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<p>The influence of 5 vol% of WC, TaC and HfC on the microstructure, bending strength, and oxidation resistance of the ZrB<sub>2</sub>-15 vol% SiC ceramics was studied. The core-shell structure (Zr, Me)B<sub>2</sub>, MeB and solid solutions based on ZrC are formed after hot-pressing. Flexural strength at 1800 ℃ was 308, 330 and 643&#xa0;MPa for materials with addition of TaC, HfC and WC, respectively. The oxidation resistance of the materials increased in the order HfC &gt; TaC &gt; WC, where the thickness of the oxide scale was 85&#xa0;μm, 90&#xa0;μm and 125&#xa0;μm, respectively. The observed mechanism of oxidation primarily depends on the additive to form the solid solution with ZrB<sub>2</sub>. When the oxidation of the additive in the shell is more energetically advantageous than the zirconium diboride, the additive is first oxidized with the formation of fine oxides, as in the case of (Zr, Ta)B<sub>2</sub>. In the case of (Zr, Hf)B<sub>2</sub>, a more oxidation-resistant shell is formed from a solid solution (Zr, Hf)O<sub>2</sub> with a zirconium oxide core, which increases the resistance to high-temperature oxidation.</p>

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Influence of HfC, TaC, WC on the microstructure, mechanical properties and oxidation resistance of ZrB2-15 vol% SiC composite ceramics

  • 期刊论文

  • 发表日期：

    2025年9月4日

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  • Dmytro Vedel,
  • Anton Osipov,
  • Mykola Brodnikovskyi,
  • Mykola Skoryk,
  • Serhii Taran,
  • Anatolii Bondar

摘要

The influence of 5 vol% of WC, TaC and HfC on the microstructure, bending strength, and oxidation resistance of the ZrB2-15 vol% SiC ceramics was studied. The core-shell structure (Zr, Me)B2, MeB and solid solutions based on ZrC are formed after hot-pressing. Flexural strength at 1800 ℃ was 308, 330 and 643 MPa for materials with addition of TaC, HfC and WC, respectively. The oxidation resistance of the materials increased in the order HfC > TaC > WC, where the thickness of the oxide scale was 85 μm, 90 μm and 125 μm, respectively. The observed mechanism of oxidation primarily depends on the additive to form the solid solution with ZrB2. When the oxidation of the additive in the shell is more energetically advantageous than the zirconium diboride, the additive is first oxidized with the formation of fine oxides, as in the case of (Zr, Ta)B2. In the case of (Zr, Hf)B2, a more oxidation-resistant shell is formed from a solid solution (Zr, Hf)O2 with a zirconium oxide core, which increases the resistance to high-temperature oxidation.