Processing and properties of PcBN composites fabricated by HPHT using PSN and Al as sintering additive  

作　　者：Ming-Liang Li Li-Xing Liang Hai-Long Wang Peng-Bo Zhao Xiao-Tong Zhao Gang Shao Rui Zhang 

机构地区：[1]School of Materials Science and Engineering,Zhengzhou University,Zhengzhou 450001,China [2]Henan Key Laboratory of Aeronautical Material and Application Technology,Zhengzhou University of Aeronautics,Zhengzhou 450052,China

出　　处：《Rare Metals》2020年第5期570-576,共7页稀有金属（英文版）

基　　金：financially supported by the National Natural Science Foundation of China(No.51402264);the Natural Science Foundation of Henan Province(No.162300410242);the Excellent Young Faculty Research Foundation of Zhengzhou University(Nos.1421320049 and 1421320044)。

摘　　要：Dense polycrystalline cubic boron nitride(PcBN)composites were fabricated by high-pressure and high-temperature(HPHT)sintering using polysilazane(PSN)and Al as sintering additive.After high-energy ball milling,the cBN fine particles were uniformly coated with PSN by ultrasonic treatment.After thermocuring and pyrolysis,the cBN–SiCN particles were mixed with Al The PcBN composites were prepared after sintering a1450°C for 10 min with a pressure of 5 GPa.The refining effect of high-energy ball milling on the c BN particles was studied by scanning electron microscopy(SEM)and laser particle size analyzer.The oxidation of the cBN particles after milling was investigated by nitrogen–oxygen analyzer.The phase composition and microstructure of the sintered PcBN composites were investigated by X-ray diffractometer(XRD)and SEM.The main phases of the sintered PcBN composites are c BN,AlN,SiC and Si3N4The conversion of cBN to hBN was inhibited by the formation of AlN.The mechanical properties of the sintered PcBN composites were improved by the appearance of SiC and Si3N4.The density and mechanical properties of the PcBN composites both increased with the content of the cBN particles increasing.The sintered sample with 60 wt%cBN,30 wt%PSN and 10 wt%Al showed the best results density of 99.7%,Vickers’hardness of(25.2±0.8)GPa and flexural strength of(602±15)MPa.

关 键 词：Polycrystalline cubic boron nitride Highpressure and high-temperature sintering High-energy ball milling Mechanical properties 

分 类 号：TQ163[化学工程—高温制品工业] TB332[一般工业技术—材料科学与工程]