cBN单晶合成效果与合成后Li基触媒组织结构的相关性研究  

Study on Correlation between Synthetic Quality of cBN Crystals and Microstructure of the Lithium Based Catalyst

作　　者：王功振[1] 许斌[1] 时永鹏[1] 吕美哲 郭全海[1] 

机构地区：[1]山东建筑大学材料科学与工程学院,济南250101 [2]山东大学材料科学与工程学院,济南250061

出　　处：《人工晶体学报》2016年第12期2752-2757,共6页Journal of Synthetic Crystals

基　　金：国家自然科学基金(51272139)

摘　　要：采用锂基触媒(Li_3N)和六方氮化硼(hBN)为原料,在静态高温高压条件下加入(270/325目)籽晶批量合成出了大颗粒立方氮化硼(cBN)单晶(>70目)。通过X射线衍射仪(XRD)对触媒层内物相进行标定,采用K值法、绝热法、RIR值等理论方法,计算出样品触媒层内各物相的质量分数,比较了单晶合成效果好与差的触媒层内物相含量的差别;利用扫描电子显微镜(SEM)对样品触媒层的形貌进行观察,比较了单晶合成效果好与差的触媒层形貌的差别。结果表明:cBN单晶合成效果不同,其触媒组织结构有着明显的差异。当单晶合成效果较好时,触媒层中Li_3BN_2的含量为49%,cBN的含量为5%,hBN的含量为46%,触媒层内存在较均匀的熔融球状组织和管状组织,且离单晶表面越近管状组织越多;当单晶合成效果较差时,触媒层中Li_3BN_2的含量为10%,cBN的含量为49%,hBN的含量为41%,触媒层内只存在熔融球状组织。分析认为,触媒层中的cBN和Li_3BN_2的含量是影响大颗粒cBN单晶合成效果的主要因素。Large particle cubic boron nitride（cBN） single crystals were synthesized through adding seed crystals （270/325mesh） by HTHP method ,using Li3N as catalyst and hBN as raw materials. In this paper ,with the X-ray diffraction experiment,using theoretical techniques of the method of K-value ,the method of RIR-value and the adiabatic method ,the compositions of every phase in catalyst layer are identified and the mass fraction of catalyst layer in every phase were calculated. The morphology of catalyst layer near cBN were characlerized by SEM to compare of different parts of catalyst layer on different results of synthesizing cBN monocrystal. The results show that when the synthetic quality is relatively superior,it is constituted uniform molten globular microstructure and rod organization in catalyst layer. From the single crystal surface, the more the number of rod like tissue, and the content of Li3BN2 is 49%, the content of cBN is 5%, and the content of hBN is 46%. When the synthetic quality is poor,it is only constituted uniform molten globular microstructure in catalyst layer,and the content of Li3BN2 is 10%, the content of cBN is 49%, and the content of hBN is 41%. The content of cBN and Li3BN2 commonlyaffect synthetic quality of the large particles eBN single crystalsin the catalyst layer.

关 键 词：Li基触媒层 CBN K值法 物相含量 组织形貌 

分 类 号：O78[理学—晶体学]