The current way of protecting aluminum alloys used for structural components of aircrafts consists in:
o using a surface anodizing pretreatment (hazardous chromated pretreatment still often used)
o then spraying either a chromated solventborne paint or a chromated waterbased paint. With this process of application, hazardous oversprays (containing chromates) are important and only 40% in average of the paint is transfered to the surface.
• PPG is the historical leader in electrodeposited paints. We have all the expertize and equipments available in that field to design new polymers, formulate anaphoretic paints, characterize surface and interphases, design ecoat lines, educate and assist users.
• PPG is also leading the Aerospace market segment for paints and sealants. We have built a strong experience in chromate free primers for corrosion protection of structural components of aircrafts.
• Based on our experience the use of anodic paint is ustified for Aerospace aluminium alloys because :
• a protective anodic layer is formed at the same time the paint deposits at the surface of the alloy during the electrophoresis process. That will allow to eliminate the current hazardous anodizing process step
• as aluminium alloys used in Aerospace cannot support temperature above 120°C, anodic paint technology only is adapted
• VOC is bellow 100g/l
• Transfer efficiency is very high (98% vs 40% for current paints used for same purpose) so almost no waste
First screening done by using an existing PPG anodic paint showed encouraging results vs Aerospace main OEMs specifications. In particular critical tests like hydraulic fluid resistance and water resistance were achieved Al2024 alloy without anodizing pretreatment. Also first corrosion tests performed on Al2024 were closed to the target (3mm max filament). We are strongly convinced that the optimisation of that technology will meet the major OEMs specifications for protecting light alloys like 2xxx, 7xxx and A
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