Ti(C,N)-TaC-Ni金属陶瓷真空烧结过程的微观结构演变与性能的研究

Microstructure Evolution and Properties of Ti(C,N)-TaC-Ni Cermet During Vacuum Sintering

用热质联用分析仪、X射线衍射仪、扫描电镜和能谱仪等研究了Ti(C,N)-5%TaC-50%Ni(质量分数,下同)和Ti(C,N)-10%TaC-50%Ni两种金属陶瓷的微观结构与性能随温度的演化过程。结果表明:白环与白芯在固相烧结阶段即开始形成,但二者的形成方式不同。烧结态的白芯与白环都是在液相烧结的早期阶段通过溶解-析出最终形成的。灰环会优先在白芯与白环上形成,同时形成部分无环结构。Ti(C,N)在高温稳定性的迅速降低是灰环含Ti量高于白环的原因。添加质量分数为5%TaC的金属陶瓷硬度随烧结温度升高快速增加至7115 MPa,随后缓慢降低至6791 MPa。

The evolution of microstructure and properties of Ti(C,N)-5%TaC-50%Ni cermets(mass fraction the same below) and Ti(C, N)-10%TaC-50%Ni cermets with temperature was studied by thermogravimetry-differential scanning calorimetry-thermogravimetry-quadrupole mass spectrometry(DSC-TG-QMS), X-ray diffraction(XRD), scanning electron microscopy(SEM), and energy-dispersive X-ray spectroscopy(EDS). The results show that the white rim and white core begin to form in solid-phase sintering, but their formation modes are different, and the white core and white rim are finally formed by dissolution-precipitation in the early stage of liquid-phase sintering. The gray rim tends to form on the white core and white rim and develop some rimless structures at the same time. The content of Ti in the gray rim is higher than that in the white rim, to which the rapid decrease in Ti(C, N) stability at high temperatures should be attributed. The hardness of cermets with 5%TaC rises rapidly to 7,115 MPa with the increase in sintering temperature before it diminishes slowly to 6,791 MPa.