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Thursday, June 10, 2004 - 1:30 PM
EMP3.1

Kinetic Metallization of Aircraft Components Using Environmentally Compliant Sacrificial Anodic Coatings

R. M. Tapphorn, M. H. Gabel, Inovati, Santa Barbara, CA

High strength steels such as 300M or A-286 (Aeromet 100) superalloys are typically used in aircraft landing gear components. Such components require a corrosion protection coating, but more importantly the coating must be abrasion and impact resistant to achieve any significant lifespan in field applications. Cadmium is a sacrificial anodic coating that continues to provide galvanic protection even when breached to expose the underlying surface. Unfortunately, the cadmium coatings are no longer environmentally acceptable by Executive Order EO13148. Thus, environmental management groups within the Department of Defense are seeking alternative materials and processes for depositing highly dense corrosion and wear resistant coatings on these high strength steel components. The closest single material to serve as a replacement for cadmium on high strength steels is aluminum. Currently, the only processes being evaluated for aluminum coatings on steel have been oxygen-free organic plating (Alumiplate), Al-Mn molten salt bath electroplating, and Ion Vapor Deposition (IVD) of aluminum. Both plating processes are still under development and require the use of electrolytic solutions. IVD aluminum coatings must be applied in a vacuum chamber and have columnar grain structure with too much porosity. Inovati has recently developed a sacrificial anodic coating called "AlTrans" that is applied to steel telecommunication racks using the Kinetic Metallization (KM) process. This aluminum composite coating yields a fully dense sacrificial metallic coating for potential cadmium replacement on aircraft components. Performance testing of this environmentally compliant coating applied to steel components with the KM process will be presented in this paper.