降温工艺对宝石级金刚石单晶品质的影响  

Effects of cooling process on qualities of Gem-diamond single crystals

作　　者：肖宏宇[1] 秦玉琨[1] 刘利娜[1] 鲍志刚[1] 唐春娟[1] 孙瑞瑞 张永胜[1] 李尚升[2] 贾晓鹏[3] Xiao Hong-Yu;Qin Yu-Kun;Liu Li-Na;Bao Zhi-Gang;Tang Chun-Juan;Sun Rui-Rui;Zhang Yong-Sheng;Li Shang-Sheng;Jia Xiao-Peng(Department of Mathematics and Physics,Luoyang Institute of Science and Technology,Luoyang 471023,China;School of Materials Science and Engineering,Henan Polytechnic University,Jiaozuo 454000,China;State Key Laboratory of Superhard Materials,Jilin University,Changchun 130012,China)

机构地区：[1]洛阳理工学院数理部,洛阳471023 [2]河南理工大学材料科学与工程学院,焦作454000 [3]吉林大学超硬材料国家重点实验室,长春130012

出　　处：《物理学报》2018年第14期98-104,共7页Acta Physica Sinica

基　　金：国家自然科学基金青年科学基金(批准号:61007023);河南省科技攻关计划(批准号:162102210275);河南省教育厅项目(批准号:16A140044;16A140012);河南省高等学校骨干教师资助计划(批准号:2015GGJS-112);河南省高等学校重点科研项目(批准号:17A430004;18A430017)资助的课题~~

摘　　要：在国产六面顶压机上,采用温度梯度法,在5.6 GPa,1200—1400?C的高压高温条件下,裂晶问题频繁出现的合成周期内,围绕裂晶现象开展了Ib型宝石级金刚石单晶的生长研究,系统考察了降温工艺对宝石级金刚石单晶品质的影响.针对宝石级金刚石单晶常见的裂纹缺陷,借助于扫描电子显微镜,分别对优质金刚石单晶和存在裂纹金刚石单晶的表面形貌进行了表征;利用微区傅里叶转换红外光谱测试手段,对上述两类晶体的N杂质含量分别进行了测试,依据测试结果,对裂晶出现的原因进行了分析;分别采用传统断电降温和缓慢降温工艺,考察了晶体生长结束后的降温工艺对宝石级金刚石单晶品质的影响.结果表明,缓慢降温工艺在很大程度上可以有效抑制裂晶问题出现.另外,从宝石级金刚石单晶品质和单晶受到的外应力两个方面着手,分别对裂晶出现的机理和采用缓慢降温工艺有效解决裂晶问题的机理进行了讨论.In the paper, under 5.6 GPa and 1200–1400？C, the type Ib diamond single crystals on defect-free [111]-oriented seed crystals are synthesized in a cubic anvil under high pressure and high temperature when the crack problem of diamond single crystal appears frequently. Highpurity Fe-Ni-Co solvents are chosen as the catalysts. Highpurity graphite powder（99.99%, purity） is selected as a carbon source. The effects of cooling process on the qualities of Gem-diamond single crystals are studied carefully. First, in order to study the common crack defects of diamond single crystals, using scanning electron microscope（SEM）, the surface morphologies of high quality diamond single crystals and crack crystals are obtained respectively. Our SEM test results show that the surfaces of the crack crystals and the high quality crystals are all very smooth. Therefore, the crack crystal problem is not directly caused by the unordered accumulation of carbon.Second, the concentrations of nitrogen in the high quality diamonds and crack crystals are measured by Fourier transform infrared. In our studies, the nitrogen content of the diamond single crystal with crack is similar to the nitrogen content of high quality single crystal, so the appearance of crystal crack is not caused by high impurity content. According to the test results and the regularity of the occurrence of crack crystals, the reasons for the occurrence of crack crystals are analyzed seriously. When the weather conditions such as seasonal change, wind, rain or snowfall are not very stable,the probability of crack crystal problem to appear will increase greatly. In our opinion, the decrease of diamond crystal quality caused by the fluctuation of external growth conditions is the internal cause of crack crystal problem appearing.After growing diamond crystals, choosing the traditional power failure mode and slowing cooling process respectively,the effect of cooling process on the quality of diamond single crystal is investigated. In the season of the crack probl

关 键 词：高温高压 Ib型金刚石 裂晶问题 缓慢降温工艺 

分 类 号：O78[理学—晶体学] TQ163[化学工程—高温制品工业]