What is Cold Spray?
Cold spray is the newest of the thermal spray processes and is mainly found in research labs at this stage of the technology's development.
Cold spray is technically not a true thermal spray process because it does not use thermal energy as the primary energy source to melt materials. Instead cold spray utilizes kinetic energy to project particles onto a prepared surface. The extreme velocities of the process cause plastic deformation of the particles on impact, which in turn creates very dense coatings. An analogy to how a cold spray coating is created is that the particles are essentially friction welded to each other during impact.
Cold spray is presently limited to a narrow set of materials, which are strain rate sensitive, within very defined limits. Some of the materials that have been successfully cold sprayed include, copper, aluminum, titanium and some cermets. Unlike other thermal spray processes cold spray does not use thermal energy so the properties of the coatings produced do not contain additional oxides from the spray process. Materials like copper can have properties close to wrought copper because of the minimal oxidation present and the intimate contact between particles.
Because this technology is relatively new and is mainly found in research laboratories there are few industries utilizing coatings produced with this technology at this time. There are several industries working on implementing the technology into real life applications including automotive and electronics.
There are few commercial applications for the technology at this time. However with the advantage of producing coatings with very low oxygen content and low porosity content, there is great interest in the technology. Applications that require excellent electrical conductivity or superior corrosion resistance are the two areas of greatest interest.