A dual-phase high-entropy boride (HEB)/carbide (HEC) ceramic with a fine grain size was synthesized by a sequential boro/carbothermal process. In the first step, an Hf–Nb–Ta–Ti–Zr-containing carbide was synthesized by a carbothermal reduction of oxides followed by the reaction of the carbide with B4C and ZrH2 to convert part of the carbide to boride. The resulting composition was ∼29 vol% HEB with an average grain size of ∼1.1 μm. Solid solution formation occurred at the densification temperature of 1900°C resulting in a relative density higher than 99%. The Vickers hardness was 26.5 ± 1.4 GPa. This is the first report of synthesizing dual-phase boride–carbide high-entropy ceramics from Carbo thermally synthesized, HEC powders.
S. M. Smith et al., "High-Entropy Boride–carbide Ceramics by Sequential Boro/carbothermal Synthesis," Journal of the American Ceramic Society, vol. 105, no. 9, pp. 5543 - 5547, Wiley, Sep 2022.
The definitive version is available at https://doi.org/10.1111/jace.18517
Materials Science and Engineering
Keywords and Phrases
borides; carbides; synthesis; ultrahigh temperature ceramics
International Standard Serial Number (ISSN)
Article - Journal
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01 Sep 2022
Honeywell Federal Manufacturing and Technologies, Grant DE-NA0002839