| 摘要 |
<p>PURPOSE:To form a protective coating film having superior adhesion and corrosion resistance on the surface of a metal member by treating the member with an acidic phosphating soln. having a specified compsn. and by coating the treated member with cationic electrodeposition paint. CONSTITUTION:An acidic phosphating soln. contg. 0.5-1.5g/l Zn ions, 0.05-2g/l Ni or Co ions, 5-30 g/l phosphate ions and 0.01-0.2g/l nitrite ions or 0.05-2g/l m-nitrobenzenesulfonate ions or further contg. 1-10g/l nitrate ions or 0.05-2g/l chlorate ions is prepd. Steel, zinc or an alloy thereof is immersed in the phosphating soln. at 40-70 deg.C for >=15sec and sprayed with the soln. for >=2sec to form a uniform, dense phosphate film having superior adhesion and corrosion resistance and suitable for use as an underlayer for coating by cationic electrodeposition by 1.5-3g/m<2>. Coating by cationic electrodeposition is then carried out as usual to form a superior protective coating film.</p> |
