한국표면공학회지 (54권6호 331-339)
Fabrication and Characterization of Ytterbium Silicates for Environmental Barrier Coating Applications
환경차폐코팅용 이터븀 실리케이트의 제조와 물성평가
최재형a, 김성원a,*
Jae-Hyeong Choia, and Seongwon Kima,*
a한국세라믹기술원 이천분원 엔지니어링세라믹센터
aEngineering Ceramics Center, Korea Institute of Ceramic Engineering and Technology, Icheon, Gyeonggi-do 17303, Korea
Environmental barrier coatings(EBCs) are applied to the SiC/SiC ceramic matrix composites(CMCs) in order to protect CMCs from being corroded with water vapor by combustion gas in gas turbine engines. Ytterbium silicates, such as ytterbium monosilicate and ytterbium disilicate, are ones of the candidate materials for EBCs due to their excellent resistance to water vapor corrosion as well as thermal-expansion match with SiC. In this study, ytterbium silicates are fabricated with 2-step solid-state synthesis targeting ytterbium disilicate. After synthesizing ytterbium monosilicate, the mixtures of ytterbium monosilicate and SiO2 are heat-treated and densified by using pressureless sintering or hot pressing with a variety of heating conditions. The phase formation, thermal expansion, and oxidation behavior are examined with fabricated specimens. The final densified bodies are found to be composites between ytterbium monosilicate and ytterbium disilicate with different ratios, which results in 4.43 to 6.72×10-6/K range of coefficients of thermal expansion. The probability of these ytterbium silicates for EBC applications is also discussed.
Environmental barrier coatings(EBCs), Ytterbium silicate, Phase formation, Thermo-physical property