Wear resistance of surfaced modified CoCr alloy with stellite alloys and boron carbide coating via laser alloying

Resistance in joint prostheses remains widely studied in terms of wear due to the loose debris that causes the implant loosening failure. The present work aims to explore the tribological behavior of surface-modified CoCr alloy using Stellite 6 and Stellite 12 coatings with and without B4C additions created via laser surface alloying. The microstructural analysis of the laser surface alloying coatings was performed using metallographic techniques, scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), atomic force microscopy (AFM), and nanoindentation tests. The tribological performance of coatings was evaluated using a pin-on-disc tribometer under dry sliding wear conditions. The experimental results showed that the Stellite 6, Stellite 12, and B4C particles were uniformly distributed in the coatings produced with the circular spot of the laser. The microstructure after laser surface alloying generates different intermetallic secondary phases as M23C6, WC, and B4C carbides, modifying the mechanical and tribological response. Tribological results of Stellite 12 with B4C additions and B4C laser surface alloying coatings showed better performance by reducing the coefficient of friction and increasing the wear resistance.