Microstructure and surface property improvement with WC-Co cermet using arc-cladding

This study aims to develop a WC-Co cermet coating on steel using cost-effective TIG-arc cladding, with the goal of enhancing steel's suitability for demanding wear environments in industries such as agriculture, mining, chemical processing, and oil refineries. The WC-Co coating is successfully deposited using the TIG heat source and the TIG processing conditions like current, scan speed affects the coating morphology. Microstructural analysis of WC-Co coated samples reveals the formation of equiaxed, columnar, cellular structure and also net-like structures at different current and arc scan speeds. X-ray diffraction study of developed surfaces confirms the existence of hard and brittle phases like WC, W₂C, Co₃W₃C, Fe₃W₃C, Co₃Fe₇, Co₃C, and Fe₇W₆. Microhardness of the developed surfaces varies from 800–1420 HV_0.1. The coated samples exhibit a wear loss (mg) of only 2.35% to 7.40% compared to the as-received steel substrate's wear loss (mg). The coating layer shows a remarkable improvement of corrosion behavior in 3.5% NaCl electrolyte. Maximum hardness, wear resistance, and corrosion potential of WC-Co coated layer is detected at lower input heat supply, i.e., 70 A current and 4 mm/s arc scan speed, because of partially or unmelted WC in the coating zone.