Research on Laser directed energy deposition of WC/ Co-based Strengthened Coating on the Surface of Automotive Stainless Steel

To enhance the wear resistance and service life of automotive 304 stainless steel surfaces, WC/Co-based composite reinforced coatings were fabricated via laser directed energy deposition. The effects of different WC particle contents on the microstructure and properties of the coatings were systematically investigated. Through optical microscopy observation, X-ray diffraction analysis, hardness testing, and friction and wear experiments, the evolution of the microstructure, phase composition, hardness variations, and wear resistance of the coatings were comprehensively analyzed. The results show that the coatings mainly consist of fcc-Co, Co₆W₆C, Fe₆W₆C, and W₂C phases. With the increase of WC particle content, the proportion of hard phases rises and significant grain refinement occurs. Both macro- and micro-hardness of the coatings increase markedly with higher WC content, reaching 86.4 HRA and 1123.7 HV₀.₅ when the WC content is 40%. Meanwhile, the wear rate of the coatings decreases significantly with the addition of WC particles, and the wear resistance is substantially improved. The enhancement in mechanical properties is attributed to second-phase strengthening, grain refinement strengthening, and dispersion strengthening mechanisms induced by WC particles. This study provides theoretical guidance and technical support for the surface modification and strengthening of automotive stainless steel components.