固体润滑国家重点实验室（LSL）知识库

NiCr–Ag composite solid lubricant coating was deposited on stainless steel by atmospheric plasma spray. The microhardness, phase composition and microstructure of as-sprayed coating were characterized. Meanwhile, the friction and wear behaviour of as-sprayed coating sliding against ceramic (Si₃N₄) ball in air, argon and oxygen were evaluated using a ball-on-disc friction and wear test rig. It was found that when sliding against Si₃N₄ in oxygen, the composite coating underwent severe oxidative wear and splat delamination, showing the highest friction coefficient and wear rate. When sliding against Si₃N₄ in argon, the composite coating had the lowest friction coefficient and wear rate; and in this case, no crack and splat delamination could be observed on the worn surface because of the elimination of oxidation of the coating and enrichment of solid lubricant silver on sliding surface in inert atmosphere. In addition, the friction coefficients of the as-sprayed coating in all three atmospheres decreased with the increase of sliding speed or load.