| 摘要 |
<p>1,243,937. Electrolytic stripping of metal coatings. BERGISCHE METALLWARENFABRIK DILLENBERG & Co., K.G. Feb. 20, 1970 [Feb. 21, 1969; Dec.18, 1969], No. 8353/70. Heading C7B. A bath for electrolytically stripping metal coatings from a steel base comprises an alkali metal nitrate, ammonium nitrate or an amine and nitric acid; a salt of an organic acid, e.g. ammonium acetate, or a neutralization product of an amine, e.g. ethylene diamine or triethanolamine, and an organic acid to buffer the bath to a pH of 5-7; and either (a) for stripping coatings from stainless steel, a water-soluble chlorine compound and/or thiocyanate in an amount of 0À5 to 10 g/l, e.g. ammonium chloride, sodium hypochlorite or ammonium thiocyanate, or (b) for stripping coatings from hardened or nitrided steel, 0À2 - 30 g/l of an aromatic hydrocarbon compound with hydroxyl groups bonded directly to the benzene nucleus, e.g. phenol, dihydroxybenzene, cresol, thymol or xylenol. The organic acid used for buffering may be acetic acid, citric acid, lactic acid or oxalic acid. The coating to be removed may be of nickel, chromium, zinc, tin, copper, cadmium or silver.</p> |
