The properties of a low expansion glass ceramics of $Li_{2}O-Al_{2}O_{3}-SiO_{2}$ system

$Li_{2}O-Al_{2}O_{3}-SiO_{2}$계 저팽창 결정화 유리의 특성

  • Kim, Bok-Hee (Div. of Advanced Materials Engineering, Chonbuk National University) ;
  • Ko, Jung-Hoon (Dept. of Hydrogen and Fuel Cells Engineering, Speciallized Graduate School, Chonbuk National University) ;
  • Nam, O-Jung (Dept. of Hydrogen and Fuel Cells Engineering, Speciallized Graduate School, Chonbuk National University) ;
  • Kang, Woo-Jin (Div. of Advanced Materials Engineering, Chonbuk National University) ;
  • Lee, Chang-Hoon (GAT Co. Ltd.)
  • 김복희 (전북대학교 신소재공학부) ;
  • 고정훈 (전북대학교 특성차대학원 수소연료전지공학과) ;
  • 남오정 (전북대학교 특성차대학원 수소연료전지공학과) ;
  • 강우진 (전북대학교 신소재공학부) ;
  • 이창훈 ((주)지에이티)
  • Published : 2009.04.30

Abstract

The glass-ceramic of the $Li_{2}O-Al_{2}O_{3}-SiO_{2}$ system was investigated to develop the low thermal expansion materials. The glass of this system was heat treated at $775^{\circ}C$ for 2 h for nucleation and subsequently at $825{\sim}900^{\circ}C$ for 2 h for crystallization. The crystal structure of the glass-ceramic of this system was a single phase of $\beta$-quartz solid solution($Li_{x}Al_{x}Si_{1-x}O_{2}$). The thermal expansion of the glass-ceramic showed $4.40{\times}10^{-7}{\sim}1.33{\times}10^{-6}K^{-1}$ between $25{\sim}300^{\circ}C$ and $1.56{\times}10^{-6}{\sim}2.53{\times}10^{-6}K^{-1}$ between $25{\sim}800^{\circ}C$, higher than lower temperature range. The mechanical strength remained almost same at around high 110 MPa with heating temperature changes.

저열팽창계수를 갖는 재료를 개발하기 위하여 $Li_{2}O-Al_{2}O_{3}-SiO_{2}$계 glass-ceramics를 제조하고 그 특성을 조사하였다. 이 계의 유리를 $775^{\circ}C$에서 2시간 가열하여 핵생성시키고 $825{\sim}900^{\circ}C$로 가열하여 2시간 결정화하였다. 결정화 유리의 결정구조는 단일상의 $\beta$-quartz solid solution($Li_{x}Al_{x}Si_{1-x}O_{2}$)이었고, 열팽창계수는 $25{\sim}300^{\circ}C$에서 $4.40{\times}10^{-7}{\sim}1.33{\times}10^{-6}K^{-1}$를, 그리고 $25{\sim}800^{\circ}C$에서는 $1.56{\times}10^{-6}{\sim}2.53{\times}10^{-6}K^{-1}$를 보였으며 저온 영역의 열팽창율보다는 고온 영역의 열팽창율이 더 높은 값을 보였다. 이 계의 결정화 유리의 기계적 강도는 결정화 온도에 의존하지 않고 대체로 110 Mpa의 높은 값을 보였다.

Keywords

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