%0 Journal Article
%A Schimpf, Christian
%A Schwarz, Marcus
%A Lathe, C.
%A Kroke, E.
%A Rafaja, D.
%T Effect of the microstructure of graphitic boron nitride on the kinetics of the formation of boron nitride high-pressure phases
%J Journal of the European Ceramic Society
%V 39
%N 4
%@ 0955-2219
%C Amsterdam [u.a.]
%I Elsevier Science
%M PUBDB-2022-01058
%P 944 - 951
%D 2019
%X 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.
%F PUB:(DE-HGF)16
%9 Journal Article
%U <Go to ISI:>//WOS:000457819600031
%R 10.1016/j.jeurceramsoc.2018.10.021
%U https://bib-pubdb1.desy.de/record/474900