Factors Affecting the Appearance of Chromium (III) Passivation Film on Galvanizing Coating

Chromium(Ⅲ)passivation technology has been increasingly used so as to meet the requirements for environment protection of electronics and electric products.Thus the factors affecting the appearance of Cr(Ⅲ)passivation film on galvanized coating were explored.It was pointed out that after the composition and dosage of the passivation agent were determined,the appearance of the resulting Cr(Ⅲ)passivation film was dependent on the degree Baume of the passivation fluid,pH value,passivation temperature,passivation duration,and the temperature at which the passivafilm was dried.At the same time,the appearance of the Cr(Ⅲ)passivation film was also related to the purity and aging of the passivation fluid,and to the galvanizing bath system and the size,shape,and surface roughness of the parts as well.