| 摘要 |
A chromating bath for anti-corrosion treatment of Zn, Zn alloy or Cd surfaces, esp. galvanised steel, comprises an aqueous soln. with a pH of 1-5 (pref. 1.2-1.8). The solution contains per litre 5-40 (pref. 7-15) g hexavalent Cr ions 5-20 (pref. 7-12) g sulphate ions, 0.1-0.3 (pref. 0.1-0.2) g Co ions, 0.1-0.65 (pref. 0.15-0.3) g Ag ions and 50-150 (pref. 70-120) ml of weak organic acid such as acetic, formic or oxalic acid. |
