Reaction Sintering of Machinable TiB2-BN-C Ceramics with In-Situ Formed h-BN Nanostructure

Oleksii Popov; Dmitry V Shtansky; Vladimir Vishnyakov; Oleksandra Klepko; Sergey Polishchuk; Magzhan K Kutzhanov; Elizaveta S Permyakova; Petro Teselko

doi:10.3390/nano12081379

Reaction Sintering of Machinable TiB₂-BN-C Ceramics with In-Situ Formed h-BN Nanostructure

Nanomaterials (Basel). 2022 Apr 18;12(8):1379. doi: 10.3390/nano12081379.

Authors

Oleksii Popov^{1

2}, Dmitry V Shtansky³, Vladimir Vishnyakov⁴, Oleksandra Klepko⁵, Sergey Polishchuk⁶, Magzhan K Kutzhanov³, Elizaveta S Permyakova³, Petro Teselko¹

Affiliations

¹ Faculty of Physics, Taras Shevchenko National University of Kiev, 01033 Kyiv, Ukraine.
² Science and Research Centre "Synthesis", 02139 Kiev, Ukraine.
³ Research Laboratory of Inorganic Nanomaterials, National University of Science and Technology "MISiS", Leninsky Prospect 4, 119049 Moscow, Russia.
⁴ Centre for Engineering Materials, University of Huddersfield, Huddersfield HD1 3DH, UK.
⁵ Inorganic Materials Vapor Phase Department, E. O. Paton Electric Welding Institute, 03150 Kyiv, Ukraine.
⁶ Department of Physics of Dispersed Systems, G. V. Kurdyumov Institute for Metal Physics of the N. A. S. of Ukraine, 03142 Kyiv, Ukraine.

Abstract

Soft TiB₂-BN-C hetero-modulus ceramics were sintered with the assistance of in-situ reactions during the hot pressing of TiN-B₄C precursors. TiB₂ formation was observed already after the hot pressing at 1100 °C, remaining the only phase identifiable by XRD even after sintering at 1500 °C. Analysis of reaction kinetics allows us to assume that the most probable reaction controlling stage is boron atoms sublimation and gas phase transfer from B₄C to TiN. Reactive sintering route allows almost full densification of TiB₂-BN-C composite ceramics at 1900 °C. The processes enable the formation of multilayer h-BN nanosheets inside the TiB₂ matrix. The manufactured TiB₂-33BN-13C ceramic with K_1C = 5.3 MPa·m^1/2 and H_V = 1.6 GPa is extremely thermal shock-resistant at least up to quenching temperature differential of 800 °C. The sintered UHTC composite can be machined into complex geometry components.

Keywords: boron nitride nanosheets; hetero-modulus ceramics; machinable ceramic; pseudoplasticity; reactive sintering; thermal shock resistance; titanium diboride.