Abstract
Cold Gas Dynamic Spray (CGDS), is a relatively new coating process in which small powder particles are accelerated to form coatings. Ductile metal powders are injected into a supersonic jet to achieve speeds of up-to approximately 1000m/s. Upon impact the powder particles dissipate their kinetic energy and form a coating without melting of the powder and unwanted heating of the substrate. In this process high deposition rates, at atmospheric conditions, of a wide range of ductile powders without phase change, grain growth or high residual stresses is possible. CGDS is ideal for production of coatings with bioactive materials, where it is desirable to maintain the chemical integrity of the powder in the coating. A twin powder feeder, that can feed two different materials in a cold gas dynamic spray system has been developed. The layered coatings of copper and aluminum are produced by this method are described.
