Normal temperature passivated zinc coating trivalent chromium color passivating agent

Abstract

The present invention discloses trivalent chromium color zinc coating passivator for passivation at normal temperature and its preparation process. The trivalent chromium color zinc coating passivator includes Cr3+ 1-7.5g / L, molybdate 1-25g / L, cobalt sulfate 5-15, ammonium bifluoride 1-8g / L, malonic acid 1-12g / L, phosphate 1-12 g / L, and silicate 0.2-6g / L. The trivalent chromium color zinc coating passivator solution has pH 1.8-2.3 regulated with sodium carbonate or nitric acid, passivating temperature of 20-35deg.c, passivating time of 30-60 sec and stoving temperature of 70-80deg.c. The present invention has the advantages of being practical and good use effect.

Description

technical field

[0001] The invention relates to a color passivation treatment agent for galvanized iron and steel. Background technique

[0002] Steel parts are usually passivated after electro-galvanizing or hot-dip galvanizing to prevent white rust in a short time. The color passivation process can form a thick iridescent passivation film mainly in red and green on the galvanized layer, which is not only beautiful but also has excellent anti-corrosion effect. Traditional hexavalent chromium color passivators cause serious pollution to the environment, and are gradually being replaced by environmentally friendly trivalent chromium passivators. It is not easy to form a colored passivation film on the galvanized layer by the trivalent chromium passivation process, because trivalent chromium ions usually can only produce blue or white passivation film, and the colored passivation film is due to the hexavalent chromium ion. obtained by the action of chromium ions. In additio...