The MAX phase borides Zr2SB and Hf2SB

Zr2SB and Hf2SB were synthesized via solid-state reactions and the crystal structures were determined by powder X-ray diffraction. Both compounds crystallize in the hexagonal Cr2AlC-type structure (P63/mmc; Z = 2; Zr2SB a = 3.5001(1) Å, c = 12.2712(2) Å; Hf2SB a = 3.4671(1) Å, c = 12.1046(2) Å). The...

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Veröffentlicht in:Solid state sciences Jg. 106; S. 106316
Hauptverfasser: Rackl, Tobias, Johrendt, Dirk
Format: Journal Article
Sprache:Englisch
Veröffentlicht: Elsevier Masson SAS 01.08.2020
Schlagworte:
Borides
DFT calculations
Elastic properties
MAX phases
Structural properties
MAX phases
Borides
Elastic properties
Structural properties
DFT calculations
ISSN:1293-2558, 1873-3085
Online-Zugang:Volltext
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Zusammenfassung:Zr2SB and Hf2SB were synthesized via solid-state reactions and the crystal structures were determined by powder X-ray diffraction. Both compounds crystallize in the hexagonal Cr2AlC-type structure (P63/mmc; Z = 2; Zr2SB a = 3.5001(1) Å, c = 12.2712(2) Å; Hf2SB a = 3.4671(1) Å, c = 12.1046(2) Å). The lattice parameters and bond lengths are slightly longer and the M6X octahedra are less distorted compared to the known carbides. Resistivity and magnetic measurements reveal that Zr2SB and Hf2SB are good metallic conductors and Pauli paramagnets. Ab-initio DFT calculations of the electronic structure confirm the nonmagnetic metallic state and show mainly ionic bonds, which are weaker than in the carbides. The elastic constants indicate that Zr2SB and Hf2SB are brittle and exhibit a less two-dimensional character compared to other MAX phases. [Display omitted] •The new MAX phase borides Zr2SB and Hf2SB have been discovered and characterized.•DFT calculations confirm the nonmagnetic metallic state and reveal mainly ionic bonds.•The bulk moduli are slightly smaller than in the carbides due to weaker Zr,Hf–B bonding.
ISSN:1293-2558
1873-3085
DOI:10.1016/j.solidstatesciences.2020.106316