Deposition of composite coatings by cold spray using stainless steel 316L, copper and Tribaloy T-700 powder mixtures

Abstract

In current paper deposition of two- and three-component composite coatings on aluminium substrate using blends of stainless steel 316L, copper and Tribaloy T-700 powders is considered. Porosity value of obtained two-component copper-stainless steel coatings was significantly less than for with pure 316L coating (~ 1.5% vs. ~ 3.5%), but coating hardness was also smaller (230–250 HV3 vs. ~ 280 HV3). Deposited three-component coatings had the lowest porosity (~ 0.5%) and highest hardness value (~ 320 HV3). Compositions of obtained coatings were not similar to ones of the initial blends. In particular, percentage of Tribaloy particles in the coating was approximately two times lower than in the mixtures, whereas the copper content in the coatings exceeds the percentage in initial blends due to significant difference between deposition efficiencies of the mixture components at tested spray parameters. Numerical simulation of particle impact parameters demonstrated that particle impact velocity of Tribaloy was significantly lower than the critical value that resulted in low deposition efficiency.