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<p>Ultra-high-temperature ceramics (UHTCs), particularly titanium diboride (TiB<sub>2</sub>), are critical for demanding applications such as thermal protection systems, wear-resistant components, and high-temperature applications. However, their strong covalent bonding and poor sinterability pose significant fabrication challenges. This study investigates the incorporation of graphitic carbon nitride (g-C<sub>3</sub>N<sub>4</sub>) as a sintering aid and reinforcing phase in TiB<sub>2</sub> composites processed via spark plasma sintering (SPS). A TiB<sub>2</sub>-10&#xa0;wt% g-C<sub>3</sub>N<sub>4</sub> composite was sintered at 1900°C under a pressure of 40&#xa0;MPa, achieving a relative density of 91.3%. Tribological evaluation via pin-on-disk testing revealed a specific wear rate of 2.455 × 10<sup>−4</sup>&#xa0;mm<sup>3</sup>/N&#xa0;m, approximately half that of monolithic TiB<sub>2</sub>, alongside an estimated hardness of 41.2&#xa0;GPa. Microstructural analysis identified carbon-rich tribofilms and probably in- situ formed B<sub>4</sub>C nanoparticles as key contributors to enhanced wear resistance. However, the composite exhibited a higher average coefficient of friction (0.67) compared to pure TiB<sub>2</sub>, attributed to less effective lubrication from the tribofilm. These findings demonstrate g-C<sub>3</sub>N<sub>4</sub> as a promising additive for improving the wear performance of TiB<sub>2</sub>-based composites while highlighting the need for further optimization to reduce frictional losses.</p>

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Wear Behavior of TiB2–C3N4 Composites Fabricated by SPS Process

  • 期刊论文

  • 出版模式：

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  • 发表日期：

    2026年5月18日

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  • Milad Sakkaki,
  • Seyed Mohammad Arab,
  • Zohre Ahmadi,
  • Mohammad Farvizi,
  • Mehdi Shahedi Asl

摘要

Ultra-high-temperature ceramics (UHTCs), particularly titanium diboride (TiB2), are critical for demanding applications such as thermal protection systems, wear-resistant components, and high-temperature applications. However, their strong covalent bonding and poor sinterability pose significant fabrication challenges. This study investigates the incorporation of graphitic carbon nitride (g-C3N4) as a sintering aid and reinforcing phase in TiB2 composites processed via spark plasma sintering (SPS). A TiB2-10 wt% g-C3N4 composite was sintered at 1900°C under a pressure of 40 MPa, achieving a relative density of 91.3%. Tribological evaluation via pin-on-disk testing revealed a specific wear rate of 2.455 × 10−4 mm3/N m, approximately half that of monolithic TiB2, alongside an estimated hardness of 41.2 GPa. Microstructural analysis identified carbon-rich tribofilms and probably in- situ formed B4C nanoparticles as key contributors to enhanced wear resistance. However, the composite exhibited a higher average coefficient of friction (0.67) compared to pure TiB2, attributed to less effective lubrication from the tribofilm. These findings demonstrate g-C3N4 as a promising additive for improving the wear performance of TiB2-based composites while highlighting the need for further optimization to reduce frictional losses.