在熔融金属溶液中石墨在金刚石稳定区结晶的可能性

本文给出了在超高压高温条件下,碳的亚稳相石墨从熔融金属溶液中结晶的实验现象,并以此为例分析了亚稳相从溶液结晶的热力学可能性。提出了促使亚稳相结晶的过饱和的概念,指出:溶液体系中的温度差是亚稳相结晶的推动力。重点给出在一个结晶条件下亚稳相石墨可能结晶的临界温度差的计算。 关键词：

THE POSSIBILITY OF THE CRYSTALLIZATION OF METASTABLE GRAPHITE FROM MOLTEN METAL SOLUTIONS UNDER THE STABLE CONDITIONS OF DIAMOND

The experimantal phenomena for the formation of graphite, -the metastable phase of carbon -from molten metal solutions under ultrahigh pressures and high temperatures are given. Taking this as an example, we have analyzed the thermodynamic possibility of the crystallization of the metastable phases from the solution. The concept of supersaturation that promotes the metastable phases to crystallize from solutions has been presented. It has been pointed out that the temperature difference in a solution system must be the driving force for crystallization of the metastable phase from, the solution. The emphasis is placed on the calculations of the critical temperature difference of the possible crystallization for the metastable graphite under a given crystallizing condition.