TY - JOUR

T1 - Formation of Compressed and Mixed-Layered Graphite on Heating Impact Diamonds

AU - Gromilov, S. A.

AU - Nikolaev, R. E.

AU - Cherepanova, S. V.

PY - 2018/3/1

Y1 - 2018/3/1

N2 - The graphitization process of impact diamonds in the helium atmosphere at 1900–1960 °C is investigated. It is shown that when an impact diamond particle with a large number of lonsdaleite defects is kept at 1900 °C for 1 min, ~5 wt.% of graphite are formed (in the paralle experiment with a particle without lonsdaleite defects the graphite formation is not observed). With an increase in the temperature to 1930 °С and 1940 °С the graphite amount increases to 70 wt.% and 80 wt.% respectively. In both cases, a mixture of two graphite phases forms: the first is turbostratic graphite with d002 = 3.38 Å; the second is compressed graphite with d002 = 3.21 Å. On heating a particle to 1960 °C graphite is formed in which the layer packing contains a large amount of defects and is a mixture of 2Н and 3R polytypes (the ratio 40:60) with a small degree of turbostratic disordering.

AB - The graphitization process of impact diamonds in the helium atmosphere at 1900–1960 °C is investigated. It is shown that when an impact diamond particle with a large number of lonsdaleite defects is kept at 1900 °C for 1 min, ~5 wt.% of graphite are formed (in the paralle experiment with a particle without lonsdaleite defects the graphite formation is not observed). With an increase in the temperature to 1930 °С and 1940 °С the graphite amount increases to 70 wt.% and 80 wt.% respectively. In both cases, a mixture of two graphite phases forms: the first is turbostratic graphite with d002 = 3.38 Å; the second is compressed graphite with d002 = 3.21 Å. On heating a particle to 1960 °C graphite is formed in which the layer packing contains a large amount of defects and is a mixture of 2Н and 3R polytypes (the ratio 40:60) with a small degree of turbostratic disordering.

KW - compressed graphite

KW - diamond

KW - graphite

KW - impact diamond

KW - lonsdaleite

KW - mixed-layered graphite

KW - simulation

KW - turbostratic disordering

KW - TRANSFORMATION

KW - HIGH-PRESSURE

KW - POWDER DIFFRACTION PATTERNS

KW - SIMULATION

KW - GRAPHITIZATION

UR - http://www.scopus.com/inward/record.url?scp=85048169376&partnerID=8YFLogxK

U2 - 10.1134/S0022476618020142

DO - 10.1134/S0022476618020142

M3 - Article

AN - SCOPUS:85048169376

VL - 59

SP - 355

EP - 364

JO - Journal of Structural Chemistry

JF - Journal of Structural Chemistry

SN - 0022-4766

IS - 2

ER -