材料科学
烧结
氧化物
三元运算
熔点
蒸发
相(物质)
稀土
化学工程
冶金
复合材料
热力学
有机化学
化学
物理
计算机科学
工程类
程序设计语言
作者
Pinar Colkesen,Gizem Kaplan,Dang‐Hyok Yoon
标识
DOI:10.1016/j.ceramint.2023.07.062
摘要
This study examined the effects of rare-earth (RE) elements such as Sc, Y, Ce, and Yb on the densification and oxidation of SiC. After adding binary or ternary RE nitrates in liquid form to β-SiC, hot pressing was performed at 1750 °C for 2 h under 20 MPa. RE nitrate was transformed into RE oxide and formed a liquid phase during sintering by a reaction with SiO2 present on the SiC surface, where the total amount of RE oxide was fixed at 5 wt%. RE-based silicate melts acted as sintering additives without decomposing SiC at high sintering temperatures. SiC containing Sc–Y as an additive showed a much higher density (≥ 99%) than SiC containing the conventional Al–Y additive (∼95%). The multicomponent RE additive with a melting point (Tm) < 1550 °C had a relatively lower density than that with a higher Tm, owing to the evaporation of the additive at 1750 °C. The density of SiC also depended on the additive composition. The oxidation test, conducted at 1300 °C for up to 168 h in air, exhibited a parabolic weight gain. The SiC sample sintered with the Sc–Yb additive achieved the highest resistance of 3.23 × 10−5 mg/cm4·s.
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