Effect of pulse shape and energy on the surface roughness and mass transfer in the electrospark coating process

The electrospark deposition process is used to improve wear performance and corrosion resistance of metal surfaces. In this study, a tungsten carbide (WC-92Co-8) coating deposited on a steel (St37) substrate using the ESD process has been carried out. Some technological parameters of coating, such as mass transfer, roughness, and diameter of droplets (splashes) that depend on pulse shapes (rectangular and triangular) and pulse energies were investigated. Amplitudes of current electrical pulse range changed from 50 to 250 A for both kinds of pulse shapes. It was found that conventional rectangular pulses were not very useful shapes for maximum mass transfer, whereas it was possible with triangular pulses to obtain maximum mass transfer results. On the other hand, the triangular pulses produced more rough surfaces than the rectangular pulses.