2024-03-28T08:52:51Zhttps://riubu.ubu.es/oai/requestoai:riubu.ubu.es:10259/55942023-03-31T12:16:38Zcom_10259_4759com_10259_2604col_10259_4760
High-entropy transition metal diborides by reactive and non-reactive spark plasma sintering: A comparative investigation
Tallarita, Giovanna
Licheri, Roberta
Garroni, Sebastiano
Barbarossa, Simone
Orrù, Roberto
Cao, Giacomo
High-entropy ceramics
Borides
Spark plasma sintering
Self-propagating high-temperature synthesis
Resistance to oxidation
The direct synthesis and consolidation by SPS (1950 °C, 20 min, 20 MPa) of high-entropy (Hf0.2Mo0.2Zr0.2Nb0.2Ti0.2)B2 from elemental powders resulted in a multiphase product. An increase of the heating rate determined a change of the mechanism governing the synthesis reaction from gradual solid-state diffusion to rapid combustion regime, while the final conversion degree was 67 wt.%. The sintered product displayed a non-uniform microstructure with the presence of 10–15 μm sized pores, due to volatilization phenomena occurring during the combustion synthesis reaction. In contrast, when the SPS process was preceded by powder synthesis via SHS, a homogeneous single-phase ceramic was obtained. Clear benefits are derived by the use of SHS, able to provide very shortly powders with elemental species very well intermixed, so that the obtainment of (Hf0.2Mo0.2Zr0.2Nb0.2Ti0.2)B2 during the subsequent SPS stage is strongly promoted. The resulting 92.5% dense product shows superior oxidation resistance with respect to individual borides prepared with the same method.
2021-01-13T11:25:12Z
2021-01-13T11:25:12Z
2021-01-13T11:25:12Z
2020-04
info:eu-repo/semantics/article
0955-2219
http://hdl.handle.net/10259/5594
10.1016/j.jeurceramsoc.2019.10.031
eng
Journal of the European Ceramic Society. 2020, V. 40, n. 4, p. 942-952
https://doi.org/10.1016/j.jeurceramsoc.2019.10.031
http://creativecommons.org/licenses/by-nc-nd/4.0/
info:eu-repo/semantics/openAccess
Attribution-NonCommercial-NoDerivatives 4.0 Internacional
Elsevier