Thermoelastic properties of ScB2, TiB2, YB4 and HoB4: Experimental and theoretical studies

Waskowska, A and Gerward, L and Olsen, J S and K, Ramesh Babu and Vaitheeswaran, G and V, Kanchana and Svane, A and Filipov, V B and Levchenko, G and Lyaschenko, A (2011) Thermoelastic properties of ScB2, TiB2, YB4 and HoB4: Experimental and theoretical studies. Acta Materialia, 59 (12). pp. 4886-4864. ISSN 1359-6454

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Abstract

High-pressure X-ray diffraction in ScB2, TiB2, YB4 and HoB4 powders and single crystals has been studied using synchrotron radiation as well as conventional X-rays. The experimental results are supported by calculations using density functional theory. ScB2, YB4 and HoB4 are hard materials (bulk modulus 180–200 GPa), while TiB2 may be classified as superhard (bulk modulus about 260 GPa). We report here first experimental and theoretical determinations of the bulk modulus for HoB4 (195(5) and 198.2 GPa, respectively), and first experimental values of the bulk modulus for ScB2 (196(2) GPa) and YB4 (185(4) GPa). No pressure-induced phase transformations are observed in any of the above borides up to about 20 GPa. A continuous temperature-driven orthorhombic distortion is observed for HoB4 below 285 K. Values of the thermal expansion coefficient are reported for ScB2 and HoB4 at 293, 200 and 100 K. The thermoelastic behavior is explained in terms of bonding characteristics.

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IITH Creators:

IITH Creators	ORCiD
V, Kanchana	UNSPECIFIED

Item Type:

Article

Additional Information:

We wish to express our sincere thanks to Dr. Natalya Shitsevalova, who has been instrumental in writing this paper. We thank Hasylab/DESY for permission to use the synchrotron radiation facility, and Dr. Wolfgang Morgenroth for helpful assistance at Station D3. We are grateful to Prof. Peter Herzig for communicating his results for YB4 prior to publication

Uncontrolled Keywords:

Borides; Bulk modulus; Elastic constants; Thermal expansion; Density functional theory

Subjects:

Physics

Divisions:

Department of Physics

Depositing User:

Team Library

Date Deposited:

29 Dec 2014 10:24

Last Modified:

14 Aug 2017 07:07