Passivation treatment after hard chrome plating is usually performed to improve the corrosion resistance and surface quality of the coating.
Author:Marisa
Passivation after hard chrome plating is usually to improve the corrosion resistance and surface quality of the coating. Common passivation methods are as follows:
Trivalent chromium passivation: Trivalent chromium passivation is a more commonly used method in recent years. It uses a chemical solution containing trivalent chromium for passivation. Compared with traditional hexavalent chromium passivation, trivalent chromium passivation is more environmentally friendly, less toxic, and has better corrosion resistance. Trivalent chromium passivators usually contain ingredients such as chromates, sulfates, and phosphates.
Hexavalent chromium passivation: Although hexavalent chromium passivation has good corrosion resistance and color, due to the high toxicity and environmental pollution risk of hexavalent chromium, this method has been restricted or gradually eliminated in many countries and regions. Hexavalent chromium passivators usually include chromic acid, chromates, etc.
Chromium-free passivation: In order to further reduce the impact on the environment, some chromium-free passivation technologies have also appeared on the market. These technologies use other metal salts (such as molybdates, silicates, titanates, etc.) or organic matter as passivators to achieve passivation of hard chrome coatings. Chromium-free passivation is not only environmentally friendly, but also can meet the requirements for corrosion resistance and appearance of the coating in some specific occasions.
Composite passivation: A passivator that combines multiple elements to achieve better passivation effects by optimizing the formula, such as combining trivalent chromium and inorganic salts, or inorganic salts and organic matter. This passivation method can provide better corrosion resistance and surface aesthetics.
The choice of passivation method depends on the specific application requirements, cost considerations, and environmental protection requirements. It is recommended that when choosing a passivator, consider its impact on the environment, try to choose an environmentally friendly passivator, and follow relevant operating specifications and safety standards.