CHROMIC ACID BASED PLATING SOLUTION AND METHOD FOR FORMING POROUS CHROMIUM PLATING LAYER ON STEEL SHEET USING THE SAME

摘要

PURPOSE: A chromic acid based plating solution is provided which can form pores in a plating layer during plating, and a method is provided which forms a porous chromium plating layer on a steel sheet using the plating solution. CONSTITUTION: The chromic acid based plating solution comprises 120 to 200 g of chromic acid, 0.5 to 1.2 g of sulphuric acid, 1.0 to 3.0 g of hydrofluorosilicic acid, 0.5 to 5.0 g of trivalent chromic ions and a balance of water per 1 liter of a plating solution. The method for forming a porous chromium plating layer comprises the process of anode electrolyzing a base steel sheet passing through electrolytic degreasing and pickling treatment at a temperature of 30 to 45 deg.C and a current density of 150 to 450 A/m2 using a chromium plating solution comprising 120 to 200 g of chromic acid, 0.5 to 1.2 g of sulphuric acid, 1.0 to 3.0 g of hydrofluorosilicic acid, 0.5 to 5.0 g of trivalent chromic ions and a balance of water per 1 liter of a plating solution.