Corrosion and Wear Resistance of Electroplating Trivalent Chromium-Carbon Coating

Abstract:

A decorative and high hardness chromium-carbon coating, electrodeposited with a trivalent chromium sulfate electrolyte, could improve the environment pollutions and toxicity of hexavalent chromium system. The trivalent chromium-carbon coatings can be deposited onto substrates directly without any buffer layer. The lifetime of various mechanical parts can be improved due to their high hardness and excellent corrosion resistance. The effect of different concentration of main salt on the composition, hardness, corrosion resistance, coefficient of friction and wear resistance of the coatings were investigated. The SEM observation of surface morphology showed that the appropriate concentration of main salt can diminish the defects caused by internal stress under excessive content, As increasing the concentration of main salt from 0.05M to 0.2M, the I_corr of the coatings would be raised from 1.04×10^-6 A/cm² to 1.26×10^-5 A/cm². XRD results showed that the structure of the coatings prepared by at 0.1 M main salt with a heat treatment at 400 °C for 1 h had Cr₇C₃ and Cr₂₃C₆ phases appeared as well as the hardness of that enhanced up to 1350 Hv than 880 Hv of the as-deposited coatings. Wear test results showed that the coatings prepared by at 0.1 M main salt via a heat treatment of 400 °C had the better wear resistance.

• Periodical: Key Engineering Materials (Volume 642)
• Pages: 45-49
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.642.45
• Online since: April 2015
• Authors: Chia Wen Liao*, Kung Hsu Hou, Hsiang Cheng Wang, Chen En Lu, Ming Der Ger
• Keywords: Chromium-Carbon, Corrosion, Electroplating Trivalent Chromium, Wear Resistance

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