Hiromu Kawai

Fabrication of ceramic coatings by improved plasma chemical vapour deposition

Abstract A triode plasma chemical vapour deposition (CVD) technique has been recently developed. A grid electrode was added to our unique diode plasma CVD apparatus which was developed and produced on the basis of the CVD method. The triode system produced TiN and Al 2 O 3 films deposited at low temperatures (773–873 K) with adhesion equivalent to or better than that of ion plated films. The films were coated onto cemented carbide inserts to evaluate their cutting performance, with results showing excellent properties.

Vapor-deposited ceramic coating: Status and prospects☆

Rapid progress has been observed in the coating technology of ceramics and diamond synthesized from the vapor phase. This paper describes its status and prospects.

Ceramic coating for valve seats and stems by plasma chemical vapor deposition

Abstract 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.