There are significant differences between trivalent chromium and hexavalent chromium in terms of their chemical properties, environmental impacts, and applications in electroplating processes. The following are the main differences between them:
Author: Anna
Difference between trivalent chromium and hexavalent chromium plating
There are significant differences between trivalent chromium and hexavalent chromium in terms of their chemical properties, environmental impacts, and applications in electroplating processes. The following are the main differences between them:
Chemical Properties
Trivalent chromium: reducing, a valence state of chromium, chemical formula Cr. generally light green in solution, reducing and oxidizing.
Hexavalent chromium: oxidizing, another valence state of chromium. It exists in the form of CrO42-(chromate) and Cr2O72-(dichromate) in water.
Environmental effects
Trivalent chromium: The toxicity is relatively low, about 1% of that of hexavalent chromium, and the pollution to the environment is small.
Hexavalent chromium: high toxicity, serious pollution to the environment, especially to water bodies.
Application in plating process
Trivalent chromium plating: It is suitable for occasions with high environmental protection requirements, and has the advantages of low toxicity, simple wastewater treatment and no chromic acid mist. It is suitable for decorative chromium plating, but the current technology limits its thickness to no more than 3μm.
Hexavalent chromium plating: traditional plating process, widely used, but serious environmental pollution, harmful to human health.
Cost difference
Trivalent chromium plating: the cost is usually higher than that of hexavalent chromium plating due to higher technical requirements and material costs.
Hexavalent chromium plating: relatively low cost, but its application is gradually restricted due to environmental regulations.
Latest Progress or Improvement
Trivalent chromium plating: In recent years, with the improvement of environmental protection awareness, trivalent chromium plating technology has been developed rapidly, especially in improving the plating performance and reducing the cost has made significant progress.
Hexavalent chromium plating: Although hexavalent chromium plating has been restricted due to environmental issues, there is still some market demand for it in some specific applications.
In summary, trivalent chromium and hexavalent chromium are significantly different in terms of chemistry, environmental impact, application in the plating process, and cost. With the strengthening of environmental regulations, trivalent chromium plating is gradually gaining favor due to its environmental advantages, especially in the field of decorative plating.