A rare earth-free wide temperature range across room temperature magnetic refrigeration material and preparation method thereof

Abstract

The invention discloses a rare earth-free wide temperature range cross-room temperature magnetic refrigeration material, the chemical general formula of which is Mn a Al b Co c Fe d Cr e Z f ; Wherein Z is one or more of Cu, Ti, Zr, Ag, Nb, and Zn, a, b, c, d, e, and f represent the atomic molar content, a+b+c+d+e+f=100, and 16≤a≤24, 16≤b≤24, 10≤c≤30, 15≤d≤28, 18≤e≤30, and 0≤f≤8. The present invention also discloses a method for preparing a rare earth-free wide temperature range cross-room temperature magnetic refrigeration material, and the prepared magnetic refrigeration material has a reversible large magnetocaloric effect within the temperature range of 240K-360K. The present invention adopts the above-mentioned rare earth-free wide temperature range cross-room temperature magnetic refrigeration material and its preparation method, which can solve the problems of high cost, narrow refrigeration temperature range and poor reversibility of existing magnetic refrigeration materials.

Description

Technical Field

[0001] The present invention relates to the technical field of magnetic refrigeration materials, and in particular to a rare earth-free magnetic refrigeration material with a wide temperature range spanning room temperature and a preparation method thereof. Background Art

[0002] Magnetic refrigeration is a new type of refrigeration method that uses the magnetocaloric effect of materials to achieve refrigeration. The magnetocaloric effect is one of the intrinsic properties of magnetic materials, and its magnitude depends on the inherent physical properties of magnetic materials. Magnetic refrigeration uses an external magnetic field to cause the magnetic moment of magnetic materials to undergo orderly or disordered changes (phase change) to cause the magnet to absorb and release heat to perform a refrigeration cycle. The magnetic refrigerant enters the high magnetic field area and releases heat to the surrounding environment; when it enters the zero / low magnetic field area, the temperature drops and heat is absorbed to achieve the purpose of refrigeration; this repeated cycle can achieve continuous refrigeration. Compared with ordinary gas refrigeration, magnetic refrigeration technology has the advantages of high entropy density, small size, simple structure, no pollution, high efficiency, low power consumption and low noise. It is a new refrigeration method with great potential in the future, and is expected to replace the gas compression refrigeration technology that is currently being used, which consumes a lot of energy and is harmful to the environment.

[0003] At present, the core technology in the field of magnetic refrigeration is still to explore and design magnetic materials with reversible large magnetocaloric effect in a wide temperature range, that is, high-performance magnetic refrigeration materials. At present, high-performance magnetic refrigeration materials near room temperature mainly include Gd 5 (Si,Ge) 4 、La(Fe,Si) 13 、Ni 2 Mn(Ga, Sn, In) and other material systems, but these materials generally have shortcomings such as high raw material cost, poor reversibility, narrow refrigeration temperature range and complex preparation process, which limit their commercial application to a certain extent. Summary of the invention

[0004] The purpose of the present invention is to provide a rare earth-free wide temperature range across room temperature magnetic refrigeration material to solve the problems of high cost, narrow refrigeration temperature range and poor reversibility of existing magnetic refrigeration materials. Another purpose of the present invention is to provide a method for preparing a rare earth-free wide temperature range across room temperature magnetic refrigeration material.

[0005] To achieve the above purpose, the present invention provides a rare earth-free wide temperature range across room temperature magnetic refrigeration material, the chemical formula of which is Mn a Al b Co c Fe d Cr e Z f; wherein Z is one or more of Cu, Ti, Zr, Ag, Nb, and Zn, a, b, c, d, e, and f represent the atomic molar content, a+b+c+d+e+f=100, and 16≤a≤24, 16≤b≤24, 10≤c≤30, 15≤d≤28, 18≤e≤30, and 0≤f≤8.

[0006] Preferably, 19≤a≤21, 19≤b≤21, 14≤c≤18, 18≤d≤24, 22≤e≤26, and 0≤f≤4.

[0007] The method for preparing the above-mentioned rare earth-free wide temperature range cross-room temperature magnetic refrigeration material comprises the following steps:

[0008] S1. Weigh 60-120 μm Mn, Al, Co, Fe, Cr, and Z metal powders according to the molar ratio in the molecular formula, and mix them uniformly by ball milling under argon protection to obtain a mixed powder;

[0009] S2, placing the mixed powder obtained in step S1 into a sealed mold, cold pressing it under a pressure of 30-80 MPa, heating it to 1000° C.-1200° C. and keeping it warm for 1-3 minutes to obtain a block alloy;

[0010] S3, removing the oxide scale from the block alloy obtained in step S2, placing it in a vacuum quartz tube for annealing, and cooling it to room temperature to obtain Mn a Al b Co c Fe d Cr e Z f Magnetic refrigeration materials.

[0011] Preferably, in S3, the annealing temperature is 700° C.-800° C., and the annealing time is 10-30 hours.

[0012] The magnetic refrigeration material prepared by the method for preparing the rare earth-free wide temperature range and room temperature magnetic refrigeration material has a reversible large magnetocaloric effect in the temperature range of 240K-360K.

[0013] The advantages and positive effects of the rare earth-free wide temperature range across room temperature magnetic refrigeration material and the preparation method thereof described in the present invention are:

[0014] 1. The present invention does not use rare earth metals, and the magnetic refrigeration materials are all conventional metal elements, which is beneficial to reducing the material cost of the magnetic refrigeration materials.

[0015] 2. The magnetic refrigeration material described in the present invention has a reversible magnetocaloric effect and excellent mechanical properties within the temperature range of 240K-360K, and can be used for room temperature magnetic refrigeration to solve the problem of narrow refrigeration temperature range.

[0016] 3. The preparation method of the present invention comprises the following steps: ball-milling and mixing metal powders, cold-pressing the mixture, and annealing the mixture after short-time high-temperature heating to obtain magnetic refrigeration materials. The preparation method is simple and can be easily realized in large-scale industrial production. DETAILED DESCRIPTION

[0017] The technical solution of the present invention is further illustrated by the following examples.

[0018] Example 1Mn 21 Al 20 Co 14 Fe 21 Cr 24 Material

[0019] S1. Weigh 100 μm Mn, Al, Co, Fe, and Cr metal powders according to the molar ratio in the molecular formula, and mix them uniformly by ball milling under argon protection to obtain a mixed powder;

[0020] S2, placing the mixed powder obtained in step S1 into a sealed mold, cold pressing it under a pressure of 60 MPa, heating it to 1100° C. and keeping it warm for 2 minutes to obtain a block alloy;

[0021] S3, remove the oxide scale from the block alloy obtained in step S2, put it into a vacuum quartz tube, heat it to 800°C, anneal it for 16 hours, and then cool it to room temperature to obtain Mn 21 Al 20 Co 14 Fe 21 Cr 24 Material.

[0022] Tests have shown that the above material has a reversible large magnetocaloric effect at 254-308K, and the maximum reversible magnetic entropy change is 1.62J / kgK under a 0-5T magnetic field change.

[0023] Example 2Mn 19 Al 19 Co 16 Fe 22 Cr 24 Material

[0024] S1. Weigh 80 μm Mn, Al, Co, Fe, and Cr metal powders according to the molar ratio in the molecular formula, and mix them uniformly by ball milling under argon protection to obtain a mixed powder;

[0025] S2, placing the mixed powder obtained in step S1 into a sealed mold, cold pressing it under a pressure of 50 MPa, heating it to 1050° C. and keeping it warm for 1 minute to obtain a block alloy;

[0026] S3, remove the oxide scale from the block alloy obtained in step S2, put it into a vacuum quartz tube, heat it to 750°C, anneal it for 24 hours, and then cool it to room temperature to obtain Mn 19 Al 19 Co 16 Fe 22 Cr 24 Material.

[0027] Tests have shown that the above material has a reversible large magnetocaloric effect at 287-342K, and the maximum reversible magnetic entropy change is 1.65J / kgK under a 0-5T magnetic field change.

[0028] Example 3Mn 20 Al 19 Co 14 Fe 22 Cr 23 Nb 2 Material

[0029] S1. Weigh 70 μm Mn, Al, Co, Fe, Cr, and Nb metal powders according to the molar ratio in the molecular formula, and mix them evenly by ball milling under argon protection to obtain a mixed powder;

[0030] S2, placing the mixed powder obtained in step S1 into a sealed mold, cold pressing it under a pressure of 70 MPa, heating it to 1150° C. and keeping it warm for 2.5 minutes to obtain a block alloy;

[0031] S3, remove the oxide scale from the block alloy obtained in step S2, put it into a vacuum quartz tube, heat it to 780°C, anneal it for 18 hours, and then cool it to room temperature to obtain Mn 20 Al 19 Co 14 Fe 22 Cr 23 Nb 2 Material.

[0032] Tests have shown that the above material has a reversible large magnetocaloric effect at 272-323K, and the maximum reversible magnetic entropy change is 1.54J / kgK under a 0-5T magnetic field change.

[0033] Example 4Mn 20 Al 18 Co 16 Fe 21 Cr 23 Zn 1 Ag 1 Material

[0034] S1. Weigh 90 μm Mn, Al, Co, Fe, Cr, Zn and Ag metal powders according to the molar ratio in the molecular formula, and mix them evenly by ball milling under argon protection to obtain mixed powder;

[0035] S2, placing the mixed powder obtained in step S1 into a sealed mold, cold pressing it under a pressure of 65 MPa, heating it to 1020° C. and keeping it warm for 1.5 minutes to obtain a block alloy;

[0036] S3, remove the oxide scale from the block alloy obtained in step S2, put it into a vacuum quartz tube, heat it to 760°C, anneal it for 24 hours, and then cool it to room temperature to obtain Mn 20 Al 18 Co 16 Fe 21 Cr 23 Zn 1 Ag 1 Magnetic refrigeration materials.

[0037] Tests have shown that the above material has a reversible large magnetocaloric effect at 268-304K, and the maximum reversible magnetic entropy change is 1.52J / kgK under a 0-5T magnetic field change.

[0038] Example 5Mn 20 Al 19 Co 13 Fe 22 Cr 23 Cu 1 Ti 1 Zr 1 Material

[0039] S1. Weigh 70 μm Mn, Al, Co, Fe, Cr, Cu, Ti, and Zr metal powders according to the molar ratio in the molecular formula, and mix them evenly by ball milling under argon protection to obtain a mixed powder;

[0040] S2, placing the mixed powder obtained in step S1 into a sealed mold, cold pressing it under a pressure of 70 MPa, heating it to 1150° C. and keeping it warm for 2.5 minutes to obtain a block alloy;

[0041] S3, remove the oxide scale from the block alloy obtained in step S2, put it into a vacuum quartz tube, heat it to 780°C, anneal it for 18 hours, and then cool it to room temperature to obtain Mn 20 Al 19 Co 13 Fe 22 Cr 23 Cu 1 Ti 1 Zr 1 Material.

[0042] Tests have shown that the above material has a reversible large magnetocaloric effect at 264-303K, and the maximum reversible magnetic entropy change is 1.55J / kgK under a 0-5T magnetic field change.

[0043] Therefore, the present invention adopts the above-mentioned rare earth-free wide temperature range across room temperature magnetic refrigeration material and its preparation method, which can solve the problems of high cost, narrow refrigeration temperature range and poor reversibility of existing magnetic refrigeration materials.

[0044] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A rare earth-free magnetic refrigeration material with a wide temperature range across room temperature. Features: The chemical formula is Mn a Al b Co c Fe d Cr e Z f ; wherein Z is one or more of Cu, Ti, Zr, Ag, Nb, and Zn, a, b, c, d, e, and f represent the atomic molar content, a+b+c+d+e+f=100, and 19≤a≤21, 18≤b≤21, 13≤c≤18, 18≤d≤24, 22≤e≤26, and 0≤f≤4.

2. A method for preparing the rare earth-free wide temperature range room temperature magnetic refrigeration material as claimed in claim 1, It is characterized in that The following steps are involved: S1. Weigh 60-120 μm Mn, Al, Co, Fe, Cr, and Z metal powders according to the molar ratio in the molecular formula, and mix them uniformly by ball milling under argon protection to obtain a mixed powder; S2, placing the mixed powder obtained in step S1 into a sealed mold, cold pressing it under a pressure of 30-80 MPa, heating it to 1000° C.-1200° C. and keeping it warm for 1-3 minutes to obtain a block alloy; S3, removing the oxide scale from the block alloy obtained in step S2, placing it in a vacuum quartz tube for annealing, and cooling it to room temperature to obtain Mn a Al b Co c Fe d Cr e Z f Magnetic refrigeration materials.

3. The method for preparing a rare earth-free wide temperature range cross-room temperature magnetic refrigeration material according to claim 2, Features: In S3, the annealing temperature is 700° C.-800° C., and the annealing time is 10-30 hours.

4. The method for preparing a rare earth-free wide temperature range cross-room temperature magnetic refrigeration material according to claim 2, Features: The prepared magnetic refrigeration material has a reversible large magnetocaloric effect in the temperature range of 240K-360K.