| 摘要 |
PURPOSE:To make the surface of a metallic material fine by pickling at a satisfactory rate of pickling while reducing the amount of smut stuck and the volume of hydrogen absorbed by using a mixed acid bath made of an aqueous soln. contg. specified amounts of hydrofluoric acid, hydrogen peroxide and hydrochloric acid or sulfuric acid. CONSTITUTION:When the metallic material, especially titanium or stainless steel is pickled in the mixed acid bath to remove oxide scale, the surface of the material can be made fine at the satisfactory rate of pickling by using an aqueous soln. contg. 0.5-5wt% hydrofluoric acid, 0.5-4wt% hydrogen peroxide and 2- 15wt% hydrochloric acid or 2-20wt% sulfuric acid as the mixed acid bath. Since the bath does not contain nitric acid, the troubles for generation of NOx and treatment of waste liquor contg. NO3 are obviated. |
