| 摘要 |
PCT No. PCT/DK92/00328 Sec. 371 Date May 13, 1994 Sec. 102(e) Date May 13, 1994 PCT Filed Nov. 10, 1992 PCT Pub. No. WO93/10278 PCT Pub. Date May 27, 1993A method and a treatment solution for posttreatment of an article with a metallic surface, where the metallic surface is made of one or more metals of a standard oxidation potential within the range -2.5 to +0.5 V. A thin coating is formed on the metallic surface by a treatment with an aqueous solution containing a molybdenum compound selected among molybdic acid and salts thereof in a concentration of 2.9 to 9.8 g/l calculated as molybdenum, as well as a compound capable of forming a heteropolymolydate, such as phosphoric acid, together with a molybdate. The treatment is performed under conditions where the metal surface is maintained at a potential within the range of -600 and -1800 mV/nhe. A corrosion-protecting and/or decorative effect is obtained which can be compared with the effect obtained by conventional chromate treatment, and which avoids the environmental and toxicologic drawbacks associated with the chromate treatment. |
