Chrome Free Aerospace Coating System 31 Jan 02

1
Chrome Free Aerospace Coating System 31 Jan 02

• Major Barnard T. Ghim
• Coatings Program Manager
• Materials Directorate
• Air Force Research Laboratory

2
Overview

• Purpose
• AFRL
• Previous Projects
• Non-chrome coating system
• Summary

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
AFRLCoatings 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
AFRLCoatings 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

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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
Common lessons learned

• 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

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Systems ApproachNon-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 doesnt mean no corrosion inhibitors
• It means nonchrome corrosion inhibitors

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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
  manufacturers 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
  513C (605F), 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
  243C (755F). Within five minutes of
  removal from the desiccator, the test panels will
  be place in a desiccator maintained at 402C
  (1043F) and relative humidity (RH) 805
  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 1213C (2505F) 24 hours
• MIL-PRF-83282C 663C (1505F) 7 days
• Skydrol LD-4 253C (775F) 30 days
• Jet Fuel JP-8 100 253C (775F) 30 days
• Distilled or Deionized Water 493C
  (1205F) 30 days

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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 603C (1405F) black body temperature,
  505 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
  65C/149F followed by 4 hours of darkness and
  water condensation at 55C/131F
• Exterior Exposure 1 year 45 south at Key West,
  FL or other approved site

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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 492C (1203F) 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 1213C (2505F) 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.

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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.

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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).

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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 603C (1405F) 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.

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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.

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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 manufacturers 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.

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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

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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

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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

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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

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Other Systems Continued

• PRIMER
• EWDY048 A/B (Type I) - PRC DeSoto ( was Spraylat)
  JG-PP primer
• TOPCOAT
• APC

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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

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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 gt 3
• Low-Temp Flexibility Mandrel Bend
• Humidity Resistance

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STILL LEFT TO DO

• Screening Test
• Downselect
• Full Assessment
• Flight Testing
• Develop system specification

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Next Milestone

• After screening testing, will deseminate results
  to see if there is interest to go further
• If successful, need weapons system buy in for
  flight testing and funding for full downselected
  testing
• If unsuccessful, will report risk factors analysis

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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)

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Summary

• Air Force unique opportunity to assess current
  state of technology in nonchrome aerospace
  coating systems