Examination of the Critical Velocity for Deposition of Particles in Cold Spraying

Abstract

Abstract The critical velocity of copper powder for particle deposition in cold spraying was estimated both experimentally and theoretically. The dependency of the critical velocity on particle temperature was examined. The theoretical relationship between deposition efficiency and critical velocity at different spray angles was utilized to estimate the critical velocity experimentally. The numerical simulation of particle impact deformation was utilized to estimate the critical velocity theoretically. The estimation was performed for Cu particle under different particle temperatures. The experimental deposition was conducted using Cu particles of different temperatures under different spray angles to reveal the evidence of the dependency of the critical velocity on particle temperature. The theoretical estimation was based on the critical velocity corresponds to the particle velocity at which the impact begins to cause the adiabatic shear instability. It is found that the critical velocity is significantly influenced by particle temperature besides the type of material. The critical velocity of particle decreased with the increase in particle temperature, which is attributed to the thermal softening effect at elevated temperatures.