Thermal Expansion of Micro- and Nanocrystalline ZrB2 Powders

— Nano- and microcrystalline ZrB 2 powders have been studied by high-temperature X-ray diffraction in the temperature range 300–1400 K, and their unit-cell parameters have been measured as functions of temperature. The thermal expansion coefficient (TEC) of ZrB 2 has been shown to be a linear functi...

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Veröffentlicht in:Inorganic materials 2020-03, Vol.56 (3), p.258-264
Hauptverfasser: Kovalev, D. Yu, Konovalikhin, S. V., Kalinnikov, G. V., Korobov, I. I., Kravchenko, S. E., Khomenko, N. Yu, Shilkin, S. P.
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Sprache:eng
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Zusammenfassung:— Nano- and microcrystalline ZrB 2 powders have been studied by high-temperature X-ray diffraction in the temperature range 300–1400 K, and their unit-cell parameters have been measured as functions of temperature. The thermal expansion coefficient (TEC) of ZrB 2 has been shown to be a linear function of temperature, and its thermal expansion has been shown to be anisotropic: in the temperature range 300–600 K, both the micro- and nanocrystalline ZrB 2 powders have anisotropic thermal expansion, with α a < α c . Above 640 K, the a -axis TEC of ZrB 2 exceeds its c -axis TEC. The thermal expansion of the nanocrystalline ZrB 2 powder has been shown to be considerably smaller than that of the microcrystalline ZrB 2 . The anomalously small thermal expansion of the nanocrystalline ZrB 2 is tentatively attributed to the effect of a boric anhydride layer on the surface of the nanoparticles.
ISSN:0020-1685
1608-3172
DOI:10.1134/S0020168520030073