Investigation and characterization of electrospark deposited chromium carbide-based coating on the steel

This study deals with some structural characteristics, mechanical properties and corrosion behaviour of the chromium carbide coatings produced on microalloy steel by using electrospark deposition (ESD) process. The present study was primarily focused on the electrical parameters of deposition process to achieve a hard and thick coating. Thus, the electrical parameters of process and material transfer were investigated systematically and then the average thicknesses of deposited layers were determined. Using electrical pulses with 0.032 C electricity (current amplitude of 300 A, pulse duration of 100 μs), it has been possible to obtain a uniform coating layer with an average thickness of 80 μm after the third coating pass. The results indicate that the coating consists of fairly hard Cr7C3 and Cr0.19Fe0.70Ni0.11 phases and the wear resistance of steel substrate, which is coated by using ESD process, is noticeably enhanced under dry sliding wear conditions. Also, while the microhardness of steel substrate is 227 Hv on average, the microhardness of coating reaches 1381 Hv onto the surface. In addition to that, the corrosion resistance of steel substrate has been improved by approximately 30%.