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Chrome Free Aerospace Coating System 31 Jan 02

Overview . PurposeAFRLPrevious ProjectsNon-chrome coating systemSummary. Purpose . Determine the current state of the technology in non-chrome aerospace coating systemsTesting as a system Previous attempts at individual component level shows limited successAssess the risk of going chrome freeProvide alternative tools for aircraft refinishing should the need arise .

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Chrome Free Aerospace Coating System 31 Jan 02

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    1. Chrome Free Aerospace Coating System 31 Jan 02 Major Barnard T. Ghim Coatings Program Manager Materials Directorate Air Force Research Laboratory

    3. Purpose Determine the current state of the technology in non-chrome aerospace coating systems Testing as a system Previous attempts at individual component level shows limited success Assess the risk of going chrome free Provide alternative tools for aircraft refinishing should the need arise

    4. AFRL Coatings Related Work MLB - R & D Paint for Life Self-assembled nanophase particles sol gel technology Permanent Primer MLSS - System Support Coatings Technology Integration Office AF Corrosion Prevention and Control Office Materials Integrity Branch

    5. AFRL Coatings Related Work Continued MLQL - Pollution Prevention Non-chromated Conversion Coatings Testing and Evaluation - March 8, 1999 From the 336 hr. salt fog test data it is evident that the non-chromated conversion coatings tested do not meet the performance requirements under MIL-C-81706.

    6. Non-chromated Conversion Coatings Testing and Evaluation Table I. Vendor Participants. Brent L71051, L7108x Bi-K No Trade Name Cape Cod Research Eldorado DoradoKote #7 Henkel Alodine 2000 Henkel Alodine 1200 (chromated control) ProCoat Brugal E-713 PPG / Man-Gill ROCC Sanchem Safeguard 7000 Solutions Technology Systems Guardthrough-M Fortune Chemical (PreKote Industries) X-IT PreKote

    7. X-it Prekote Richard Buchi - Ogden Air Logistics Center F-16 AETC Need test results with nonchromated primer and topcoat as a system Some work already accomplished

    8. No single component performs as well as hexavalent chrome component by itself Certain niche applications promising Test as a system Baseline is important Systems managers always want more data Common lessons learned

    9. Systems Approach Non-chrome Coating System Testing Get everyone on the same page Get rid of chrome Work testing as a system How are we different Focus on total nonchrome system This doesn’t mean no corrosion inhibitors It means nonchrome corrosion inhibitors

    10. Non-chrome Coating System Testing Meeting 30-31 May 2001 Project Kickoff at Wright-Patterson CTIO Develop a performance requirement document Sources Sought to find the best system Screening Test Downselect Full Assessment Flight Testing Develop system specification

    11. Non-chrome Coating System Testing Continued Sources Sought Requirements Surface Appearance: The system components will be applied to test panels initially after mixing and any induction period as defined by the manufacturer’s instructions. The finish, air dried for no less than 24 hours subsequent to final component application, shall exhibit a uniform, smooth surface, free from runs, sags, bubbles, streaks, hazing, seeding, dusting, floating, mottling, or other defects.

    12. Non-chrome Coating System Testing Continued Sources Sought Requirements Color: The coating system shall match the applicable color standard in Federal Color Standard 595a with a color difference (?E) less than or equal to 1.0 when tested in accordance with ASTM D 2244. Gloss: When tested according to ASTM D 523, the specular gloss of the system shall be as follows: Camouflage Colors 85° angle of incidence 9 max 60° angle of incidence 5 maximum Semi-gloss Colors 60° angle of incidence 15 min, 45 maximum Gloss Colors 60° angle of incidence 85 min

    13. Non-chrome Coating System Testing Continued Sources Sought Requirements Adhesion: When tested according to Method 6301, Federal Standard 141C (wet tape test), no component of the system shall peel or delaminate from the substrate or any other component of the system Ambient Temperature Flexibility: Test panels, prepared with the coating system, will be tested with a GE Impact-Flexibility Tester, or equivalent. The coating system shall exhibit no cracking or adhesion loss at 40 percent elongation.

    14. Non-chrome Coating System Testing Continued Sources Sought Requirements Low-temperature Flexibility: Test panels, prepared with the coating system, will be tested in accordance with ASTM D 522, Method B, at ­51°±3°C (­60°±5°F), using a 1.0 inch mandrel for gloss and semi-gloss colors and a 2.0 inch mandrel for camouflage colors. The coating shall exhibit no cracking after testing, when examined with the unaided eye.

    15. Non-chrome Coating System Testing Continued Sources Sought Requirements Salt Spray Corrosion Resistance: Test panels coated with the complete coating system will be scribed (using a scribing machine to insure consistency of panels), through the coating to the substrate, and placed in a 5 percent salt spray cabinet for 2000 hours as described in ASTM B 117. The panels shall not exhibit blistering or lifting of any coating components and shall exhibit no substrate corrosion.

    16. Non-chrome Coating System Testing Continued Sources Sought Requirements Filiform Corrosion Resistance: Scribed test panels will be placed vertically in a desiccator containing 12 Normal (N) HCl for one hour at 24°±3°C (75°±5°F). Within five minutes of removal from the desiccator, the test panels will be place in a desiccator maintained at 40°±2°C (104°±3°F) and relative humidity (RH) 80±5 percent for 1000 hours. Upon removal, the test panels shall not exhibit filiform corrosion extending beyond 0.25 inch from the scribe, and the majority of the filaments shall be less than 0.125 inch in length

    17. Non-chrome Coating System Testing Continued Sources Sought Requirements Fluid Resistance: The coating, applied to test panels, shall withstand immersion as follows: Fluid Fluid Temperature Immersion Time (min) MIL-L-23699F 121°±3°C (250°±5°F) 24 hours MIL-PRF-83282C 66°±3°C (150°±5°F) 7 days Skydrol LD-4 25°±3°C (77°±5°F) 30 days* Jet Fuel JP-8 +100 25°±3°C (77°±5°F) 30 days Distilled or Deionized Water 49°±3°C (120°±5°F) 30 days

    18. Non-chrome Coating System Testing Continued Sources Sought Requirements Weathering Resistance: Panels, prepared with the coating system, shall exhibit a color difference (?E) no greater than 1.0 (relative to the color before exposure) when tested in accordance with ASTM D 2244, after exposure to the weathering conditions specified below: Xenon Arc 2000 hours 102 minutes of light only, followed by 18 minutes of light plus water spray, at 60°±3°C (140°±5°F) black body temperature, 50±5% RH and 0.3 to 0.4 watt/meter2 intensity (spectral irradiance) at 340nm QUV-B 1000 hours 8 hours with a UVB-313 lamp at 65°C/149°F followed by 4 hours of darkness and water condensation at 55°C/131°F Exterior Exposure 1 year 45° south at Key West, FL or other approved site

    19. Non-chrome Coating System Testing Continued Sources Sought Requirements Humidity Resistance: Panels prepared with the coating system, shall withstand exposure for no less than 30 days in a humidity cabinet maintained at 49°±2°C (120°±3°F) and 100% relative humidity (RH), in accordance with ASTM D 2247, without blistering, softening, exhibiting any loss of adhesion, nor other coating system defects. Heat Resistance: The coating system shall withstand exposure to 121°±3°C (250°±5°F) for no less than 60 minutes. After exposure, the coating system shall exhibit a color difference (?E) no greater than 1.0 when tested in accordance with ASTM D 2244

    20. Non-chrome Coating System Testing Continued Sources Sought Requirements Solvent Resistance: The coating system shall withstand repeated rubbing with a cotton, terrycloth rag soaked in methyl ethyl ketone (MEK). The rag will be rubbed back and forth 25 times (50 passes) over the coating system, using firm finger pressure. 1.2 Tape Resistance: On test panels prepared with the coating system and air dried no more than 24 hours (subsequent to the final component application), but at least 12 hours, a strip of masking tape (3M #250 or equivalent), no less than 1 inch wide will be applied and pressed down with one pass of a roller weighing no less than 4.5 lb.

    21. Non-chrome Coating System Testing Continued Sources Sought Requirements Cleanability: The coating system shall exhibit adequate cleanability when soiled with a carbon black / MIL-PRF-83282 (Hydraulic Fluid) mixture and cleaned with MIL-PRF-85570 (Cleaning Compound, Aircraft, Exterior) Type II solution. Cleaning efficiency shall be at least 75 percent, as calculated from L values (per ASTM D 2244) of the coating system prior to soiling, while soiled, and after cleaning: Strippability: The coating system shall be strippable by all removal methods in use at Air Force Air Logistics Centers. Current stripping methods include chemical stripping (methylene chloride, benzyl alcohol based and EA chemicals), medium pressure water, and plastic media blast (Type V hardness).

    22. Non-chrome Coating System Testing Continued Sources Sought Requirements Toxicity: Coating system components shall have no adverse effect on the health of personnel when used for its intended purpose and with the precautions as identified on shipping containers and on the material safety data sheet. Composition: Cadmium and cadmium compounds, and chromium and chromium compounds are prohibited from the formulation of any component of the coating system. Non-volatile portions of the components shall contain not more than 0.06 percent by weight of lead metal or lead compounds.

    23. Non-chrome Coating System Testing Continued Sources Sought Requirements Solvent Content: All coating system components shall meet appropriate NESHAP requirements. Storage Stability: The unopened contents of each coating system component, as packaged by the manufacturer, shall meet all coating system materials and performance target requirements after storage for a period of one year where the daily temperature of the ambient air is maintained at 1.7? to 46? C (35? to 115? F).

    24. Non-chrome Coating System Testing Continued Sources Sought Requirements Accelerated Storage Stability: The coating system shall meet all the requirements specified herein after the components, as packaged by the manufacturer, have been tested in accordance with ASTM D 1849 at 60°±3°C (140°±5°F) for 7 days. Freeze Thaw Stability: The coating system shall meet all the requirements specified herein after the components, as packaged by the manufacturer, have been subjected to five cycles of freezing and thawing.

    25. Non-chrome Coating System Testing Continued Sources Sought Requirements Odor: The odor of the coating system materials, as packaged components, admixed components, and as a film after application, shall be characteristic of the materials used in manufacture and shall not be obnoxious when tested in accordance with ASTM D 1296. Viscosity and Pot Life: The viscosity/consistency of coating system components shall be suitable for manual application methods at Air Force Air Logistics Centers. The “working time” for all components shall be at least 4 hours.

    26. Non-chrome Coating System Testing Continued Sources Sought Requirements Mixing: All components of each material in the coating system shall mix readily, with a hand-held paddle, to a homogenous product. Powdered materials shall be readily soluble when mixed according to manufacturer’s instructions. Drying Time: When tested according to ASTM D1640, coating system components shall be dry to a tack free state within 5 hours, and dry hard within 12 hours.

    27. Sources Sought Responses Akzo Nobel – 3 Systems M790 Cleaner + AVIOX CF HS Primer (Proprietary Ketamine System)+ PD 5000 Used in maintenance applications by KLM and Swiss Air, more than 50 aircraft over 4 years Strong adhesion, good filiform performance M790/AL 5200 + PD296-149CF High Solids Epoxy Primer + PD 5000 AL5200 + 10PW22-XX (Successor to JG-PP Primer) + PD 5000 Successor to JG-PP Primer (10PW22-2) Increased Elongation

    28. Sources Sought Responses U.S. Paint – 1 System Alodine 5200 + “AWL-IN-ONE” NC Corrosion Inhibiting PU Base Coat + Stain Resistant High Solids Flattening Clear Coat SICO – 1 System Deanco Alu-Coat NC + Sicopoxy 577-630 Epoxy High Solids + Acrythane Aviation 584 (MIL-PRF-85285 qualified?) Alu-Coat is the best non-chrome conversion coat offering from Deanco – the Canadian licensee of Turco Products Primer based on resin system of 577-511 chromated MIL-PRF-23377 qualified primer

    29. Sources Sought Responses Adheron 1 - System Aeroprime- Al 5200 pretreatment + HS XLP 352 A/B Epoxy Primer + Aerothane-APC XLP 350 A/B APT (no non-chromated surface prep) Primer to be submitted for MIL-PRF-23377 qualification Deft – 2 Systems (According to the Deft contact, the lab is promising at least two systems, and possibly a third) System 1 System 2

    30. Other Systems PRETREATMENTS Alodine 5200 X-it PreKote SANCHEM CC-6100/7000 A.C.Tech 131 (Commercial version of Boegel) TCP (trivalent Cr) Trivalent Chromium Northrop Grumman Wipe Solvent Wipe solvent with silane adhesion promoter, Pending results of current testing

    31. Other Systems Continued PRIMER EWDY048 A/B (Type I) - PRC DeSoto ( was Spraylat) JG-PP primer TOPCOAT APC

    32. CONTROL/BENCHMARKS Control Surface Preparation - Alodine 1200 Primer - MIL-PRF-23377 Topcoat - APC Benchmark Surface Preparation - Alodine 1200 Primer - EWDY048 A/B (Type I) - JG-PP nonchrome Topcoat - APC

    33. SCREENING TESTS Scribed Neutral Salt Spray 2000 Hours / Until Failure Filiform Corrosion Resistance 1000 Hours Wet Tape Adhesion 24 Hour Soak Ambient-Temp Flexibility – GE Impact Weathering Resistance – Xenon Arc 3000 Hours / Until delta E > 3 Low-Temp Flexibility – Mandrel Bend Humidity Resistance

    34. STILL LEFT TO DO Screening Test Downselect Full Assessment Flight Testing Develop system specification

    35. Next Milestone

    36. SCHEDULE Systems getting finalized CTIO scheduling testing Eric Brooman (ITB) taking over project

    37. Funding SAIC on contract through calendar year 2002 to oversee and coordinate project UDRI (CTIO) on contract through calendar year 2002 to complete screening testing FY02 3600 funding cut ($260K)

    38. Summary Air Force unique opportunity to assess current state of technology in nonchrome aerospace coating systems

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