【摘要】 通常黑铬的电镀都是采用六价铬的镀液,但镀液的毒性大,污染环境,效率低。三价铬毒性比六价铬小得多,效率也较高,但镀液不稳定,颜色晦暗,附着力差。本文作者通过试验,提出了用三价铬电镀黑铬的槽液组成:CrCl₃.6H₂O 53.6 g/L,（NH₄）2C₂O₄50.0g/L,H₃BO₃1.2g/L,NH₄C180g/L,CoCl₂.6H₂O2.8g/L,BaCO₃7.6g/L(用于除去S0₄^2-),H₂C₂O₄6.0g/L。并且指出,在此电镀液组成的条件下,草酸的含量是形成合格镀层的关键。更多还原

【Abstract】 Cr⁶⁺ bath is usually used for black chromium plating, but it is unsatisfactory, due to it’s toxicity, environment pollution and low current efficiency. Cr³⁺ is much better than Cr⁶⁺ both in less pollution and current efficiency, however, the bath is unstable, coatings darker and its adherence poor. Through a series of tests, a preferable Cr³⁺ bath composition for black chromium plating is proposed as follows: CrQl₃H₂O 53.6g/L, （NH₄）₂C₂O₄ 50.0g/L, H₃BO₃ 31.2g/L, NH₄C1 80g/L, CoCl₂.6H₂O 2.8g/L, BaCO₃ 7.6g/L(to remove SO₄^2-), H₂C₂O₄ 6.0g/L. It is pointed out that according to this bath composition, the key to obtain coatings up to standard lied in the content of oxalic acid.(更多还原