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CN-119430913-B - Method for improving electric clamping effect of barium titanate-based ferroelectric perovskite electric clamping material

CN119430913BCN 119430913 BCN119430913 BCN 119430913BCN-119430913-B

Abstract

A process for improving the electric card effect of ferroelectric perovskite material includes such steps as weighing Ba source, sr source, ca source, hf source, sn source, zr source and Ti source, proportional mixing, presintering to obtain (Ba x Sr y Ca z A 1‑x‑y‑z )(Hf a Sn b Zr c Ti d B 1‑a‑b‑c‑d )O 3 powder, fine grinding, mixing with adhesive, granulating, shaping, ageing and demoulding to obtain ceramic blank, sintering to obtain high-electric card performance barium titanate-base ferroelectric perovskite material, solid-phase synthesizing with barium titanate ceramic as substrate, introducing the precursors of Zr, hf, sn, sr and Ca, and multi-element doping to A, B position to replace BaTiO 3 material, and high-temp sintering. The method has the advantages of simple preparation condition, mature process, low cost and high reliability. Under the induction of an electric field, huge entropy change and an electric card effect are generated.

Inventors

  • QIAN XIAOSHI
  • Du Feihong

Assignees

  • 上海交通大学

Dates

Publication Date
20260512
Application Date
20241128

Claims (4)

  1. 1. A preparation method of a barium titanate-based ferroelectric perovskite electric card material is characterized in that the barium titanate-based ferroelectric perovskite electric card material is (Ba 0.8 Sr 0.199 Ca 0.001 )(Hf 0.025 Sn 0.025 Zr 0.025 Ti 0.925 )O 3 、(Ba 0.8 Sr 0.2 )(Hf 0.02 Sn 0.02 Zr 0.02 Ti 0.94 )O 3 、(Ba 0.8 Sr 0.199 Ca 0.001 )(Hf 0.03 Sn 0.03 Zr 0.03 Ti 0.91 )O 3 or (Ba 0.905 Sr 0.09 Ca 0.005 )(Hf 0.0307 Sn 0.0307 Zr 0.0307 Ti 0.9079 )O 3 ), and the preparation method comprises the steps of weighing BaCO 3 、SrCO 3 、CaCO 3 、HfO 2 、SnO 2 、ZrO 2 、TiO 2 , uniformly mixing according to a stoichiometric ratio, presintering to obtain powder, fine grinding, mixing with a binder, granulating, forming, aging and plastic discharging to obtain a ceramic biscuit, and finally sintering to obtain the barium titanate-based ferroelectric perovskite electric card material with high electric card performance; the presintered is that in the atmosphere of oxygen, air or nitrogen, the temperature is raised to 1100-1400 ℃ at the temperature rising speed of 2-5 DEG Cmin -1 , the temperature is kept for 1-6 hours, and the furnace is cooled; the aging is carried out for 22-48 hours at room temperature; The plastic discharge is that in oxygen or air atmosphere, the temperature is raised to 600-800 ℃ at the temperature rising rate of not higher than 2 DEG Cmin -1 , and the temperature is kept for 1-3 hours; The sintering is that in the atmosphere of oxygen, air or nitrogen, the temperature is raised to 1300-1500 ℃ at the temperature rising rate of 2-5 DEG Cmin -1 , the temperature is kept for 1-6 hours, and the furnace is cooled to the room temperature after the sintering is completed.
  2. 2. The preparation method of claim 1, wherein the binder is polyvinyl alcohol, polyethylene glycol, polystyrene, methylcellulose or a combination thereof, and the amount of the binder is 5-10wt% of the mass of the ceramic powder.
  3. 3. A barium titanate-based ferroelectric perovskite electrical card material, characterized in that it is prepared by the method of claim 1 or 2.
  4. 4. The application of the barium titanate-based ferroelectric perovskite electric card material prepared by the method according to claim 1 or 2 or the application of the barium titanate-based ferroelectric perovskite electric card material according to claim 3 is characterized in that magnetron sputtering gold plating is carried out on the surface of the barium titanate-based ferroelectric perovskite electric card material, and a gold electrode layer is obtained after 30-180 s of deposition under vacuum with a current of 0.2-0.3 nA.

Description

Method for improving electric clamping effect of barium titanate-based ferroelectric perovskite electric clamping material Technical Field The invention relates to a technology in the field of all-solid-state refrigeration materials, in particular to a method for improving the electric clamping effect of a barium titanate-based ferroelectric perovskite electric clamping material. Background The electric card effect is an important development direction of the development of novel refrigeration equipment, and doping is an effective means for improving the performance of electric card materials. However, the existing doping technology has no great change to the whole material structure due to the small doping quantity or single doping type. The electrocaloric effect is essentially a thermal effect caused by the transition of a polarized structure between ordered and disordered under the action of an electric field. Therefore, the multi-element co-doping method can obviously improve the electric card effect. Disclosure of Invention Aiming at the defects that the prior art cannot realize the inorganic ferroelectric material with super-large electric card strength under the high electric field and the prior inorganic ferroelectric material cannot realize the large electric card effect and the wide working temperature range, the invention provides a method for improving the electric card effect of a ferroelectric perovskite material, which takes barium titanate ceramics as a matrix, introduces element precursors such as zirconium, hafnium, tin, strontium, calcium and the like into the solid-phase synthesis, simultaneously substitutes a BaTiO 3 material with multi-element doping at A, B positions, and carries out high-temperature sintering after blending to obtain a finished product. The method has the advantages of simple preparation condition, mature process, low cost and high reliability. Under the induction of an electric field, huge entropy change and an electric card effect are generated. The invention is realized by the following technical scheme: The invention relates to a method for improving the electric clamping effect of a barium titanate-based ferroelectric perovskite electric clamping material, which comprises the steps of weighing a Ba source, a Sr source, a Ca source, a Hf source, a Sn source, a Zr source and a Ti source, uniformly mixing according to a stoichiometric ratio, presintering to obtain (BaxSryCazA1-x-y-z)(HfaSnbZrcTidB1-a-b-c-d)O3 powder, fine grinding, mixing with a binder, granulating, forming, aging and plastic discharging to obtain a ceramic biscuit, and finally sintering to obtain the barium titanate-based ferroelectric perovskite electric clamping material with high electric clamping performance, wherein x is more than or equal to 0.6 and less than or equal to 1, y is more than or equal to 0.4, 0<z is more than or equal to 0.4, 0<a is more than or equal to 0.3, 0<b is more than or equal to 0.3, 0<c is more than or equal to 0.3, and d is more than or equal to 0.7 and less than or equal to 1. The stoichiometric ratio refers to the chemical composition ratio of (BaxSryCazA1-x-y-z)(HfaSnbZrcTidB1-a-b-c-d)O3 materials occupied by each element. The Ba source, sr source, ca source, hf source, sn source, zr source and Ti source are oxides containing the element or salts and hydroxides which can be decomposed into the required oxides at high temperature, such as BaO, srO, caO or Ba (OH) 2、Sr(OH)2、Ca(OH)2, etc., and are preferably BaCO 3、SrCO3、CaCO3、HfO2、SnO2、ZrO2、TiO2. The pre-sintering is to heat the material for 1-6 hours, preferably 2-4 hours, in oxygen, air or nitrogen atmosphere at a heating rate of 2-5 DEG Cmin -1 to 1100-1400 ℃ and cool the material with a furnace. The binder is polyvinyl alcohol, polyethylene glycol, polystyrene, methylcellulose or a combination thereof, and the dosage of the binder is 5-10wt% of the mass of the ceramic powder. The aging means aging for 22-48 hours, preferably 22-26 hours, at room temperature. The plastic discharge is that in the oxygen or air atmosphere, the temperature is raised to 600-800 ℃ at the temperature rising rate of not higher than 2 DEG Cmin -1, the temperature is kept for 1-3 hours, and the plastic discharge temperature is preferably 650-750 ℃. The sintering is to raise the temperature to 1300-1500 ℃ at a heating rate of 2-5 DEG Cmin -1 in oxygen, air or nitrogen atmosphere, preferably 1300-1400 ℃ for 1-6 hours, and then cool to room temperature along with furnace after sintering. The invention relates to a barium titanate-based ferroelectric perovskite electric card material prepared by the method, in particular to a barium titanate-based ferroelectric perovskite electric card material prepared by the method (Ba0.8Sr0.199Ca0.001)(Hf0.025Sn0.025Zr0.025Ti0.925)O3、(Ba0.8Sr0.2)(Hf0.02Sn0.02Zr0.02Ti0.94)O3、 (Ba 0.8Sr0.199Ca0.001)(Hf0.03Sn0.03Zr0.03Ti0.91)O3 or (Ba 0.905Sr0.09Ca0.005)(Hf0.0307Sn0.0307Zr0.0307Ti0.9079)O3). The invention rela