통합 검색 | Korea Science

Phase Distribution, Microstructure, and Electrical Characteristics of NASICON Compounds

N.H. Cho;Kang, Hee-Bok;Kim, Y.H.
- The Korean Journal of Ceramics
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- 제1권4호
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- pp.179-184
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- 1995
Sodium superionic conductor (NASICON) compounds were prepared. The effects of sintering temperature and cooling rate on the formation and the distribution of crystalline NASICON and $ZrO_3$ second phase were investigated. In the von Alpen-type composition, the $ZrO_2$ second phase is in thermal equilibrium with the crystalline NASICON above $1320^{\circ}C$, but when cooled through 1260-$1320^{\circ}C$ crystalline NASICON was formed by reaction between $ZrO_2$ and liquid phase. Very slow cooling ($1^{\circ}C$/hr) to $1260^{\circ}C$ from sintering temperature decreased the amount of sodium which prevents the formation of the crystalline NASICON resulted high number of $ZrO_2$ grains near the surface of some sintered bodies. Maximum electrical conductivity of 0.200 ohm-1cm-1 was obtained at $300^{\circ}C$ for well-sintered samples with little $ZrO_3$. On the other hand, low conductivities were obtained for rapid-cooled samples which have less dense microstructure.
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심미보철용 코어재료와 베니어 세라믹 계면의 전단결합강도 비교 (Shear Bond Strength between Veneered Ceramics and Core Materials for Esthetic Restorations)

김기원;박항민;정인성
- 대한치과기공학회지
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- 제31권2호
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- pp.45-52
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- 2009
Esthetic restorations have been widely used in dental practice, although many studies have focused on the development and improvement of all ceramic restorations. The success of esthetic restorations depends primarily on an optimal bond strength between various veneered ceramics and core materials for esthetic restorations. The purpose of this study was to compare the shear bond strength between various veneered ceramics and core materials for esthetic restorations. 30 metal cores and 20 zirconia cores were fabricated and divided into five groups according to veneered ceramic materials such as Creation porcelain powder, Cercon Ceram Kiss, and IPS e.max ZirPress. Thirty spacimens were prepared using Creation porcelain powder, veneered 3mm height and 3mm in diameter, over the metal cores (n=10). Twenty specimens were prepared using Cercon Ceram Kiss and Zirpress, veneered 3mm height and 3mm in diameter, over the zirconia cores (n=10). The shear bond strength test was performed in a universal testing machine with a crosshead speed of 1mm/min. Ultimate shear bond strength data were analyzed with One-way ANOVA and the Scheffe's test (p=.05). Within the limits of this study, the following conclusions were drawn: The mean shear bond strengths (MPa) were: 18.44 for Uni metal VH/Creation (NCUC); 18.72 for Heraenium/Creation (NCHC); 16.23 for Wirobond C/Creation (NCWC); 13.88 for Zirconia core/$110{\mu}m$ $Al_2O_3$ sandblasting/Cercon Ceram Kiss (ZS110P); 14.61 for Zirconia core/No surface treatment/IPS e.max ZirPress (ZNTH). The mean shear bond strength for NCUC (Uni metal VH/Creation), NCHC (Heraenium/Creation) and NCWC (Wirobond C/Creation) were significantly superior to ZS110P (Zirconia core/$110{\mu}m$ $Al_2O_3$ sandblasting/Cercon Ceram Kiss) and ZNTH(Zirconia core/No surface treatment/IPS e.max ZirPress) (p<0.05).
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수종의 이장재가 복합레진의 중합수축에 미치는 영향 (EFFECT OF VARIOUS LINERS ON THE POLYMERIZATION SHRINKAGE OF COMPOSITE RESIN)

최지원;이상호;이난영
- 대한소아치과학회지
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- 제33권4호
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- pp.606-614
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- 2006
이 연구의 목적은 이장재의 종류에 따른 광중합형 복합레진 충전 후 중합수축을 비교함으로써 중합수축 감소를 보이는 좀 더 우수한 재료의 조합을 모색하고자 시행되었다. 이장재로는 유동형 레진, 컴포머, 광중합 글래스아이오노머를 사용하였고 수축응력을 측정하기 위해 스트레인 게이지를 사용하였다. 표본은 광원의 종류, 이장재의 종류에 따라 8개의 군으로 나눠졌다. 스트레인 게이지를 아크릴릭 링에 부착하고 strainmeter에 연결한 후 각 군에 따라 이장재 적용 후 광중합 하고 이장재 중합 후 750초간 수축응력을 측정하였다. 결과는 Repeated measures ANOVA와 Tukey test를 이용해 통계학적으로 분석하였다. 이상의 실험을 통해 얻은 결과는 다음과 같다. 1. 이장재를 사용하지 않은 군보다 이장재를 사용한 군의 중합수축이 적었으나 Ionosit을 사용한 군에서는 유의한 차이는 없었다(p>0.05). 2, Tetric flow 또는 Vitrebond를 이장재로 사용하는 것이 Ionosit을 사용하는 것보다 중합 수축이 적었다(p<0.05). 3. Tetric flow 이장재를 한 군은 광원에 따른 수축력의 차이가 적었고 Vitrebond와 Ionosit 이장재를 한 군은 할로겐 광원보다 LED 광원에서 수축응력이 컸으나 유의한 차이는 없었다(p>0.05).
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