Research on how to obtain SiN composites with high hardness and toughness at lower temperatures is important. SiN composites with onion-like carbon (OLC)-TiN were prepared using high pressure and high temperature techniques. The effects of TiN and OLC additives on the mechanical properties and microstructure of the silicon nitride ceramics were analyzed. During the sintering process, the vacancies in TiN promoted the formation of the TiCN interface between the three compositions, whose particles were homogeneously dispersed in the silicon nitride matrix with strong bonding to the substrate. OLC (10vol.%)-TiN (10vol.%)-SiN composites were prepared at 5 GPa, 1500 °C and held for 15 min. The Vickers hardness and fracture toughness were determined to be 18.6 GPa and 6.6 MPa m, flexural strength of 531 MPa, and showed higher high-temperature hardness. This was higher than the typical values reported for SiN ceramics (15–17 GPa). This work provides a new strategy for low-temperature of SiN composites with both high hardness and high toughness.

中文翻译：

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洋葱状碳/TiN0.3增强Si3N4复合材料的合成与表征

研究如何在较低温度下获得高硬度和高韧性的SiN复合材料具有重要意义。采用高压高温技术制备了具有洋葱状碳（OLC）-TiN 的 SiN 复合材料。分析了TiN和OLC添加剂对氮化硅陶瓷力学性能和微观结构的影响。在烧结过程中，TiN中的空位促进了三种成分之间TiCN界面的形成，其颗粒均匀分散在氮化硅基体中，与基体结合牢固。OLC (10vol.%)-TiN (10vol.%)-SiN 复合材料在 5 GPa、1500 °C 下制备并保持 15 分钟。测得维氏硬度和断裂韧性分别为18.6 GPa和6.6 MPa·m，弯曲强度为531 MPa，并表现出较高的高温硬度。这高于 SiN 陶瓷报道的典型值 (15–17 GPa)。该工作为低温高硬度、高韧性SiN复合材料提供了新的策略。