| 摘要 |
<p>Metal surface conditioning... By contacting the passivated surface of carbon steel, normally unaffected by an acid pickling solution, with a sulphuric or hydrochloride aicd pickling solution for at least five minutes, by contacting the surface thus treated with an aqueous, alkaline permanganate solution containing from about 5 to 50 g/l of an alkali metal permanganate and from approximately 10 to 200 g/l of an alkali metal hydroxide, and then again contacting the surface with an acid pickling solution for a period sufficient to produce a matt finish on the surface. The combination of the acid pickling solution followed by the alkaline permanganate solution attacks the passivated surface of the carbon steel, thus making the acid pickling solution effective in producing a matt finish.</p> |
