TY  - JOUR
AU  - Schimpf, Christian
AU  - Schwarz, Marcus
AU  - Lathe, C.
AU  - Kroke, E.
AU  - Rafaja, D.
TI  - Effect of the microstructure of graphitic boron nitride on the kinetics of the formation of boron nitride high-pressure phases
JO  - Journal of the European Ceramic Society
VL  - 39
IS  - 4
SN  - 0955-2219
CY  - Amsterdam [u.a.]
PB  - Elsevier Science
M1  - PUBDB-2022-01058
SP  - 944 - 951
PY  - 2019
AB  - Three types of hexagonal boron nitride (h-BN) with graphitic crystal structure having different microstructures were subjected to high pressures (HP) and high temperatures (HT), and the kinetics of the phase transitions to the sp<sup>3</sup>-hybridized phases (w-BN, c-BN) was studied using in situ synchrotron diffraction. The analysis of the phase transformation kinetics revealed the transformation paths and activation energies E<sub>a</sub> of the transformation of h-BN to the high-pressure forms of BN for different microstructures of h-BN. Defect-poor h-BN transforms to metastable wurtzitic BN (w-BN) with E<sub>a</sub> ≈ 0.3 eV/at. Defect-rich forms of h-BN transform directly to c-BN, but with a higher activation energy. It was observed that the turbostratic disorder in h-BN retards the phase transition as compared to h-BN containing corrugated basal planes and a low degree of turbostracity. The experimental results are discussed in view of the microstructure changes during the HP/HT treatment and compared to available theoretical phase transition models.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000457819600031
DO  - DOI:10.1016/j.jeurceramsoc.2018.10.021
UR  - https://bib-pubdb1.desy.de/record/474900
ER  -