Accession Number : AD1029080

Title :   Non-chromate Passivation for LHE ZnNi

Descriptive Note : Technical Report,01 Oct 2015,30 Jan 2017

Corporate Author : Missouri University of Science and Technology Rolla United States

Personal Author(s) : O'Keefe,Matt

Full Text :

Report Date : 01 Mar 2017

Pagination or Media Count : 42

Abstract : Missouri University of Science and Technology (Missouri S and T) collaborated with Dipsol of America (Dipsol) and Boeing Research and Technology (BR and T) to develop and evaluate low contact resistance passivation layers for Department of Defense electrical system components. Specifically, the team examined five different types of passivation layers that were free of hexavalent chromium for low hydrogen embrittlement (LHE) ZnNi coatings. Passivations included a trivalent chromium passivation (TCP or Cr(III)), a Co-Free TCP, and a Modified Co-Free TCP developed at Dipsol as well as two cerium based conversion coatings (CeCCs) developed at Missouri S and T using cerium chloride and cerium nitrate sources. Hexavalent chromium passivation on electroplated ZnNi was used as a reference. Characterization of the electrical, electrochemical, corrosion, and materials performance of the passivation layers was done to evaluate the corrosion performance and electrical resistance after neutral salt spray exposure. The major outcome of this project was to identify the most promising passivation layer(s) that are free of hexavalent chromium and can be used on LHE ZnNi plated electrical connectors for military electrical system components.

Descriptors :   PASSIVATION (METALLURGY) , coatings , corrosion resistance , electrical resistance , test methods

Subject Categories : Metallurgy and Metallography

Distribution Statement : APPROVED FOR PUBLIC RELEASE