Blank Vladimir D, Churkin Valentin D, Kulnitskiy Boris A, Perezhogin Igor A, Kirichenko Alexey N, Denisov Viktor N, Erohin Sergey V, Sorokin Pavel B, Popov Mikhail Yu
Technological Institute for Superhard and Novel Carbon Materials, 142190, Centralnaya Str. 7a, Troitsk, Moscow, Russia. National University of Science and Technology MISiS, 119049, Leninskiy prospekt 4, Moscow, Russia. Moscow Institute of Physics and Technology State University, 141700, Institutskiy per. 9, Dolgoprudny, Moscow Region, Russia.
Nanotechnology. 2018 Mar 16;29(11):115603. doi: 10.1088/1361-6528/aaa857.
Phase diagrams of carbon, and those focusing on the graphite-to-diamond transitional conditions in particular, are of great interest for fundamental and applied research. The present study introduces a number of experiments carried out to convert graphite under high-pressure conditions, showing a formation of stable phase of fullerene-type onions cross-linked by sp-bonds in the 55-115 GPa pressure range instead of diamonds formation (even at temperature 2000-3000 K) and the already formed diamonds turn into carbon onions. Our results refute the widespread idea that diamonds can form at any pressure from 2.2 to 1000 GPa. The phase diagram built within this study allows us not only to explain the existing numerous experimental data on the formation of diamond from graphite, but also to make assumptions about the conditions of its growth in Earth's crust.
碳的相图，尤其是聚焦于石墨到金刚石转变条件的相图，对于基础研究和应用研究都极具吸引力。本研究介绍了一系列在高压条件下将石墨转化的实验，结果表明在55 - 115吉帕的压力范围内，形成的是通过sp键交联的富勒烯型洋葱状稳定相，而非金刚石（即使在2000 - 3000 K的温度下），并且已形成的金刚石会转变为碳洋葱。我们的结果驳斥了普遍认为在2.2至1000吉帕的任何压力下都能形成金刚石的观点。本研究构建的相图不仅能解释现有的众多关于从石墨形成金刚石的实验数据，还能对其在地壳中生长的条件做出假设。
