Research on Phase Composition and Hardness of Laser Cladding Ni-based SiC Composite Coatings

Abstract. Laser cladding is an advanced material surface modification technology. Studies shows that laser cladding can significantly improve the surface integrated performance of the metal substrate. In this way, a large number of advanced and precious alloy can be replaced and saved. In this paper, SiC ceramic reinforced Ni-base composite coating was made on the surface of Q235 steel by 2kW power laser processing system. Through the analysis of the phase and the composition about the composite coating, the regular of the organization performance under the influence of process parameters and the cladding materials can be found. X-ray diffract meter (XRD) and scanning electron microscopy (SEM) with energy spectrum analyzer (EDS) were used to analysis the phase of cladding specimen and the composition of the distribution of cladding specimen respectively. Finally, the hardness were tested, getting the following conclusion: the phase of composite coating are mainly composed of (Fe, Ni) solid solution, intermetallic compound, Cr₂Ni₃, Cr₂₃C₆ carbide and other intermediate phase composition; the diffusion of the atom between the composite coating and the substrate is conducive to improve the bonding strength; the hardness increased first and then decreased. The maximum hardness can reach 3.7 times to the substrate.