Performance Characteristics And Depot Application Experience With A Reduced Chromate Coating System

1. AACP 2005 AF-Corrosion Conf.ppt | 16 March 2005 Performance Characteristics And Depot Application Experience With A Reduced Chromate Coating System Joseph H. Osborne Boeing Phantom Works � Seattle

2. AACP 2005 Aging Aircraft.ppt | 2 Chromate Reduction US Air Force Goal � Eliminate chromates by 2009 Drivers for reducing chromate OSHA rules EPA rules Chromates used in primers, sealants for corrosion protection Interior use (structure, fuel tanks) are �permanent� Replaced only when structural modifications or repairs are made Exterior use (fuselage) are replaced periodically Depot maintenance, structural inspection Frequent touchup and repair Generates significant exposure and waste treatment $100K - $500K for strip and repaint aircraft Replacing chromates on legacy vehicles requires care Designs and material selection made with chromates in mind New protection schemes must interact with existing structure Increasingly strict Environmental regulations are driving changes in materials and processes used to build and maintain aircraft. Chromates are a particular target as they can cause cancer in workers and are toxic in the environment. OSHA has regulations in work to lower the exposure limits from 50 mg/day to 1 mg/day or lower. Much discussion during the week regarding ramifications of this change. A tentative goal of the AF is to eliminate use of chromates by 2009. Aggressive. Need to identify new materials and processes to achieve. Chromates widely used for corrosion protection of aluminum and steel structure and components. Use poses different risks depending on where it is in the system. The OEM production environment benefits from good control of the production environment. Field operations are more difficultMaterials used on interior are rarely maintained. Risk to field operation an d maintenance personnel is minimal. Exterior materials are often maintained in field operations and are routinely replaced during the operational life of the vehicle. These materials represent the greatest risk to workers and waste treatment. AACP program goal is to valdiate performace and producibiltiy of a reduced chromate coating systemIncreasingly strict Environmental regulations are driving changes in materials and processes used to build and maintain aircraft. Chromates are a particular target as they can cause cancer in workers and are toxic in the environment. OSHA has regulations in work to lower the exposure limits from 50 mg/day to 1 mg/day or lower. Much discussion during the week regarding ramifications of this change. A tentative goal of the AF is to eliminate use of chromates by 2009. Aggressive. Need to identify new materials and processes to achieve. Chromates widely used for corrosion protection of aluminum and steel structure and components. Use poses different risks depending on where it is in the system. The OEM production environment benefits from good control of the production environment. Field operations are more difficultMaterials used on interior are rarely maintained. Risk to field operation an d maintenance personnel is minimal. Exterior materials are often maintained in field operations and are routinely replaced during the operational life of the vehicle. These materials represent the greatest risk to workers and waste treatment. AACP program goal is to valdiate performace and producibiltiy of a reduced chromate coating system

3. AACP 2005 Aging Aircraft.ppt | 3 Getting the Chromate �Out� AACP Program Goal � Production demonstration of a reduced chromate coating system for exterior applications AC 131/Boegel with chromated primer plus APC topcoat Performance goal: equivalent to existing system Overall roadmap of where we want to go with coatings to mitigate our dependence on hexavalent chromium. Current state of art systems need some chromate for adequate performance so can�t completely eliminate yet. Strategies to reduce chromate have two paths, use nonchromate primer or use nonchromate conversion coating. Choice depends on what major driver � airborne or waterborne � is the most important. Locally determined. Least perfomance risk is to maintain chromate primer as primer dominates performance. However, primer contains the bulk of the chromates in the coating system. Nonchromate primers are evolving rapidly and are becoming increasingly capable. Overall roadmap of where we want to go with coatings to mitigate our dependence on hexavalent chromium. Current state of art systems need some chromate for adequate performance so can�t completely eliminate yet. Strategies to reduce chromate have two paths, use nonchromate primer or use nonchromate conversion coating. Choice depends on what major driver � airborne or waterborne � is the most important. Locally determined. Least perfomance risk is to maintain chromate primer as primer dominates performance. However, primer contains the bulk of the chromates in the coating system. Nonchromate primers are evolving rapidly and are becoming increasingly capable.

4. AACP 2005 Aging Aircraft.ppt | 4 Presentation Overview Describe AACP Program Engineering Performance Data Describe applications �scorecard� Phase II activities Summary Overview of talk. Won�t spend much time on engineering properties. Repeated tests show that in the laboratory it is difficult to show conditions that will cause coating system failures (adhesion, corrosion). Correlating laboratory data with operational experience is one of the goals of AACP. Focus in this talk is the production application of AC-131BB, lessons learned from that application, and a look ahead to the second half of the program.Overview of talk. Won�t spend much time on engineering properties. Repeated tests show that in the laboratory it is difficult to show conditions that will cause coating system failures (adhesion, corrosion). Correlating laboratory data with operational experience is one of the goals of AACP. Focus in this talk is the production application of AC-131BB, lessons learned from that application, and a look ahead to the second half of the program.

5. AACP 2005 Aging Aircraft.ppt | 5 Advanced Aircraft Corrosion Protection Program Transition demonstration of coating system Objective: transition technology from lab to field Funding through ASC/AAA Phase I � Performance Verification and Optimization Inspection techniques Cleaning & deoxidizing Requirements Large volume application procedures Coatings removal processes Verify overall system performance Phase II � Operational Testing Monitor coating system applied on operational aircraft Validate enhanced processing methods and 2nd gen materials