Abstract
By cold spraying, coatings are produced without significant heating of the spray powder and the substrate material. The powder particles are accelerated in a preheated gas stream to velocities of more than 500 m/s without melting and form a dense and tightly bonded coating. Bonding occurs only due to plastic deformation and the heat created thereby. Due to the absence of melting of the powder particles during cold spraying, several negative phenomenon, such as oxidation and phase transformations associated with thermal spray processes, such as HVOF, arc, flame and plasma spray can be minimized or avoided. This paper presents an overview of cold spray process developments and of coating characteristics. A variety of metallic powders having a low or high melting temperature including Cu, Al, Ti as well as alloys were sprayed onto different substrate materials, and the microstructure and properties of the coatings were evaluated.
