Update on alternatives for cadmium coatings on military electrical connectors

SummaryThe most promising candidate coating processes to replace cadmium and hexavalent chromium in electrical connector applications are technologies that are already being used on electrical connectors to some extent, or demonstrate both considerable promise for the application and sufficient maturity. These include:
• Electroplated aluminum (AlumiPlate®)
• Electroplated alkaline zinc-nickel (5–15% nickel in the deposit)
• Electroplated tin-zinc (at least 20% zinc in the deposit)Future efforts will focus on these three most promising candidates. In addition, to support efforts being undertaken by electrical connector manufacturers, two EN-based technologies, both incorporating occluded particles, will also be evaluated. Coatings with both CCCs and TCPs will be considered, as available, and cadmium with CCC will be used as the control.The most promising candidate coating processes from emerging alternatives were also identified. These are technologies that show promise for electrical connector applications, but require further development for the electrical connectors employed by TARDEC. These include:
• Alloys deposited from ionic liquids
• Magnetron sputtered aluminum alloys
• Tin-indium alloysFuture efforts may consider these candidates as the technology matures and becomes more feasible for electrical connectors.