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ASETSDefense Technica

Rowan Technol

Libe

2/2012 Army Corrosio

Eliminating Cr6+, Cd, and other hazardo

without compromising performance

Army Corrosion Summit, 2010
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2

ASETSDefense

ASETSDefense (Advanced Surface E

Technologies for a Sustainable Defe

initiative set up to assist DoD organ

vendors to adopt alternatives to coa

cause environmental and health pro

 Defined as info source in 2009 Cr6+  Information, assistance, databases Workshops
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3

DoD Vehicle WorkshopNASF Sur/Fin, Grand Rapids, MI, Ju

2010

What new regulations are coming down the roaWhat are the options to meet them?What works and what does not , what does it ta

processes work well?

What are the barriers to adopting new approacWhat new technologies are needed, and how c

technologies be used more effectively?

For info: www.nasf.org and www.asetsdefens
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4

CHANGES THAT DON’T WOWeapons programs and vendors are making changes t

materials such as chromates, Cd plate, VOCs. But ther

do it wrong than to do it right.Perception is that giving up chromates etc gives up per

smart changes can often improve performance.
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5

Replacing Cd‐plated bolt

GTEs: most fasteners are now For C‐fiber composites Ti fastePeople sometimes forget that and Ti fasteners are galvanicawith Al frames and Al armor

2139Al+CARC

2024Al bolts Stainless bolts 
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6

Direct‐to‐metal painting

Now used on MRAPs and other veh

chromate wash

 Some vehicles already rusting comi

3⁄4 More urgent to get vehicles in thea

about initial corrosion

 All non‐chromate processes are ver

process conditions

 Can be fixed on repaint
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7

Al pretreats

USAF has qualified Prekote in place 

conversion of Al aircraft skins (TO 1

Boeing uses AC130/131 (Boegel)These are both paint adhesion prom

corrosion inhibitors

 Cannot be used without paint syste
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8

Incompatible coatings

In order to avoid use of ch

some people are combinin

work well alone, but not in 

Example: Shipboard opticAl and coated with Ni

 Galvanic corrosion

Electrical connectors: Upd

as MIL‐DTL‐38999L allow A

electroless Ni‐PTFE coating

 Care needed to avoid galv
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9

REGULATORY CLIMATE CHA
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April 2009 DoD Memo o

April 8 ‘09 USD

restricting Cr6+ 

effective altern

satisfactory per

Requires Progra

(PEO) and Corro

Prevention Exe

certify if no acc

Effect will be to 

Cr6+‐free coatin

methods

DFARS to be iss

Info and database on Cr6+alternatives available at www.asetsdefense.org
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Intent of the Memo

Eliminate use of chromate materiprocesses in new weapons syste

there are no satisfactory alternati

Eliminate Cr6+ in legacy systems 

are modified or overhaul methods 

“The Defense Acquisition Regulation Council will prepare contracts prohibiting use of Cr6+containing materials in all 

unless specifically approved by the Government.”

“Application of this policy to legacy systems will be limited where alternatives can be inserted in the system modificaupdated maintenance procedures.”
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PEO must take manufacturability and performance into acc

Cost-effectivenessAny change in performanceAcceptable ESOH for alternativeLong term availabilityTechnical feasibility, MRL ≥ 8

 Ready for at least low rate productio

3⁄4 Stable production methods 3⁄4 QA/QC established3⁄4 Adequate supply chain for limited p

Cr6+ use can continue if alternatives not 
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Defense Federal AcquRegulation Suppleme(DFARS) Modification

 Defense Acquisition Regulation Council is dr

Rule for the DFARS to be published in Feder

 Prohibition on Use of Cr6+

3⁄4 DoD contracts cannot include specifications or stan

containing materials or using Cr6+ processes

 Exceptions 

3⁄4 Cr6+ can be used if authorized at PEO/flag level, in c

Corrosion Control and Prevention Executive

3⁄4 Does not apply to legacy systems, but alternatives t

considered during system modifications, follow-on updates of maintenance procedure

 DFARS clause would make Cr6+ concentratio

same as in RoHS

3⁄4 <0.1% by weight in any homogeneous material

See ASETSDefense Workshop, Denver, Septembe
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14

Primary EU regulations

RoHSReduction of Hazardous Substances

REACHRegistration, Evaluat

Restriction of Chemi

RoHS is related to WEEE (Waste

Electrical and ElectronicEquipment)

RoHS

 Pb, Hg, Cr6+, PBB, PBDE < 0.1at% Cd < 0.01at% Military and aerospace regarded

as exempt

o But expectation of Cd plating

exemption being eliminated for

all commercial products

All chemicals 

with EChA

 Even if use

Evaluate toxi

 Identify SV

Very High 

CMRs (Car

Reprotoxic

Some SVHCs 

(perhaps effe

You must hav

use other SV
http://www.asetsdefense.org Teaming website: www.materialoptions.com Keith Legg 

Obeying the rules of the 

 Comp

equip

the Ecomp

3⁄4 W

sa

 For m

bigge

meet

requifasten

no co

 What 

envir

will b

 No homogeneous layer can contain >0.1% Cr6+

or >0.01% Cd by weight

 “Homogeneous layer” means any layer that 

cannot in principle be mechanically disjointed

 Not a % of whole item. Cd is a homogeneous 

layer and chromate another

Zn or Cd <0.01wt% Cd

<0.1wt% Cr6+

<0.1wt% Cr6+
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16

RoHS – Restriction of Ha

Substances

Strictly covers electrical systems an

these days that covers almost anyth

RoHS (and its companions WEEE an

to elimination of Cd and Cr6+ from c

Forcing consideration of alternativefor everything else (including aircraEU discussing extending to other eq

Hat

3⁄4 DoD and aerospace are3⁄4 Sole users of Cd plating3⁄4 Primary remaining users of Cr6+

conversion coatings and primers
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17

EU Directive 67/548/EEC Classification, Packaging and of Dangerous Substances

Listing a substance as CMR Cat 1 or 2 makesubject to Restriction under REACHNew materials frequently added under “Ad

Technical Progress” (ATPs)

 30th ATP, Aug 08, added 380 new subst

516 and removed 3

3⁄4 Added Ni sulphate, dichloride, dinitrate

plating chemicals)

3⁄4 Boric acid (boric‐sulfuric acid anodizing

 31st ATP, Jan 09 added 385 new substa

83 and removed 4

3⁄4 110 Ni compounds now included

 New materials added by read‐across, w

data (e.g. Ni salts)

Seems like a simple regulation on labels for chemicals.Is a means of bringing large numbers of chemicals under REACH restriction with minimal evidence of toxicity
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18

REACH and chromates – 

sustainment in EU

REACH controls and restricts CM(carcinogenic, mutagenic, reprotoin (Annex I of Directive 67/548/Eand Labeling of Dangerous SubsSodium Dichromate was put forwcandidate substance” for inclusioAnnex XIV (Authorization) in Jun

 Decided not to prioritize for inclu ECHA intends to bring it up agai Listing has triggered downstream 

requirements for Na dichromate

 EU looking to expand to more ch

“...the most effective option is to group and prioritise relevant chromincluding sodium dichromate, together” (ECHA Committee Recommbe back, probably with all the other chromates (just as with Ni salts

Sodium dichromate is used in conversion coatings and to make chromic acid (used in hard chrome plating)
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REACH impact – Impacts

expected on platforms b

EU ~next 5‐10 yrs

Chromate conversion coatings,

primers

 Cr6+ essentially banned for all

electronics by RoHS

 Expect restriction/ authorization

all chromates under REACH

Chromated primers – need quals

 Aircraft/vehicle repaint

Cd plating

 Cd on vehicles already restricted Next Cd for aircraft electronics Later Cd for aircraft structures

Ni becoming serious issue

 Big concern for wear/corrosion

Sodium 

precurschromi

 Cr p

3⁄4 

Berylliu

 Airc

hyd

Al‐Be a

 Opt

Berylliu

 Hea

insu

 Sma
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REACH Impact on DoD

 Issue for sust Loss of local 

chemicals an

 Uncertain wh

for military v

 Time scales f

scales for saf

 Defense Exem

present

3⁄4 Serious iss

paint on p
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21

USAGE AND REPLACEMENT 

MUCH DO WE KNOW?
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22

Rule 1: There is no perfe

Specs, approval requirements, test 

designed to accommodate existing 

strengths and weaknesses

The only materials that ever meet tof Cd or Cr6+ in every way are Cd or No matter how great an alternative always be one test where it is not a

 Is that a critical requirement? Can we live with it and still do bette
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23

Rule 2: Alternatives alwamore care

Everything else has a higher Coeffic

Screwupability (COSa) than Cd and 

Alternatives to chromate conversio

process‐sensitive

If you use chrome‐free primer you h

good job with the pretreat

Alternative electroplates and HVOF 

difficult than hard chrome plating

Cd alternatives: AlumiPlate requires 

line, while ZnNi electroplate must h

alloy balance all over the componen
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24

Rule 3: Alternatives alwamore up‐front

Up‐front cost is almost always highe

 Partly this is because of the extrem

Cr6+ conversion, Cd, hard chrome, e

 Partly this is because alternatives a

available or used in as high volume

However, cost of ownership (LCC) fr

 Performance often (by no means al Lower ESOH cost (rarely >10%) Lower demil and disposal cost Lower liability risk for use, spills, wa
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25

Are there alternatives thimprove performance?

Replace hard chrome with HVOF W

hydraulic actuators, most other app

 HVOF WC‐CoCr typically far less we WC‐Co has worse corrosion than ha

recommended

Replace Dow and HAE on Mg alloys and brush Tagnite

 Much better corrosion, damage tol

Replace Cd with AlumiPlate

 Much better corrosion resistance

Cr6+‐free primer: 44GN‐098 non‐Cr 

corrosion than chromated in F‐35 te
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26

Cr6+ usage in DoD

Cr6+‐containing coatings Cr6+ processes, 

Chromate conversioncoatingsChromate sealersChromated primersChromate washesChromated metallic‐ceramics

Hard chromChromic acChromic ac

Cr6+ (CrVI, hexavalent chrome, chromate) is our primary corr

Cr6+-containing coatings are a problem for sustainment (repaint, to

Cr6+ processes are primarily a problem for OEMs a
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Cr6+‐free coatings

Material Status of alternatives

Chromate conversion coating

Trivalent chrome and non-Cr commergood as Cr6+. Used on cars, Boeing 7

systems, USAF T.O. 1-1-8 Prekote; N

Chromate primers Non-Cr primers commercially availabl

Apache. Performance good on Cr6+ co

toward total non-Cr6+

Chromate finish system Low temperature powder coat and UV 

validation to replace primer/topcoat fo

No Cr6+, low VOC. In development

Chromate conversion of Mg

Tagnite now used on EFV gearbox, soAH-64, CH-53. Performance much be

and anodize. DoD use still very limited

Metallic-ceramics Low-Cr and non-Cr available commer

uncertain

Chromate washes Direct-to-metal used for MRAP. Poor 
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Cr6+‐free processes now 

Material StatusHard chrome plating HVOF on F-35 landing gear, all new c

landing gear. Being implemented for 

Chromic acid anodize TFSAA approved by NAVAIR, BSAA bNon-Cr primer In production on F-35, AH-64 Apache 
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High Velocity Oxy‐Fuel (Hprocess to replace hard c

 Most new landin

now use HVOF W

hard chrome on 

pins, actuators

3⁄4 Military and c

 Many hydraulics 

actuator rods

3⁄4 E.g. Parker Ae3⁄4 Caterpillar ne

 Seal manufactur

finish and seal d

3⁄4 E.g. Greene, T

 Standard indust

3⁄4 Several equip

powder supp

houses world

Method of choice for hard chrome

replacement on aircraft

 Landing gear, actuators, flap tracks,

other wear surfaces

 Commercial off‐road vehicles OEM, MRO
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HVOF standard on Cater

road hydraulics, shocks

Brad Beardsley ASETSDefense Worksh

100 ton Cater

Truck strut

Chrome 682 hrs salt mine

HVOF 3200 hrs salt mine

HVOF truck hydraulic production
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31

Tagnite to replace Dow 1

HAE

Widely used for gearbo

commercial helicopters

Authorized for military 

only one implementatio

EFV transmission (RR AMuch better corrosion 

damage tolerance than 

Repair by brush Tagnite
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32

Cr3+ to replace chromate

conversion

NAVAIR TCP (Tri‐Chrome Pretreat) n

from QPL list of commercial supplie

 Works well when used correctly More sensitive than chromate to pr Currently under test as chromate w
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33

PreKote and AC‐130/131 

replace chromate conve

USAF TO 1‐1‐8 specifies PreKote as alternative for aircraft paintingBoeing now uses AC‐130/131 to preBoth of these are adhesion promote

corrosion inhibitors

 Cannot be used without paint syste
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34

AlumiPlate to replace Cd 

Electroplated high purity Al coatingHas to be done in oxygen‐free line

 JCAT testing shows AlumiPlate has 

corrosion resistance than Cd

 Much better stress corrosion cracki

Used on F‐35, F‐22, F‐16, M119 How

Super Cobra, and other systems

F-35 MLG torque arm

Upper Cd, lower AlumiPlate
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35

LHE ZnNi to replace LHE Ti‐Cd plate

Looks good in all Boeing testi

 Available from Atotech and D

3⁄4 Not yet fully available comm

 ASETSDefense Workshop 09

Tran)

LHE Zn14Ni currently in test a

 Landing gear

Both ZnNi and AlumiPlate req

 Usually polymer type
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36

Al and Zn filled coatings 

replace Cd on fasteners

Ceramic or polymer base with Zn anDip spin or sprayUsed on all commercial automotive 

 Several suppliers (Dorken, Delta, M E.g. Magni 565 is modern version o

tested as best TACOM testing in lat

3⁄4 Inorganic Zn‐rich basecoat, organic 

modified topcoat

Not good for fine threads

S
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37

Powder coats and UV cu

to replace high VOC pain

Powder coats now formulated for lo

cure

 Good corrosion resistance and dam

UV very rapid cure (seconds)

 Saves standing around waiting for p Reduces painting from days to hour

Demonstrations of both methods o
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38

Wire arc spray to reducecorrosion – vehicles, tow

Not a direct replacement for a toxic 

reduces environmental impact and 

corrosion and repaint frequencyHigh up‐front cost, lower cost of owWire arc Zn15Al on GSE, Patrick AFBWire arc Zn, NASA towers
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39

Problems still outstandin

Chromate‐free paint system

 Can be done, performance not yet  Cr3+ treatments process‐sensitive First chrome‐free finish B‐777 flying 

Chromate wash for armor

 No alternative yet that works as we

testing under way

Rework coatings for Mg

 Brush Tagnite can be used on Tagni

Cd alternatives still in discussion

 ZnNi or AlumiPlate
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40

ASETSDEFENSE SOURCES O

INFORMATION
http://www.asetsdefense.org Teaming website: www.materialoptions.com Keith Legg 

41

DoD Vehicle WorkshopNASF Sur/Fin, Grand Rapids, MI, Ju

2010

What new regulations are coming down the roaWhat are the options to meet them?What works and what does not , what does it ta

processes work well?

What are the barriers to adopting new approacWhat new technologies are needed, and how c

technologies be used more effectively?

For info: www.nasf.org and www.asetsdefens
http://www.asetsdefense.org Teaming website: www.materialoptions.com Keith Legg 

ASETSDefensehttp://www.asetsdefens
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Quick Links basic inform
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44

SURFACE ENGINEERING DA

http://db.asetsdefense.o
http://www.asetsdefense.org Teaming website: www.materialoptions.com Keith Legg 

Database – Simple searc

Designed to answer question “What alternative to hard chrome (etc) is available (authorized, implemented, spec’d) for my type of system and application?”
http://www.asetsdefense.org Teaming website: www.materialoptions.com Keith Legg 

Detail search

Search for specific materials, systemtests, people, organizations

corrosion
http://www.asetsdefense.org Teaming website: www.materialoptions.com Keith Legg 

Database Documents