Mass loss of copper alloy electrode during TiB2 coating by electrospark deposition

Titanium diboride was deposited on the surface of spot-welding electrodes for zinc coated steel sheets due to its high electrical and thermal conductivity and potential to prolong the lifespan of the electrodes, and mass of the electrodes was measured after every 30 s during depositing. The results showed that the as-deposited electrodes are losing their mass during the process, which is completely different from the deposition of TiC. Evaporation of copper and oxidation of TiB2 at high temperature generated by electrosparking play the most important roles in the mass loss. Cutting and flaking of the brittle coating also contribute to the mass loss. The cracks within the coating are channels for the leakage of the evaporated substrate material. The mass of the electrodes decreases as the pulse energy increases with the voltage increasing. Pre-coated nickel contributes to the mass loss of the electrodes too.