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Cadmium has been identified by the United States Army's Tank and Automotive Command as a threat to worker health and the environment. Based on already completed cadmium substitute testing, an evaluation program was conducted to quantitatively analyze the resistance to vibrational loosening, torque-tension properties, environmentally assisted cracking susceptibility, and corrosion properties of zinc-based alternatives to cadmium, with and without supplemental coatings. The primary performance issues studied were fastener behavior after vibrational joint motion, mechanical performance in corrosive environments, and realistic corrosion performance. Data was generated from various laboratory evaluations and natural marine exposure of fasteners under loaded conditions. Test specimens were prepared by applying electrochemically sacrificial plating layers and supplemental coatings to 1/2-20 UNC Fine, Grade 8 fasteners and 4340 steel tensile specimens.

Cadmium has been identified by the United States Army's Tank and Automotive Command as a threat to worker health and the environment. Based on already completed cadmium substitute testing, an evaluation program was conducted to quantify the performance of environmentally acceptable, multi-layer coatings that could be directly substituted for cadmium on threaded fasteners. The performance issues investigated included coating system lubricity and corrosion control performance. Data were generated from both natural marine atmosphere exposure tests and laboratory evaluations. Test specimens were prepared by applying sacrificial plating layers and lubricous topcoat materials to commercially available 1/2-20 UNC Fine, Grade 5 fasteners. Experimental analyses included realistic torque-tension curve development, marine atmosphere exposure testing, and ASTM B 117 salt fog evaluations.