高温高压下Fe-Ni-C系合成金刚石的研究

 以工业纯单质铁粉和单质镍粉为主要原料，采用粉末冶金方法制备了Fe-Ni-C系反应体系，在六面顶压机上进行了金刚石合成实验。Raman光谱和X射线衍射结果表明，采用这种方法获得的粒径为200~500 μm，呈六-八面体聚形的晶体为立方金刚石单晶。通过对常规力学性能的检测发现，金刚石的品位较高，超过SMD25级锯片级金刚石的要求。分析认为，高温高压下金刚石自Fe-Ni-C系形核是一个触媒不断溶解催化碳原子的过程。大量的实验结果可以证实，金刚石在Fe-Ni-C系长大所需的碳原子来自于在γ-(Fe，Ni)吸引作用下、从(Fe，Ni)₃C中不断脱溶的碳。金属包覆膜在这一过程中不但起到了输送碳原子的作用，还以独特的方式促成了碳原子由sp²π杂化态向sp³杂化态的转变。

Study on Synthesizing Diamond from Fe-Ni-C System at High Temperature and High Pressure

The synthesizing diamond experiment was carried out with iron-based catalysts made by powder metallurgy using industrial iron and nickel powder as stuff at cubic high pressure apparatus. By employing Raman spectroscopy and X-ray diffraction, it can be proved that the crystal gotten from the experiment whose grain size is 200~500 μm is cubic diamond single crystal. The results of the mechanical property test indicate that the quality of diamond exceeds the standard of SMD25. By analysis, it can be judged that the process of diamond nucleation is the one that the molten alloy dissolves and catalyses the carbon atoms. Based on a lot of results, it can be illustrated that the carbon, which is needed for diamond growth, comes from the (Fe,Ni)₃C under the absorption of γ-(Fe,Ni) and the film is not only the diffuse path of carbon, but also the catalysts of structure deformation.