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In-situ complex-phase gadolinium-based magnetic refrigeration material having magnetic entropy change platform and preparation method thereof

A magnetic refrigeration material, magnetic entropy change technology, applied in magnetic materials, heat exchange materials, chemical instruments and methods, etc., can solve the problems of low theoretical density, unavoidable transition layer problem, reduction of material magnetocaloric effect, etc. Simple preparation process

Inactive Publication Date: 2013-04-10
UNIV OF ELECTRONICS SCI & TECH OF CHINA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] The material density obtained by the powder sintering process is usually lower than the theoretical density of the material, and the existence of gaps and cavities between particles will affect the heat transfer of the material; in addition, the sintering process inevitably produces the transition layer problem between heterogeneous materials, resulting in the magnetic properties of the material. Reduced thermal effect

Method used

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  • In-situ complex-phase gadolinium-based magnetic refrigeration material having magnetic entropy change platform and preparation method thereof
  • In-situ complex-phase gadolinium-based magnetic refrigeration material having magnetic entropy change platform and preparation method thereof
  • In-situ complex-phase gadolinium-based magnetic refrigeration material having magnetic entropy change platform and preparation method thereof

Examples

Experimental program
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Effect test

Embodiment 1

[0053] Example 1 Gd 53 Co 19 Al 28 Preparation, Structure and Magnetic Entropy Change of Multiphase Polycrystalline Alloys

[0054] Gadolinium (Gd) with a purity of more than 99.2% (mass percent), cobalt (Co) and aluminum (Al) with a purity of more than 99.9% (mass percent) are classified as Gd 53 Co 19 Al 28 The chemical formula is weighed, and the prepared raw materials are put into a non-consumable vacuum arc furnace in an argon atmosphere adsorbed by titanium, and the vacuum is evacuated to 3×10 by a two-stage vacuum device of a mechanical pump and a diffusion pump. -5 Torr or more; after 1~2 times of cleaning with high-purity argon cleaning method, under the protection of high-purity argon gas slightly higher than 1 standard atmosphere, it is repeatedly turned and smelted for 3~4 times, and the desired alloy is obtained after solidification. X-ray diffraction analysis indicated that the alloy contained Gd 2 Al, Gd 2 Co 2 Al and GdCo 0.74 Al 1.26 Three alloy phas...

Embodiment 2

[0055] Example 2 Gd 52.5 Co 17.5 Al 30 Preparation, Structure and Magnetic Entropy Change of Multiphase Polycrystalline Alloys

[0056] Gadolinium (Gd) with a purity of more than 99.2% (mass percent), cobalt (Co) and aluminum (Al) with a purity of more than 99.9% (mass percent) are classified as Gd 52.5 Co 17.5 Al 30 The chemical formula is weighed, and the prepared raw materials are put into a non-consumable vacuum arc furnace in an argon atmosphere adsorbed by titanium, and the vacuum is evacuated to 3×10 by a two-stage vacuum device of a mechanical pump and a diffusion pump. -5 Torr or more; after 1~2 times of cleaning with high-purity argon cleaning method, under the protection of high-purity argon gas slightly higher than 1 standard atmosphere, it is repeatedly turned and smelted for 3~4 times, and the desired alloy is obtained after solidification. X-ray diffraction analysis indicated that the alloy contained Gd 2 Al, Gd 2 Co 2 Al two alloy phases. The temperatu...

Embodiment 3

[0057] Example 3 Gd 52.5 Co 16.5 Al 31 Preparation, Structure and Magnetic Entropy Change of Composite Amorphous Crystals

[0058] Gadolinium (Gd) with a purity of more than 99.2% (mass percent), cobalt (Co) and aluminum (Al) with a purity of more than 99.9% (mass percent) are classified as Gd 52.5 Co 16.5 Al 31 The chemical formula is weighed, and the prepared raw materials are put into a non-consumable vacuum arc furnace in an argon atmosphere adsorbed by titanium, and the vacuum is evacuated to 3×10 by a two-stage vacuum device of a mechanical pump and a diffusion pump. -5 Torr or more; after 1~2 times of cleaning with high-purity argon gas, the master alloy is prepared by repeated inversion and smelting 3~4 times under the protection of high-purity argon gas with a pressure slightly higher than 1 standard atmosphere. The master alloy smelted according to the above steps was put into a water-cooled suction casting copper crucible in a vacuum arc furnace, and the alloy ...

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Abstract

The invention relates to a magnetic refrigeration material having a platform phenomenon on a magnetic entropy change curve and a preparation method thereof. The alloy takes gadolinium as a main component, and the composition can be represented by a formula of GdaCobAlc, wherein 50.0<=a<=55.0, 15.0<=b<=20.0, 25.0<=c<=31.0, and a+b+c=100. The alloy is prepared through the following steps: proportioning Gd having a purity not lower than 99.2% (percentage by mass), Co having a purity not lower than 99.9% and Al having a purity not lower than 99.9% according to the specified atom percents, repeatedly melting the alloy in an argon atmosphere arc furnace until the components are uniform, and solidifying to obtain a mother alloy cast ingot containing multiple crystal phases; and further performing a water cooling and copper mold suction casting process on part of the mother alloy to obtain a cylindrical sample containing amorphous phases and crystal phases. The Gd-Co-Al mother alloy cast ingot and the suction casting sample thereof provided by the invention have a complex-phase structure; the platform phenomenon exists on the magnetic entropy change curve of the alloy in the vicinity of a magnetic ordering temperature; and the magnetic refrigeration material is suitable for being used as a magnetic refrigeration working medium for an Ericsson cycle and has wide application prospects in the aspect of magnetic refrigeration technologies.

Description

technical field [0001] The invention relates to the field of magnetic materials, in particular to a gadolinium-based magnetic refrigeration material with magnetocaloric effect and a preparation method thereof. technical background [0002] Compared with the commonly used gas compression refrigeration technology, magnetic refrigeration has the advantages of green, energy saving, easy miniaturization, etc. prospect. [0003] For most ferromagnetic materials, the characteristics of the change of magnetic entropy change with temperature are: near the magnetic order temperature, the magnetic entropy change of the material reaches the maximum value; on both sides of the magnetic order temperature, as the temperature increases Both high and low, the magnetic entropy change decreases. [0004] In magnetic refrigerators, the Erickson cycle is a very important cycle. In the refrigeration temperature region above 15K, since the lattice entropy of solid matter accounts for a large pr...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C28/00H01F1/047C09K5/14
Inventor 付浩滕保华王明轩
Owner UNIV OF ELECTRONICS SCI & TECH OF CHINA