소결조제와 열처리 분위기가 $(1-x)CaTiO_3-xLaAlO_3$ 계의 소결 및 마이크로파 유전특성에 미치는 영향 |
이경태, 여동훈1, 문종하 |
전남대학교 무기재료공학과 1한국과학기술연구원 세라믹스부 |
Effect of Sintering Additives and Annealing Atmospheres on the Microwave Dielectric and Sintering Characteristics of $(1-x)CaTiO_3-xLaAlO_3$ System |
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ABSTRACT |
The effects of the annealing atmospheres(O2, N2) and sintering additives that Bi2O3 is a major composition on the microwave dielectric and sintering propertie of (1-x)CaTiO3-xLaAlO3 system were investigated. The annealing atmospheres and the increase of annealing time after sintering did not affect the relative dielectric constant($varepsilon$r) and temperature coefficient of resonant frequency($tau$f) of (1-x)CaTiO3-xLaAlO3 system. However, the Q.f0 values of (1-x)CaTiO3-xLaAlO3 were very sensitive to annealing atmospheres. As the annealing time increased under O2 atmosphere the Q.f0 values of (1-x)CaTiO3-xLaAlO3 enhanced untill 10 hrs in 0.3$leq$x$leq$0.6 region, but degraded over that time. The increasing rate of Q.f0 value increased wth increasing x. On the other hand, as the annealing time increased under N2 atmosphere the Q.f0 values were constant in x$leq$0.6 region, increased gradually in x$geq$0.7 region. When 0.97Bi2O3-0.03Al2O3 and 0.76Bi2O3-0.24NiO of 3wt% as sintering additives were added to (Ca0.5La0.5) (Ti0.5Al0.5)O3 (x=0.5) the sintering temperature of 1$600^{circ}C$ was lowered to 140$0^{circ}C$, and the relative dielectric constant($varepsilon$r) and temperature coefficient of resonant frequency($tau$f) were not nearly changed. The addition of 0.97Bi2O3-0.03Al2O3 and 0.76Bi2O3-0.24NiO of 3wt% to (Ca0.5La0.5)(Ti0.5Al0.5)O3 made the Q.f0 values to be lower about 15% and 34%, respectively. |
Key words:
$(1-x)CaTiO_3-xLaAlO_3$ system, Microwave dielectric properties, Annealing atmosphere, Additives, Relative dielectric constant, Temperature coefficient of resonant frequency, Q |
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