Characterization of the cold spray deposition of a wide variety of polymeric powders

The cold spray deposition of high-density polyethylene, polyurethane, polystyrene, polyamide 12, and ultrahigh molecular weight polyethylene on a variety of polymeric substrates was studied. A variety of different process conditions were studied in order to develop deposition windows over temperature-velocity space for each particle/substrate combination. The deposition windows for each polymer powder were shown to expand as the particle and substrate temperatures were increased. In general, lower glass transition temperature materials were found to deposit more easily and with larger deposition efficiency. Nano-indentation and adhesive/cohesive strength experiments were conducted on the cold sprayed samples and the results were found to be statistically identical to those of corresponding melt-cast samples. Microstructural characterization showed little to no porosity in the deposited polymer films. Finally, deposition efficiency was studied as a function of the tilt angle of the substrate to better understand potential of this technology for additive manufacturing three-dimensional components. A critical tilt angle was found above which successful deposition was not possible. This critical tilt angle was found to increase with increasing impact velocity.