The P, T phase and reaction diagram for elemental carbon, 1979

Abstract

A brief history of the many investigations of the pressure/temperature phase diagrams of elemental carbon is given. The strengths and weaknesses of the various proposed diagrams are discussed, and the areas where additional or better experimental data are needed are pointed out. Many questions still remain about linear solid carbons; about the low-pressure/high-temperature solid/liquid/vapor triple point; about the melting line of diamond; about the existence of a high-pressure metallic phase; and about the existence of two liquid phases, one insulator and the other metallic.

New evidence of meteoritic origin of the Tunguska cosmic body

“…It is well known that nanocrystalline γ-Fe is stable at ambient conditions and does not transform into α-Fe, which is stable at room temperature (Gleiter, 1989). According to the carbon stability field diagram (Bundy, 1980) graphite can co-exists with diamond at T = 1400-900 o C and P = 7-5 GPa, whereas the stability boundary between diamond-graphite and lonsdaleite are still unknown. Thus, the collected data together with measurements suggests that the studied Tunguska samples most likely represent small remnants of an iron meteorite, which is also strongly supported by the high ratio of Fe:Ni = 22:1 and Ni/Co =26 (Sobotovich et al, 1985).…”

From soft to superhard: Fifty years of experiments on cold-compressed graphite

“…For a review of these carbon materials, please see the other sections in this special issue [19][20][21]. Additionally, there have been several reviews on the high-pressure, high-temperature behavior of carbon [22][23][24][25], however, in this review, we pay special attention to the long-standing controversies on the structural transitions of graphite at high pressures under room temperature conditions as shown through experiments.…”

Future Directions in Carbon Science

“…One outstanding breakthrough that occurred in carbon science during my early scientific career was the synthesis of diamond in the laboratory under conditions of high temperature and pressure (1,2). This development had a major impact on science by sparking excitement in new materials synthesis, and on technology by spawning the modern tool-and-dye industry and the diamond-coating industry.…”