阅读说明：本技术 稀土RE2ZnMnO6氧化物磁制冷材料及其制备方法 (Rare earth RE 2ZnMnO6Oxide magnetic refrigeration material and preparation method thereof ) 是由 张义坤 吴兵兵 郭丹 王雅鸣 马龙飞 任忠鸣 于 2019-12-18 设计创作，主要内容包括：本发明公开了一种稀土基氧化物磁制冷材料及其制备方法,磁制冷材料化学式为RE<Sub>2</Sub>ZnMnO<Sub>6</Sub>,其中RE为钆Gd、铽Tb、镝Dy、钬Ho、铒Er和铥Tm中的任意一种或任意几种元素。采用溶胶凝胶法制备：首先将RE硝酸盐、乙酸锌以及硝酸锰混合,加入去离子水形成溶胶；然后将溶胶水浴加热蒸干形成凝胶；再将凝胶研磨成粉煅烧并随炉冷却至室温；在收集粉末压片成型后,在马弗炉中煅烧后冷却得到成品。本发明制备的RE<Sub>2</Sub>ZnMnO<Sub>6</Sub>氧化物材料在0～7T磁场变化下,等温磁熵变介于11.53到25.26J/kg K之间,可应用于低温区磁制冷方面,本发明材料及其制备方法具有成本低廉、方法简单适用于工业化优势。(The invention discloses a rare earth-based oxide magnetic refrigeration material and a preparation method thereof, wherein the magnetic refrigeration material has a chemical formula of RE 2 ZnMnO 6 Wherein RE is any one or more elements of gadolinium Gd, terbium Tb, dysprosium Dy, holmium Ho, erbium Er and thulium Tm. The preparation method comprises the following steps: firstly, mixing RE nitrate, zinc acetate and manganese nitrate, and adding deionized water to form sol; then heating the sol in a water bath and evaporating to dryness to form gel; grinding the gel into powder, calcining and cooling to room temperature along with the furnace; and after collecting powder tablets and forming, calcining in a muffle furnace and cooling to obtain a finished product. RE prepared by the invention 2 ZnMnO 6 The isothermal magnetic entropy change of the oxide material is between 11.53 and 25.26J/kg K under the change of a 0-7T magnetic field, and the oxide material can be applied to the aspect of low-temperature-region magnetic refrigeration.)

1. A rare earth base oxide magnetic refrigeration material is characterized in that: having the chemical formula RE ₂ZnMnO₆Wherein RE is any one element or any several elements of gadolinium Gd, terbium Tb, dysprosium Dy, holmium Ho, erbium Er and thulium Tm.

2. The rare earth-based oxide magnetic refrigeration material according to claim 1, characterized in that: the RE ₂ZnMnO₆The oxide material has a monoclinic crystal structure and belongs to the P121/C1 space group; wherein RE ₂ZnMnO₆Under the change of a magnetic field of 0-5T, the isothermal magnetic entropy change of the oxide material is between 7.22 and 16.27J/kg K; under the magnetic field change of 0-7T, the isothermal magnetic entropy change is between 11.53-25.26J/kg K.

3. The rare earth-based oxide magnetic refrigeration material according to claim 1, characterized in that: under the change of a magnetic field of 0-5T, the isothermal magnetic entropy change is between 7.22 and 16.27J/kg K.

4. The rare earth-based oxide magnetic refrigeration material according to claim 1, characterized in that: the phase transition temperature is 2.2-6.8K.

5. A method for preparing a rare earth-based oxide magnetic refrigeration material according to claim 1, which comprises the following steps:

a. RE nitrate is used as a rare earth raw material, the RE nitrate is any one or a mixture of any more of gadolinium nitrate, terbium nitrate, dysprosium nitrate, holmium nitrate, erbium nitrate and thulium nitrate, the RE nitrate, zinc acetate and manganese nitrate are added into 100m L deionized water according to the ratio of 2: 1: 1 for mixing, and the mixture is stirred at room temperature until the mixture is completely dissolved to form sol;

b. Placing the sol prepared in the step a in a water bath at 70-90 ℃, heating and evaporating to remove water until gel is formed, and then drying the gel at a temperature of not higher than 100 ℃ to obtain dry gel;

c. B, grinding the xerogel obtained in the step b into powder, calcining for 6-8 hours at 480-600 ℃ in a muffle furnace, and then cooling to room temperature along with the furnace to obtain calcined product powder;

d. And c, collecting the product powder obtained after the calcination in the step b, fully grinding, tabletting and forming, putting into a crucible, continuously calcining at the high temperature of 1100-1300 ℃ for 36-48 h by using a muffle furnace, and cooling to room temperature along with the furnace to obtain the rare earth-based oxide magnetic refrigeration material finished product.

6. The method for preparing rare earth-based oxide magnetic refrigeration material according to claim 5, characterized in that: in the step b, the sol is placed in a water bath at the temperature of 75-90 ℃, and the water is evaporated by heating.

7. The method for preparing rare earth-based oxide magnetic refrigeration material according to claim 5, characterized in that: in the step c, after the xerogel is ground into powder, the powder is calcined for 6-8 hours at 480-580 ℃ by a muffle furnace.

8. The method for preparing rare earth-based oxide magnetic refrigeration material according to claim 5, characterized in that: and in the step d, after tabletting and forming the product powder, continuously calcining the product powder for 36-48 hours at 1100-1250 ℃ by using a muffle furnace at high temperature.

9. The method for preparing rare earth-based oxide magnetic refrigeration material according to claim 5, characterized in that: in the step d, a tablet machine is utilized to tablet and form the product powder, and the crucible is a corundum crucible.

Technical Field

The invention relates to a metal oxide magnetic refrigeration material and a preparation method thereof, in particular to a rare earth zinc manganese oxide magnetic refrigeration material and a preparation method thereof, which are applied to the technical field of magnetic functional materials.

Background

Magnetic refrigeration is mainly applied to the field of low-temperature refrigeration at present, such as parameter detection and data processing systems of spacecrafts such as satellites and spacecrafts, auxiliary liquid helium refrigeration, creation of extremely low temperature conditions and the like. The selection of magnetic refrigeration materials is the key of the magnetic refrigeration technology. An ideal magnetic refrigeration material refers to a magnet having a large magnetic entropy change in a wide temperature range and a low magnetic field.

The magnetic refrigeration material is a pollution-free refrigeration working medium material which achieves the refrigeration purpose by utilizing a magnetocaloric effect (also called magnetic card effect or magnetic entropy effect). Specifically, the strength of an external magnetic field is changed to enable the magnetic moment of the material to generate ordered and disordered changes (phase change), so that the heat absorption and heat release effects of the magnet are triggered to carry out refrigeration cycle. The magnetic moment of the magnetic refrigeration material changes to an ordered state under a high magnetic field, heat is emitted to the surrounding environment, and in a low magnetic field area, the magnetic moment changes to an unordered state to absorb the heat, so that the aim of continuous refrigeration can be fulfilled by repeated circulation. Compared with the traditional gas circulation refrigeration, the magnetic refrigeration device has small volume, no pollution, low noise, high efficiency and low power consumption, the refrigeration efficiency is not limited by the circulation of a heat engine, and the magnetic refrigeration device can be used in microgravity environments such as space and the like. Magnetic refrigeration is a refrigeration mode with strong competitiveness.

Although the wide application of magnetic refrigeration technology is not mature due to the limitation of many factors at present, the magnetic refrigeration has the advantages of no pollution, low noise and the like compared with the traditional gas compression refrigeration, and is a new refrigeration mode with potential in the future. However, the key to the realization of industrialization is to find a high-performance magnetic refrigeration material, so the design and manufacture of the high-performance magnetic refrigeration material become a technical problem to be solved urgently.

Disclosure of Invention

In order to solve the problems of the prior art, the invention aims to provide a magnetic refrigeration material of rare earth-based oxide and a method thereof, and the magnetic refrigeration material is characterized in that the chemical formula of the magnetic refrigeration material is RE ₂ZnMnO₆Wherein RE is gadolinium Gd, terbium Tb, dysprosium Dy and holmium One, two or more of Ho, erbium Er or thulium Tm, RE ₂ZnMnO₆Under the change of a 0-7T magnetic field, the isothermal magnetic entropy change of the oxide material is between 11.53 and 25.26J/kg K, so that a larger magnetic entropy change advantage is obtained, and the oxide material can be applied to the aspect of low-temperature-region magnetic refrigeration.

In order to achieve the purpose, the invention adopts the following technical scheme:

A rare earth-based oxide magnetic refrigeration material with the chemical formula of RE ₂ZnMnO₆Wherein RE is any one element or any several elements of gadolinium Gd, terbium Tb, dysprosium Dy, holmium Ho, erbium Er and thulium Tm.

As a preferred technical solution of the present invention, the RE ₂ZnMnO₆The oxide material has a monoclinic crystal structure and belongs to the P121/C1 space group; wherein RE ₂ZnMnO₆Under the change of a magnetic field of 0-5T, the isothermal magnetic entropy change of the oxide material is between 7.22 and 16.27J/kg K; under the magnetic field change of 0-7T, the isothermal magnetic entropy change is between 11.53-25.26J/kg K.

As a preferable technical scheme of the invention, the isothermal magnetic entropy change of the rare earth-based oxide magnetic refrigeration material is between 7.22 and 16.27J/kg K under the change of a 0-5T magnetic field.

As the preferable technical scheme of the invention, the phase transition temperature of the rare earth-based oxide magnetic refrigeration material is 2.2-6.8K.

The invention relates to a preparation method of a rare earth-based oxide magnetic refrigeration material, which comprises the following steps:

a. RE nitrate is used as a rare earth raw material, the RE nitrate is any one or a mixture of any more of gadolinium nitrate, terbium nitrate, dysprosium nitrate, holmium nitrate, erbium nitrate and thulium nitrate, the RE nitrate, zinc acetate and manganese nitrate are added into 100m L deionized water according to the ratio of 2: 1: 1 for mixing, and the mixture is stirred at room temperature until the mixture is completely dissolved to form sol;

b. Placing the sol prepared in the step a in a water bath at 70-90 ℃, heating and evaporating to remove water until gel is formed, and then drying the gel at a temperature of not higher than 100 ℃ to obtain dry gel;

c. B, grinding the xerogel obtained in the step b into powder, calcining for 6-8 hours at 480-600 ℃ in a muffle furnace, and then cooling to room temperature along with the furnace to obtain calcined product powder;

d. And c, collecting the product powder obtained after the calcination in the step b, fully grinding, tabletting and forming, putting into a crucible, continuously calcining at the high temperature of 1100-1300 ℃ for 36-48 h by using a muffle furnace, and cooling to room temperature along with the furnace to obtain the magnetic refrigeration material finished product of the rare earth-based oxide.

In the step b, the sol is placed in a water bath at the temperature of 75-90 ℃, and the water is evaporated by heating.

In the step c, after the xerogel is ground into powder, the powder is calcined for 6-8 hours at 480-580 ℃ by a muffle furnace.

In the step d, after the product powder is tabletted and molded, high-temperature calcination is carried out for 36-48 h at 1100-1250 ℃ in a muffle furnace.

In the step d, the powder is tabletted and formed by a tablet machine, and the crucible is a corundum crucible.

Compared with the prior art, the invention has the following obvious and prominent substantive characteristics and remarkable advantages:

1. RE for magnetic refrigeration ₂ZnMnO₆Under the change of a 0-7T magnetic field, the isothermal magnetic entropy change of the composite oxide material is between 11.53 and 25.26J/kg K, so that RE ₂ZnMnO₆The oxide material can be applied to low-temperature magnetic refrigeration and has obvious advantages;

2. The method of the invention adopts twice calcination to improve RE ₂ZnMnO₆The quality of the composite oxide material can better exert the magnetic entropy change performance of the material, and the high-performance magnetic refrigeration material can be prepared.

3. The method has the advantages of low cost, simple preparation method, suitability for industrialization and certain application prospect in the field of low-temperature magnetic refrigeration.

Detailed Description

The above scheme is further illustrated by the following specific examples, which are detailed in the following preferred embodiments of the invention: