Abstract: In this paper, the contact materials with copper substrate covered by silver coating is fabricated for high-voltage disconnector by adopting powder metallurgy (PM) techniques. Through comparative tests on the performance of electroplated silver coating and the PM silver-coated layer in terms of corrosion and sulfur resistance, adhesion strength and micro-Vickers hardness, the feasibilities of using PM techniques to produce contact materials are studied. The test results indicate that the interface between the silver-coated layer and the copper matrix is tightly coupled without any noticeable defects and the adhesion strength meets the requirements of GB/T 5270—2005. The corrosion resistance of the PM silver-coated layer is close to that of the electroplated silver layer while the sulfur tolerance of the PM silver-coated layer is basically identical to the electroplated silver coating, but the surface hardness of the PM silver-coated layer is significantly higher than that of the electroplated silver layer, which is helpful to improve the wear resistance to some extent. The research in this paper shows that the method of powder metallurgy technology to produce high-voltage switch contacts is feasible theoretically, but to further promote practical applications, more research on engineering applications should be carried out.

Key words: high-voltage disconnector, silver coating, powder metallurgy, contact material property