镀锌层三价铬钝化在防腐蚀能力上无法满足一些工件高防腐蚀性能的要求,为此,采用锌镍合金进行三价铬钝化,通过盐雾试验考察了其防腐蚀能力。钝化液主要成分:77g/LCr(NO3)3.9H2O,13g/L(COOH)2,15g/LCH2(COOH)2,2g/L马来酸酐,8g/LCo(NO3)2.6H2O,5mL/L含硅化合物。结果表明,控制pH值在1.6~2.0,温度60~70℃,时间30s以上,所得钝化膜防腐蚀能力超过常规镀锌六价铬钝化膜。锌镍镀层三价铬钝化既保护了环境,又能满足工件高防腐蚀性能的要求。
Designation: A 743/A 743M –03 Standard Speci?cation for Castings, Iron-Chromium, Iron-Chromium-Nickel, Corrosion Resistant, for General Application 1 This standard is issuedunder the ?xed designation A 743/A 743M; the number immediately following the designation indicates the year of original adoption or, in the caseof revision, the year of last revision. A number in parenthesesindicates the year