Effects of Heat Treatment Temperature on Properties of Hard Chromium Coating

Microhardness and wear resistance of a hard chromium coating obtained with a solution containing organic additive were investigated as a function of heat treatment temperature. Meanwhile, XPS, EDAX and X-ray diffraction analyses were conducted to reveal the underlying micromechanism. It was found that: (1) the microhardness and the wear resistance both were significantly improved when the coating was heat-treated at 200℃~300℃ for 1 hour; (2) the content of carbon element within coating was rather high; (3) no changes in crystal structure could be detected for the heat-treated coating. Based on the above results,it was suggested that some sort of organic carbonides must be generated during the heat-treatment, which should be responsible for the properties and improvements.