Effect of a conical separation region on cold gas-dynamic spraying

Results of an experimental and numerical study of the effect of conical separation regions artificially generated ahead of the target owing to impingement of a supersonic two-phase jet on the character of motion of particles smaller than 1 µm in diameter and on the process of cold gas-dynamic spraying as a whole are presented. Calculations predict a noticeable effect of the conical separation region artificially generated ahead of the target on the character of particle motion; in particular, the maximum velocity of the particle impact onto the target is found to be greater than that during spraying without the spike. Thus, the possibility of formation of a coating from particles smaller than 1 µm in diameter is demonstrated, and recommendations for implementation of the process in practice are given.