Microstructural Evolution and Wear Behavior of HVOF Spraying WC/Co Coatings Produced by Laser Cladding

G. Lian, M. Jean Fujian University of Technology, School of Mechanical and Automotive Engineering, 350118 Fuzhou, China

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This study reports that laser-treated HVOF-spray coated surfaces of WC/Co composite were fabricated on 45 carbon substrates using laser treatment technology. The hardfacing coatings were applied by combining two different techniques of HVOF spraying and laser irradiation. Wear behavior of the coatings was systematically investigated, and microstructural evolution of the laser melted HVOF-sprayed coatings was characterized and compared with that of HVOF-sprayed coatings. Microstructural observation shows that both coatings exhibit similar phases, but there are differences in the formation of tungsten carbide, micro-hardness distribution, closely packed structures and wear behaviors of the coatings. Coatings with evenly distributed WC ceramic phases and a better bonding mechanism to the substrate alloy were obtained by laser-based HVOF spraying treatment. The results of this study indicate that the wear behaviors of the HVOF-sprayed WC/Co composite coatings prepared by laser irradiation are much better than those of the plain HVOF-sprayed coating. The wear volume loss of HVOF-sprayed WC/Co composite coating prepared by laser melting treatment is the lowest, only 50% of that of the HVOF-sprayed coating, thereby providing better wear resistant properties. Overall, the increase in wear resistance was attributed to the formation of dendritic-tungsten carbide, high micro-hardness distribution and to closely packed structures of the coatings.

DOI:10.12693/APhysPolA.134.93 topics: WC/Co, laser melting, high velocity oxygen fuel, mechanical properties, microstructure