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Holmium-bismuth magnetic refrigeration material and preparation method and application thereof

A technology for magnetic refrigeration materials and single crystal materials, which is applied in the growth of polycrystalline materials, chemical instruments and methods, and single crystal growth. Low cost and low energy consumption

Pending Publication Date: 2022-07-22
TAIYUAN UNIVERSITY OF SCIENCE AND TECHNOLOGY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Materials with continuous positive and negative magnetic entropy changes only exist in first-order phase change materials. Most of the positive magnetocaloric effects reported so far have shown small magnetic entropy changes, and they can only be maintained under low magnetic field conditions. As the magnetic field increases, the antiferromagnetic coupling becomes weaker leading to the disappearance of the positive MCE

Method used

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  • Holmium-bismuth magnetic refrigeration material and preparation method and application thereof
  • Holmium-bismuth magnetic refrigeration material and preparation method and application thereof
  • Holmium-bismuth magnetic refrigeration material and preparation method and application thereof

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Effect test

Embodiment 1

[0046] A preparation method of a holmium-bismuth magnetic refrigeration material, comprising the following steps:

[0047] S1, holmium element and bismuth element are weighed according to atomic ratio as 1:10 bulk Ho raw material and granular metal Bi raw material; Wherein, the purity of described bulk Ho raw material is 99.99%;

[0048] S2, first, select a suitable cylindrical alumina crucible according to the raw material weighed in step S1, mix the raw material weighed in step S1 and put it into the alumina crucible, and cover the top of the alumina crucible with quartz wool, The purpose is to ensure that the HoBi sample obtained during centrifugation is separated from the excess co-solvent Bi; then, the alumina crucible is placed in a tantalum tube, and the lid of the tantalum tube is tightly closed by external pressure; finally, the quartz tube is evacuated and filled with argon, and hydrogen-oxygen Flame-sealed quartz tube, and the alumina crucible is sealed in the vacuu...

Embodiment 2

[0054] A preparation method of holmium-bismuth polycrystalline material, comprising the following steps:

[0055] S1. Weigh the granular metal Bi raw material and the bulk Ho raw material according to the atomic ratio of 1:1; wherein, the purity of the bulk Ho raw material is 99.99%;

[0056] S2, first, select a suitable cylindrical alumina crucible according to the raw material weighed in step S1, mix the raw material weighed in step S1 and put it into the alumina crucible, then, place the alumina crucible in a quartz tube, and vacuumize the quartz tube Fill with argon and seal the quartz tube with oxyhydrogen flame;

[0057] S3, polycrystalline growth: the vacuum quartz tube sealed in step S2 is heated from room temperature to 900° C., kept for 5 hours, and then slowly cooled to room temperature at a cooling rate of 4K / h;

[0058] S4, taking out the vacuum quartz tube cooled in step S3 to obtain a holmium-bismuth polycrystalline powder material;

[0059] S5, the powder sam...

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Abstract

The invention discloses a holmium-bismuth magnetic refrigeration material and a preparation method and application thereof, and belongs to the technical field of magnetic refrigeration, the holmium-bismuth magnetic refrigeration material is a holmium-bismuth single crystal material or a holmium-bismuth polycrystalline material, the chemical formula of the holmium-bismuth magnetic refrigeration material is HoBi, the holmium-bismuth magnetic refrigeration material has a sodium chloride type cubic crystal structure, the space group is Fm-3m, and the phase change temperature of the holmium-bismuth magnetic refrigeration material is 3.7 K and 6K; the holmium-bismuth single crystal and polycrystalline material can be used for multi-stage refrigeration and adiabatic demagnetization in a liquid helium temperature zone. The invention also provides a preparation method of the holmium-bismuth single crystal and polycrystalline material. The holmium-bismuth magnetic refrigeration material provided by the invention has a hysteresis-free characteristic, can realize high magnetic entropy change in a liquid helium temperature region, has a relatively large low-field continuous positive and negative magnetothermal effect under a high magnetic field condition, has a relatively large negative magnetothermal effect under a high field, can be applied to a general magnetic refrigeration technology, and also can be applied to a high-temperature magnetic refrigeration technology. And the method can be applied to the aspects of multi-stage refrigeration and adiabatic demagnetization technologies.

Description

technical field [0001] The invention belongs to the technical field of magnetic refrigeration, and specifically relates to a holmium-bismuth magnetic refrigeration material and a preparation method and application thereof. Background technique [0002] Refrigeration technology plays an important role in human production and life. From people's daily life, to industrial and agricultural production, medical and health, and national defense technology, refrigeration technology is inseparable. With the advancement of industrialization and the improvement of human living standards, people's demand for refrigeration is increasing, which inevitably brings huge energy consumption and environmental pressure. Currently commonly used refrigeration equipment, such as air conditioners and refrigerators, use conventional gas expansion and compression refrigeration. This refrigeration technology has low thermal efficiency and uses Freon and other environmentally polluting substances as ref...

Claims

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Application Information

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IPC IPC(8): C30B1/02C30B29/52
CPCC30B29/52C30B1/02
Inventor 张艳孙志刚胡季帆
Owner TAIYUAN UNIVERSITY OF SCIENCE AND TECHNOLOGY