고온가압으로 소결한 고순도 이트리아 세라믹 소결체의 산화반응 특성 |
최진삼, 신동우, 배원태 |
경상대학교 세라믹공학전공 |
Characteristics of Thermal Oxidation on Hot-Pressed Pure Yttria Ceramics |
Jinsam Choi, Dong Woo Shin, Won Tae Bae |
Department of Ceramic Engineering, Gyeongsang National University |
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ABSTRACT |
We investigated the characteristics of hot-pressed pure yttria ceramics, and annealed them in an oxidation atmosphere. Regardless of the heat treatment in the oxidation atmosphere, XRD analysis showed that all the samples had a $Y_2O_3$ phase without structural change. Even though the color variation of the hot-pressed $Y_2O_3$ ceramics was due to the sintering temperatures, the oxidation process turned the color of the $Y_2O_3$ ceramics into white. The color change during oxidation treatment appears to be related to oxygen defects. In addition, oxygen defects also affected the weight change and microstructure of the $Y_2O_3$ ceramics. The $Y_2O_3$ ceramic sintered at $1600^{circ}C$ had a $5.03g/cm^3$ density, which is close to the theoretical density of $Y_2O_3$. As the sintering temperature increased, small homogeneous grains grew to large grains which affected the Vickers hardness. $Y_2O_3$ ceramics hot-pressed at $1600^{circ}C$ and annealed at $1200^{circ}C$ had a flexural strength of 140MPa. |
Key words:
Hot-pressed yttria ceramics, Oxidation, Homogeneous grain, Density |
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