The ultrahigh-temperature ceramic (UHTC) Ta₄HfC₅ is one of the most promising candidate materials suitable for the use in hypersonic aircrafts because of its excellent thermophysical and thermomechanical performance. However, the poor sintering ability is one of the main reasons restricting its potential application. To overcome this obstacle, Si₂BC₃N ceramic was used to densify the tantalum hafnium carbide solid solution. Thus, dense Ta₄HfC₅-Si₂BC₃N ceramics were synthesized by hot-pressing sintering. The resulting composite ceramic was comprised of crystalline Ta₄HfC₅, SiC and BN(C) phases. A “tadpole-like” shape of SiC and BN(C) connecting phase was formed accompanied by rapid grain growth at 2100°C, increasing the fracture toughness to 3.47 ± 0.12 MPa m^1/2. The growth mechanism of the Ta₄HfC₅ grains gradually changed from grain-boundary sliding by volume diffusion to grain boundary diffusion, attributed to the grain growth activation energy changing from 112.4 to 250.7 ± 29.3 kJ mol⁻¹ with increasing sintering temperature.

超高温陶瓷（UHTC）Ta ₄ HfC ₅因其优异的热物理和热机械性能而成为最有前途的适用于高超音速飞行器的候选材料之一。然而，较差的烧结能力是限制其潜在应用的主要原因之一。为了克服这个障碍，使用Si ₂ BC ₃ N陶瓷来致密碳化钽铪固溶体。由此，通过热压烧结合成了致密的Ta ₄ HfC ₅ -Si ₂ BC _{3 N陶瓷。所得复合陶瓷由结晶Ta 4} HfC ₅组成、SiC 和 BN(C) 相。在2100℃时，伴随着晶粒的快速长大，形成了“蝌蚪状”形状的SiC和BN(C)连接相，使断裂韧性增加至3.47±0.12 MPa m ^1/2。_{Ta 4} HfC ₅晶粒的生长机制逐渐从体积扩散的晶界滑动转变为晶界扩散，这归因于随着烧结温度的升高，晶粒生长活化能从112.4变化到250.7±29.3 kJ mol -1 ^。