超高压下熔媒法人造金刚石合成机制研究的重要进展

本文对熔媒法人造金刚石的实验、观察和分析,包括熔媒金属(FC或m)、石墨(g)和金刚石(D)存在状态、结晶状况、微观结构和结构特征及其各自结果的分析讨论等研究作了报导.在此基础上对人造金刚石的合成机制作出有机统一整体的讨论如下:(1)形成D结晶基元相变必要条件的特征,可以认为在m熔化过程中发生的助熔激发效应.由于m的d带空穴同g的π-电子相互作用产生各种集团和原子,特别是具有近程有序与密排面结构的原子集团,从而形成一种具有适当尺寸和可变组元的类填隙式固溶体-复合原子集团;(2)形成D结晶基元相变充分条件的特征,可以认为在前述的复合原子集团中的密排面间隙部位发生m的催化激发效应.由于m的价电子处于激发态统计权重增高达到d3s或类sp3状态,诱发处于复合原子集团中类g原子集团实现sp2转移sp3状态.形成一种具有可变组分、不稳定的或部分稳定的类间隙相.这种间隙相式复合原子集团是相变的产物,也是在非平衡态下具有扩散性的主要结晶基底和结晶基元;(3)人造金刚石体系中m/g相互作用的必要和充分条件的特征可用它们的界面结合特征方程作判据来描述.这种判据取决于反映在它们表面和界面上几何结构、电子结构和尺寸等效应(与原子-分子层次结构及相互作用状态有关)的表面能、界面能和有效尺寸.所推导的方程对人造金刚石体系中相互作用,即熔媒激发复合效应的最适合状态提供重要的科学依据和有效技术途径.

Important Progress in Study on Synthesizing Mechanism of Synthetic Diamond with Flux-catalyst Method at Superhigh Pressure

Investigations made on experiments, observations and analyses of synthetic diamond (SD)with flux-catalyst method including existing state, crystallized status, microstructure and structural characteristics of flux-catalyst metal (FC or m), graphite (g)and diamond (D)as well as discussion of results in separation are reported in this paper. Based on the former, the synthesizing mechanism of SD is further discussed in an organic whole as close as possible as following. ( 1 ) Characteristics of the necessary conditions for the phase transition forming D crystallizing unit are considered as a flux excited effect of m occurred in its molten process generating their various clusters and atoms, especially the complex clusters with a short range order structure and a close-packed plane because of interaction for d-band holes of m with π-electrons of g forming a kind of interstitial solid solution or the like with suitable dimension and variable component-complex cluster; (2) Characteristics of the sufficient conditions for the phase transition forming D crystallizing unit are considered as a catalyst excited effect of m occurred much more at interstices between their atomic clusters with close-arranged plane in the former. It is because of increasing the statistical weight of valence electrons for m in excited state as in d3s or sp3 state like and its inducing carbon clusters of g and the like contained in the former from sp2 into sp3 state. The non-stable or partially stable interstitial compounds with variable components and the like can be formed. This kind of complex cluster with interstitial compound and the like is the result of the phase transition and can be both the crystallizing substrate and crystallizing unit with diffusivity in the main under non-equilibrium state;(3 )Characteristics of the necessary and sufficient conditions for the interaction between m/g in the system of SD are described by the characteristic equation of interface binding as criteria to be depended on their surface energy, interface surface energy and effective dimension reflected upon the effect of geometric structure, electronic structure and dimension (related with the state of atomic-molecular level layer structure and interaction)on their surface and interface surface. They provide an optimal state of interaction,namely, flux-catalyst excited-complex effect, with an important scientific basis and an effectively technology way for SD.