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 |
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Format: | Artikel |
Sprache: | eng |
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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. |
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ISSN: | 0020-1685 1608-3172 |
DOI: | 10.1134/S0020168520030073 |