Cailiao Baohu (Mar 2024)
Research on Wear Resistance of MoSi<sub>2</sub> Particle Reinforced Co Based Coatings by Laser Cladding
Abstract
The application of austenitic stainless steel is limited due to its low hardness and poor wear resistance, and improving the surface properties of stainless steel has important engineering significance to promote its application. In this work, composite coatings of MoSi2 reinforced Co-based alloys with different mass fractions(0, 20%, 40%) were prepared using laser cladding technology. Scanning electron microscope(SEM), X-ray diffractometer(XRD), electron probe microanalyzer(EPMA) and other methods were used to study the effects of the additive amount of MoSi2 on the microstructure, phase composition, hardness and friction and wear properties of the composite coating. Results showed that the addition of MoSi2 changed the microstructure of the composite coating from columnar crystals to equiaxed crystals and planar dendrites, and had the effect of refining the structure. As the MoSi2 content increased, the microhardness and wear resistance of the Co-based composite coating also increased. When the MoSi2 content was 40%, the microhardness of the MoSi2/Co-based composite coating was as high as 1 455 HV0.2, and the wear rate was 6.9×10-5 mm3/(N·m). Moreover, the hard phases(Cr5Si3, MoSi2, Mo5Si3 and Co2Mo3) and the new solid solution(Fe, Cr, Co) Si2 precipitated during solidification significantly improved the wear resistance of the composite coating. The wear mechanism of MoSi2 reinforced Co based alloy coatings changed with the increase of MoSi2 content, and specifically, it's transformed from the synergistic effect of abrasive wear, adhesive wear and plastic deformation into adhesive wear, brittle micro fracture and oxidative wear.
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