Evaluation of environmental barrier coatings for SiC/SiC composites

H. Nakayama, K. Morishita, S. Ochiai, T. Sekigawa, K. Aoyama, A. Ikawa

Research output: Chapter in Book/Report/Conference proceedingConference contribution

2 Citations (Scopus)

Abstract

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, so Environmental Barrier Coatings (EBCs) are indispensable. We have investigated some oxides and rare-earth silicates as topcoat candidates 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 SiC/SiC composites. In this study, rare-earth silicates such as lutetium silicates, 8YSZ and ZrO2-SiO2 were selected as topcoat candidates. They were exposed in the water containing atmosphere at a temperature 1673K for 100 hr under a total pressure 0.96 MPa and under an atmospheric pressure. Mass changes, structure of crystals and microstructures were investigated after the exposure experiments in order to evaluate the thermal stability of those materials. After this evaluation, lutetium silicates were considered to be promising for topcoat materials. Lutetium silicates were coated on SiC/SiC composites, and their fracture toughness and microstructures were investigated and reported in this paper.

Original languageEnglish
Title of host publicationAdvanced Ceramic Coatings and Interfaces - A Collection of Papers Presented at the 30th International Conference on Advanced Ceramics and Composites
Pages161-170
Number of pages10
Edition3
Publication statusPublished - Dec 1 2006
Externally publishedYes
EventAdvanced Ceramic Coatings and Interfaces - 30th International Conference on Advanced Ceramics and Composites - Cocoa Beach, FL, United States
Duration: Jan 22 2006Jan 27 2006

Publication series

NameCeramic Engineering and Science Proceedings
Number3
Volume27
ISSN (Print)0196-6219

Other

OtherAdvanced Ceramic Coatings and Interfaces - 30th International Conference on Advanced Ceramics and Composites
CountryUnited States
CityCocoa Beach, FL
Period1/22/061/27/06

All Science Journal Classification (ASJC) codes

  • Ceramics and Composites
  • Materials Chemistry

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  • Cite this

    Nakayama, H., Morishita, K., Ochiai, S., Sekigawa, T., Aoyama, K., & Ikawa, A. (2006). Evaluation of environmental barrier coatings for SiC/SiC composites. In Advanced Ceramic Coatings and Interfaces - A Collection of Papers Presented at the 30th International Conference on Advanced Ceramics and Composites (3 ed., pp. 161-170). (Ceramic Engineering and Science Proceedings; Vol. 27, No. 3).