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High Temperature Thermal Conductivities in La2Ce2O7−Gd2Ce2O7−Y2Ce2O7 Pyrochlore System for Thermal Barrier Coatings

열차폐코팅용 La2Ce2O7−Gd2Ce2O7−Y2Ce2O7 Pyrochlore계의 고온 열전도도

  • 윤소영 (요업(세라믹)기술원 구조세라믹부) ;
  • 이성민 (요업(세라믹)기술원 구조세라믹부) ;
  • 심광보 (한양대학교 신소재공학과) ;
  • 김형태 (요업(세라믹)기술원 구조세라믹부)
  • Published : 2007.07.31

Abstract

Thermal conductivities in $La_2Ce_2O_7-Gd_2Ce_2O_7-Y_2Ce_2O_7$ ternary system have been investigated. Pyrochlore phases formed at all ternary compositions and their sinterbilities were decreased with La addition. Thermal conductivities showed a minimum value at $La_2Ce_2O_7$ with moderate increases as $Y^{3+}$ and $Gd^{3+}$ ions replaced $La^{3+}$. Thermal expansion anomaly observed in $La_2Ce_2O_7$, which might be detrimental to TBC application, were suppressed by $Y^{3+}$ and $Gd^{3+}$ additions, with resultant thermal conductivities, $1.3{\sim}1.5 W/mK$ at $1000^{\circ}C$.

Keywords

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