Effect of Processing Parameters on the Deposition Characteristics and Microstructure of Vacuum Kinetic Sprayed Ceramics

Vacuum kinetic spraying is a relatively new coating process by which ceramic coatings can be produced without significant heating of the sprayed powder and substrate. This technique is considered as a promising coating method that can be used in various applications, such as in the fabrication of display devices, dye-sensitized solar cell, optical devices as well as bio-implants. In this study, submicron-sized AlN, TiO₂, Al₂O₃ and TiN powders with various fracture toughness were coated respectively on Si, glass, Al and stainless steel substrates with different hardness. The effects of processing parameters, such as pressure and mass flow of gas on the microstructure and surface morphologies of the films were investigated by means of X-ray diffraction, field emission scanning electron microscopy and transmission electron microscopy. These analyses demonstrate that the microstructure can be attributed to the physical/mechanical properties of the materials and the processing parameters. On the basis of these criteria, the films microstructure and the processing parameters are optimized for these particle-substrate combinations.