The coating of spot weld caps with Fe and Ni based intermetallics by using esd

In this study, the common 20 G type copper spot welding caps, which are used in industry, are coated with Fe and Ni based Fe3Al, FeAl, Ni3Al, NiAl intermetallic by Electro Spark Deposition method and compared with normal caps in terms of application capabilities. During coating the speed and frequency variables of the device were kept constant, the electrical voltage was adjusted by 3 different powers for each coating materials and 12 different coating characters were formed. After the ESD coating process, 50 spot welding process was applied in the same parameters with each cap. Various test were performed on the spot welding samples selected from specific process sequences and their welding capabilities were compared. After welding process, the deformations of the cap tips were observed and their application life was examined. As a result of the investigations, it was found that the spot weld applied with caps coated with Ni-based intermetallic materials gave better result than the other spot welds. It was observed that both welding and cap tip deformations increased as coating voltage increased.