**5.4. Electrostatic Spray-Assisted Vapor Deposition method (ESAVD)**

TBCs, such as 8 wt. % Y2O3–ZrO2 (YSZ), provide effective thermal barrier to the gas turbine blades and are able to protect them, leading to further increase in the operating temperature. A novel and cost-effective electrostatic spray-assisted vapor deposition (ESAVD) technique was utilized to prepare YSZ coatings, which involves spraying atomized zirconium and yttrium alkoxide precursor droplets within an electric field wherein they are subjected to decomposition and/or chemical reactions in the vapor phase near the heated substrate. The coatings were characterized by scanning electron microscopy, X-ray diffraction, and Raman spectroscopy. Vyas and Choy [28] produced thick and uniform YSZ films using the ESAVD method. Raman spectroscopy identified carbon to be present in the as-deposited coatings. When heat treatment of the YSZ coating was conducted at 1,000°C for 2 h, carbon was removed and the adhesion of the TBC coating to the bond coat improved [28].
