Research Advances of Trivalent Chromium Black Passivation Process

Based on references from abroad and home, the main composition and mechanism of trivalent chromium solution, as well as film properties and characteristics are reported firstly. Some typical trivalent chromium black passivation technologies are introduced systemically. As hexavalent chromium is a high toxicity material, the trivalent chromium black passivation with non-chromate passivation should be widely investigated together in order to replace hexavalent black passivation.