Investigation of ternary metal dodecaborides (M1M2M3)B12 (M1, M2 and M3 = Zr, Y, Hf and Gd)

Georgiy Akopov; Inwhan Roh; Zachary C. Sobell; Michael T. Yeung; Richard B. Kaner

doi:10.1039/C8DT00563J

Investigation of ternary metal dodecaborides (M₁M₂M₃)B₁₂ (M₁, M₂ and M₃ = Zr, Y, Hf and Gd)†

Georgiy Akopov,

^a Inwhan Roh,^a Zachary C. Sobell,^a Michael T. Yeung

^b and Richard B. Kaner

*^acd

Author affiliations

* Corresponding authors

^a Department of Chemistry and Biochemistry, University of California, Los Angeles (UCLA), Los Angeles, CA 90095, USA
E-mail: kaner@chem.ucla.edu

^b Department of Chemistry, Northwestern University, Evanston, IL 60208, USA

^c Department of Materials Science and Engineering, University of California, Los Angeles (UCLA), Los Angeles, CA 90095, USA

^d California NanoSystems Institute (CNSI), University of California, Los Angeles (UCLA), Los Angeles, CA 90095, USA

Abstract

Samples of metal borides with a nominal composition of ((M₁)_(1−x−z)(M₂)_(x)(M₃)_(z)) : 20B (M₁, M₂ and M₃ = Zr, Y, Hf and Gd) were prepared by arc-melting and studied for phase composition (using powder X-ray diffraction (PXRD) and energy dispersive X-ray spectroscopy (EDS)) and mechanical properties (Vickers hardness). Ternary metal dodecaboride phases were successfully synthesized for the majority of compositions, including stabilization of two high-pressure (6.5 GPa) phases (cubic-UB₁₂ structure), HfB₁₂ and GdB₁₂, in (Zr_1−x−zHf_xGd_z) : 20B and (Y_1−x−zHf_xGd_z) : 20B nominal alloy compositions. Unit cell refinement for the samples showed solid solution formation in most cases. Vickers hardness measurements indicated that most samples possess enhanced hardness in comparison to their parent phases, with the alloy (Zr_0.50Y_0.25Gd_0.25) : 20B having a hardness of 46.9 ± 2.4 GPa compared to 41.3 ± 1.1 and 41.6 ± 1.3 GPa for alloy compositions of 1.0 Zr : 20B and 1.0 Y : 20B, respectively, at 0.49 N of applied load. Using the data from this manuscript as well as previous work, pseudo-ternary phase diagrams (at a constant boron content) have been constructed.

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Article information

DOI: https://doi.org/10.1039/C8DT00563J
Article type: Paper
Submitted: 10 Febr. 2018
Accepted: 06 Apr. 2018
First published: 06 Apr. 2018

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Dalton Trans., 2018,47, 6683-6691

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Investigation of ternary metal dodecaborides (M₁M₂M₃)B₁₂ (M₁, M₂ and M₃ = Zr, Y, Hf and Gd)

G. Akopov, I. Roh, Z. C. Sobell, M. T. Yeung and R. B. Kaner, Dalton Trans., 2018, 47, 6683 DOI: 10.1039/C8DT00563J

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