Microstructure and properties of Ag/SnO₂ coatings prepared by cold spraying

Cold spraying was used to fabricate Ag/SnO₂ coatings on copper substrate with high energy ball milled Ag/SnO₂ composite powders. The cold sprayed coatings were annealed under vacuum at a temperature of 600°C and 850°C for 2h. Vickers microhardness and arc erosion tests were conducted to determine the mechanical properties and arc erosion properties of the coatings. The effect of annealing temperature on the microstructure, microhardness and arc erosion of the coatings was investigated. It was found that cold sprayed Ag/SnO₂ coatings exhibited denser microstructure and better coating-substrate interface after annealing at 850°C. The hardness of Ag/SnO₂ coatings was evidently influenced by annealing temperature. The arc erosion test results indicated that the arc erosion properties of cold sprayed Ag/SnO₂ coatings can be improved significantly by annealing; the coatings annealed at 850°C showed the best arc erosion properties.