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<p>Silicon carbide (SiC) presents significant challenges for densification due to its strong covalent bonds and low self-diffusion rates. The incorporation of additives is essential for facilitating this densification process. This study examines rare-earth-free B<sub>2</sub>O<sub>3</sub>-based binary oxide systems: B<sub>2</sub>O<sub>3</sub>–Li<sub>2</sub>O, B<sub>2</sub>O<sub>3</sub>–MgO, and B<sub>2</sub>O<sub>3</sub>–Al<sub>2</sub>O<sub>3</sub>, evaluating their effectiveness as liquid-phase sintering aids for β-SiC. Commercial β-SiC (90 wt%) was mixed with 10 wt% of each additive and subjected to hot pressing at 1750&#xa0;°C for one hour under 20&#xa0;MPa in an argon atmosphere. Densification was measured using Archimedes’ principle, while phase evolution was assessed through X-ray diffraction (XRD), with microstructural evaluations conducted via scanning electron microscopy (SEM). Relative densities achieved were reported as follows: B<sub>2</sub>O<sub>3</sub>–Al<sub>2</sub>O<sub>3</sub> at 97.5%, B<sub>2</sub>O<sub>3</sub>–MgO at 93.8%, B<sub>2</sub>O<sub>3</sub>–Li<sub>2</sub>O at 84.2%, and B<sub>2</sub>O<sub>3</sub>-only at 76.6%. Microstructural analysis showed that the B<sub>2</sub>O<sub>3</sub>–Al<sub>2</sub>O<sub>3</sub> system had a dense structure with an average grain size of 1.03 ± 0.02&#xa0;μm and a porosity of 2.68%. In contrast, the B<sub>2</sub>O<sub>3</sub>–MgO system had a slightly larger average grain size of 1.06 ± 0.04&#xa0;μm and porosity of 6.67%. XRD analysis indicated a transition from β-SiC to α-SiC in all samples, with the B<sub>2</sub>O<sub>3</sub>–Al<sub>2</sub>O<sub>3</sub> system showing the highest fraction of α-SiC. This study highlights the advantage of liquids in improving SiC densification, establishing B<sub>2</sub>O<sub>3</sub>–Al<sub>2</sub>O<sub>3</sub> as a cost-effective alternative to rare-earth additives.</p> Graphical abstract <p></p>

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Revealing the role of B2O3-based binary oxide systems in the liquid phase sintering of silicon carbide

  • 期刊论文

  • 发表日期：

    2026年4月11日

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  • Alfian Noviyanto,
  • Ratih Amalia,
  • Bagas Haqi Arrosyid,
  • Didik Aryanto,
  • Nurato Nurato,
  • Imam Hidayat,
  • Nanda Hendra Pratama

摘要

Silicon carbide (SiC) presents significant challenges for densification due to its strong covalent bonds and low self-diffusion rates. The incorporation of additives is essential for facilitating this densification process. This study examines rare-earth-free B2O3-based binary oxide systems: B2O3–Li2O, B2O3–MgO, and B2O3–Al2O3, evaluating their effectiveness as liquid-phase sintering aids for β-SiC. Commercial β-SiC (90 wt%) was mixed with 10 wt% of each additive and subjected to hot pressing at 1750 °C for one hour under 20 MPa in an argon atmosphere. Densification was measured using Archimedes’ principle, while phase evolution was assessed through X-ray diffraction (XRD), with microstructural evaluations conducted via scanning electron microscopy (SEM). Relative densities achieved were reported as follows: B2O3–Al2O3 at 97.5%, B2O3–MgO at 93.8%, B2O3–Li2O at 84.2%, and B2O3-only at 76.6%. Microstructural analysis showed that the B2O3–Al2O3 system had a dense structure with an average grain size of 1.03 ± 0.02 μm and a porosity of 2.68%. In contrast, the B2O3–MgO system had a slightly larger average grain size of 1.06 ± 0.04 μm and porosity of 6.67%. XRD analysis indicated a transition from β-SiC to α-SiC in all samples, with the B2O3–Al2O3 system showing the highest fraction of α-SiC. This study highlights the advantage of liquids in improving SiC densification, establishing B2O3–Al2O3 as a cost-effective alternative to rare-earth additives.

Graphical abstract