Synthesis, densification and oxidation study of lanthanum hexaboride
Synthesis, densification and oxidation study of lanthanum hexaboride
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DOI：
10.1016/j.jeurceramsoc.2013.11.023
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发表时间：
2014-05
影响因子：
5.7
通讯作者：
J. Sonber;K. Sairam;T. Murthy;A. Nagaraj;C. Subramanian;R. C. Hubli
中科院分区：
文献类型：
--
作者：
J. Sonber;K. Sairam;T. Murthy;A. Nagaraj;C. Subramanian;R. C. Hubli
本文介绍了 LaB6 的合成、致密化和氧化研究的研究结果。 LaB6是通过碳化硼还原La2O3合成的。研究了温度对产品质量的影响。纯 LaB6 粉末是在 1500 °C 真空下获得的。在 1950 °C 下无压烧结 LaB6 粉末的密度仅为理论值的 85.1%。热压在相同的操作温度下产生接近理论的密度。测得致密 LaB6 的硬度和断裂韧性分别为 20 GPa 和 3.02 MPa m1/2。通过热重分析进行的氧化研究表明，氧化在 500 °C 时缓慢开始，在 700 °C 时加速。等温氧化研究表明，在 900 °C 的氧化条件下，LaB6 表面会形成保护性氧化层。即使在空气中暴露 64 小时后，仍观察到表面存在连续的保护性氧化层。
This paper presents the result of investigation carried out on the synthesis, densification and oxidation studies of LaB6. LaB6was synthesized by boron carbide reduction of La2O3. Effect of temperature on product quality was investigated. Pure LaB6powder was obtained at 1500 °C, in vacuum. Pressureless sintering at 1950 °C of LaB6powder resulted in a density of only 85.1% of the theoretical value. Hot pressing resulted in near theoretical density at the same operating temperature. Hardness and fracture toughness of the dense LaB6was measured as 20 GPa and 3.02 MPa m1/2respectively. Oxidation study by thermogravimetry revealed that oxidation starts slowly at 500 °C and accelerates at 700 °C. Isothermal oxidation study revealed that protective oxide layer forms on LaB6surface on oxidation at 900 °C. The presence of protective continuous oxide layer on the surface was observed even after 64 h exposure in air atmosphere.