서지주요정보
이트리아-안정화 지르코니아 세라믹스의 이온전도특성에 관한 연구 = Ionic conduction characteristics of Yttria-stabilized Zirconia ceramics
서명 / 저자 이트리아-안정화 지르코니아 세라믹스의 이온전도특성에 관한 연구 = Ionic conduction characteristics of Yttria-stabilized Zirconia ceramics / 김영호.
저자명 김영호 ; Kim, Young-Ho
발행사항 [대전 : 한국과학기술원, 1994].
Online Access 원문보기 원문인쇄

소장정보

등록번호

8005061

소장위치/청구기호

학술문화관(문화관) 보존서고

DCM 94002

휴대폰 전송

도서상태

이용가능

대출가능

반납예정일

초록정보

Fully-stabilized cubic zirconia is a good candidate for solid electrilyte because of high electrical conductivity. but the enhancement of sinterablity and mechamical properties are required in that it has microstructural characteristics. Therefore this study was performed on two different ways. First, we have studied the effect of microstructural change including grain size, second phase and grain boundary segregation on the electrical properties of $ZrO_2$ - 9.3mol% $Y_2O_3$ added by $Bi_2O_3$ for enhancing sinteribility. Secondly, we investigated high temperature thermal aging characterisitics of $ZrO_2$ - 3mol% $Y_2O_3$ added by $Al_2O_3$ and $CeO_2$ for the improvement of low temperature degradation. Relative densities near 95% and fine-grained microstructure could be achieved at sintering temperatures as low as 1350 to 1400℃ as reported elsewhere. Monoclinic second phases and $Y^{3+}$, $Bi^{3+}$ segregation at grain boundary were also observed. It has been reported that small addition of $Bi_2O_3$ decreased the electrical conductivity by about several times. We found that the electrical conductivity could be increased by the change of grain boundary structure, while nonconducting second phases were formed. 0.7~2.3 mol% $Bi_2O_3$ gave an increase of about 1.4 times higher in electrical conductivity than undoped one due to grain boundary cleaning effects. Grain boundary cleaning effect was achieved by the formation of highly conductive intergrannular contact region which originated fron nonwetting liquid. This facts were analyzed by the correlations between microstructural models, electrical equivalent circutis and corresponding impedance spectra. We proposed that the critical grain size of tetragonal zirconia was about 0.5㎛ for prohibiting low temperature thermal degradation. This critical grain size is nearlu achieved by normal ceramic processing. Therefore we investigated the effedt of $Al_2O_3$ and $CeO_2$ addition on the low temperature thermal degradation. the addition of 2 mol% $CeO_2$ effectively improved low temperature thermal degradation by the supression of tetragonal to monoclinic transition. But the addition of $Al_2O_3$ was not so effective because grain size was increased for increased sintering temperature. High temperature thermal degradation mechanism of TZP was analyzed by thermal aging kinetics. The degradation mechanism of TZP for the initial stage of thermal annealing was inferred defect ordering process. $CeO_2$-containing TZP showed the best resistance to high temperature thermal degradation. It had the smallest coefficient of time dependence of intragrain resistivity although it had the largest coefficient of time dependence of grain boundary resistyvity. The ratio of grain boundary resistivity to intragrain resistivity was small in compared with pure TZP and $Al_2O_3$-containing TZP and therefore time-dependent change of grain boundary resistivity could be neglected.

서지기타정보

서지기타정보
청구기호 {DCM 94002
형태사항 iv, 123 p. : 삽도 ; 26 cm
언어 한국어
일반주기 저자명의 영문표기 : Young-Ho Kim
지도교수의 한글표기 : 김호기
지도교수의 영문표기 : Ho-Gi Kim
학위논문 학위논문(박사) - 한국과학기술원 : 무기재료공학과,
서지주기 참고문헌 : p. 118-123
주제 Electrode.
Conduction electrons.
Zirconium oxide.
Ceramics.
Segregation.
이온 전도. --과학기술용어시소러스
안정화. --과학기술용어시소러스
산화이트륨. --과학기술용어시소러스
전극.
지르코니아.
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