A-site high-entropy perovskite oxide MeTiO3 thermoelectric ceramic and preparation method thereof

Abstract

The invention discloses A-site high-entropy perovskite oxide MeTiO3 thermoelectric ceramic and a preparation method thereof. The A-site high-entropy perovskite oxide MeTiO3 has a single-phase perovskite structure, the elements in the A-site high-entropy perovskite oxide MeTiO3 are uniformly distributed without agglomeration, and the A-site high-entropy perovskite oxide MeTiO3 has thermoelectric performance and can be used in the field of thermoelectric materials. The chemical composition of the A-bit high-entropy perovskite oxide MeTiO3 is (Ca < 0.2 > Sr < 0.2 > Ba < 0.2 > La < 0.2 > Pb < 0.2 >) TiO3, (Ca < 0.25 > Sr < 0.25 > Ba < 0.25 > La < 0.25 >) TiO3, (Ca < 0.25 > Sr < 0.25 > Ba < 0.25 > Pb < 0.25 >) TiO3, (Ca < 0.25 > Sr < 0.25 > Ba < 0.25 > Nd < 0.25 >) TiO3, (Ca < 0.25 > Sr < 0.25 > Ba < 0.25 > Sm < 0.25 >) TiO3, and (Ca < 0.25 > Sr < 0.25 > Ba < 0.25 > Eu < 0.25 >) TiO3. According to the invention, the high entropy of the perovskite structure is realized, the disorder degree of atom arrangement in the material composition is improved, the phonon scattering is increased, and the thermal conductivity is reduced, so that the thermoelectric performance is improved. In the sintering process, oxygen atoms are migrated and discharged through oxygen vacancies in material crystal lattices, the porosity is reduced, the ceramic density is improved, meanwhile, the oxygen vacancy concentration is improved, and the carrier concentration of the material is improved. By adopting a reduction annealing process of argon and carbon powder, the semiconduction of perovskite oxide is realized, the carrier concentration of the ceramic is improved, the conductivity is improved, and the thermoelectric performance is further improved.

Description

technical field [0001] The invention relates to the field of high-entropy oxides, in particular to an A-site high-entropy oxide MeTiO 3 Thermoelectric ceramics and methods for their preparation. Background technique [0002] In 2004, the concept of "high-entropy alloys" (HEAs) was proposed. Cantor et al. prepared a single-phase multi-component alloy with stable configuration entropy for the first time. Since then, high-entropy engineering has been extensively studied in the field of alloys. Until 2015, entropy-stabilized oxides (Mg 0.2 Zn 0.2 co 0.2 Cu 0.2 Zn 0.2 After )O was reported, the concept of high entropy entered the field of ceramics. This not only confirms the driving force of entropy, but also opens up new ideas for the study of high-entropy non-metallic materials. High-entropy systems usually have four high-entropy effects: high-entropy effects in thermodynamics; hysteretic diffusion effects in kinetics; lattice distortion effects in structure; and cocktai...

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Problems solved by technology

In this paper, a series of high-entropy perovskite oxides Ba(Zr 0.2 Ti 0.2 sn 0.2 f 0.2 Me 0.2 )O 3 (Me=Y 3+ ,Nb 5+ , Ta 5+ ,V 5+ ,Mo 6+ ,W 6 + ), and its dielectric properties were studied, but the high-entropy perovskite oxide does not have thermoelectric properties, so it cannot be used in the field of thermoelectric materials

[0009] CaCO has not been seen so far 3 , SrCO 3 、BaCO 3 、La 2 o 3 , PbO, Nd 2 o 3 、Sm 2 o 3 、Eu 2 o 3 and TiO 2 Preparation of high-entropy perovskite-structured oxides (Ca 0.2 Sr 0.2 Ba 0.2 La 0.2 Pb 0.2 )TiO 3 , (Ca 0.25 Sr 0.25 Ba 0.25 Me 0.25 )TiO 3 Report on (Me=La, Pb, Nd, Sm, Eu) Materials and Their Thermoelectric Properties

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