烧结压力对碳化钽陶瓷维氏硬度的影响

为了探究烧结压力对不同晶粒尺寸碳化钽(TaC)力学性能的影响,通过高温高压技术对纳米、微米尺寸TaC粉末进行高温高压烧结,制备不同烧结条件下的块状TaC陶瓷。利用X射线衍射等表征方法对烧结样品的物相、元素分布、压痕形态进行表征,结果表明:TaC在烧结过程中物相稳定,且无杂质渗入。利用维氏硬度计对不同烧结压力(3.0、4.0和5.5 GPa)条件下的3种陶瓷样品进行维氏硬度测试,并进行微观结构分析,结果表明:随着烧结压力由3.0 GPa提升到5.5 GPa,微米尺寸TaC的维氏硬度(21.0 GPa)优于3.0、4.0 GPa下的纳米尺寸TaC维氏硬度(17.5、19.2 GPa)。此外,研究发现,测试维氏硬度时,3.0 kg应用载荷对测试TaC维氏硬度更加精确。研究结果对结构陶瓷烧结和超高温陶瓷硬度研究具有指导意义。

Effects of Sintering Pressure on the Vickers Hardness of TaC

To study the effects of the sintering pressure on the mechanical properties of TaC with various grain sizes,nano-and micro-sized TaC powders are sintered at high pressure and high temperature(HPHT)to acquire bulk TaC ceramics under different sintering conditions.Different characterization approaches,such as X-ray diffraction(XRD),are used to observe phase,elements distribution,and indentation state.The observations reveal that the TaC phase is stable during the sintering process and there is no impurity infiltration.Three ceramic samples at the various sintering pressures(3.0,4.0,5.5 GPa)are measured by the Vickers hardness tester and their microstructures are also analyzed.The results show that as the sintering pressure increases from 3.0 GPa to 5.5 GPa,the Vickers hardness of Micro-5.5-TaC(21.0 GPa)is higher than that of Nano-3.0-TaC(17.5 GPa)and Nano-4.0-TaC(19.2 GPa).In addition,it is found that 3.0 kg is the most accurate load for measuring the Vickers hardness.This study has a guiding significance for sintering structural ceramics and exploring the Vickers hardness of ultra-high temperature ceramics(UHTCs).