Effect of TiB₂-B₄C reinforcement and laser remelting on the microstructural, mechanical, and tribological performance of HVOF sprayed WC-10Co-4Cr coating

Surface degradation due to severe sliding and abrasive wear remains a critical challenge for components used in energy, processing, and material handling industries. In the present study, WC-10Co-4Cr coatings reinforced with 5 wt% TiB₂ and 5 wt% B₄C were deposited on SS304 steel using the high velocity oxy-fuel spraying process, followed by controlled laser remelting to improve coating integrity. Microstructural analysis revealed that the incorporation of ceramic reinforcements increased hardness from 1027 HV to 1167 HV, while laser remelting further enhanced it to 1262 HV and reduced coating porosity to below 1 %. Phase analysis confirmed the retention of the WC phase, along with partial dissolution of TiB₂ into the Co-Cr binder during remelting, leading to microstructural refinement. Tribological evaluation demonstrated a significant reduction in mass loss for the remelted composite coating under both pin-on-disc and dry sliding abrasion conditions, accompanied by a transition in the dominant wear mechanism from severe abrasive ploughing to mild oxidative micro-shear. The results highlight the synergistic effect of dual ceramic reinforcement and laser remelting in developing dense, hard, and wear-resistant cermet coatings suitable for demanding industrial applications.