Flash Joule Heating-Boro/Carbothermal Reduction (FJH-BCTR): An approach for the instantaneous synthesis of transition metal diborides

Transition metal diborides (TMB2), such as ZrB2 and HfB2, are a class of ultra-high-temperature ceramics (UHTCs) that have attracted considerable attention due to their performance in extreme environments. Their implementation is burdened by the high energetic requirement of traditional synthetic procedures. Here, we report a novel methodology, termed as Flash Joule Heating-Boro/Carbothermal Reduction (FJH-BCTR), for the…

Unlocking synergistic benefits of the calcium looping-calcium hydroxide integration for energy storage: A perspective on sorbent performance

Calcium Looping has recently attracted attention as a high temperature thermochemical energy storage system. However, significant sintering due to the high temperatures hampers the recyclability of CaO. Hydration and hydroxylation has been explored as a method to regenerate the spent CaO. This study investigates a novel synergistic integration of carbonation (CaCO3/CaO) and hydroxylation (CaO/Ca(OH)2) reactions.…

Fine-grained BCZT piezoelectric ceramics by combining high-energy mechanochemical synthesis and hot-press sintering

Different stoichiometries of lead-free BaZr0.2Ti0.8O3-Ba0.7Ca0.3TiO3 (BCZT) prepared by mechanosynthesis and sintered by either conventional sintering (CS) or hot pressing (HP) techniques were studied to establish the dependence of piezoelectric and dielectric properties on sintering parameters and microstructure. All synthesized stoichiometries showed a pseudocubic perovskite phase with homogeneously distributed A- and B-cations in the structure. The…

Structural, Mössbauer and magnetic study of (Mn0.2Co0.2Ni0.2Cu0.2X0.2) Fe2O4 (X=Fe, Mg) spinel high-entropy oxides fabricated via reactive flash sintering

Herein, it is reported the concomitant synthesis and sintering in a single step of (Mn0.2Co0.2Ni0.2Cu0.2X0.2)Fe2O4 (X=Fe, Mg), a spinel-structured high-entropy oxides, by the reactive flash sintering technique. A single phase, identified with a spinel crystal structure Fd3m, was obtained in just 30 min at a furnace temperature of 1173 K. The structural and magnetic properties…

Influence of the atmosphere on the formation of high-entropy oxides within the Co–Cu–Fe–Mg–Mn–Ni–O system via reactive flash sintering

In this study, the feasibility of preparing quinary equimolar high-entropy oxides within the Co–Cu–Fe–Mg–Mn–Ni–O system was explored using the reactive flash sintering (RFS) technique. Various compositions were tested using this technique under atmosphere pressure, leading to the formation of two primary phases: rock-salt and spinel. Conversely, a new high-entropy oxide was produced as a single-phase…

Advancements in the integration and understanding of the Sestak-Berggren generalized conversion function for heterogeneous kinetics

Kinetic models are relevant to describe heterogeneous kinetic processes; a number of kinetic models and their mathematical expressions have been reported in the literature, many of these based on idealistic conditions in terms of geometrical constrain and driving forces. Alternatively, the semi-empirical Sestak-Berggren (SB) conversion function, which was proposed as a general equation, encompasses a…