ABSTRACT

In this study, the compositions 4TaC-1HfC and 1TaC-1HfC ceramics were prepared via hot pressing 5 vol.-% La₂O₃-doped TaC-HfC powder mixtures in temperature range of 1700–2000°C. The effect of sintering temperature on the densification of the two compositions was assessed. Highly dense TaC-HfC ceramics were obtained after hot pressing at sintering temperature of 1750°C or greater, depending on the composition. The elastic properties, electrical conductivity, hardness, fracture toughness and flexural strength of the resulting highly dense ceramics were evaluated. The results show that the elastic properties, hardness and fracture toughness were insensitive to the composition, but the electrical conductivity and room temperature strength. On the other hand, the strength of the two compositions substantially degraded as the temperature increased from room temperature to 1000°C and the degradation depended on the composition. Subsequently, the strength gradually decreased with further increasing temperature up to 1400°C, but this decrease was insensitive to the composition.

摘要

在这项研究中，组成成分4TaC-1HfC和1TaC-1HfC陶瓷是通过热压5体积％La ₂ O ₃制备的掺杂的TaC-HfC粉末混合物，温度范围为1700-2000°C。评估了烧结温度对两种组合物的致密化的影响。根据组成，在烧结温度为1750°C或更高的温度下热压后，可获得高密度的TaC-HfC陶瓷。评价所得高密度陶瓷的弹性，导电率，硬度，断裂韧性和弯曲强度。结果表明，弹性性能，硬度和断裂韧性对组成不敏感，但对电导率和室温强度不敏感。另一方面，随着温度从室温升高到1000℃，两种组合物的强度显着降低，并且降解取决于组合物。随后，