Инд. авторы:	Palyanov Y.N., Borzdov Y.M., Kupriyanov I.N., Khokhryakov A.F.
Заглавие:	Effect of H 2O on diamond crystal growth in metal-carbon systems
Библ. ссылка:	Palyanov Y.N., Borzdov Y.M., Kupriyanov I.N., Khokhryakov A.F. Effect of H 2O on diamond crystal growth in metal-carbon systems // Crystal Growth & Design. - 2012. - Vol.12. - Iss. 11. - P.5571-5578. - ISSN 1528-7483. - EISSN 1528-7505.
Внешние системы:	DOI: 10.1021/cg301111g; SCOPUS: 2-s2.0-84868688242;
Реферат:	eng: In this paper, we report on the influence of the H 2O additive in the metal melt on the growth processes, morphology, and defect-and-impurity structure of diamond crystals. As a source of water, a mixture of Mg(OH) 2 and SiO 2 was used, which reacted under the experimental conditions following the reaction 2Mg(OH) 2 + SiO 2 = Mg 2SiO 4 + 2H 2O. The main experiments were performed in the Ni 0.7Fe 0.3-C system at a pressure of 6 GPa, a temperature of 1370 °C, a duration of 15 h, and a H 2O concentration (CH 2O) ranging from 0 to 0.5 wt %. It is found that, as the H 2O content increases from 0 to 0.2 wt %, the diamond morphology changes from bulky octahedra to {111} platelike crystals and then to {111} dendrites. Further increases in CH 2O in the range of 0.22-0.4 wt % result in crystallization of bulky rhombic dodecahedra and then {110} dendrites. At a CH 2O higher than approximately 0.43 wt %, nucleation and growth of diamond are completely terminated and only graphite crystallizes. The systematic changes in diamond growth and morphology are accompanied by a decrease in nitrogen impurity concentration in diamond from 220-230 to 40-50 ppm, an increase in the density of microinclusions, and the appearance in the IR spectra of a peak at 2840 cm -1, related to hydrocarbons. © 2012 American Chemical Society.
Ключевые слова:	Diamonds; Morphology; Hydrocarbons; Crystal structure; Crystal impurities; Crystal growth; Systematic changes; Plate-like crystals; Nucleation and growth; Nitrogen impurity; Microinclusions; Metal melts; IR spectrum; Growth process; Experimental conditions; Diamond morphology; Diamond growth; Diamond crystals; C-systems;
Издано:	2012
Физ. характеристика:	с.5571-5578