Phase diagram of carbon and the factors limiting the quantity and size of natural diamonds. (5th February 2018)

• Record Type: Journal Article
• Authors: 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
• Is Part Of: Nanotechnology. Volume 29:Number 11(2018)
• Publication Date: 2018-02-05
• Subjects: phase diagram of carbon -- onions -- graphite -- diamond -- high pressure; Nanotechnology -- Periodicals; Nanotechnology -- Periodicals; Nanotechnology; Publications périodiques; Nanotechnologies; Periodicals; 620.5
• DOI: 10.1088/1361-6528/aaa857
• Languages: English
• ISSNs: 0957-4484

Abstract

Abstract: 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 3 -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.