Search Results

New vapor deposited zinc alloy coatings, which are Zn-Mg, Zn-Al, Zn-Cr, Zn-Ni and Zn-Ti coatings, have been developed by vapor deposition pilot-line. Morphology of surface structure, depth profile of alloy composition and crystal structure have been studied for these coatings. Zn-Mg alloy coated steel sheet showed the best corrosion resistance. The corrosion behavior of this coating has been investigted. The coating surface is densely covered with a corrosion product layer composed of ZnC12·4Zn(OH)2, which could play a role as a protective barrier film. The corrosion potential remains active enough to give the substrate galvanic protection for a long time in a corrosive environment. Attention has been directed to corrosion resistance for automobile body panels in recent years and several types of zinc coated steel sheets has been developed for automotive usage.