1. Hexavalent Chromium Alternatives for BDS AFCPCO Chrome Free Coating System Technical Interchange Meeting
Steve Gaydos & Waynie Schuette (Presenter)
BR&T- STL | Chemical Technology
January 18, 2018

2. BDS (Boeing Defense Systems) Process Specifications:
BAC Specifications (Legacy Boeing Aircraft – Seattle, WA)
P8A (737)
KC-46 (767)
Chinook H-47
PS Specifications (Legacy McDonnell Aircraft – St. Louis, MO)
F/A-18
F-15
Missile and Bomb Programs
DPS Specifications (Legacy Douglas Aircraft – Long Beach, CA)
C-17
HP Specifications (Legacy Hughes Aircraft – Mesa, AZ)
Apache AH-64

3. Environment and Safety
Alkaline Cleaning/Aqueous Degreasing
In Approval Process
Being Evaluated
In Use in Aerospace
Specification
Title
BAC5763
Emulsion Cleaning and Aqueous Degreasing
BAC5749
Alkaline Cleaning
PS 12030
Key Requirements
Ability to clean
Water-Break-free surface required (BAC5749 only)
no pitting or IGA
State of the technology
All chromated alkaline cleaners have been replaced with non-chromated alkaline cleaners
Challenges
Cleaners are not universal, they need to be selected based on the prevalent contaminant
Projects in Work
Performance
Environment and Safety
Manufacturability
Tech Progress
Brulin Ultra filtration
remove contaminants
add back surfactants
More consistent chemistry and contaminant levels
Chemical reduction
Reduce down time
Chemical costs

4. Environment and Safety
Etching Cleaning and Etch for Penetrant (Aluminum)
In Approval Process
Being Evaluated
In Use in Aerospace
Specification
Title
BAC5786
Etch Cleaning of Aluminum Alloys PS
Pickling Aluminum Alloys
Key Requirements
Controlled Etch rate
Min Surface roughness
No End Grain Pitting
No Intergranular Attack
State of the technology
All approved solutions are Hexavalent Chrome free
Challenges
Some suppliers are not using BAC5786 solutions and are still use hexavalent-chrome containing acid etch for etch for penetrant
Need a non-chrome etch for copper
Projects in Work
Performance
Environment and Safety
Manufacturability
Tech Progress
TEA filtration – solutions are typically dumped due to high smut content interfering with parts or equipment
Consistent process conditions
Reduce hazardous waste
Reduced chemical handling
Reduce down time
Are there opportunities with new tanklines to change from acid etching to alkaline etching?

5. Approved Alternatives Environment and Safety
Anodizing – Approved Alternatives
Specification
Title
BAC PS 13201, Type I
Chromic Acid Anodize (CAA)
BAC5632
Boric Sulfuric Acid Anodize (BSAA)
DPS
Thin Film Sulfuric Acid Anodize
Key Requirements
Salt spray – standalone
Salt spray - painted
Paint Adhesion
No EGP/IGA
Approved Alternatives
Performance
Environment and Safety
Manufacturability
BSAA - approved alternative to CAA (drawing and sub-drawing)
Improved process robustness
Eliminates hex chrome in anodize bath.
Requires Dilute Chrome Seal
Requires tighter temperature controls and sometimes cooling
Not approved for other OEM’s
BSAA and CAA Class 5 – Unsealed Anodize
Approved for 100% painted (drawing and sub drawing)
Part specific approvals
Improved robustness
Limited to parts that are 100% painted
Eliminates chrome seal
Enables non-chrome deox (if all parts are Class 5)
Requires segregation of sealed and unsealed parts
Eliminates salt spray requirement if all parts are Class 5
16 hour time limit between anodize and prime. (BAC 5632, PSD 6-31)
Boegel/BMS10-128
(drawing and sub drawing)
Limited approval for 100% primed thin sheet metal parts
Drawing approval for other
No hex chrome
Out of tankline – Spray process
No Rinse
Cleaning processes still in tankline in most cases
Bath Life extension BSAA – membrane technology to remove Al and Cu
Electrowinning to remove Cu
Consistent bath chemistry
Reduce hazardous waste
Reduce chemical handling
Reduce tank down time
Since our previous meeting, who has started implementing Class 5 anodize? If not why?

6. Class 5 Anodizing – Unsealed Time Extension Consideration
Facilities Controls
Temporary Protection of Parts
i.e. cover with Kraft paper
Isolated area for Unsealed Anodize Part Storage
Clean (procedure and initialed log book)
Clearly identified (signs, taped off)
For example (taped off floor or contained area)
Dedicated material handling (clean)
Minimize part handling
Minimize part/anodize damage (don’t stack boxes on parts)
Administrative Controls
Training
Area cleaning procedures and log (General area and isolated storage area)
Part handling and protection procedures
Discrepancy procedures
 Need to add unsealed anodize as alternative to MIL-A-8625 for painted parts

7. Environment and Safety
Anodizing – Technology Development
In Approval Process
Being Evaluated
In Use in Aerospace
Projects In Work
Performance
Environment and Safety
Manufacturability
Tech Progress
Accelerated Sulfuric Acid Anodize (ASAA)
Unsealed
Sealed
Paint adhesion
Painted corrosion resistance
Does not contain chromic or boric acid
Non-Chrome Seals
Trivalent Chrome (TCP)
Eliminates hexavalent chrome seal
TCP Seals work at room temperature – significant energy savings
Tartaric Sulfuric Acid Anodize TSAA
No hex chrome
Airbus is expanding usage to replace CAA
Fume Suppressant for CAA
PFOS Alternative for Fumetrol 140 not available. Scrubber or foam blanket are only options to continue using CAA
TBD
Failed – no acceptable alternative for Fumetrol 140
Elimination of Fumetrol 140 (PFOS) for CAA has forced switch to BSAA on some BDS parts.

8. Environment and Safety
Chromate Conversion Coating – Approved Alternatives
Specification
Title
BAC5719
PS 13209
Chemical Conversion Coating for Aluminum and Aluminum Alloys
BAC5663
Sol-gel Conversion Coating for Aluminum Alloys
Key Requirements
Salt spray – standalone
Salt spray - painted
Paint Adhesion
EGP/IGA
Approved Alternative
Performance
Environment and Safety
Manufacturability
Boegel/BMS10-128
(drawing and sub drawing)
Used as adhesion promoter
Limited approval for 100% primed thin sheet metal parts
Drawing approval for other
Does not meet requirements in MIL-DTL or MIL-DTL-5541
No hex chrome
Out of tankline
No Rinse
Cleaning processes still in tankline in most cases
Primarily used as surface prep during final paint on exterior of aircraft.

9. TCP CC Implemented on Non-Critical Parts per MIL-DTL-5541, Type II
Chromate Conversion Coating
In Approval Process
Being Evaluated
In Use in Aerospace
Projects In Work
Performance
Environment
Manufacturability
Trivalent Chrome
CST-SurTec TCP
Metalast TCP
Luster-On TCP
Socomore TCS/PACS
Unreliable corrosion performance on 2000 series Al alloys with TCP (Trivalent Chrome Pretreatment) materials
No Cr+6
In process, waste stream, on part
May require specific surface prep processes such as a specific deoxidizer*
May require secondary processes (seal)*
Touch-up
Boegel (No Rinse)
Alodine 871 (No Rinse)
SurTec 650V (Rinse required)
TCP Coating thickness effects primer adhesion and corrosion performance
No Hex Chrome
Tri Chrome (TCP)
Boegel, sensitive to surface activation procedures (keytones)
TCP – Unreliable corrosion performance on 2000 Al, No Hex chrome – In process, In waste stream.
TCP CC Implemented on Non-Critical Parts per MIL-DTL-5541, Type II
*New tanklines should consider extra tank space to accommodate alternative processes

10. Environment and Safety
Titanium Cleaning, Etching, Alpha Case and Penetrant
Specification
Title
BAC5753 PS
Cleaning, Descaling and Surface Preparation of Titanium and Titanium Alloys
BAC5842 PS
Chemical Milling Titanium and Titanium Alloys
In Approval Process
Being Evaluated
In Use in Aerospace
Key Requirements
Hydrogen Pick-up
Water-break-free
Etch rate
Etch uniformity
Surface roughness
State of the technology
No HF Free etch cleaners available
Membrane technology commercially available to extend bath life (minimize HF usage and handling)
Chrome free alternatives available for most applications and predominantly used
Challenges
Uniform metal removal
Hydrogen Pick-up
Technologies
Performance
Environment and Safety
Manufacturability
Tech Readiness
Progress
Bath Life Extension
Diffusion Dialysis
Remove dissolved Ti from etch solution for more consistent chemistry and lower contaminant levels
Reduce hazardous waste – minimize tank dumps
Reduce down time
Chemical costs
Additional equipment costs

11. Environment and Safety
Titanium Conversion Coating
Specification
Title
BAC5861
Phosphate Fluoride
BAC5665
Sol-gel on Titanium
PS 13204
Sol-gel, Alodine 5700 and 5700 Wipes
State of the technology
BAC5665 Sol-gel is approved for most adhesion applications
Base line for painted titanium for 787
Global Substitution Drawing approved for 747, 767, and 777 for all painted titanium
737 approved on a case by case basis
For stainless steel paint preparation, non-Chrome alternatives now allowed per PS13204
Key Requirements
Adhesion
Fatigue
Challenges
Process robustness
Projects in Work
Performance
Environment and Safety
Manufacturability
Tech Readiness
Progress
Currently no projects in work

12. Environment and Safety
Stainless Steel Passivation
Specification
Title
BAC5625
Citric Acid Passivation
BAC5753 & 5758
Descale of Ti, Ni, and Co Alloy Parts
PS 13001
Key Requirements
Corrosion Resistance
Non-Etching
State of the technology
Citric Acid
Alternative for Nitric Acid and Nitric Acid + Dichromate Passivation Solutions
Permitted for most stainless steel alloys
Citric acid solutions used to remove steel shot peen residue from Ti, Ni and Co alloy parts.
Challenges
None
Projects in Work
Performance
Environment and Safety
Manufacturability
Tech Readiness
Progress
Currently no projects in work

13. Alternative Processes Environment and Safety
Chrome Plating
In Approval Process
Being Evaluated
In Use in Aerospace
Specification
Title
BAC5709
PS 13002
Hard Chrome Plating
Key Requirements
Wear/lubricity
Adhesion
Challenges
All require drawing approval - changes
Alternative Processes
Performance
Environment and Safety
Manufacturability
Tech Readiness
Progress
HVOF Thermal Spray (BAC 5851)
Performs better than chrome plate.
Line of sight process. Cannot do ID surfaces
Electroless Ni (BAC 5728)
Adhesion is not as good as chrome plate.
Currently Ni is not regulated
Electroless Ni plating solution requires constant maintenance
DLC Diamond Like Coating (BAC 5984)
Thin coating ( ~5 microns) but very hard (15 to 28 Ga)
Requires new equipment.
Only one supplier approved.
Tri-Chrome Plating
Need to improve microstructure (crack pattern) and adhesion
No Cr+6
Drop in replacement

14. BDS Paint Primers
Non-Cr Primers Are Available and are Being Added to BDS Programs on a Case-By-Case Basis
Typically Allowed on Outer Mold Line (OML)
F-15, final paint tie-coat, Deft 44GN098 and Deft 02GN084 (on hold)
F/A-18, final paint tie-coat, Hentzen 17176KEP (replaced Koroflex)
Advanced Systems, Deft 65GN015 Zero Cr+6/Zero VOC primer (never qualified to MIL-PRF-23377)
Considered for Paint On The Line applications (still a possibility)
Massive Ordnance Penetrator (MOP)
Al parts: MIL-DTL-5541 Type II,  MIL-PRF class N, MIL-PRF-85285
Steel parts: Sand Blast + MIL-PRF-26915, MIL-PRF-85285
Joint Direct Attack Munition (JDAM)
Al parts: SA Anodize + HW Seal with MIL-PRF-85582, Type 1, Class N, gray or MIL-P-23377, Type 1, Class N, gray
Steel: Powder Coat
Small Diameter Bomb (SDB)
Al parts: SA Anodize + Ni Acetate Seal
Steel parts: Zn Phosphate
Steel and Al parts: TT-P-2756A Chromate-free, self-priming, polyurethane coating material (grey), DEFT 03GY0369 SELF-PRIMING TOPCOAT, COLOR NO

15. BDS- STL Paint Primer
Non-Cr Primers Are Available and are Being Added to BDS Programs on a Case-By-Case Basis
Typically Allowed on OML
C-17, Deft 97GY160 Advanced Multifunctional Coating
Approved for field level touch-up
AH-64 Apache, All surfaces
Deft 44GN098, Mil-PRF-85582, Class N
767 Italian Tanker, OML direct to metal final paint
Deft 02GN084, Mil-PRF-23377, Class N
V-22 landing gear bays, Hentzen 17176KEP
CH-47 Chinook, Final paint tie-coat, Deft 02GN084
KC-46A Tanker – Under Review
Challenges
All Mil Spec non-chrome primers qualified with a chromated surface treatment
(chromate conversion coating or chromate sealed anodize)
Will need to requalify all non-chrome primers when non-chrome surface treatments
are implemented