Studies on yttria stabilized zirconia coating developed by pulsed laser deposition

Yttria stabilized zirconia is widely used as the coating material for heat, corrosion, and wear resistance application due to its low thermal conductivity and superior thermo-mechanical property. In the present study, yttria stabilized zirconia coating was developed on silicon substrate by pulsed laser deposition technique. The effect of substrate temperature on the characteristics and properties of the coating was studied in details. Following deposition, the thin films were subjected to microstructural characterization, phase and compositional analysis, residual stress analysis, and nano-indentation. There is formation of amorphous YSZ when coating was conducted at room temperature, however, with increase in substrate temperature the deposited YSZ was crystalline. The morphology of deposited YSZ was columnar in all the temperatures of deposition. X-ray diffraction analyses of thin films evidences the formation of tetragonal YSZ, though the precursor powder/pellet used as target was partially monoclinic in nature. Crystallite size and lattice strain analysis confirms that the coating is nanocrystalline. The thickness of deposited layer varied from 0.2 urn to 1.5 urn. Nanoindentation analyses shows that the Young's modulus and hardness of the yttria stabilized zirconia thin films was significantly improved to 238-279 GPa and 14-23 GPa, respectively as compared to 155 GPa (Young's modulus) and 10 GPa (hardness) of similar coating developed by plasma spray deposition route. Hence, it may be concluded that pulsed laser deposition is an effective route for development of yttria stabilized zirconia with improved properties