Ir and Pt epitaxial films were grown on (0001), (112̄0), and (011̄2) sapphire by metalorganic chemical vapor deposition using Ir- or Pt-acetylacetonate precursors. The epitaxial growth was achieved at deposition temperatures between 500 and 600 °C with the addition of oxygen to the source vapor. The film orientation and epitaxial relationships between films and substrates were determined by x-ray diffraction, x-ray pole figures, and reflection high energy electron diffraction. Ir films on (112̄0) sapphire grow in [100] orientation. Ir or Pt films on (011̄2) and (0001) sapphire grow in [111] orientation. Ir films on (0001) sapphire contain two in-plane orientations related by a 180° rotation, while Pt films containing only one in-plane orientation can be obtained on (011̄2) and (0001) sapphire.

Yttria stabilized zirconia (YSZ) can be employed as thermal barrier coatings (TBCs) on Ni-based super alloys in gas turbines and aircraft engines. The YSZ coatings have been fabricated by atmospheric plasma spraying or electron-beam physical vapor deposition. The increase in operation temperature of gas turbines demands another fabrication process to obtain high quality TBCs. Chemical vapor deposition (CVD) can be an alternative route to prepare TBCs due to excellent conformal coverage and columnar microstructure. This paper reviews the fabrication of YSZ films by conventional thermal CVD and plasma CVD intended for TBCs. A new laser CVD developed by our group with a high deposition rate of 660 mm h 21 was also briefly introduced.