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Diamond formation through metastable liquid carbon

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Abstract

It is known that carbon melts at temperatures around 4000 K or higher, and, therefore, this will be for the first time, when liquid carbon state formation preserved within diamond is documented in a carbon-carbonate system at the PT-conditions around 8.0 GPa and 2000 K, that is essentially far from the carbon diagram liquid field, so the newly reported liquid carbon was formed by neither fusion nor condensation. Based on a preponderance of such a strong circumstantial evidence, as morphological features of globular glass-like carbon inclusions within the globular-textured host diamond crystals resulting from liquid segregation process under synthesis conditions, it is suggested, that the produced carbon state has general properties of liquid and is formed through agglomeration alongside with diffusion process of carbon within carbonate melt solvent, and, thus, can potentially open a novel route for liquid carbon production and manufacturing of advanced high-refractory alloys and high-temperature compounds at lower than commonly accepted standard temperatures. A new model of diamond formation via metastable liquid carbon is presented. DOI information: 10.1016/j.diamond.2015.12.015 The following personal article link can provide free access to the full text article, which is valid until February 24, 2016: http://authors.elsevier.com/a/1SKHU3IYYkPuqV
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Shumilova T.G., Isaenko S.I., Tkachev S.N. Diamond formation through metastable liquid
carbon. Diamond & Related Materials 62 (2016) 42–48.
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