Self-lubricating Coating Prepared by Electro- spark Deposition Using Electrode with Drilled Holes at End Face

Abstract

Cu-MoS2 self-lubricating coatings were prepared on high speed steel by electro-spark deposition (ESD) by electrode with drilled holes at the end of faces. The holes were filled with MoS2. The composition and micro morphology of the coatings were analysed. The effects of capacitance and deposition time on coating thickness were studied, and also the friction performance and wear mechanism were studied. The results show that there is nothing but MoS2 and Cu exist in the coating fabricated by this way. The micrographs show that the coating surface is uneven and many pores existing on the surface, showing typical characteristics of ESD; the surface quality is the best when it was prepared in the 3rd grade capacitance. Coating thickness firstly increases and then decreases with the increase of capacitance and deposition time. The self-lubricating coating prepared in the 3rd-grade capacitance has the lowest friction coefficient. The friction coefficients of the self-lubricating coatings prepared in the 1st and the 3rd grades stay almost constant with the increase of friction time. The friction coefficient of self-lubricating coatings prepared in the 5th grade show a clear upward trend when friction time increases. Scanning electron microscope images show shear-slip phenomenon on the wear surface.

Keywords

• electro-spark deposition
• self-lubricating coating
• micro morphology
• friction and wear