Microstructural and tribological properties of cold sprayed high content SiCp/Al coating by SiCp mild-oxidation treatment

Abstract

This paper presents the results of the influence of irregular SiC particles, treated by mild-oxidation at 1100 °C, on deposition behavior (deposit rate, surface finish roughness), and deposition body (microstructure, friction, and wear). Coatings are obtained using the cold-sprayed method, employing a powder mixture comprising 36 vol% irregular SiC powder treated by mild-oxidation and 64 vol% aluminum powder as feedstock. Results show that the silicon carbide particles are treated by mild-oxidation, the external surface of silicon carbide particles is predominantly composed of soft ceramic silica, and the particle edges are passivated. The results indicate that, under identical cold-sprayed process conditions, both the deposition amount of the coating and the retention amount of SiC particles increased. The particle fragmentation and particle distribution of SiC are obviously improved. The coating did not exhibit any harmful phases. Local weak metallurgical bonding is found at the interface of SiCp and Al matrix. Furthermore, the coating's porosity decreased, after SiCp mild-oxidation, the friction coefficient (0.5716) is decreased by 12.9 %, and the wear amount (0.159 mm3/N·m) is decreased by 64.7 %. A dense and uniformly distributed aluminum matrix composite coating with a high SiC particles content is achieved.