Cold Spraying on Materials with Low Erosion Resistance

The paper describes a cold spray process intended for deposition of aluminum coatings onto the surface of materials prone to erosion damage. The particles were accelerated in an ejector nozzle, with the working gas being air. Particle velocities were measured at the nozzle exit using nozzles of different geometries, in the temperature range from 300 to 600 K. Also, substrate mass change coefficients were measured. For the first time, it was shown that the erosion adhesion transition may occur at different particle velocities (500 and 385 m/s) yet at roughly one and the same air stagnation temperature (similar to 570 K). At lower stagnation temperatures, erosion is observed and, in compliance with general physical principles, higher erosion coefficients correspond to higher particle velocities.