The influence of process gas pressure on the deposition of titanium dioxide by the cold spray process

The characteristics and the properties of cold spray ceramic coating depend on the feedstock powder characteristics, and on the operating parameters, such as the pressure of the process gas. This important parameter is easily controlled during cold spraying. This study investigates the effect of process gas pressure on the fabrication of TiO2 coating, with nitrogen used as the processing gas, at three different pressures. Microstructural characterization and phase analysis of the feedstock powder and as-deposited coating were carried out by optical microscopy (OM), field emission scanning electron microscopy (FESEM) and X-ray diffraction (XRD). The results show that, in comparison to metals that need high velocity for successful bonding and coating formation, ceramic particles need lower velocity and lower process-gas pressure to build up coating, due to the brittleness of ceramic particles. It is also observed that the thickness of the coating increases when the process gas pressure is decreased.

Keywords:

Cold spray , Process gas pressure , Titanium dioxide , Coating