Tribological properties of atmospheric plasma sprayed Cr3C2-NiCr/20% nickel-coated graphite self-lubricating coatings

Using atmospheric plasma spraying technology, Cr3C2-NiCr (CN)and Cr3C2-NiCr/20 % Nickel-coated graphite (CG) composite coatings were successfully deposited on 304 stainless steel substrates, with three different spraying distance parameters designed to optimize the experiment. The study investigated the influence of nickel-coated graphite on the structure, hardness, porosity, and friction-wear performance of the composite coatings. Wear mechanisms were investigated based on analyses of morphologies and chemical states of the worn surfaces of the CG composite coatings. Our results demonstrate that the CG coating exhibits lower friction coefficients, ranging from 0.24 to 0.28, than that of the CN coating. The incorporation of nickel-coated graphite leads to formation of a solid-lubricating film at friction interface, lowering friction and wear. What's more, presence of nickel-coated graphite mitigates brittleness of the CN coating, as is deemed important for improving abrasion resistance of the coatings.