A preparation method of a room temperature magnetic refrigerating working material Gd5Si2Ge2

A magnetic refrigeration and working fluid technology, applied in the direction of magnetic materials, inorganic materials, magnetic objects, etc., can solve the problems of inappropriate heat treatment, affecting the efficiency of magnetic refrigeration, magnetic moment and magnetic domain difficulty, etc., and achieve fast response to magnetic field sensitivity. , Improve the magnetic moment density and magnetic domain density, the effect of small external magnetic field

Inactive Publication Date: 2009-03-04
SHANGHAI UNIV +1
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Problems solved by technology

One is that due to improper heat treatment in the process, it is difficult to arrange the magnetic moments and magnetic domains inside the material in an orderly and disorderly manner, and a high external magnetic field must be required to rearrange the chaotic magnetic moments and magnetic domains; the other is The second is that the magnetic domain and magnetic moment fail to achieve a complete transformation of order and disorder under the change of the magnetic field, thus affecting the efficiency of magnetic refrigeration.

Method used

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  • A preparation method of a room temperature magnetic refrigerating working material Gd5Si2Ge2

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Embodiment 1

[0020] The technological process and steps of the embodiment of the present invention are as follows:

[0021] (1) First, the treated high-purity raw materials Gd, Si, Ge are replaced with Gd 5 Si 2 Ge 2 The stoichiometric formula is carried out to obtain the batch material, and the batch material is placed in a vacuum degree of 5.0×10 -2 Melting in an intermediate frequency induction furnace of Pa in an argon-filled atmosphere to obtain an alloy ingot; then crushing it into particles with an average particle size of 1.0mm under a protective atmosphere, and grinding the particles to an average particle size in a high-energy ball mill under a protective liquid 20um powder;

[0022] (2) The above Gd 5 Si 2 Ge 2 The powder is packed in a mold cavity with a material with high magnetic permeability along the direction of the magnetic field (see figure 1 ), magnetization is performed before the powder is pressed, that is, the powder is subjected to magnetic field orientation ...

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Abstract

The preparation method and magnetic treatment for Gd5Si2Ge2 comprise: (1) preparing the Gd5Si2Ge2 alloy ingot as traditional powder metallurgic method, crushing and grinding in protective atmosphere to obtain the powder with size as 2-30um; (2) loading the powder into mould cavity with high magnetic conductivity along magnetic field; (3) in special forming device, pressing first on 0.4-4.0kg / cm2 pressure then on 150-215MPa isostatic pressure; (4) vacuum sintering the compaction with 2.5-7.0*10-3Pa vacuum degree at 850-1500Deg, then vacuum thermal treating with same vacuum degree at 850-1000Deg, and obtaining the objective product.

Description

technical field [0001] The invention relates to a room temperature magnetic refrigerant material Gd 5 Si 2 Ge 2 The preparation method belongs to the technical field of special alloy material preparation and magnetic treatment. Background technique [0002] High-tech green magnetic refrigeration technology, compared with traditional refrigeration technology, has the advantages of no damage to the ozone layer, no greenhouse effect, low noise, high reliability, and high efficiency. At present, the development of magnetic refrigeration technology is limited by the low magnetocaloric effect of its core material magnetic refrigeration working medium; for this reason, domestic and foreign scientists use very high external magnetic fields such as superconducting magnetic fields and electromagnet magnetic fields to excite magnetic refrigeration workers. The mass produces a high magnetocaloric effect. Due to the complex structure and high price of these magnetic fields, it brings...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C22C1/04B22F9/08B22F9/04B22F3/12H01F1/153H01F1/22
Inventor 侯雪玲孔俊峰李士涛张少杰张岸倪建森徐晖沈绍义周邦新
Owner SHANGHAI UNIV
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