ADVANCES IN REPLACEMENTS FOR CADMIUM PLATING IN AEROSPACE APPLICATIONS

This paper examines some of the problems associated with the replaceme nt of cadmium plating for the protection of aircraft components and fa steners manufactured from steel. It reviews the range of coatings whic h are available commercially and are currently being considered as alt ernatives to cadmium plating. Results of research being undertaken int o the corrosion behaviour and galvanic compatibility of electrodeposit ed zinc alloy coatings and aluminium-magnesium alloy coatings are pres ented. Other aspects of coating performance are also considered includ ing frictional properties, effects of coatings on fatigue strength, hy drogen embrittlement of steels and the repair of damaged coatings. It is concluded that although the corrosion performance of cadmium platin g may be achieved with several coating systems, no one coating is like ly to be acceptable as a replacement for cadmium for all aerospace app lications.