2024-03-28T13:00:32Zhttps://riubu.ubu.es/oai/requestoai:riubu.ubu.es:10259/55942023-03-31T12:16:38Zcom_10259_4759com_10259_2604col_10259_4760
00925njm 22002777a 4500
dc
Tallarita, Giovanna
author
Licheri, Roberta
author
Garroni, Sebastiano
author
Barbarossa, Simone
author
Orrù, Roberto
author
Cao, Giacomo
author
2020-04
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.
0955-2219
http://hdl.handle.net/10259/5594
10.1016/j.jeurceramsoc.2019.10.031
High-entropy ceramics
Borides
Spark plasma sintering
Self-propagating high-temperature synthesis
Resistance to oxidation
High-entropy transition metal diborides by reactive and non-reactive spark plasma sintering: A comparative investigation