Microstructure and wear resistance of Co-based/Cr3C2 coatings with CeO2

Metal-ceramic composite powders consisted of the single self-fluxing alloys reinforced with ceramic particles such as WC, Cr3C2 and TiC. Co-based/Cr3C2 composite coatings with CeO2 were prepared on Cr12MoV surface by laser cladding process. The dilution ratio, microstructure and phases of the coatings were analysed by scanning electron microscopy equipped with energy-dispersive X-ray spectroscopy and X-ray diffraction. Microhardness and wear behaviour were measured by digital microhardness tester and dry sliding wear tester, respectively. The obtained results demonstrated that adding CeO2 to the coatings could result in the decrease in dilution ratio. CeO2, with the appropriate amounts, could validly refine the grain and reduce interplanar spacing. Phases of the coatings principally included gamma-Co, Cr23C6 and some undissolved Cr3C2. New compounds Ce2Co17, Ce6Ni7Si4 appeared with CeO2 addition. However, the specific shape of undissolved Cr3C2 particles was hardly observed. Furthermore, both microhardness and wear resistance of the coatings were improved after adding CeO2.