| 摘要 |
PURPOSE:To improve the paint adhesiveness of an electrolytic tin plate in the stage of producing the electrolytic tin plate by tin plating of a steel plate by dipping the steel plate into an aq. soln. prepd. by incorporating specific ions into an essential material consisting of soluble chromic acid salts after a reflow treatment of tin plating. CONSTITUTION:The surface of the steel plate is cleaned by degreasing and pickling and thereafter the steel plate is subjected to tin plating and further to the reflow treatment to form the electrolytic tin plate. The plate is immediately dipped into the aq. soln. which contains chromic anhydride, sodium chromate, sodium dichromate, sodium acetate and other soluble chromic acid salts as the essential material and is added with an assistant contg. either or both of an SO<2->4 ion source such as sulfuric acid and F-ion source such as NH4F or HF, is adjusted to 1-3pH and is kept at >=95 deg.C. The content of SnO2 on the tin surface after the reflow treatment is decreased and the amt. of the chromate film is increased. The steel plate is rinsed and dried and the electrolytic tin plate having the excellent corrosion resistance and paint adhesiveness is produced.
|
