About changes of the single diamond crystal form during its growth by the temperature gradient method
Babich Yu. V., Feigelson B. N., Sonin V. M., ChepurovA. I.
Zapiski RMO (Proceedings of the Russian Mineralogical Society). 2016. V. 145. N 5. P. 74-83
Peculiarities of crystal form and development of growth sectors were studied for single octahedral diamond crystals grown by the temperature gradient method in closed metal-carbon system under high pressure (60 specimens were used). It was determined that the diamond crystals shows regular increasing of the «upper» octahedral growth sectors relatively to the «lower» ones, while the crystal was growing. This tendency is characterized by mass dependence of angle between the considered groups of sectors, and it is connected with the change of their relative growth rates. On the initial stage the difference of the growth rates between the sectors is minimal, but their ratio can increase up to 1:3 and higher during further growth. The described growth features may be explained by specificity of the temperature gradient growth of diamond at high pressure (oriented location of carbon source, limited growth space). Considerable variation of the relative growth rates indicates that the internal structure and local growth conditions should be taken into account when synthetic diamonds obtained by temperature gradient method are used for researches where growth rate can take an effect (surface morphology, origin of inclusions, intake of impurities, etc.).
Key words: high pressure, temperature gradient method, diamond, single crystals.