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<p>A simple and effective method is proposed for producing polycrystalline La<sub>1-<i>x</i></sub>Ce<sub><i>x</i></sub>B<sub>6</sub> (LaB<sub>6</sub>, La<sub>0.75</sub>Ce<sub>0.25</sub>B<sub>6</sub>, La<sub>0.5</sub>Ce<sub>0.5</sub>B<sub>6</sub>, La<sub>0.25</sub>Ce<sub>0.75</sub>B<sub>6</sub>, and CeB<sub>6</sub>)-Al<sub>2</sub>O<sub>3</sub> ceramics. La<sub>1-<i>x</i></sub>Ce<sub><i>x</i></sub>B<sub>6</sub> solid-solution powders were first prepared by the reaction between lanthanum oxides, cerium oxides, boron carbide, and aluminum powders at 1573&#xa0;K, during which a trace amount of Al<sub>2</sub>O<sub>3</sub> (1–3&#xa0;wt.%) was inevitably introduced. Subsequently, highly dense (&gt;&#xa0;98.5%) La<sub>1-<i>x</i></sub>Ce<sub><i>x</i></sub>B<sub>6</sub>-Al<sub>2</sub>O<sub>3</sub> ceramics were produced using spark plasma sintering (SPS) technology at 1850°C, and the results revealed that the existence of Al<sub>2</sub>O<sub>3</sub> can enhance the mechanical properties of La<sub>1-<i>x</i></sub>Ce<sub><i>x</i></sub>B<sub>6</sub> by pinning the grain boundaries and refining the grains. Among the samples, the La<sub>0.5</sub>Ce<sub>0.5</sub>B<sub>6</sub>-Al<sub>2</sub>O<sub>3</sub> composition exhibited the most excellent mechanical properties, which were 22.8&#xa0;GPa, 4.14&#xa0;MPa&#xa0;m<sup>1/2</sup>, and 271&#xa0;MPa for the Vickers hardness, fracture toughness, and flexural strength, respectively. Moreover, compared to the polycrystalline LaB<sub>6</sub> and CeB<sub>6</sub> bulks, the work functions of La<sub>1-<i>x</i></sub>Ce<sub><i>x</i></sub>B<sub>6</sub> bulks were lower, and the presence of Al<sub>2</sub>O<sub>3</sub> had a slight influence on the work function of La<sub>1-<i>x</i></sub>Ce<sub><i>x</i></sub>B<sub>6</sub>.</p>

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Densification and Properties of La1-xCexB6-Al2O3 Ceramics Prepared by Spark Plasma Sintering

  • 期刊论文

  • 发表日期：

    2025年2月24日

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  • Ya-Long Wang,
  • Xiao-Hui Yang,
  • Guo-Hua Zhang

摘要

A simple and effective method is proposed for producing polycrystalline La1-xCexB6 (LaB6, La0.75Ce0.25B6, La0.5Ce0.5B6, La0.25Ce0.75B6, and CeB6)-Al2O3 ceramics. La1-xCexB6 solid-solution powders were first prepared by the reaction between lanthanum oxides, cerium oxides, boron carbide, and aluminum powders at 1573 K, during which a trace amount of Al2O3 (1–3 wt.%) was inevitably introduced. Subsequently, highly dense (> 98.5%) La1-xCexB6-Al2O3 ceramics were produced using spark plasma sintering (SPS) technology at 1850°C, and the results revealed that the existence of Al2O3 can enhance the mechanical properties of La1-xCexB6 by pinning the grain boundaries and refining the grains. Among the samples, the La0.5Ce0.5B6-Al2O3 composition exhibited the most excellent mechanical properties, which were 22.8 GPa, 4.14 MPa m1/2, and 271 MPa for the Vickers hardness, fracture toughness, and flexural strength, respectively. Moreover, compared to the polycrystalline LaB6 and CeB6 bulks, the work functions of La1-xCexB6 bulks were lower, and the presence of Al2O3 had a slight influence on the work function of La1-xCexB6.