Surface modification of resistance welding electrodes by electro-spark deposited composite coatings Part II. Metallurgical behavior during welding

Electrodes with monolithic TiCP/Ni coatings and multi-layer Ni/(TiCP/Ni)/Ni coatings were used to resistance spot weld Zn-coated sheet steel to investigate metallurgical behaviour of the coatings during welding. Scanning electron microscopy, energy-dispersive X-ray analysis and X-ray diffraction were employed to characterize the microstructure of coatings, reactions of electrodes with Zn-coating and alloy layer formation. The results showed …