Abstract The present research aims to investigate the influences of SiC reinforcement and h-BN additive on the relative density, microstructure, and thermodynamic aspects of TiB2-based ceramics. Three different specimens, including monolithic TiB2, TiB2–SiC, and TiB2-SiC-BN were fabricated using spark plasma sintering (SPS) at 1900 °C. A dwelling time of 7 min and an external pressure of 40 MPa were applied as the sintering conditions. The characteristics of SPSed monolithic TiB2 and the prepared composites were studied using X-ray diffractometry, thermodynamic inspections, and scanning electron microscopy. These assessments unveiled the in-situ formation of TiC and graphitized carbon in the TiB2–SiC preparation process, whereas no carbon was detected in the composite doped with h-BN. Introducing SiC had immense impact on the relative density of both composites, yielding near fully dense ceramics. The intergranular type was the dominant fracture mode in the all three TiB2-based ceramics. Moreover, the addition of secondary phase substantially refined the microstructure of TiB2, reaching ceramics with finer grains than the undoped ceramic.

中文翻译：

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BN和SiC的共添加对SPS法致密化TiB2基复合材料微观结构的影响

摘要 本研究旨在研究碳化硅增强材料和 h-BN 添加剂对 TiB2 基陶瓷的相对密度、微观结构和热力学方面的影响。三种不同的试样，包括整体 TiB2、TiB2-SiC 和 TiB2-SiC-BN，在 1900 °C 下使用放电等离子体烧结 (SPS) 制造。7 分钟的停留时间和 40 兆帕的外部压力被用作烧结条件。使用 X 射线衍射、热力学检查和扫描电子显微镜研究了 SPSed 整体 TiB2 和制备的复合材料的特性。这些评估揭示了 TiB2-SiC 制备过程中 TiC 和石墨化碳的原位形成，而在掺杂 h-BN 的复合材料中未检测到碳。引入 SiC 对两种复合材料的相对密度产生了巨大影响，产生了接近完全致密的陶瓷。晶间型是所有三种 TiB2 基陶瓷的主要断裂模式。此外，第二相的加入显着改善了 TiB2 的微观结构，达到比未掺杂陶瓷具有更细晶粒的陶瓷。