Microstructure and properties of cold sprayed composite coatings

Abstract

Purpose: The composite coatings containing incorporated ceramic achieve a wide spectrum of enhanced properties, resulting from a combination of features from a ductile matrix and hard particles. This article attempts to explain how the alumina addition to Ni powder influences the microstructure and mechanical properties of the composite Ni-Al2O3 coatings cold sprayed on the 7075 Al alloy. Design/methodology/approach: The coatings were formed during a deposition of the powder particles step by step which impacts with high velocities onto the substrate, deform, and adhere to it or to other particles. Findings: The incorporation of Al2O3 in the Ni matrix induced a larger plastic deformation of the powder particles and reduced the porosity of the coatings. The Ni-Al2O3 coatings were characterized by a lower surface roughness compared to Ni deposits. The Young modulus of the Ni-Al2O3 coatings were found to be higher than Ni coating.