The Effect of Cr Particle Size on Cr Deposition Efficiency during Cold Spraying

Cold spraying is employed to prepare Cu-Cr coatings with mixed Cu-Cr composite powders about different Cr particle sizes. The effect of size on deposition efficiency during cold spraying is studied. The result shows that Cu-Cr coatings have dense microstructure, crack-free interface and homogeneous distribution of Cr particles. There is no visible crack in the interface or among layers when magnification is 1000x after annealing at 800 degrees C for 3 h, which indicates Cu-Cr coating still bond tightly with the substrate. The EDS analysis results suggest that relative deposition efficiency of - 5, - 25 and - 45 mu m Cr are 26.14, 54.4 and 58.14%, respectively. Cr deposition efficiency increases with particle size under 25 mu m. But when particle size exceeds 25 mu m, it has slight effect on deposition efficiency. The Cr relative deposition efficiency reaches 58.14%, which is almost three times than reported before, and Cr content increases to 29.07%. The mechanical property of Cu-Cr coatings with - 45 mu m Cr is better than others. Therefore, it is feasible to choose - 45 mu m Cr to deposit coatings with high Cr content and achieve Cu-Cr alloys coatings with excellent comprehensive performance.