Effect of electro spark deposition process parameters on WC-Co coating on H13 steel

H13 steel is the primary choice for the material of Aluminum Die casting molds. The life of these tools is usually enhanced by the application of WC-Co coating using electro spark deposition (ESD) process. The objective of this study is to establish the effect of ESD process parameters including voltage, duty cycle, and frequency on the characteristics of WC-Co coating on H13 steel. Design of experiment technique was used and coating thickness, coating hardness, and occurrence of defects in the coatings were studied. The results indicated that coating cracking at low spark energy is different from that at high spark energy. Moreover, it was found that by increasing spark energy, coating hardness and thickness increases. It is also shown that process parameters have interactive effects on the coating features and there is an optimum condition for achieving a sound coating. The maximum coating hardness was obtained at high spark energies.