Surface modification of resistance welding electrode by electro-spark deposited composite coatings: Part I. Coating characterization

To improve electrode life during resistance spot welding of Zn-coated steel sheets, a monolithic TiCP/Ni composite coating was deposited onto the surface of a Cu–Cr–Zr electrode by an electro-spark deposition process. The coating was designed as a barrier to prevent electrodes from alloying with the Zn-coating leading to degradation by pitting or erosion. Some coated electrodes were also subjected to laser treatment in order to eliminate cracks …