| 摘要 |
Corrosion-resistance of stainless steel is improved by electrolytically coating it with zinc and then buffing the coating so that its presence is not apparent to the eye but enough zinc is left on the steel to fill its microscopic pits and voids. Typically the coating thickness is such as to represent 0.01-1 gram/sq.foot. Stainless steel trims for attaching to a mild steel panel may be formed by coating flat stainless steel with zinc, mechanically forming the resulting blank into the trim, and then buffing what is to be the visible surface. The resulting panel-trim assembly shows improved resistance to disfiguring rust-bleeding from the mild steel panel. Typically a stainless steel containing 10-30% Cr with or without one or more of Ni (up to 30%), Mo, V, Ti, Nb, W, B, N, and Se, is subjected to alkali cleaning and an activating dip in sulphuric acid which is terminated before hydrogen evolution effects pitting, and is then briefly connected as anode in the plating bath before cathodic deposition. The plating solution may be a cyanide bath at a temperature of 50-100 DEG F. containing also powdered zinc and activated carbon or an acid sulphate bath of pH 3-4 at a temperature of 45-150 DEG F. containing also magnesium sulphate. |
