서지주요정보
$Nb^{+5}$ doped $BaTiO_3$ 계에서 PTCR현상에 대한 열처리 효과 = Effects of heat treatment on the PTCR of $BaTiO_3$ ceramics doped by $Nb^{+5}$
서명 / 저자 $Nb^{+5}$ doped $BaTiO_3$ 계에서 PTCR현상에 대한 열처리 효과 = Effects of heat treatment on the PTCR of $BaTiO_3$ ceramics doped by $Nb^{+5}$ / 문영우.
저자명 문영우 ; Moon, Young-Woo
발행사항 [서울 : 한국과학기술원, 1985].
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소장정보

등록번호

4103299

소장위치/청구기호

학술문화관(문화관) 보존서고

MMS 8512

SMS전송

도서상태

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대출가능

반납예정일

초록정보

This study was concerned with the mechanism of PTCR in $BaTiO_3$ ceramics doped by $Nb^{+5}$. Since the vacancy compensation layer in the grain boundary of n-type doped $BaTiO_3$ ceramics has been known as a major factor for surface state to give PTCR as proposed by J. Daniel et. al.(1978), the dependence of PTCR on such vacancy compensation layer was attempted to be confirmed experimentally in this study. For the experiment, $BaTiO_3$ ceramics doped by $Nb^{+5}$ were synthesized by using $BaTiO_3$ powders prepared by a chemical coprecipitation method. Quenching at various temperatures, annealing at various temperatures after sintering and the change of density of $BaTiO_3$ ceramic were adopted to induce difference in the thickness of vacancy compensation layer so as to exhibit different degree of PTCR effect each other. The measurement of $Ba^{++}$ concentration in the grain and grain boundary by EDAX as well as the degree of PTCR effect itself were conducted to each specimen in order to evaluate the formation of the vacancy compensation layer. It was found that ⅰ) either decrease in the temperature for quenching or increase in the temperature for annealing improves the PTCR effect clearly, ⅱ) increase in $Ba^{++}$ concentration in the grain boundary results in the improvement of PTCR effect, ⅲ) decrease in the density of the $BaTiO_3$ in a narrow range exhibits increase in PTCR effect slightly. It was concluded that all the experimental results gave the evidence for the dependence of PTCR effect on the vacancy compensation layer in the grain boundary which had been induced possibly by the $Ba^{++}$ diffusion by the heat treatment conducted.

서지기타정보

서지기타정보
청구기호 {MMS 8512
형태사항 [iii], 54 p. : 삽도 ; 26 cm
언어 한국어
일반주기 저자명의 영문표기 : Young-Woo Moon
지도교수의 한글표기 : 정형진
지도교수의 영문표기 : Hyung-Jin Jung
학위논문 학위논문(석사) - 한국과학기술원 : 재료공학과,
서지주기 참고문헌 : p. 51-52
주제 Ceramics.
열처리 조건. --과학기술용어시소러스
첨가물 효과. --과학기술용어시소러스
공침. --과학기술용어시소러스
Coprecipitation.
Positive temperature coefficient resistivity.
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