Scholarlink

<p>Solid solutions (Zr<sub><i>x</i></sub>Hf<sub>1−</sub><sub><i>х</i></sub>)B<sub>2</sub> and (Zr<sub><i>x</i></sub>Hf<sub>1−</sub><sub><i>х</i></sub>)B<sub>2</sub>-15 vol.% SiC were obtained by hot pressing. The formation of a&#xa0;homogeneous solid solution occurs at an equimolar ratio. The core-shell structure was formed in the composite with 25&#xa0;and 75&#xa0;at.% HfB<sub>2</sub>. In the first case, pure zirconium diboride was the core, and in the second, it was pure hafnium diboride. The shell composition corresponded to the chemical formula (Zr<sub>0.75</sub>Hf<sub>0.25</sub>)B<sub>2</sub> or (Zr<sub>0.25</sub>Hf<sub>0.75</sub>)B<sub>2</sub>, respectively. The formation of an equimolar solid solution results in a&#xa0;28% increase in high-temperature bending strength in comparison to ZrB<sub>2</sub>-15 vol.% SiC or HfB<sub>2</sub>-15 vol.% SiC due to the mixed-mode fracture of ceramics at high temperature. At the same time, higher oxidation resistance was observed in a&#xa0;solid solution close to hafnium diboride composition due to the formation of (Hf<sub>0.75</sub>Zr<sub>0.25</sub>)SiO<sub>4</sub> and HfSiO<sub>4</sub> phases on the scale surface, which reduces the diffusion of oxygen into the material.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

High-temperature properties of ZrB2-HfB2 and ZrB2-HfB2-SiC solid solutions

  • 期刊论文

  • 发表日期：

    2025年8月1日

查看全文
  • D. V. Vedel,
  • P. V. Mazur,
  • I. V. Kozak,
  • A. Ye. Osipov,
  • M. P. Brodnikovskyi

摘要

Solid solutions (ZrxHf1−х)B2 and (ZrxHf1−х)B2-15 vol.% SiC were obtained by hot pressing. The formation of a homogeneous solid solution occurs at an equimolar ratio. The core-shell structure was formed in the composite with 25 and 75 at.% HfB2. In the first case, pure zirconium diboride was the core, and in the second, it was pure hafnium diboride. The shell composition corresponded to the chemical formula (Zr0.75Hf0.25)B2 or (Zr0.25Hf0.75)B2, respectively. The formation of an equimolar solid solution results in a 28% increase in high-temperature bending strength in comparison to ZrB2-15 vol.% SiC or HfB2-15 vol.% SiC due to the mixed-mode fracture of ceramics at high temperature. At the same time, higher oxidation resistance was observed in a solid solution close to hafnium diboride composition due to the formation of (Hf0.75Zr0.25)SiO4 and HfSiO4 phases on the scale surface, which reduces the diffusion of oxygen into the material.