Abstract
Zirconia is commonly used for thermal barrier coatings (TBCs) because of excellent mechanical and thermal properties. While practical high-speed deposition processes such as atmospheric plasma spray (APS) and electron-beam physical vapor deposition (EB-PVD) have been employed in TBCs, chemical vapor deposition (CVD) has been regarded to be inappropriate due to low deposition rates. However, we have successfully achieved highest deposition rates of 108 and 660μm h-1 with conventional MOCVD and newly developed laser CVD, respectively. The high-speed CVDs are significantly effective to improve the thermal barrier characteristics by the formation of nanopores in columnar zirconia grains. The laser CVD is also applicable for the extremely high-speed deposition of other oxides, such as Y2O3, TiO2 and Al2O3, at deposition rates around 2 to 3 mm h-1.
