Si_3N_4晶须结合剂合成PCBN微观组织结构的研究

本文以Si3N4晶须为结合剂,高温高压下合成了聚晶立方氮化硼,烧结压力为5～7GPa,温度为1400～1500℃,选用了石墨管+NaCl管+钼杯组装方式。采用金相显微镜、扫描电镜和X射线衍射仪等仪器设备研究了产品PCBN的组织结构。金相显微镜结果表明,PCBN的表面组织比较均匀。扫描电镜结果表明,PCBN的烧结情况良好,结合剂对CBN高温润湿情况良好。X射线衍射结果表明,有新的物相生成。

Study of micro-structure of PCBN with Si3N4 whisker binders

In this paper, PCBN （polycrystalline cubic boron nitride）is synthesized by using Si3N4 whisker as the binders in the assembly way of pure graphite pot ＋ NaC1 tube ＋ molybdenum cup under the pressure of 5 - 7 GPa and the temperature of 1 400 -1 500 ℃. The micro-structure of PCBN is studied by metallographic microscope, scanning electron microscope （SEM） and X-ray diffraction （XRD）. Metallographic microscope results show that the surface of PCBN is homogeneous. SEM results show that PCBN is well sintered. The Si3 N4 whisker binders improve the wettability of the bond to CBN grains. XRD results indicate that there are new phases produced in sintering process.