 October 2010WP-0411 Supplemental Report35August2009 **TABLE 18** 

**NCO**

**- P COATING COSTS.** 

Cost item Quantity Unit Ann fixed Unit Ann Cost

% workload replaced

– ID EHC 19%

Average ID part plated area 0.4 sq ft

ID plating workload 34 sq ft

Average ID plating process time 8.43 hr

nCo

- P Summary costs

Direct production labor $280 $/sq ft $ 49,790

Indirect production labor $2 $/sq ft $358

Direct materials $42 $/sq ft $7,480

Indirect materials $1 $/sq ft $130

Utilities $66 $/sq ft $11,761

Environmental $9 $/sq ft $1,554

Total $399 $/sq ft $71,073

nCo

- P breakdown

Water use: rinse + makeup 262,800 gal/yr* $628

Water use /sq ft $3.53 $/sq ft 1,476 gal/sq ft

Plating power /sq ft $1.03 $/sq ft 14 kWh/sq ft $183

Tank heater power (steam) $61.52 $/sq ft 8,760 hr/yr $10,950

Utilities total $66.07 $/sq ft

Scrubber energy cost $0.00 $/sq ft $0 $/yr

Scrubber maintenance cost $0.00 $/sq ft $0 $/yr

Stack testing, inspection $0.00 $/sq ft $0 $/yr

NESHAP monitoring $0.00 $/sq ft 0 hr/yr $0

NESHAP reporting, training $0.00 $/sq ft 0 hr/yr $0

Haz waste management $0.00 $/sq ft 0 hr/yr $0

Haz waste disposal 2,167 lb/yr $65

Haz waste disposal /sq ft $0.37 $/sq ft 12 lb/sq ft

Wastewater treatment 1,752 gal/yr $1,489

Wastewater treatment /sq ft $8.37 $/sq ft 10 gal/sq ft

Environmental total $8.73 $/sq ft $1,554 $/yr

* Estimate based on high bath temperature, with bath heated 24/7

Note: Depreciation not included in these costsWP

- 0411 Supplement al Report 36 October 2010WP-0411 Supplemental Report36August2009

5.3 COST

- BENEFIT ANALYSIS FOR FRC

- SE

5.3.1 Capital cost

Capital cost ( **Table 1**  **9** ) depends on whether an existing line is to be modified or a new

line is to be installed. In either case the pulse plating rectifier, carbon filtration and

plating tank for anode production are required. But modifying an existing line avoids the

requir ement for additional tanks.

Note that we assume that the anode will typically be in the form of a plated rod rather

than Co chips in a basket. This is because for many ID coating applications plated rod

is the only viable approach, which requires the ins tallation of a plating tank even if it is

used for only some of the part production.

5.3.2 Direct manufacturing cost

Most of the labor cost of electroplating is involved with masking, demasking, setup,

insertion and removal from the plating tank, and maintaini ng the plating system. T he

shorter plating cycle for Co P has little effect on the labor hours. Because the nCoP bath

requires more maintenance for carbon filtration, and anode rods must be plated, the

labor hours are somewhat higher for nCoP. In additio n, the cost of chemicals is higher, **TABLE 19** 

**NCO**

**- P CAPITAL AND ADOPTI**  **ON COSTS.**

nCo

- P capital cost

Stripping tank, rectifier & wiring $130,000

Maskant tank $45,000

Activation tank, rectifier & wiring $130,000

Plating rectifier & wiring* $130,000

Carbon filtration equipment * $6,000

Co anode tank* $4,000

Total $445,000

nCo

- P adoption cost (initial chemicals)

Stripping chemicals $29,600

Maskant $15,000

Plating chemicals $18,100

Chemicals for anode tank $3,000

Total $65,700

Inflation rate 0%

Discount rate 3.00%

Depreciable life of equipment 15 yr

Salvage value 10%

* For modification of existing plating lineWP

- 0411 Supplement al Report 37 October 2010WP-0411 Supplemental Report37August2009 as is the cost of utilities because of the higher bath temperature, which requires more

make

- up water.

The direct cost of nCo

- P vs hard chrome plating is summarized in **Table 20** 

. The nCo

- P

direct cost is about slightly higher than hard chrome plating. However, when we add in

the indirect costs and the environmental costs nCo

- P costs $400/sq ft while hard

chrome costs $940/sq ft ( **Table 17**  **and Table**  **18 )** 

. This is of course a very high unit

cost , which comes about because, as shown in **Table 16**  , the plating volume is less

than 200 sq ft/year, spreading all the fixed costs over a very small production volume.

This unit cost would obviously be very much lower if the total workload were larger.

5.3.3 Cost

- benefit for replacing full plating line

**Tab le**  **21** show s the 15

- year metrics for replacement of an entire line in an existing

plating shop (which is equipped with all the necessary facilities, including heating and

air handling). The cumulative cost for the relacement is shown as a function of time in

**Figure 12** 

**.**

**TABLE 21** 

**15**

**– YEAR FINANCIAL PERFO**  **RMANCE FOR TOTAL LIN E REPLACEMENT AT** 

**FRC**

**- SE.** 

- 2 sigma Value +2 sigma

NPV ($53,711) $222,830 $499,370

IRR 12% 15% 17%

ROI 13% 17% 21%

Payback

period 13.7 8.5 5.9 **TABLE 20** 

**DIRECT PRODUCTION CO ST PER SQUARE FOOT** 

**COMPARISON.**

Cost per sq ft plated nCo

- P EHC

Direct production labor $ 280 $ 265

Direct materials $ 42 $ 26

Utilities $ 66 $ 86

$388 $377WP

- 0411 Supplement al Report 38 October 2010WP-0411 Supplemental Report38August2009

($600,000) ($400,000) ($200,000) $0 $200,000 $400,000 $600,000

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15Net Present Value (NPV)

Year NPV

- Cost based

NPV

- 2 std dev

- 1 std dev

+1 std dev

+2 std dev

**FIGURE 13** 

**. NPV AS A FUNCTION OF**  **NUMBER OF YEARS INCL UDED IN ITS** 

**CALCULATION FOR TOTA L LINE REPLACEMENT A**  **T FRC**

**- SE (WITH**  **2 σ**  **LINES).** - $800,000 - $600,000 - $400,000 - $200,000 $0 $200,000 $400,000 $600,000

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

Year Cumulative cost, with 2

- sigma lines

**FIGURE 12**  **. CUMULATIVE COST AS A FUNCTION O**  **F TIME FOR TOTAL LIN E** 

**REPLACEMENT AT FRC**

**- SE (WITH 2**  **σ LINES).** WP

- 0411 Supplement al Report 39 October 2010WP-0411 Supplemental Report39August2009

Note that in Table 21 , the Internal Rate of Return and the Return on Investment are

both annualized returns, not total returns, and they are based on the annual cost saving.

For this reason t he IRR and ROI can both be positive even when the NPV is negative,

because the cumulative cost always slopes down. This is illustrated in the plot of Figure

13 which shows how NPV varies as a function of the number of years over which the

NPV calculation is run. Note that NPV can still be negative even beyond the payback

period, when cumulative cost has gone negative, because NPV discounts the value of

money in the out years.

Although nCo

- P is a more expensive process than hard chrome plating , and althou gh it

requires capital investment, it saves money because it eliminates the need for the Cr 6+

scrubber, which costs more than $60,000 per year to maintain. What this means,

however, is that adopting nCoP will only be cost

- effective if it is used to comple tely

eliminate hard chrome. If the scrubber is retained for other processes, or the chrome

plating line is maintained, then savings will not be realized.

5.3.4 Cost

- benefit for modifying existing plating line

In many cases nCoP will be implemented in an exist ing line. In this case only the items

in **Table 19**  that are marked with an asterisk will need to be purchased as capital

equipment. In that case the NPV is significantly higher and the payback far faster

because o f the lower front

- end cost of $140,000 instead of $445,000 (see **Figure 14**  &

**Figure 15**  )

.

**TABLE 22** 

**15**

**– YEAR FINANCIAL PERFO**  **RMANCE FOR PLATING L INE MODIFICATION AT** 

**FRC**

**- SE.** 

15 year -2 sigma Value +2 sigma

NPV $481,358 $737,410 $993,463

IRR 36% 42% 47%

ROI 31% 42% 53%

Payback period 3.7 2.6 2.0WP

- 0411 Supplement al Report 40 October 2010WP-0411 Supplemental Report40August2009

5.3.5 Effect of rework

Hard chrome plating is a very forgiving process that continues to plate even when tank

chemistry or plating conditions are not optimum. It has been found that nCo

- P, on the

other hand, is much more sensitive to contamination in the bath, particularly in the form

of hydrocarbons. Contamination causes holidays in the coating, necessitating stripping

and replating. While contamination can be controlled through proper bath maintenance, - $1,400,000 - $1,200,000 - $1,000,000 - $800,000 - $600,000 - $400,000 - $200,000 $0 $200,000 $400,000

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

Year Cumulative cost, with 2

- sigma lines

**FIGURE 14**  **. CUMULATIVE COST AS A FUNCTION OF TIME F**  **OR PLATING LINE**

**MODIFICATION AT FRC**

**- SE (WITH**  **2 σ**  **LINES)**

**.**

($400,000) ($ 200

, 000 ) $0 $200,000 $400,000 $600,000 $800,000 $1,000,000 $1,200,000

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15Net Present Value (NPV)

Year NPV

- Cost based

NPV

- 2 std dev

- 1 std dev

+ 1 std dev

+2 std dev

($400,000) ($ 200

, 000 ) $0 $200,000 $400,000 $600,000 $800,000 $1,000,000 $1,200,000

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15Net Present Value (NPV)

Year NPV

- Cost based

NPV

- 2 std dev

- 1 std dev

+ 1 std dev

+2 std dev

**FIGURE 15** 

**. NPV AS A FUNCTION OF**  **NUMBER OF YEARS INCL UDED IN ITS** 

**CALCULATION FOR PLAT ING LINE MODIFICATIO**  **N AT FRC** 

**- SE (WITH**  **2 σ**  **LINES)**

**.**WP

- 0411 Supplement al Report 41 October 2010WP-0411 Supplemental Report41August2009 including carbon filtration and periodic dummying , we would expect that the incidence of

rework would increase to some extent with the use of a more sensitive process.

Rework requires that the part be demasked, stripped, remasked and replated. The

result of increased rework is illustrated in **Figure 16**  assuming hard chrome rework is

essentially zero, which is FRC

- SE experience.

It is clear that, because it adds to production cost, rework reduces the payback from the

technology. If rework increases to 20% the NPV drops to zero. It is therefore very

important to maintain tank performance and ensure proper operator training in both tank

maintenance and processing methods.

5.4 OPTIMUM METHOD OF AD OPTION

As we have seen, adoption of nCo

- P will impose a net cost unless it completely

replaces chrome plating. nCo

- P plating will not begin to realize savings until the chrome

scrubber is removed. If the changeover takes several years as components are tested

and qualified then savings will not begin until chrome plating is completely eliminated

and the scrubber shut down. Thus the optimum method of adoption is to qualify and

move to production with the new coating as quickly as possible. ($800,000) ($600,000) ($400,000) ($200,000) $0 $200,000 $400,000 $600,000

0% 5% 10% 15% 20% 25% 30%NPV

nCo

- P rework rate

**FIGURE 16** 

**. NPV AS A FUNCTION OF**  **REWORK RATE (TOTAL P LATING LINE** 

**REPLACEMENT)**

**.**WP

- 0411 Supplement al Report 42 October 2010WP-0411 Supplemental Report42August2009 

### 6.0 CONCLUSION

Optimized plating deposition parameters wer e obtained using a Design of Experiment

(DOE) approach. These parameters were validated through supplemental testing and

found to be non

- embrittling with improved fatigue and neutral salt fog corrosion

performance as compared to hard chromium electroplate. The nCoP deposit did exhibit

reduced hardness (560 VHN) and reduced taber wear abrasion performance as

compared to hard chromium electroplate.

Producibility evaluations were performed utilizing a J52 Shaft section and a J52

Coupling component. Optimized plating parameters were successfully demonstrated on

both ID & OD areas. The above plated components were then finished machined at

FRC

- SE with no observable defects.

Final established and optimized parameters are :

**•** Current Density: 125 mA/cm 2

**•** Frequency : 25 Hz

**•** Duty Cycle: 50%WP

- 0411 Supplement al Report 43 October 2010WP-0411 Supplemental Report43August2009



### 7.0 S U MMARY

nCo

- P is an alternative electroplating process to EHC. The coating is very similar in

appearance to EHC. The difference between this coating and standard cobalt

- , nickel

or EHC

- based coatin gs is the grain size of the deposit.

Nanocrystalline metals and alloys:

Electrodeposited nanocrystalline metals and

alloys have an average grain size of roughly 5

- 15

nm. This is a reduction of about 1000 times that

of the grain size of standard polycr ystalline

electrodeposited coatings. These nanocrystalline

coating s ha ve fully dense and equiaxed

micro structure s; a s the coating is built up there is

no grain growth or columnar growth

. Typical

p roperties that are improved by reducing the

grain size to the nanocrystalline scale include:

Hardness : Up to 3

- 5X increase

Yield Strength : Up to 5

- 9X increase

Ultimate Tensile Strength: Up to 3

- 5X increase

Co efficient of Friction: Up to 50% reduction

nCo

- P Process ( **Table 23**  ): Like EHC, nCo

- P is produced by electrodeposition.

However, there are some key process differences as detailed below:

Anodes: Consumable cobalt anodes are used for the nCo

- P process. These include

cobalt pieces held in titanium baskets (OD plating an d large ID plating), or cobalt

- coated

titanium rods (small ID plating). This is in contrast to EHC which uses non

- consumable

lead anodes.

Pretreatment: Like for EHC, recommended pretreatments vary with substrate material.

Pretreatment steps are similar to EHC with one notable exception, in that activation

does not take place in the plating tank. A separate process tank(s) is required for this

step.

Masking: Wax

- based maskants used for EHC cannot be used for the nCo

- P process.

Alternate dip and brush

- on mas kants are under investigation. Select electroplater’s

tapes can be used.

Efficiency and Plating Rate: The nCo

- P process is significantly more efficient than EHC,

thus resulting in much higher plating rates and increased process throughput.

Environmental: In contrast to EHC, air emissions from the nCo

- P process do not

contain harmful Cr 6+ . Air emissions from the nCo

- P process are below the OSHA PEL

for cobalt. No scrubbers are required for the nCo

- P process, however, local ventilation

is suggested to remov e steam from the area for worker comfort.

Hydrogen Embrittlement: Due to the high current efficiency, less hydrogen is generated

for the nCo

- P process compared to the EHC process. Nonetheless, hydrogen

embrittlement relief bakeouts are currently recommende d for high strength steels. This

is similar to practices used for EHC.WP

- 0411 Supplement al Report 44 October 2010WP-0411 Supplemental Report44August2009 Bath stability: The plating bath is very stable with only minor additions being required

for pH balance and for the alloying compound. Since the anodes are consumable, no

additions of cobalt salts are required.

Equipment: Similar electroplating equipment to EHC is required (i.e. tank, heater, pump,

filter, buss bars, DI water supply, electrical connections to rectifier), however, the

materials of construction must be compatible with th e nCo

- P plating bath. Unlike EHC,

a pulse rectifier is required for the nCo

- P process.

nCo

- P Properties ( **Table 24** ): There are a number of key properties of the nCo

- P that

improves the performance when compared to EHC.

Appearance: The coating is similar i n appearance to EHC.

Corrosion Protection: The coating has significantly improved corrosion protection over

EHC, owing to the fully dense structure of the nCo

- P coating.

Sliding Wear: The volume loss of material in sliding pin on disc wear tests is roughly

one half that of EHC. Preliminary rod

- seal wear testing suggests that nCoP has

comparable seal leakage to EHC.

Lubricity: The coefficient of friction is approximately 20% less than EHC.

Abrasive wear: EHC does have higher abrasive wear performance. nCo

- P may not be

the most appropriate choice for EHC replacement in applications where abrasive wear

mechanisms are known to operate. It is recommended that these be thoroughly

reviewed and tested on a case

- by

- case basis.

Hardness : EHC has higher hardness. However, hardness does not necessarily

correlate with sliding wear behavior, as evidenced by the improved sliding wear

performance of nCo

- P compared to EHC.

Fatigue: In early testing, nCo

- P has shown significantly improved fatigue performance

compared to EHC. In some cases, the nCo

- P fatigue performance is comparable to the

bare material.

**TABLE 23**  **COMPARISON OF NCO**

**- P AND EHC PROCESSES** 

**.** nCo

- P EHC

Cathodic Current Efficiency 85

- 95% 15

- 35%

Deposition Rate 0.002”

- 0.008” per hour 0. 0005”

- 0.001” per hour

Anodes Consumable cobalt Non

- consumable lead

Hydrogen Embrittlement Post

- plate bakeout required Post

- plate bakeout required

Emission Analysis Below OSHA limits Cr +6WP

- 0411 Supplemental Report 45 October 2010WP-0411 Supplemental Report45August2009EHCMicrocracked-Min. 600 VHN-<1%9-11 x 10-6mm3/Nm0.7Severe4 mg/1000 cycles0.003” thickFail 165 h0.004” thickProtection Rating 2(ASTM B537) @ 1000 hoursCracked–Exceeds cohesivestrengthSignificant debit compared tobare at all loads.nCo-PFree from pits, microcracks andpores8-15 nm550-600 VHN (as-deposited)600-750 VHN (heat treated)2-7%6-7 x 10-6mm3/Nm0.4-0.5Mild17 mg/1000 cycles0.003” thickPass 165 h0.002” thickProtection Rating 7(ASTM B537) @ 1000 hours10-15 ksi (Tensile)Comparable to bare athighloads.Small debit compared to bare at lowloads.Credit compared to EHC.ApplicableStandardN/AN/AASTM B578ASTM B489ASTM G99ASTM G99ASTM G99ASTM D4060ASTM B117N/AN/ATest MethodVisual andmicroscopicinspectionX-Ray DiffractometryVickersMicrohardnessBend TestPin on Disc(Al2O3Ball)Pin on Disc(Al2O3Ball)Pin on Disc(Al2O3Ball)Taber Wear(CS-17 wheels)Salt SprayInternal Stress TestRotating BeamFatiguePropertyAppearance andporosityGrain SizeHardnessDuctilityAdhesive WearCoefficient offrictionPin WearAbrasive WearCorrosionDeposit StressFatigue**TABLE 24** **COMPARISON OF NCO -** **P AND EHC PROPERTIES .** WP

- 0411 Supplemental Report 46 October 2010WP-0411 Supplemental Report46August2009 

### 8.0 APPENDIX: ROD & SEAL TEST

8.1 HYDRAULIC SEAL AND P ISTON ROD COATING EV ALUATION OF NCOP

Rod and seal testing was performed in accordance with the HCAT Joint Test Protocol

(JTP) to determine nCoP coating compat ibility with common hydraulic and pneumatic

seal materials. This JTP had been developed for testing HVOF coated rods (30

September 2003). The detailed test report is summarized in AIR 4.3.5 “Test Report For

Hard Chrome Alternatives Team Phase III Hydraul ic Seal and Piston Rod Coating

Evaluation of Nanocrystalline

- Cobalt

- Phosphorus”. Four rods were prepared at Fleet

Readiness Center Southeast (FRC

- SE) and sent to Integran Technologies Inc. for nCoP

electroplating.

8.1.1 Test Summary

Different surface finish conditions were evaluated on each of the four rods as follows:

(1) 12

- 16 min Ra, (2) 6

- 9 min Ra, (3) superfinished to <4 min Ra, and (4) heat treated at

300°C to maximize coating hardness, then ground to 6

- 9 min Ra. Each rod was tested

against the same fo ur seal configurations in the HVOF JTP: (1) MIL

- P

- 83461 O

- ring and

PTFE cap strip, (2) MIL

- P

- 83461 O

- ring and 2 backup rings, (3) Fluorosilicone O

- ring

with PTFE cap strip, (4) Spring energized PTFE seal. As there were only four positions

on the test equi pment for different coatings/conditions, hard chrome controls were not

run simultaneously.

8.1.2 Test Execution

The original test plan included fluid temperatures ranging from

- 40°F to 275°F, with

~80,000 sinusoidal full strokes superimposed with ~480,000 dith er strokes. However,

during testing, an incorrect computer stroke profile had been selected and run for the

first five days of testing. At that time testing was stopped and the test sponsor

authorized a revised test schedule to adjust the cycles to equat e approximately to that

originally planned. Hydraulic pressure ranged from between 2500

- 3000 psi.

8.1.3 Test Results

– Leakage Rate s

Leakage rates for all coating finishes are shown in **Figure 17** 

. For comparison, EHC

data from prior testing (not done in the same test as nCo

- P) are also included. Leakage

rates for all nCo

- P coating finishes were acceptable for the duration of the test. Failure

criterion is a leakage rate exceeding 1 drop for 25 full strokes, although t his is different

than the combination with the dither strokes. The superfinished nCo

- P rod resulted in

the least accumulated leakage over the test duration, followed by the heat treated rod,

while the rougher ground finishes resulted in the highest leakag e (6

- 9 and 12

- 16 min Ra

finishes). For one seal configuration during 1 hour near the end of the test very slightly

exceeded this rate (24.4 cycles per drop), however, this configuration leaks by design at

cold temperatures so it wasn’t considered signific ant.WP

- 0411 Supplemental Report 47 October 2010WP-0411 Supplemental Report47August2009

Rod/Seal Leakage

MIL-P-83461 O-ring w/ Capstrip Vs 4 Rods

0 10 20 30 40 50 60

0 10 20 30 40 50 60 70 80 90 100 110 120 130

Test HoursLeakage (mL)

Ground 12-16 in Ra

Ground 6-9 in Ra Ground 12 Superfinish <4 min Ra

Heat treated 300°C Ground 6-9 min Ra Cr O-ring/cap Rod/Seal Leakage

MIL-P-83461 O-ring w/ 2 backup ring Vs 4 Rods

0 10 20 30 40 50 60

0 10 20 30 40 50 60 70 80 90 100 110 120 130

Test HoursLeakage (mL)

Ground 12-16 in Ra

Ground 6-9 in Ra

Ground 12 Superfinish <4 min Ra

Heat treated 300°C Ground 6-9 min Ra

Cr O-ring/backups

Rod/Seal Leakage

Spring Energized PTFE Vs 4 Rods

0 10 20 30 40 50 60

0 10 20 30 40 50 60 70 80 90 100 110 120 130

Test HoursLeakage (mL)

Ground 12-16 in Ra

Ground 6-9 in Ra

Ground 12 Superfinish <4 min Raseal

Heat treated 300°C Ground 6-9 min Ra

Cr SE PTFE Rod/Seal Leakage

Fluorosilicone O-ring w/ PTFE Cap Vs 4 Rods

0 10 20 30 40 50 60

0 10 20 30 40 50 60 70 80 90 100 110 120 130

Test HoursLeakage (mL)

Ground 12-16 in Ra

Ground 6-9 in Ra

Ground 12 Superfinish <4 min Ra

Heat treated 300°C Ground 6-9 min Ra

Cr FS O-ring/cap

**FIGURE 17** 

**. LEAKAGE RATES FOR NC**  **O**

**- P COATINGS WITH VARI**  **OUS SURFACE**

**FINISHES AND DIFFERE NT SEAL CONFIGURATIO**  **NS. FOR REFERENCE, E HC** 

**DATA FROM PRIOR TEST S ARE INCLUDED.** 

8.1.4 Test Results

– Seal Condition

At the conclusion of the test, rods and seals were removed from the test fixture,

inspected and photographed, and then shipped to Supfina Inc. where seals were

disassembled and inspected. Seal damage was noted for certain configurations. The

AIR 4.3.5 test report concluded t hat the cap

- strip seals failed due to excessive wear,

and the seals with the most wear were noted on the rods with rougher finish. Seal

images are available in the full report. Their recommendation was that a better

simulation of flight conditions would incorporate a test under loaded conditions,

including side loads.