Effect of nano-Cu-coated MoS₂ added to SiC-Ni60 coatings on their organization and frictional wear properties

The nano-Cu/MoS₂ nickel-based alloy clad layer was prepared on 42CrMo steel substrate by laser cladding method. The organization and wear and friction reduction properties of the nano-Cu/MoS₂ clad layer with different contents were investigated by scanning electron microscopy, XRD, microhardness tester and friction wear tester. The results show that the nano-Cu/MoS₂ nickel-based alloy clad layer prepared by laser cladding technology has fine equiaxed crystals in the middle and upper part of the layer, and mainly has columnar crystals in the middle and lower part of the layer near the fusion line. After the addition of nano-Cu/MoS₂ particles, the equiaxed grains in the middle part of the cladding layer were partially transformed into strips, metal sulfide (CrS) and soft metallic copper were produced in the cladding layer, and some fine MoS₂ particles were distributed at the grain boundaries; affected by the lubrication phase and partial grain coarsening compared with C1 (0% nano-Cu/MoS₂), C2 ~ C4 (5% ~ 15% nano Cu/MoS₂) the hardness of the clad layer decreased significantly but 1.45 ~ 2.06 times compared with the substrate, with good mechanical properties; while the frictional mass loss increased up to 0.0198 g and the friction coefficient decreased gradually, the lowest friction coefficient of the clad layer (0.4430) was significantly lower than C1. Considering the mechanical properties, friction coefficient and friction mass loss, the mechanical and tribological properties of the molten layer are good at 10% nano-Cu/MoS₂ content, 290 w laser power and 6 mm/s scanning speed.