c'BN超高压颗粒破碎规律及其对PcBN烧结特性影响  

Crushing Law of c’BN Particles under Ultra-High Pressure and Its Influence on Characteristics of Sintered PcBN

作　　者：谢辉 邓福铭[2] 尹自信 沈倩倩 冯飞[3] Xie Hui;Deng Fuming;Yin Zixin;Shen Qianqian;Feng Fei(School of Mechanical and Electronic Engineering,Suzhou University,Suzhou Anhui 234000,China;Institute of Superhard Tool Materials,China University of Mining&Technology-Beijing,Beijing 10083,China;Henan Huanghe Cyclone Co.,Ltd,Change Henan 461500,China)

机构地区：[1]宿州学院机械与电子工程学院,安徽宿州234000 [2]中国矿业大学(北京)超硬刀具材料研究所,北京100083 [3]河南黄河旋风股份有限公司,河南长葛461500

出　　处：《硬质合金》2024年第2期113-122,共10页Cemented Carbides

基　　金：宿州学院博士(后)科研启动基金(2023BSK010);安徽省高校优秀科研创新团队(2023AH010055)。

摘　　要：以立方氮化硼与碳/氮化物陶瓷微粉为初始颗粒,分别设计了常温超高压挤压与高温高压烧结实验,利用激光粒度分析仪、SEM、XRD等进行表征。研究表明,超高压挤压1min即完成了颗粒破碎与86.47%以上的致密化过程,颗粒破碎机制为脆性断裂与晶内裂纹,破碎后极易团聚且流动性较差;cBN颗粒破碎率与晶粒尺寸正相关;cBN与陶瓷微粉均具有超高压与高温高压的两次颗粒致密化过程。颗粒破碎形成的活性表面与细颗粒有助于烧结致密化,但颗粒破碎引起的裂纹等“内伤”亦会对烧结体性能产生负面影响。Cubic boron nitride(cBN)and carbon/nitride ceramic micro-powder were used as initial particles,and the extrusion experiment at room temperature and ultra-high pressure and sintering experiment at high temperature and high pressure were designed,respectively.Characterization was carried out using a laser particle size analyzer,SEM,and XRD.The study results show that the particle crushing and densification process of over 86.47% are completed within one minute under extrusion at ultra-high pressure.The particle crushing mechanism is manifested as brittle fractures and the formation of intragranular cracks.After crushing,it is easy to aggregate and has poor fluidity.The crushing rate of cBN particles is positively correlated with their grain size.Both cBN and ceramic micro-powder undergo two densification processes at ultrahigh pressure,as well as high temperature and high pressure.The active surface and fine particles formed by particle crushing contribute to sintering densification.However,“internal injuries”such as cracks caused by particle crushing have a negative impact on the performance of the sintered body.

关 键 词：超高压 挤压破碎 CBN 团聚性 压缩率 

分 类 号：TQ128[化学工程—无机化工]