Effects of WC Particle Types on the Microstructures and Properties of WC-Reinforced Ni60 Composite Coatings Produced by Laser Cladding

WC-reinforced Ni60 composite coatings with different types of WC particles were prepared on 304 stainless steel surface by laser cladding. The influences of spherical WC, shaped WC, and flocculent WC on the microstructures and properties of composite coatings were investigated. The results showed that three types of WC particles distribute differently in the cladding coatings, with spherical WC particles stacking at the bottom, shaped WC aggregating at middle and lower parts, with flocculent WC particles dispersing homogeneously. The hardnesses, wear resistances, corrosion resistances, and thermal shock resistances of the coatings are significantly improved compared with the stainless steel substrate, regardless of the type of WC that is added, and especially with regard to the microhardness of the cladding coating; the addition of spherical or shaped WC particles can be up to 2000 HV0.05 in some areas. Flocculent WC, shaped WC, and spherical WC demonstrate large to small improvements in that order. From the results mentioned above, the addition of flocculent WC can produce a cladding coating with a uniform distribution of WC that is of higher quality compared with those from spherical WC and shaped WC.