Microstructure and Properties of Cu-Cr Coatings deposited by Cold Spraying

Abstract Cold spraying is used to deposit coatings on a copper substrate with mixed Cu-Cr composite powders. The morphology evolution of Cu and Cr phase during cold spray is studied. And the mechanical properties of Cu-Cr coating is researched. Results indicate that ductile copper shows heavy plastic deformation, brittle chromium shows some crack and even break during cold spraying. Cold sprayed coatings show a good adhesion with substrate and a homogeneous distribution of Cr particles in the microstructure. The Cr contents of coatings are 13.06 % -16.01 % which obviously reduce compared to feedstock (45.00 %) due to the high hardness and poor deformation. The hardness of Cu-Cr coatings is 145.7 Hv. Copper further deform during the wear process while chromium show evidence of brittle fracture. The dominant wear mechanism for the Cu-Cr coatings is plastic deformation and delamination. The electrical conductivity of pure Cu coatings and Cu-Cr coatings are 73.28 % and 53.49 % IACS, respectively. Cu-Cr coatings have similar hardness and electrical conductivity as of Cu75Cr25 alloy ingots (VIM). The results indicate that cold spray technique provides an effective approach to manufacture uniform and dense Cu-Cr coatings with accepted physical and mechanical properties.