Abstract
Chemical vapor deposition (CVD) has been commonly employed as a thin film processing, whereas thick films and bulk ceramic materials can be also obtained by modifying and optimizing CVD conditions and apparatus. The development of highly-functional bulk ceramic materials and thick films by CVD has been reviewed in this paper. Monolithic Ti3SiC2 bulk material was synthesized by CVD, and was identified as a machinable soft ceramic material. SiC and Si3N4 are hardly sinterable materials, thus sintering aids are inevitable to consolidate these powders. However, such aids would yield significant deterioration of their high-temperature performance. Thermal CVD can provide bulk bodies by enhancing deposition rates. CVD SiC bulk body was used to investigate intrinsic nature of SiC, particularly high-temperature oxidation mechanism. By introducing laser in CVD, the deposition rate was tremendously increased several 100 to 1000 times greater than that of conventional CVD. Laser CVD enabled one to realize thermal barrier coating of yttria stabilized zirconia (YSZ). This YSZ coating contained a large amount of nanopores being beneficial for thermal insulation. Plasma enhanced CVD produced characteristic Ru-C film, where Ru nano-particles dispersed in an amorphous C matrix. This film can be a promising catalytic electrode for oxygen sensors and fuel cells.
