高长径比柱状金刚石的高温高压合成与机理研究

为了拓展金刚石的种类和解决金刚石工具使用过程中因把持力不足造成的使用寿命降低等, 在中国式六面顶压机上, 通过对FeNi触媒成分和工艺的优化, 成功合成出高质量长径比大于2.5, 平均粒度在0.8—1.0 mm的柱状金刚石晶体. 该晶体独特的形貌, 将极大改善金刚石工具的在使用过程中出现的"脱粒"现象. 另外, 实验中发现, 柱状金刚石晶体的生长速度也远大于传统晶体的生长速度. 采用扫描电镜(SEM)和能谱(EDS)等手段对柱状金刚石晶体及晶体周围触媒成分进行了表征; 结果表明, 柱状金刚石晶体在生长过程中存在{100}和{111}晶面拉长, 以及包覆在晶体周围的触媒成分偏析. 在此基础上, 阐明了柱状晶体生长机理.

Synthesis and growth mechanism of high length-diameter ratio strip-shape diamond by HPHT

To extend the kind of diamond and solve the low life of diamond tools because of the insufficiency of holding force,the stripshape diamond with more than 2.5 in length-diameter ratio and 0.8—1.0 mm in length is synthesized by optimizing FeNi based catalyst composition and using the technology in the China-type cubic anvil high pressure apparatus.Because of the unique morphology,the threshing phenomenon appearing in the using of diamond tools is controlled effectively.Furthermore,we find that the growth rate of strip-shape diamond is much faster than that of the conventional diamond.Strip-shape diamond morphology and catalyst composition around the growing diamond crystal are characterized by SEM and EDS.The results indicate that the facets of diamond crystal are elongated along {100} and {111} faces and catalyst compositions around the growing diamond crystal become segregated.On this basis,we illustrate the growth mechanism of strip-shape diamond.