中文摘要：

本文利用掺硅FeNi粉末触媒，在国产六面顶压机上进行了金刚石单晶的合成实验，研究了高温高压条件下，Fe—Ni—Si—C体系合成金刚石单晶的成核特性。结果表明，由于掺Si量的不同，合成金刚石的最低生长条件（压力和温度）并没有太大的改变；但随着触媒中掺Sj量的增加，其成核量也随之增加；通过光学成像显微镜观测发现，合成出的金刚石晶体同FeNi—C体系合成的晶体的颜色和形貌具有较大的区别，出现了“两极分化”现象，主要表现为部分晶体质量好，而部分晶体则质量很差（晶体呈浅黑色，晶形不完整等），且随触媒中掺甄量的增加，质量差的晶体比率增高。对不同合成条件的棒料进行X—ray检测发现，在金刚石合成条件下有FeSi和Fe，si的生成，台阶压力时间的长短直接影响FeSi、Fe3si的粒度。我们推测，难熔化合物FeSi和Fe3si参与成核，导致金刚石成核量增加，而这种金刚石的“异形核”存在，会导致晶形不够完整和包裹体的产生。

英文摘要：

In this article, diamond single crystal synthetic experiments were carried out in cubic press using Silicon-contained FeNi powder as catalyst. The nucleation properties of diamond in FeNi-Si-C system under HPHT were researched. The result indicates that, the minimum growth conditions, pressure and temperature, for diamond formation have not changed with the content of silicon. However, the amount of nucleation has a tendency to increase with the increasing of silicon content. Using optical microscope, we find that the color and morphology of the synthetic diamond crystal from FeNi-Si-C system have greater differences to that from FeNi-C system. The phenomenon of ＂Polarization＂ has appeared. That is to say, some crystals are of high quality, while the rest are of poor quality, they are light black and incomplete. And the rate of poor quality crystal tends to increase with the increase of Si content in synthesis system. X-ray diffractions of the synthesis bars, which were obtained under different conditions, show that FeSi and Fe3Si may have formed under synthesis conditions. Based on the fact that the granularity of Fe3Si increased with the increase time at step pressure, we infer that the high-inching compound FeSi and Fe3Si participate in nucleation in the form of ＂ heteromorphy nuclear＂. This caused the increase of the amount of nucleation. And the formation of ＂heteromorphy nuclear＂ may have lead to the formation of inclusions and the incompletion of crystals.