Formation of Nitrogen Supersaturated (Nitrogen-Rich) MeN Nitrides at Thermobaric Sintering of PcBN Composites of cBN-{TiN, ZrN, HfN, VN, NbN}–Al Systems

Authors N.M. Bilyavina1, V.Z. Turkevich2 , A.M. Kuryliuk1 , D.A. Stratiichuk2 , O.I. Nakonechna1

1Taras Shevchenko National University of Kyiv, 01601 Kyiv, Ukraine

2V. Bakul Institute for Superhard Materials of the National Academy of Sciences of Ukraine, 04074 Kyiv, Ukraine

Issue Volume 16, Year 2024, Number 2
Dates Received 18 February 2024; revised manuscript received 14 April 2024; published online 29 April 2024
Citation N.M. Bilyavina, V.Z. Turkevich, et al., J. Nano- Electron. Phys. 16 No 2, 02013 (2024)
PACS Number(s) 72.80.Tm, 81.05.Je
Keywords High pressure, High temperatures, cBN composite, MeN nitrides, X-ray diffraction (19) , Crystal structure (8) , Nitrogen migration.

The crystal structure of MeN nitrides, existing in the surface layers of PcBN composites of cBN-{TiN, ZrN, HfN, VN, NbN}–Al systems (composition, vol. %: cBN: MeN: Al as (60:35:5, vol. %) sintered at high pressure and high temperature (HPHT, 7.7 GPa, 1600-2450 °C), was studied in detail using the X-ray diffraction structural analysis method. It was shown that the crystal structure of each MeN nitride belonges to the modified NaCl type structure with an additional position partially filled by the nitrogen atoms. The presence of such a position leads to a certain excess of nitrogen on the sample's surface, the source of which is nitrides from the depth of the composite. It is shown that the diffusion of nitrogen atoms through defects and lattice sites of MeN crystal lattices from the bulk to the surface of composite plays an important role in the formation of crystal structures of MeN nitrides at the barothermal conditions. Using the results of X-ray diffraction structural calculations as reference values, the main parameters of this diffusion process (activation energy and rate constant) were determined for cBN-{TiN, HfN, VN, NbN}-Al composites. It is shown that the activation energy of diffusion increases in HfN → TiN → VN → NbN series and correlates with the formation enthalpy of each MeN nitrides.

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