Metal Finishing Guide Book

2011-2012 Surface Finishing Guidebook

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hex-chrome alternatives UPDATE ON ALTERNATIVES FOR CADMIUM COATINGS ON MILITARY ELECTRICAL CONNECTORS BY ROB MASON, CEF, MARGO NEIDBALSON, AND MELISSA KLINGENBERG, PHD, CONCURRENT TECHNOLOGIES CORPORATION (CTC), JOHNSTOWN, PA., AND LARGO, FLA., AND PARMINDER KHABRA AND CARL HANDSY, UNITED STATES ARMY TANK-AUTOMOTIVE RESEARCH DEVELOPMENT AND ENGINEERING CENTER (TARDEC), WARREN, MICH. The metal finishing industry has been impacted by numerous regulatory actions related to the hazardous materials that are used in decorative and functional coat- ing processes. These environmental regulations are applicable to both com- mercial and government facilities. In addition, Executive Order (EO) 13423, Strengthening Federal Environmental, Energy, and Transportation Management, and EO 13514, Federal Leadership in Environmental, Energy, and Economic Performance, were recently enacted. These EOs require government agencies to reduce the quanti- ty of toxic and hazardous chemicals and materials acquired, used, or disposed. Cadmium and hexavalent chromium are very toxic and carcinogenic materi- als heavily regulated by the Environmental Protection Agency (EPA) and the Occupational Safety and Health Administration (OSHA). In addition, hexavalent chromium is among the three hazardous materials that the Department of Defense (DoD) has targeted for reduction to meet the requirements of the EO 13423. Due to the toxicity and carcinogenicity, as well as the numerous regula- tory actions related to these materials, the U.S. Army Tank-automotive Research Development and Engineering Center (TARDEC) has been working to eliminate or reduce the use of cadmium and hexavalent chromium in ground vehicles and related systems. The National Defense Center for Energy and Environment (NDCEE), operated by Concurrent Technologies Corporation (CTC), has been tasked to support TARDEC's activities in this area. Specifically, the protective shells of electrical connectors currently used in mil- itary ground systems are cadmium plated and then chromated with chromate con- version coatings (CCCs) to provide additional corrosion protection. The afore- mentioned regulatory concerns underscore a need to find alternatives to the currently used coating processes to reduce environmental and safety risks. However, the replacement of cadmium for any application is not a trivial task. Cadmium has been used as a protective coating for electrical connectors for many years because of the numerous properties that it imparts to the overall com- ponent. Key properties that cadmium coatings impart to electrical connector shells include: 1,2 • Ease of manufacturing • Ease of repair • Electrical conductivity • Electromagnetic compatibility (EMC)/electromagnetic interference (EMI) effectiveness 308

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