Method for manufacturing magnetic refrigeration material and magnetic refrigeration material

Abstract

To provide a method for manufacturing magnetic refrigeration material, the method enabling the magnetic transition temperature of the magnetic refrigeration material to be accurately adjusted, and magnetic refrigeration material having accurately adjusted magnetic transition temperature.SOLUTION: A method for manufacturing magnetic refrigeration material according to the present invention includes the steps of: preparing predetermined first magnetic refrigeration material and predetermined second magnetic refrigeration material different from the first magnetic refrigeration material; and mixing the first magnetic refrigeration material and the second magnetic refrigeration material to obtain third magnetic refrigeration material. The content of the first magnetic refrigeration material and the content of the second magnetic refrigeration material in the third magnetic refrigeration material are determined by the magnetic transition temperature of the first magnetic refrigeration material and of the second magnetic refrigeration material and of the target magnetic transition temperature of the third magnetic refrigeration material. The magnetic refrigeration material according to the present invention contains at least a predetermined first magnetic refrigeration material and a predetermined second magnetic refrigeration material different from the first magnetic refrigeration material, and the absolute value of the difference between the magnetic transition temperature and the target magnetic transition temperature is 0.7K or less.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a magnetic refrigeration material whose magnetic transition temperature can be precisely controlled, and a method for producing the same. [Background technology]

[0002] Because fluorocarbons are ozone-depleting substances and greenhouse gases, new refrigeration and air-conditioning systems that do not use fluorocarbons are attracting attention for environmental conservation. Although active development of refrigerants to replace fluorocarbons has been underway, no new refrigerants that are satisfactory in terms of performance, cost, and safety have yet been put into practical use.

[0003] On the other hand, unlike conventional refrigeration and air conditioning systems, magnetic refrigeration systems that utilize the change in entropy (magnetocaloric effect, ΔS) that accompanies an increase in magnetic field are attracting attention. Materials with a large absolute value of ΔS include Mn(As 1-x Sb x ) (Patent Document 1) and La(Fe 1-x Si x ) 13 H x (Patent Document 2) and others are cited. In particular, the former has a very large ΔS of -30 J / kgK, making it a potential excellent magnetic refrigeration material. However, Mn(As 1-x Sb x ) is difficult to apply in practice because of the toxicity of As. 1-x Si x ) 13 H x ΔS is about 25J / kgK and Mn(As 1-x Sb x ), and its constituent elements are non-toxic and not rare metals, making it the most promising material. Also, the change in ΔS is proportional to the Curie temperature (T c ) and a single material can only operate at a certain temperature, so refrigeration systems that require a wide temperature difference cannot be created. Therefore, methods such as replacing some of the components with other elements are used to change the operating temperature.

[0004] These substances are required to operate near room temperature (about -70 to +70 °C). However, unlike conventional magnetic refrigeration, which has been used as a means of generating extremely low temperatures that are difficult to generate by gas refrigeration, there is a problem that the magnetocaloric effect decreases because lattice vibrations cannot be ignored at the above operating temperatures. The AMR (Active Magnetic Regenerative) cycle that utilizes this lattice vibration as a heat storage effect has been developed, and a refrigeration and air conditioning system near room temperature utilizing the magnetocaloric effect has become realistic.

[0005] In the AMR cycle, a magnetic refrigeration material is filled in a state having a gap through which a heat medium such as water can pass (referred to as a bed portion). The heat medium can move to the high-temperature end and the low-temperature end through the gap. With the heat medium on the low-temperature end side, a magnetic field is applied to the bed portion with a permanent magnet or the like to lower the entropy of the magnetic refrigeration material and raise the temperature of the magnetic refrigeration material. The heat medium is moved from the low-temperature end side to the high-temperature end side. At this time, the heat medium receives heat from the magnetic refrigeration material, moves to the high-temperature end side, and exhausts heat using a heat exchanger at the high-temperature end. Subsequently, when the magnetic field of the permanent magnet is removed, the entropy of the magnetic refrigeration material increases and the temperature decreases. The heat medium is moved from the high-temperature end side to the low-temperature end side. At this time, the heat medium is cooled by the magnetic refrigeration material. The cooled heat medium absorbs heat in the heat exchanger. By repeating this cycle, a temperature difference is generated between the high-temperature end and the low-temperature end, and a refrigeration cycle is created.

[0006] In the AMR cycle, the temperature difference that can be generated by a single-composition material is about 2 to 10 K depending on the material. In order to generate a large temperature difference as required for applications such as refrigerators and air conditioners, magnetic refrigeration materials having different magnetic transition temperatures (T c ) are filled in order from the high-temperature end side to the low-temperature end side with T c being high to low (cascade filling), and a large temperature difference can be generated by performing heat exchange between adjacent magnetic refrigeration materials. At this time, in order for heat exchange to occur, the operating temperatures need to overlap to some extent between adjacent magnetic refrigeration materials. Therefore, each magnetic refrigeration material constituting the cascade takes into account the half-value width of the material and T cneeds to be controlled.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0008] However, in order to further improve the efficiency of heat exchange in the AMR cycle using cascade filling, it is necessary to more precisely adjust the magnetic transition temperature (T c ) of each magnetic refrigeration material constituting the cascade. For example, in the case of the promising material La(Fe 1-x Si x ) 13 H[[ID=3,6]] x even if T c is adjusted, there is a risk of manufacturing variation of about 1 K with respect to the target T c . When a material with T c deviating from the target is incorporated into an AMR device and operated, performance degradation such as the failure to generate the target temperature difference due to the deterioration of the cascade connection due to the variation of T c , or an increase in the time required to generate the temperature difference, is likely to occur.

[0009] The present invention has been made in view of the above circumstances, and an object thereof is to provide a method for manufacturing a magnetic refrigeration material capable of precisely adjusting the magnetic transition temperature of the magnetic refrigeration material and a magnetic refrigeration material capable of precisely adjusting the magnetic transition temperature.

Means for Solving the Problems

[0010] As a result of intensive studies to achieve the above object, the present inventors have found that by mixing two or more magnetic refrigeration materials having a transition temperature difference / half value width of 0.9 or less and different magnetic transition temperatures in a predetermined ratio, the magnetic transition temperature of the magnetic refrigeration material can be adjusted to within 0.7 K of the target magnetic transition temperature, and thus the present invention has been completed. That is, the present invention provides the following means [1] to [5]. [1] A step of preparing a first magnetic refrigeration material satisfying the following formula (1) and a second magnetic refrigeration material different from the first magnetic refrigeration material and satisfying the following formula (2), and a step of mixing the first magnetic refrigeration material and the second magnetic refrigeration material to obtain a third magnetic refrigeration material, wherein the content (A1) of the first magnetic refrigeration material and the content (A2) of the second magnetic refrigeration material in the third magnetic refrigeration material satisfy the following formulas (3) to (4) with respect to a total of 100 parts by mass of the content (A1) of the first magnetic refrigeration material and the content (A2) of the second magnetic refrigeration material. A method for producing a magnetic refrigeration material. -0.9 ≦ (T 1 - T 2 ) / W 1 ≦ 0.9 (1) -0.9 ≦ (T 1 - T 2 ) / W 2 ≦ 0.9 (2) ((T 2 - T T ) / (T 2 - T 1 )) × 100 - 20 ≦ A 1 ≦ ((T 2 - T T ) / (T 2 - T 1 )) × 100 + 20 (3) ((T 1 - T T ) / (T 1 - T 2 )) × 100 - 20 ≦ A 2 ≦ ((T 1 - T T ) / (T 1 - T 2 )) × 100 + 20 (4) Here, T 1 represents the magnetic transition temperature (K) of the first magnetic refrigeration material, T 2 represents the magnetic transition temperature (K) of the second magnetic refrigeration material, W 1 represents the half value width (K) of the peak of the curve showing the temperature dependence of the magnetic entropy change of the first magnetic refrigeration material, W 2 represents the half value width (K) of the peak of the curve showing the temperature dependence of the magnetic entropy change of the second magnetic refrigeration material, and T T represents the target magnetic transition temperature (K) of the third magnetic refrigeration material. [2]At least one of the first magnetic refrigeration material and the second magnetic refrigeration material is a material obtained by mixing two types of magnetic refrigeration materials, In the two types of magnetic refrigeration materials, the absolute value of the value obtained by dividing the difference between the magnetic transition temperatures of the two types of magnetic refrigeration materials by the full width at half maximum of the peak of the curve showing the temperature dependence of the magnetic entropy change is 0.9 or less respectively. The method for producing a magnetic refrigeration material according to [1] above. [3]The method for producing a magnetic refrigeration material according to [1] or [2] above, wherein the first magnetic refrigeration material further satisfies the following formula (5), and the second magnetic refrigeration material further satisfies the following formula (6). -0.4 ≦ (T1 - T2) / W1 ≦ 0.4 (5) -0.4 ≦ (T1 - T2) / W2 ≦ 0.4 (6) Here, T1 represents the magnetic transition temperature (K) of the first magnetic refrigeration material, T2 represents the magnetic transition temperature (K) of the second magnetic refrigeration material, W1 represents the full width at half maximum (K) of the peak of the curve showing the temperature dependence of the magnetic entropy change of the first magnetic refrigeration material, and W2 represents the full width at half maximum (K) of the peak of the curve showing the temperature dependence of the magnetic entropy change of the second magnetic refrigeration material. [4]The absolute value of the difference (T3 - T T )(K) between the magnetic transition temperature (T3)(K) of the third magnetic refrigeration material and the target magnetic transition temperature (T T ) is 0.7 K or less. The method for producing a magnetic refrigeration material according to any one of [1] to [3] above. [5]A magnetic refrigeration material containing at least a first magnetic refrigeration material that satisfies the following formula (7) and a second magnetic refrigeration material that is different from the first magnetic refrigeration material and satisfies the following formula (8), and the absolute value of the difference between the magnetic transition temperature and the target magnetic transition temperature is 0.7 K or less. -0.9 ≦ (T1 - T2) / W1 ≦ 0.9 (7) -0.9 ≦ (T1 - T2) / W2 ≦ 0.9 (8) Here, T1 represents the magnetic transition temperature (K) of the first magnetic refrigeration material, T2 represents the magnetic transition temperature (K) of the second magnetic refrigeration material, W1 represents the full width at half maximum (K) of the peak of the curve showing the temperature dependence of the magnetic entropy change of the first magnetic refrigeration material, and W2 represents the full width at half maximum (K) of the peak of the curve showing the temperature dependence of the magnetic entropy change of the second magnetic refrigeration material.

Advantages of the Invention

[0011] According to the present invention, it is possible to provide a magnetic refrigeration material capable of accurately adjusting the magnetic transition temperature (T c ).

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Figure 3

Embodiments for Carrying Out the Invention

[0013] [Method for Manufacturing Magnetic Refrigeration Material] The method for manufacturing a magnetic refrigeration material of the present invention includes a step of preparing a first magnetic refrigeration material satisfying the following formula (1) and a second magnetic refrigeration material different from the first magnetic refrigeration material and satisfying the following formula (2), and a step of mixing the first magnetic refrigeration material and the second magnetic refrigeration material to obtain a third magnetic refrigeration material. The content (A1) of the first magnetic refrigeration material and the content (A2) of the second magnetic refrigeration material in the third magnetic refrigeration material satisfy the following formulas (3) to (4) with respect to a total of 100 parts by mass of the content (A1) of the first magnetic refrigeration material and the content (A2) of the second magnetic refrigeration material. -0.9 ≦ (T1 - T2) / W1 ≦ 0.9 (1) -0.9 ≦ (T1 - T2) / W2 ≦ 0.9 (2) ((T2 - T T ) / (T2 - T1))×100 - 20 ≦ A1 ≦ ((T2 - TT ) / (T2 - T1)) × 100 + 20 (3) ((T1 - T T ) / (T1 - T2)) × 100 - 20 ≤ A2 ≤ ((T1 - T T ) / (T1 - T2)) × 100 + 20 (4) Here, T1 represents the magnetic transition temperature (K) of the first magnetic refrigeration material, T2 represents the magnetic transition temperature (K) of the second magnetic refrigeration material, W1 represents the full width at half maximum (K) of the peak of the curve showing the temperature dependence of the magnetic entropy change of the first magnetic refrigeration material, W2 represents the full width at half maximum (K) of the peak of the curve showing the temperature dependence of the magnetic entropy change of the second magnetic refrigeration material, and T T represents the target magnetic transition temperature of the third magnetic refrigeration material. In the AMR cycle, the magnetic refrigeration materials are filled into the head part in order from the one with the higher magnetic transition temperature to the one with the lower magnetic transition temperature. Therefore, a plurality of magnetic refrigeration materials with the magnetic transition temperature changed in order from the one with the higher magnetic transition temperature to the one with the lower magnetic transition temperature are required. The target magnetic transition temperature (T T ) of the third magnetic refrigeration material is, for example, the magnetic transition temperature required as the magnetic refrigeration material constituting the head part of the AMR cycle.

[0014] The first magnetic refrigeration material and the second magnetic refrigeration material used in the method for manufacturing the magnetic refrigeration material of the present invention preferably contain at least one alloy selected from the group consisting of R - Fe - Si - based alloys (R is a rare earth element) and R - Fe - Si - H - based alloys (R is a rare earth element) having a NaZn 13 type structure from the viewpoints of stably obtaining a large magnetocaloric effect in the room temperature range and not containing toxic elements. Here, the R - Fe - Si - based alloy can be obtained by melting, casting, and homogenization treatment according to a conventional method. Also, the R - Fe - Si - H - based alloy can be obtained by melting, casting, homogenization treatment, and hydrogenation treatment according to a conventional method. The content of the above alloy in the first magnetic refrigeration material and the second magnetic refrigeration material is preferably 90% by mass or more, more preferably 95% by mass or more, and still more preferably 98% by mass or more, respectively.

[0015] The main component is NaZn13 R-Fe-Si based alloys having a NaZn 13 type structure include, for example, R 1 (Fe,Si) 13 compounds (R 1 : 7.14 atomic %) as the main component. As the alloy composition of this alloy, R 1 is 6 to 10 atomic % (R 1 is one or more selected from rare earth elements and Zr, and La is essential), and the Si content is preferably 9 to 12 atomic % of the elements other than R in the compound. Further, by substituting a part of Fe in the R 1 (Fe,Si) 1 (Fe,Si) 13 compound with M (one or more elements selected from the group consisting of Co, Mn, Ni, Al, Zr, Nb, W, Ta, Cr, Cu, Ag, Ga, Ti, and Sn), a series of alloys with different Curie temperatures (for example, R1(Fe,M,Si) 13 having a NaZn 13 type structure and R 1 : 7.14 atomic %) as the main component) can be produced.

[0016] The above alloys can be obtained by melting the raw material metal or alloy in a vacuum or an inert gas, preferably in an Ar atmosphere, and then casting it into a flat mold or a book mold, or by casting using a liquid quenching method or a strip casting method. It is also preferable to obtain a powdered alloy by an atomization method. Depending on the alloy composition, the cast alloy may consist of a primary α-Fe phase and an R-Si phase (R is a rare earth element). In this case, in order to generate an R(Fe,Si) 13 compound (R is a rare earth element), a homogenization treatment may be performed in the vicinity of or below the decomposition temperature of the compound (which depends greatly on the alloy composition and is about 900 to 1300 °C) for a predetermined time (which depends on the microstructure and is 10 hours to 30 days).

[0017] R(Fe,Si) 13The homogenized alloy with the compound as the main component shows brittleness and can be easily made into powder with a size of several hundred micrometers or less by mechanical grinding. When absorbing H, heat treatment may be carried out in a hydrogen atmosphere after coarse grinding or without coarse grinding. The treatment conditions are changed according to the amount of hydrogen to be absorbed, but generally, it is preferable to carry out heat treatment at a hydrogen partial pressure of about 0.1 to 0.5 MPa, at 200 to 500 °C for about 1 to 20 hours. The alloy after hydrogenation treatment becomes even more brittle and often becomes powder with a size of several hundred micrometers or less when taken out.

[0018] The first magnetic refrigeration material used in the method for manufacturing the magnetic refrigeration material of the present invention satisfies the above formula (1), and the second magnetic refrigeration material used in the method for manufacturing the magnetic refrigeration material of the present invention satisfies the above formula (2). If the first magnetic refrigeration material does not satisfy the above formula (1) and the second magnetic refrigeration material does not satisfy the above formula (2), the peak of the curve showing the temperature dependence (ΔS-T characteristics) of the entropy change in the third magnetic refrigeration material obtained after mixing the first magnetic refrigeration material and the second magnetic refrigeration material will split into two peaks. As a result, the third magnetic refrigeration material will apparently have two magnetic transition temperatures, and the heat exchange efficiency of the AMR cycle filled with the magnetic refrigeration material may deteriorate. From such a viewpoint, it is preferable that the first magnetic refrigeration material further satisfies the following formula (5-1), the second magnetic refrigeration material further satisfies the following formula (6-1), it is preferable that the first magnetic refrigeration material further satisfies the following formula (5-2), and the second magnetic refrigeration material further satisfies the following formula (6-2). In addition, when the first magnetic refrigeration material and the second magnetic refrigeration material are used in combination, the value of ΔS may be smaller than when the first magnetic refrigeration material or the second magnetic refrigeration material is used alone. However, by having the first magnetic refrigeration material and the second magnetic refrigeration material satisfy the following formula, the reduction rate of ΔS due to the combination of the first magnetic refrigeration material and the second magnetic refrigeration material can be further reduced. -0.4 ≦ (T1 - T2) / W1 ≦ 0.4 (5-1) -0.4 ≦ (T1 - T2) / W2 ≦ 0.4 (6-1) -0.2 ≦ (T1 - T2) / W1 ≦ 0.2 (5-2) -0.2 ≦ (T1 - T2) / W2 ≦ 0.2 (6-2) Here, T1 represents the magnetic transition temperature (K) of the first magnetic refrigeration material, T2 represents the magnetic transition temperature (K) of the second magnetic refrigeration material, W1 represents the full width at half maximum (K) of the peak of the curve showing the ΔS-T characteristics of the first magnetic refrigeration material, and W2 represents the full width at half maximum (K) of the peak of the curve showing the ΔS-T characteristics of the second magnetic refrigeration material.

[0019] The ΔS-T characteristics of the magnetic refrigeration material can be derived as follows. Using a vibrating sample magnetometer (VSM), measure the magnetic moment (M) of the magnetic refrigeration material from high temperature to low temperature under a magnetic field with a step of 0.2 T from 0 T to 1 T, and obtain the detailed temperature (T) and magnetic field (H) dependence (M(T,H)) of the magnetic moment (M). Next, substitute this result into the following formula to derive the ΔS-T characteristics of the magnetic refrigeration material.

Equation

[0020] The full width at half maximum (K) of the peak of the curve showing the ΔS-T characteristics of the magnetic refrigeration material is defined as follows in this specification. Let the value of ΔS at the peak of the curve showing the ΔS-T characteristics be ΔS Max When this is the case, the absolute value of the difference (Ta - Tb) between two temperatures (Ta, Tb) at which the value of ΔS at the peak becomes half of the value of ΔS Max is taken as the full width at half maximum.

[0021] Mix the first magnetic refrigeration material and the second magnetic refrigeration material to obtain a third magnetic refrigeration material. Here, the content (A1) of the first magnetic refrigeration material and the content (A2) of the second magnetic refrigeration material in the third magnetic refrigeration material satisfy the above formulas (3) to (4) with respect to a total of 100 parts by mass. If the content (A1) (parts by mass) of the first magnetic refrigeration material and the content (A2) (parts by mass) of the second magnetic refrigeration material do not satisfy the above formulas (3) to (4), the magnetic transition temperature of the third magnetic refrigeration material will be the target magnetic transition temperature (TT ) may not be accurately adjusted. The difference (T3 - T T ) between the magnetic transition temperature (T3) (K) of the third magnetic refrigeration material and the target magnetic transition temperature (T T ) has an absolute value of, for example, 0.7 K or less, preferably 0.5 K or less, and more preferably 0.3 K or less. Note that since the measurement error of the magnetic transition temperature includes about ±0.2 °C, an error of about 20 parts by mass will occur in the above formulas (3) and (4). However, if the deviation is within 20 parts by mass, the influence on the system is small. Therefore, in the above formulas (3) and (4), the value of 20 is subtracted and added. The mixing method is not particularly limited, but for example, it can be performed by a V blender.

[0022] From the viewpoint of further accurately adjusting the magnetic transition temperature of the third magnetic refrigeration material, the content (A1) of the first magnetic refrigeration material and the content (A2) of the second magnetic refrigeration material in the third magnetic refrigeration material, with respect to a total of 100 parts by mass, preferably satisfy the following formulas (3-1) and (4-1), more preferably satisfy the following formulas (3-2) and (4-2), still more preferably satisfy the following formulas (3-3) and (4-3), and even more preferably satisfy the following formulas (3-4) and (4-4). ((T2 - T T ) / (T2 - T1)) × 100 - 10 ≤ A1 ≤ ((T2 - T T ) / (T2 - T1)) × 100 + 10 (3-1) ((T1 - T T ) / (T1 - T2)) × 100 - 10 ≤ A2 ≤ ((T1 - T T ) / (T1 - T2)) × 100 + 10 (4-1) ((T2 - T T ) / (T2 - T1)) × 100 - 5 ≤ A1 ≤ ((T2 - T T ) / (T2 - T1)) × 100 + 5 (3-2) ((T1 - T T ) / (T1 - T2)) × 100 - 5 ≤ A2 ≤ ((T1 - T T) / (T1 - T2)) × 100 + 5 (4 - 2) ((T2 - T T ) / (T2 - T1)) × 100 - 3 ≤ A1 ≤ ((T2 - T T ) / (T2 - T1)) × 100 + 3 (3 - 3) ((T1 - T T ) / (T1 - T2)) × 100 - 3 ≤ A2 ≤ ((T1 - T T ) / (T1 - T2)) × 100 + 3 (4 - 3) ((T2 - T T ) / (T2 - T1)) × 100 - 1 ≤ A1 ≤ ((T2 - T T ) / (T2 - T1)) × 100 + 1 (3 - 4) ((T1 - T T ) / (T1 - T2)) × 100 - 1 ≤ A2 ≤ ((T1 - T T ) / (T1 - T2)) × 100 + 1 (4 - 4)

[0023] Also, one of the first magnetic refrigeration material and the second magnetic refrigeration material may be a material obtained by mixing two types of magnetic refrigeration materials, or both the first magnetic refrigeration material and the second magnetic refrigeration material may be materials obtained by mixing two types of magnetic refrigeration materials. In this case, in the two types of magnetic refrigeration materials that respectively constitute the first magnetic refrigeration material and the second magnetic refrigeration material, the absolute value of the value obtained by dividing the difference between the magnetic transition temperatures of the two types of magnetic refrigeration materials by the full width at half maximum of the peak of the curve showing the temperature dependence of the magnetic entropy change is preferably 0.9 or less, more preferably 0.4 or less, and even more preferably 0.2 or less.

[0024] In the magnetic refrigeration material produced as described above, it is possible to suppress the variation in the transition temperature within 0.7 K with respect to the target magnetic transition temperature (T T ), and it is possible to sufficiently satisfy the accuracy of the magnetic transition temperature required when applying the magnetic refrigeration material to the AMR cycle.

[0025] [Magnetic Refrigeration Material] The magnetic refrigeration material of the present invention contains at least a first magnetic refrigeration material satisfying the following formula (7-1) and preferably satisfying the following formula (7-2), and a second magnetic refrigeration material different from the first magnetic refrigeration material and satisfying the following formula (8-1) and preferably satisfying the following formula (8-2). The absolute value of the difference between the magnetic transition temperature and the target magnetic transition temperature is 0.7 K or less, preferably 0.5 K or less, and more preferably 0.3 K or less. -0.9 ≦ (T1 - T2) / W1 ≦ 0.9 (7-1) -0.4 ≦ (T1 - T2) / W1 ≦ 0.4 (7-2) -0.9 ≦ (T1 - T2) / W2 ≦ 0.9 (8-1) -0.4 ≦ (T1 - T2) / W2 ≦ 0.4 (8-2) Here, T1 represents the magnetic transition temperature (K) of the first magnetic refrigeration material, T2 represents the magnetic transition temperature (K) of the second magnetic refrigeration material, W1 represents the full width at half maximum (K) of the peak of the curve showing the temperature dependence of the magnetic entropy change of the first magnetic refrigeration material, and W2 represents the full width at half maximum (K) of the peak of the curve showing the temperature dependence of the magnetic entropy change of the second magnetic refrigeration material.

[0026] Since the first magnetic refrigeration material and the second magnetic refrigeration material of the magnetic refrigeration material of the present invention are the same as those described in the manufacturing method of the magnetic refrigeration material of the present invention, the description of the first magnetic refrigeration material and the second magnetic refrigeration material of the magnetic refrigeration material of the present invention is omitted.

[0027] The magnetic refrigeration material of the present invention may contain magnetic refrigeration materials other than the first magnetic refrigeration material and the second magnetic refrigeration material as long as the effects of the present invention are not inhibited.

Examples

[0028] Examples and comparative examples are shown below to explain the present invention in more detail, but the present invention is not limited thereto.

[0029] [ΔS-T Characteristics of Magnetic Refrigeration Material] The ΔS-T characteristics of the magnetic refrigeration material were measured using a VSM (Versa Lab, manufactured by Quantum Design) to determine the temperature and magnetic field dependencies of the magnetic moment of the magnetic refrigeration material. From these results, the ΔS-T characteristics of the magnetic refrigeration material were derived by the method described in the above specification. Also, the average value (ΔS av ) of the ΔS value (ΔS1) at the peak apex of the ΔS-T characteristics of the first magnetic refrigeration material and the ΔS value (ΔS2) at the peak apex of the ΔS-T characteristics of the second magnetic refrigeration material, with respect to av the reduction rate ((ΔS av -ΔS3) / ΔS

[0030] [Example 1] Alloys 1 and 2 with the compositions shown in Table 1 were prepared. These alloys were each subjected to heat treatment at a heat treatment temperature of 1160 °C for a heat treatment time of 50 hours to homogenize the alloys. Thereafter, hydrogenation treatment was performed at a treatment temperature of 450 °C, a treatment time of 8 hours, and a pressure of 0.27 MPa to produce the first magnetic refrigeration material from alloy 1 and the second magnetic refrigeration material from alloy 2, respectively. Note that the first magnetic refrigeration material and the second magnetic refrigeration material have different magnetic transition temperatures for the first magnetic refrigeration material and the second magnetic refrigeration material by changing the contents of Fe and Mn. Table 2 shows the full width at half maximum and the magnetic transition temperature of the first magnetic refrigeration material and the second magnetic refrigeration material, and the value obtained by dividing the magnetic transition temperature difference between the first magnetic refrigeration material and the second magnetic refrigeration material by the full width at half maximum (magnetic transition temperature difference / full width at half maximum). Note that the blending amounts of the first magnetic refrigeration material and the second magnetic refrigeration material were determined according to the following equations (9) and (10) so that the magnetic transition temperature of the third magnetic refrigeration material obtained by mixing the first magnetic refrigeration material and the second magnetic refrigeration material would be 298.8 K (target magnetic transition temperature). Table 2 shows the magnetic transition temperature and the reduction rate of the ΔS value of the obtained third magnetic refrigeration material, and FIG. 1 shows the ΔS-T characteristics of the obtained third magnetic refrigeration material. Blending amount (mass %) of the first magnetic refrigeration material = ((T2 - T T ) / (T2 - T1)) × 100 (9) Blending amount (mass %) of the second magnetic refrigeration material = ((T1 - T T ) / (T1 - T2)) × 100 (10) Here, T1 represents the magnetic transition temperature (K) of the first magnetic refrigeration material, T2 represents the magnetic transition temperature (K) of the second magnetic refrigeration material, and T T represents the target magnetic transition temperature (K).

[0031] [Comparative Example 1] Alloys 1 and 2 having the compositions shown in Table 1 were prepared. For these alloys, the same treatment as in Example 1 was carried out to produce the first magnetic refrigeration material from Alloy 1 and the second magnetic refrigeration material from Alloy 2, respectively. Note that the magnetic transition temperatures of the first magnetic refrigeration material and the second magnetic refrigeration material are made different by changing the Mn content. Table 2 shows the full width at half maximum, magnetic transition temperature, and magnetic transition temperature difference / full width at half maximum of the first magnetic refrigeration material and the second magnetic refrigeration material. In addition, the blending amounts of the first magnetic refrigeration material and the second magnetic refrigeration material were determined according to the above equations (9) and (10) so that the magnetic transition temperature of the third magnetic refrigeration material obtained by mixing the first magnetic refrigeration material and the second magnetic refrigeration material would be 295.6 K (the target magnetic transition temperature). Table 2 shows the magnetic transition temperature and the reduction rate of the value of ΔS of the obtained third magnetic refrigeration material, and FIG. 2 shows the ΔS-T characteristics of the obtained third magnetic refrigeration material.

[0032] [Examples 2 to 8] Alloy 1 and Alloy 2 having the compositions shown in Table 1 were prepared. For these alloys, the same treatment as in Example 1 was carried out to produce a first magnetic refrigeration material from Alloy 1 and a second magnetic refrigeration material from Alloy 2, respectively. Note that the magnetic transition temperatures of the first magnetic refrigeration material and the second magnetic refrigeration material are made different by changing the contents of Fe and Mn. Table 2 shows the full width at half maximum, magnetic transition temperature, and magnetic transition temperature difference / full width at half maximum of the first magnetic refrigeration material and the second magnetic refrigeration material. Note that the blending amounts of the first magnetic refrigeration material and the second magnetic refrigeration material were determined according to the above equations (9) and (10) so that the magnetic transition temperature of the third magnetic refrigeration material obtained by mixing the first magnetic refrigeration material and the second magnetic refrigeration material would be the target magnetic transition temperature shown in Table 2. Table 2 shows the magnetic transition temperature and the reduction rate of the value of ΔS of the obtained third magnetic refrigeration material.

[0033] [Example 9] In Example 9, the third magnetic refrigeration material produced in Example 6 was used as the first magnetic refrigeration material, and the third magnetic refrigeration material produced in Example 7 was used as the second magnetic refrigeration material. Table 2 shows the full width at half maximum, magnetic transition temperature, and magnetic transition temperature difference / full width at half maximum of the first magnetic refrigeration material and the second magnetic refrigeration material. Note that the blending amounts of the first magnetic refrigeration material and the second magnetic refrigeration material were determined according to the above equations (9) and (10) so that the magnetic transition temperature of the third magnetic refrigeration material obtained by mixing the first magnetic refrigeration material and the second magnetic refrigeration material would be the target magnetic transition temperature shown in Table 2. Table 2 shows the magnetic transition temperature and the reduction rate of the value of ΔS of the obtained third magnetic refrigeration material, and FIG. 3 shows the ΔS-T characteristics of the obtained third magnetic refrigeration material.

[0034] [Comparative Example 2] The blending amount of the first magnetic refrigeration material was changed to a blending amount reduced by 40% from the blending amount determined according to the above equation (9). Also, the blending amount of the second magnetic refrigeration material was changed to a blending amount increased by 40% from the blending amount determined according to the above equation (10). Otherwise, a third magnetic refrigeration material was produced in the same manner as in Example 1. Table 2 shows the magnetic transition temperature and the reduction rate of the value of ΔS of the obtained third magnetic refrigeration material.

[0035]

Table 1

[0036]

Table 2

[0037] From these results, by mixing the first magnetic refrigeration material and the second magnetic refrigeration material in a blending amount that satisfies the above formulas (3) and (4), it was found that it is possible to manufacture a third magnetic refrigeration material having a target magnetic transition temperature with an accuracy within a range of 0.7 K or less with respect to the target magnetic transition temperature. That is, the magnetic transition temperature of the magnetic refrigeration material could be accurately controlled. Also, in Examples 3 and 9 where the value of the magnetic transition temperature difference / full width at half maximum was greater than 0.4 and 0.9 or less, the rate of decrease in ΔS was large, whereas in those where the value of the magnetic transition temperature difference / full width at half maximum was 0.4 or less, it was found that the rate of decrease in ΔS decreased.

[0038] The ΔS-T characteristics of Example 1 are shown in FIG. 1. Since the magnetic transition temperature difference / full width at half maximum of the first magnetic refrigeration material and the second magnetic refrigeration material was 0.9 or less, the peaks of the ΔS-T characteristics were not separated.

[0039] The ΔS-T characteristics of Comparative Example 1 are shown in FIG. 2. Since the magnetic transition temperature difference / full width at half maximum of the first magnetic refrigeration material and the second magnetic refrigeration material was greater than 0.9, the peaks of the ΔS-T characteristics were separated into two. For this reason, it was not possible to define one magnetic transition temperature of the third magnetic refrigeration material. In addition, if the third magnetic refrigeration material has a plurality of magnetic transition temperatures, it becomes difficult to use the third magnetic refrigeration material as a magnetic refrigeration material to be cascade-filled and used in an AMR cycle.

[0040] The ΔS-T characteristics of Example 9 are shown in Fig. 3. The magnetic transition temperature difference / full width at half maximum of the first magnetic refrigeration material and the second magnetic refrigeration material was 0.8, and the decrease rate of ΔS was large. However, since the value of the magnetic transition temperature difference / full width at half maximum was 0.9 or less, the peaks of the ΔS-T characteristics were not separated, and the deviation of the measured magnetic transition temperature from the target magnetic transition temperature of the third magnetic refrigeration material was 0.7 K or less.

[0041] In Comparative Example 2, since the mixing ratio of the first magnetic refrigeration material and the second magnetic refrigeration material did not satisfy the above equations (3) and (4), the deviation of the measured magnetic transition temperature from the target magnetic transition temperature of the third magnetic refrigeration material was as large as 0.8 K.

Claims

1. A bed part filled with magnetic refrigeration materials having different magnetic transition temperatures, wherein the magnetic refrigeration materials having different magnetic transition temperatures are cascade-filled from the high-temperature end side to the low-temperature end side from those having a high magnetic transition temperature to those having a low magnetic transition temperature, at least one of the magnetic refrigeration materials having different magnetic transition temperatures contains at least a first magnetic refrigeration material satisfying the following formula (7) and a second magnetic refrigeration material different from the first magnetic refrigeration material and satisfying the following formula (8), wherein the first magnetic refrigeration material and the second magnetic refrigeration material each contain at least one alloy selected from the group consisting of an R—Fe—Si-based alloy (R is a rare earth element) and an R—Fe—Si—H-based alloy (R is a rare earth element), and the bed part for an AMR device. -0.9 ≤ (T 1 - T ２ ) / W １ ≤ 0.9 (7) -0.9 ≤ (T 1 - T ２ ) / W ２ ≤ 0.9 (8) Here, T １ represents the magnetic transition temperature (K) of the first magnetic refrigeration material, and T ２ represents the magnetic transition temperature (K) of the second magnetic refrigeration material. W １ represents the full width at half maximum (K) of the peak of the curve showing the temperature dependence of the magnetic entropy change of the first magnetic refrigeration material, and W ２ represents the full width at half maximum (K) of the peak of the curve showing the temperature dependence of the magnetic entropy change of the second magnetic refrigeration material.

2. An AMR device having the bed part according to Claim 1.

3. A step of preparing a first magnetic refrigeration material satisfying the following formula (1) and a second magnetic refrigeration material different from the first magnetic refrigeration material and satisfying the following formula (2), a step of mixing the first magnetic refrigeration material and the second magnetic refrigeration material to obtain a third magnetic refrigeration material, and a step of obtaining a bed part by cascade-filling magnetic refrigeration materials having different magnetic transition temperatures from the high-temperature end side to the low-temperature end side from those having a high magnetic transition temperature to those having a low magnetic transition temperature, wherein at least one of the magnetic refrigeration materials having different magnetic transition temperatures is the third magnetic refrigeration material, The content of the first magnetic refrigeration material (A １ ) and the content of the second magnetic refrigeration material (A ２ ) in the third magnetic refrigeration material, with respect to a total of 100 parts by mass, the content of the first magnetic refrigeration material (A １ ) and the content of the second magnetic refrigeration material (A ２ ) satisfy the following formulas (3) to (4), and the first magnetic refrigeration material and the second magnetic refrigeration material each contain at least one alloy selected from the group consisting of an R—Fe—Si-based alloy (R is a rare earth element) and an R—Fe—Si—H-based alloy (R is a rare earth element), and the manufacturing method of the bed part for an AMR device. -0.9 ≤ (T 1 - T ２ ) / W １ ≤ 0.9 (1) -0.9 ≤ (T 1 - T ２ ) / W ２ ≤ 0.9 (2) ((T ２ - T Ｔ ) / (T ２ - T １ )) × 100 - 20 ≤ A １ ≤ ((T ２ - T Ｔ ) / (T ２ - T １ )) × 100 + 20 (3) ((T １ -T Ｔ ) / (T 1 -T ２ ))×100 - 20 ≤ A ２ ≤ ((T １ -T Ｔ ) / (T 1 -T ２ ))×100 + 20 (4) Here, T １ represents the magnetic transition temperature (K) of the first magnetic refrigeration material, and T ２ represents the magnetic transition temperature (K) of the second magnetic refrigeration material. W １ represents the full width at half maximum (K) of the peak of the curve showing the temperature dependence of the magnetic entropy change of the first magnetic refrigeration material. W ２ represents the full width at half maximum (K) of the peak of the curve showing the temperature dependence of the magnetic entropy change of the second magnetic refrigeration material. T Ｔ represents the target magnetic transition temperature (K) of the third magnetic refrigeration material.

4. A manufacturing method of an AMR device including the manufacturing method of the bed part for an AMR device according to Claim 3.

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