Properties of Pure Silver Coating and Pure Silver/Silver-Graphite Composite Coating Prepared in KI System

Pure silver coating and pure silver/silver-graphite composite coating were prepared on the surface of copper substrate by the method of electro-deposition in a system of KI. The adhesion strength, wear resistance, corrosion resistance, thermal conductivity and resistivity of the pure silver coating and pure silver/silver-graphite composite coating were investigated. The adhesion strength of the pure silver coating and pure silver/silver-graphite composite coating on copper substrate met the requirement of GB/T 5270-2005 standard. The average friction coefficient and wear rate of the pure silver/silver-graphite composite coating were 0.178 and 2.457×10^-11 mm³·N^-1·m^-1 respectively, much less than those of pure silver coating, 0.515 and 6.501×10^-11 mm³·N^-1·m^-1. The pure silver/silver-graphite composite coating exhibited better wear resistance and worse corrosion resistance compared with the pure silver coating. The thermal conductivity of the pure silver/silver-graphite composite coating was obviously better than that of the pure silver coating, but the resistivity of the pure silver/silver-graphite composite coating was higher than that of the pure silver coating.