Electrophysical Characteristics of cBN–NbN Composite Ceramics Doped with Al2O3, Si3N4, and SiC
Yu. Yu. Rumyantseva1,2, L. O. Romanko1, I. P. Fesenko1, D. O. Savchenko1, V. Z. Turkevych1, S. Karcz2
1V. M. Bakul Institute for Superhard Materials, NAS of Ukraine, 2 Avtozavodska Str., UA-04074 Kyiv, Ukraine
2Łukasiewicz - Krakow Institute of Technology, 73 Zakopińska Str, 30-011 Krakow, Poland
Received: 19.02.2023; final version - 13.04.2023. Download: PDF
Different additives’ influence on electric conductivity of ‘dielectric/conductor’-type composites (namely, polycrystalline cBN-based composites contained cBN as a dielectric phase and NbN as a conductor phase) is investigated. Investigated samples are obtained by the application of HPHT (high pressure-high temperature) sintering (P = 7.7 GPa, T = 2000°C). Electrical-resistance dependences on the temperature and applied voltage are measured for all samples. Obtained results’ analysis shows that all sintered samples have a semiconductor nature of conductivity. It is interesting that addition dielectrics (Al2O3, Si3N4) as well as semiconductor (SiC) leads to the electric-conductivity improve (drop in electrical resistance) for cBN–NbN composites in some degree (despite the lower electrical conductivity of these substances). Alumina whiskers’ addition to cBN–NbN composites leads to a more significant drop in electrical resistance compared to powder particles’ addition (from 1.85 to 0.72 Ohm⋅cm for samples with whiskers (Al2O3w) and from 1.35 to 0.17 Ohm⋅cm for samples with Al2O3 powder). Hence, as concluded, the sample electrical conductivity is affected by both the additive particles’ morphology and the grain boundaries’ state of the sintered polycrystalline ceramics.
Key words: dielectric, cBN, conductor, NbN, composite, additives, Al2O3, Si3N4, SiC, electrical resistance.
URL: https://mfint.imp.kiev.ua/en/abstract/v45/i06/0723.html
DOI: https://doi.org/10.15407/mfint.45.06.0723
PACS: 72.60.+g, 72.80.Ey, 72.80.Tm, 81.05.Je, 81.05.Mh, 81.40.Rs, 81.70.-q
Citation: Yu. Yu. Rumyantseva, L. O. Romanko, I. P. Fesenko, D. O. Savchenko, V. Z. Turkevych, and S. Karcz, Electrophysical Characteristics of cBN–NbN Composite Ceramics Doped with Al2O3, Si3N4, and SiC, Metallofiz. Noveishie Tekhnol., 45, No. 6: 723—732 (2023)