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To extend the lifetime of the valve seats and stems used in nuclear power plants, we have developed a unique ceramic coating technique using plasma chemical vapor deposition (CVD). Multilayer coatings of Al 2 O 3 /TiN/TiC, Al 2 O 3 /TiC and TiN/TiC were deposited onto Stellite and stainless steel substrates. The mechanical and physical properties of the coatings were evaluated by various methods. The coated specimens showed good wear resistance in a high-temperature water environment. Corrosion resistance was evaluated in an autoclave at a temperature of 548 K for 200 h. The coated specimens showed excellent performance in reducing the cobalt level dissolved in the testing solution. The weight loss of the multilayer-coated AISI403 specimen, as evaluated by a cavitation erosion test, was less than 1% of that of the uncoated AISI403. However, for the coated Stellite-padded AISI316L substrate, the weight loss was almost the same as that of the uncoated specimen.

Amorphous Si1−xSnx:H films were deposited by Sputter Assisted Plasma CVD (SAP-CVD) which used glow discharge to decompose silane gas and to sputter a solid tin target simultaneously. Resulting films contain tin as 0

Deposition technique of a-SiGe:H and its application to a stacked solar sell were investigated. Properties of a-SiGe:H were improved by a glow discharge method with a negatively biased substrate, and a mercury sensitized photo CVD under lower pressure. An a-SiGe:H single junction solar cell was improved by slight boron doping to an i layer and insertion of a buffer layer into a p/i interface. A conversion efficiency of more than 10 % was obtained by a triple stacked solar cell on a alass substrate.

Hydrogenated amorphous silicon germanium (a—SiGe:H) films were deposited by photo—chemical vapor deposition (Photo—CVD) of SiH4 and GeH4 with mercury sensitizer. Their band gap was controlled from 0.9 eV to 1.9 eV by changing the gas ratio of SiH4 and GeH4. High quality opto—electrical properties have been obtained for thea—SiGe:H films by Photo—CVD. Hydrogen termination and microstructure of a-SiGe:H were investigated by infrared absorption and transmission electron microscopy. Ana—Si:H solar cell and an a—Si:H/a—SiGe:H stacked solar cell were made, each of which has conversion efficiency 5.3% and 5.1%, respectively.