Room temperature magnetic cooling material

A magnetic refrigeration material and room temperature technology, applied in the field of magnetic refrigeration materials, can solve the problems of large thermal hysteresis, inappropriate Curie point, and large magnetic hysteresis of magnetic refrigeration materials, and achieve small thermal hysteresis and appropriate Curie point , the effect of small hysteresis

Inactive Publication Date: 2012-03-14
INST OF METAL RESEARCH - CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0010] However, the existing magnetic refrigeration materials have disadvantages such as large thermal hysteresis, large magnetic hysteresis, rare earth content, and inappropriate Curie point, which limit their applications.

Method used

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  • Room temperature magnetic cooling material

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0033] Mix the raw materials Mn, P, and B uniformly according to the proportion, then crush them, press the mixture into a block with a pressure higher than 500 atmospheres, place it in a quartz tube filled with argon, and sinter it at 200°C for 2 days, and then heated to 950 ° C, sintered for 7 days. Then cool it to room temperature, grind it, press it into blocks, place it in a quartz tube filled with argon, heat it to 950°C, and sinter it for 7 days. Finally, it is cooled to room temperature by water quenching to obtain a magnetic cold material (see figure 1 ).

Embodiment 2

[0035] Prepare magnetic refrigeration material A according to the above method, wherein the atomic percentages of each component are: Mn: 62.3%, P: 12.8%, B remainder, the main phase Mn of gained magnetic refrigeration material A 5 PB 2 Accounting for 95% of the total weight, the X-ray diffraction pattern analysis is carried out to the magnetic refrigeration material A (see figure 2 ). Such as figure 2 Shown in: the main phase is Mn with tetragonal structure 5 PB 2 , the space group is I4 / mcm.

Embodiment 3

[0037] Prepare magnetic refrigeration material B according to the above method, wherein the atomic percentages of each component are respectively: Mn: 62%, P: 13%, B surplus, the main phase Mn of the gained magnetic refrigeration material B 5 PB 2 70% of the total weight,

[0038] Place the magnetic refrigeration material B in the magnetic field, and observe its magnetization curve (see image 3 ). Among them, the squares in the figure represent the magnetization curve when the temperature drops to 12°C without applying a magnetic field, and then the temperature rises to 47°C with a 100Oe magnetic field; the circle represents that the temperature drops from 47°C with a 100Oe magnetic field Magnetization curve up to 12°C;

[0039] therefore, image 3 It shows that the magnetic transition point of the magnetic refrigeration material B is about 302K (29°C), there is no hysteresis above 302K, and it is a second-order phase transition.

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Abstract

The invention provides a room temperature magnetic cooling material, which is characterized by containing Mn, P and B elements simultaneously, with Mn5PB2 as the main phase, a space group of I4 / mcm and a quadrangle structure. Specifically, the main phase Mn5PB2 accounts for 60-100 wt% of the magnetic cooling material. The material of the invention has the advantages of small thermal hysteresis, small magnetic hysteresis, no rare earth, and proper Curie point. In a 3000 Oe magnetic field, the magnetic intensity of Mn5PB2 can be 80% of a saturation value, so that Mn5PB2 can be applied in a 3000 Oe magnetic field established by a relatively low permanent magnet NdFeB, thus making the volume of a magnetic cooling machine small.

Description

technical field [0001] The invention relates to a magnetic refrigeration material, and in particular provides a room-temperature magnetic refrigeration material that does not contain rare earths, has small thermal hysteresis and magnetic hysteresis, and undergoes a secondary phase transition near room temperature; it can be applied under a relatively low magnetic field. The 3000Oe magnetic field can be established with permanent magnet NdFeB, making the magnetic refrigerator small in size. Background technique [0002] Since the discovery of the magnetocaloric effect in 1881, the research and application of magnetic refrigeration in the field of low temperature has become increasingly mature. Magnetic refrigeration near room temperature has not been mentioned on the agenda until the last 30 years. In particular, refrigerators, air conditioners, etc. are generally realized by gas compression, and their fluorine-containing refrigerants have the disadvantages of destroying the...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C22/00
Inventor 谢志高耿殿禹张志东
Owner INST OF METAL RESEARCH - CHINESE ACAD OF SCI
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