The Performance of Three Alternative Coatings to Electroplated Cadmium for Corrosion Protection in Fastener Applications
Abstract:
The Army uses cadmium over a broad range of applications, including the production, maintenance, and repair of weapons systems and related components. The useful properties of this element have made it the number one choice for fasteners and similar components where corrosion resistance and lubricity are a concern. However, cadmium is a known carcinogen and poses health risks to those coming in contact with it. Executive Order 12856, Federal Compliance With Right-to-Know Laws and Pollution Prevention Requirements, was enacted in 1993 with the intent of reducing the total release of toxic chemicals into the environment by 50 by 1999. As such, intense research efforts have been underway to develop a coating or coating system that provides similar, if not better, properties than cadmium. ARL examined three alternatives to cadmium for corrosion protection in AH-64 fastener applications, including ion-vapor-deposited IVD aluminum, a MIL-T-83483 antiseize compound, and a MIL-C-16173 corrosion preventative compound. It was concluded that the antiseize compound and the corrosion preventative compound were not adequate replacements for cadmium based upon unacceptable fastener and aluminum block corrosion. IVD was deemed comparable to cadmium based upon the torque values, fastener corrosion, and block corrosion results.