The effect of TiC/Al2O3 composite ceramic reinforcement on tribological behavior of laser cladding Ni60 alloys coatings

The composite coating reinforced with TiC and Al2O3 ceramic particles were fabricated on the Cr12MoV steel by laser cladding. The cross-section, microstructure, phase, microhardness and wear resistance of the composite coating were investigated by the optical microscope (OM), scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD), Vickers microhardness tester and dry sliding wear testing machine, respectively. An obvious crack occurs in the coating when the content of the ceramic reinforcement is 15%. Composite coatings have good metallurgical bonding with the substrate when the content of the ceramic is less 15%. The phases of the composite coatings are composed of solid solutions (Ni-Cr-Fe and γ-(Fe,Ni)), chromic carbides (Cr3C2 and Cr2C), ferric carbide (Fe3C) and ceramics (TiC and Al2O3). The composite ceramics that Ti-rich alloy compound was coating unfused Al2O3 and TiC ceramics respectively were generated in the coating. A part of Ti element and C element, dissolved from the original TiC ceramic, precipitate from the matrix to form new TiC ceramic. These kinds of composite ceramic particles significantly improved the wear resistance of the coating via enhancing the bonding strength between the ceramic particles and the matrix.