Influence of hexagonal boron nitride nanosheets on phase transformation, microstructure evolution and mechanical properties of Si3N4 ceramics

0542944 - ÚFM 2022 RIV GB eng J - Journal Article
Tatarková, M. - Tatarko, P. - Kovalčíková, A. - Dlouhý, Ivo - Dusza, J. - Šajgalík, P.
Influence of hexagonal boron nitride nanosheets on phase transformation, microstructure evolution and mechanical properties of Si3N4 ceramics.
Journal of the European Ceramic Society. Roč. 41, č. 10 (2021), s. 5115-5126. ISSN 0955-2219. E-ISSN 1873-619X
Grant - others:AV ČR(CZ) SAV-18-12; AV ČR(CZ) SAV-21-04
Program: Bilaterální spolupráce; Bilaterální spolupráce
Institutional support: RVO:68081723
Keywords : fracture-toughness * fabrication * composites * nanocomposites * nanotubes * behavior * Silicon nitride * Boron nitride nanosheets * Microstructure * Toughening * Mechanical properties
OECD category: Ceramics
Impact factor: 6.364, year: 2021
Method of publishing: Limited access
https://www.sciencedirect.com/science/article/pii/S0955221921000972?via%3Dihub

Fully dense Si3N4 materials with 1 wt.% (- 1.5 vol.%) and 2 wt.% (- 3.0 vol.%) h-BN nanosheets were prepared by spark plasma sintering at 1750 degrees C with the dwell of 7 min under a pressure of 50 MPa in a vacuum. BN nanosheets with different dimensions were prepared by ultrasound-assisted liquid phase exfoliation of h-BN powder, followed by centrifugation at different speeds (1000 rpm and 3000 rpm). The addition of BN nanosheets hindered the particle rearrangement stage of sintering, which resulted in the delayed alpha>beta phase transformation of Si3N4. To study a direct effect of BN nanosheets on the mechanical properties of Si3N4, the results were compared to the monolithic Si3N4 with similar grain size and alpha/beta-Si3N4 ratio. The addition of 2 wt.% h-BN nanosheets (1000 rpm) increased both the fracture toughness (- 26 %) and the strength (- 45 %) of Si3N4, when compared to the monolithic Si3N4 with similar microstructure.
Permanent Link: http://hdl.handle.net/11104/0320318