Quest and evaluation of topcoat materials for environmental barrier coatings of SiC/SiC composites

H. Nakayama, K. Morishita, S. Ochiai, T. Sekigawa, K. Aoyama, T. Oi, M. Yamamoto, K. Okamura, M. Sato

研究成果: Contribution to journalArticle査読

3 被引用数 (Scopus)


SiC fiber reinforced SiC matrix (SiC/SiC) composites are one of the most promising materials for high temperature structural applications such as power generation and propulsion systems. SiC/SiC composites are, however, susceptible to accelerated attacks in water vapor environments through oxidation and volatilization reaction. For protection from such attacks, Environmental Barrier Coatings (EBCs) are indispensable. We have investigated some oxides and rare-earth silicates as topcoat candidate materials for EBCs. Topcoat materials must be stable in the high-water-vapor pressurized environments at high temperatures. Also, it is important that the thermal expansion coefficient of topcoat materials is similar to that of the SiC/SiC composites. In this study, first, zirconium oxides, lutetium silicates and yttrium silicates were selected as topcoat candidate materials. They were exposed in a water-containing atmosphere at a temperature of 1673 K for 100 h under a total pressure 0.96 MPa. Mass changes, structure of crystals and microstructures were investigated after the exposure experiments in order to evaluate the thermal stability of these materials. After their estimation, lutetium silicates were considered to be promising for topcoat materials. Then, lutetium silicates were coated as the topcoat of an EBC system on SiC/SiC composites, and their fracture toughness and microstructures were investigated after exposure to an oxidizing atmosphere. The evaluation results of the topcoat materials are reported in this paper.

ジャーナルKey Engineering Materials
出版ステータス出版済み - 2006

All Science Journal Classification (ASJC) codes

  • 材料科学(全般)
  • 材料力学
  • 機械工学


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