Abstract:In this paper, the fine silver, silver-graphite and fine silver/silver graphite composite coatings were prepared on copper substrate by the electro-deposition method. The influence of treatment temperature on the contact resistance of three types of composite coating was particularly investigated. At room temperature, the contact resistance of the composite coatings has lower than that of the fine silver coating under the same torque. After heat treatment from 25 ℃ to 240 ℃, there are no significant differences of contact resistance for three types of coating. With the increase of treatment temperature from 240 ℃ to 600 ℃, the contact resistance of the fine silver coating and silver/silver-graphite composite coating gradually increased, and achieved the values of 54.3 μΩ and 42.6 μΩ under the 5 N m torque, respectively. However, the contact resistance of the silver-graphite composite coating rapidly increased with treatment temperature from 240 ℃ to 600 ℃, and achieved the values of 125.5 μΩ at 480 ℃ with the phenomenon of serious desquamate on the coating surface.