TY - JOUR

T1 - HPHT diamond crystallization in the Mg-Si-C system

T2 - Effect of Mg/Si composition

AU - Palyanov, Yuri

AU - Kupriyanov, Igor

AU - Borzdov, Yuri

AU - Nechaev, Denis

AU - Bataleva, Yuliya

PY - 2017/5/1

Y1 - 2017/5/1

N2 - Crystallization of diamond in the Mg-Si-C system has been studied at 7.5 GPa and 1800°C with the Mg-Si compositions spanning the range from Mg-C to Si-C end-systems. It is found that as Si content of the system increases from 0 to 2 wt %, the degree of the graphite-to-diamond conversion increases from about 50 to 100% and remains at about this level up to 20 wt % Si. A further increase in Si content of the system leads to a decrease in the graphite-to-diamond conversion degree down to complete termination of diamond synthesis at Si content >50 wt %. Depending on the Si content crystallization of diamond, joint crystallization of diamond and silicon carbide and crystallization of silicon carbide only are found to take place. The cubic growth of diamond, typical of the Mg-C system, transforms to the cube-octahedron upon adding 1 wt % Si and then to the octahedron at a Si content of 2 wt % and higher. The crystallized diamonds are studied by a suite of optical spectroscopy techniques and the major characteristics of their defect-and-impurity structure are revealed. The correlations between the Si content of the Mg-Si-C system and the properties of the produced diamond crystals are established.

AB - Crystallization of diamond in the Mg-Si-C system has been studied at 7.5 GPa and 1800°C with the Mg-Si compositions spanning the range from Mg-C to Si-C end-systems. It is found that as Si content of the system increases from 0 to 2 wt %, the degree of the graphite-to-diamond conversion increases from about 50 to 100% and remains at about this level up to 20 wt % Si. A further increase in Si content of the system leads to a decrease in the graphite-to-diamond conversion degree down to complete termination of diamond synthesis at Si content >50 wt %. Depending on the Si content crystallization of diamond, joint crystallization of diamond and silicon carbide and crystallization of silicon carbide only are found to take place. The cubic growth of diamond, typical of the Mg-C system, transforms to the cube-octahedron upon adding 1 wt % Si and then to the octahedron at a Si content of 2 wt % and higher. The crystallized diamonds are studied by a suite of optical spectroscopy techniques and the major characteristics of their defect-and-impurity structure are revealed. The correlations between the Si content of the Mg-Si-C system and the properties of the produced diamond crystals are established.

KW - Characterization

KW - Crystal morphology

KW - Crystallization

KW - Defects

KW - Diamond

KW - High pressure high temperature

KW - PHOSPHORUS

KW - HIGH-PRESSURE

KW - CARBON SYSTEM

KW - IMPURITY

KW - CATALYST

KW - HIGH-TEMPERATURE CONDITIONS

KW - MAGNESIUM-BASED SYSTEMS

KW - crystal morphology

KW - diamond

KW - GERMANIUM

KW - high pressure high temperature

KW - defects

KW - GROWTH

KW - crystallization

KW - CRYSTALS

KW - characterization

UR - http://www.scopus.com/inward/record.url?scp=85019075644&partnerID=8YFLogxK

U2 - 10.3390/cryst7050119

DO - 10.3390/cryst7050119

M3 - Article

AN - SCOPUS:85019075644

VL - 7

JO - Crystals

JF - Crystals

SN - 2073-4352

IS - 5

M1 - 119

ER -