CHROMIUM-FREE RUST PREVENTIVE COATING STEEL

摘要

PROBLEM TO BE SOLVED: To produce inexpensive non-chromium rust preventive coating steel having corrosion resistance equal to or above that of rust preventive treated steel using chromium. SOLUTION: The surface layer of zinc series metallic coating steel, aluminum- coated steel or noncoated steel is provided with a rust preventive coating layer composed of an organic resin of 100 pts.wt. a thiocarbonyl group-contg. compd. of 0.4 to 50 pts.wt. and a silane coupling compd. of 0.01 to 20 pts.wt. as solid contents. The rust preventive coating layer may contain a phosphoric acid compd. of 0.01 to 20 pts.wt., or may contain particulate silica of 1 to 500 pts.wt. as well.