Classifications

• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C38/00—Ferrous alloys, e.g. steel alloys
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
  • F25B21/00—Machines, plants or systems, using electric or magnetic effects
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
  • H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
  • H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials

Definitions

• the present invention relates to a magnetic refrigeration composite material, a method for manufacturing the same, and a magnetic refrigeration device.
• Conventional gas compression type refrigeration and refrigeration equipment uses a compressor to compress, liquefy, and radiate heat from a gaseous refrigerant such as fluorocarbon, and then transports the compressed refrigerant to a location (such as an evaporator) where cold energy is to be supplied or generated. It is a mechanism that cools the object to be cooled by vaporizing and expanding it.
• a gaseous refrigerant such as fluorocarbon
• Magnetic refrigeration systems are attracting attention as one of these new refrigeration and refrigeration systems.
• Certain magnetic materials exhibit an exothermic reaction with a large calorific value when a magnetic field is applied near the magnetic transition temperature (Curie temperature; Tc), and an endothermic reaction when the magnetic field is removed; this is called the magnetocaloric effect.
• Tc magnetic transition temperature
• the magnetocaloric effect depends on the material used and the amount of change in the magnetic field due to application and removal of the magnetic field. Examples of devices that apply the magnetocaloric effect include magnetic heat pumps and magnetic refrigeration devices.
• the main components of the device include a magnetic refrigeration material (magnetic refrigeration material bed), a means for applying and removing a magnetic field to the magnetic refrigeration material (e.g., a pair of magnets and a device that drives the magnets), and a warm heat generated by the magnetic refrigeration material.
• a magnetic refrigeration material magnetic refrigeration material bed
• a means for applying and removing a magnetic field to the magnetic refrigeration material e.g., a pair of magnets and a device that drives the magnets
• a warm heat generated by the magnetic refrigeration material e.g., a pair of magnets and a device that drives the magnets
• a warm heat generated by the magnetic refrigeration material e.g., a pair of magnets and a device that drives the magnets
• heat transport systems that extract cold energy to the outside.
• a permanent magnet with high magnetic force is used as a magnetic field source, and by combining it with a magnetic refrigeration material having a large magnetocaloric effect, a magnetic refrigeration device or the like having a high
• An example of a magnetic refrigeration system is one in which the amount of cold energy associated with heat absorption obtained by the magnetocaloric effect of a magnetic refrigeration material is transported to a place of cooling action using a heat transport medium.
• the magnetic refrigeration material is installed in a magnetic refrigeration device, which is the core of the magnetic refrigeration system.
• it is necessary to achieve high refrigeration efficiency, such as high heat exchangeability with the heat transport medium and low pressure loss, and the material composition and shape are being studied.
• the magnetic refrigeration material is required to have high heat exchangeability and excellent formability so that it can be formed into various shapes.
• a certain degree of strength is also required to prevent the magnetic refrigeration material inside the device from being damaged by impact to the magnetic refrigeration device.
• Patent Document 1 describes a step of molding a powder raw material of La (Fe, Si) 13 by a spark plasma sintering method at a sintering temperature of 950 to 1200°C, a step of occluding hydrogen after molding, and a step of molding.
• US Pat. No. 5,001,002 discloses a method of forming a mixture in which magnetocaloric alloy powder is dispersed in a matrix formed by one or several organic binders.
• Patent Document 3 discloses that La A Si B H C Fe bal (in atomic %, 6.4 ⁇ A ⁇ 7.8%, 9 ⁇ B ⁇ 10.2%, 6 ⁇ C ⁇ 9%, balance Fe and unavoidable impurities) ) is coated with a Sn or Sn alloy-based metal film, and then heat treated in an inert gas atmosphere at 100°C to 300°C to bond the magnetic particles to each other, resulting in a porosity of 20 % to 35% bulk material is disclosed.
• Patent Document 4 discloses that when a powder raw material of La(Fe, Si) 13 is molded at a pressure of 286 MPa or more and a heating temperature of 600° C. or less, a metal powder (such as copper or aluminum) is used to assist in bonding the powder raw material. Discloses a method of manufacturing a magnetic refrigeration material by adding powder).
• Patent Document 1 uses a discharge plasma sintering method, and the sintering temperature is as high as 950 to 1200°C.
• High-temperature heat treatment causes a dehydrogenation reaction, which makes it difficult to control the Curie temperature, and also deteriorates the dimensional accuracy of the molded product due to expansion and contraction.
• the molded body cannot be made into a plate shape unless grinding, polishing, etc. are performed.
• Patent Document 2 can obtain a magnetocaloric element molded to a thickness of 0.2 to 2 mm by using a polymer binder, the molded body with a large amount of resin (resin amount 20 vol% or more), the performance is insufficient due to a decrease in thermal conductivity and density of the molded body. Furthermore, if the amount of resin is small, the bond between the powders will be insufficient and the powder will become brittle, which may cause cracks and chips.
• the technology disclosed in Patent Document 3 has a high bonding force between raw material particles, it uses a metal or alloy with a low melting point, so heat treatment may cause alloying with magnetic particles and reduce magnetic refrigeration performance. be.
• Patent Document 4 uses metal powder to obtain binding force in order to assist the bonding between raw material particles, but in order to obtain high binding force, a large amount of metal powder is used. As a result, moldability may deteriorate. Furthermore, depending on the metal powder used, there is a large difference in specific gravity from the powder raw material of La(Fe, Si) 13 , making it impossible to mix uniformly, creating areas with low binding strength, and making it difficult to form into a plate shape.
• the magnetic refrigeration material is molded into a desired and suitable shape according to the specifications of the refrigeration equipment, etc. in which the material is incorporated. Further, for the purpose of improving heat exchange performance, for example, an uneven shape or a protrusion shape may be provided on the material surface in order to increase the specific surface area. Therefore, it is desirable that the magnetic refrigeration material not only have a high magnetocaloric effect but also have excellent formability.
• the object of the present invention is to provide a plate-shaped magnetic refrigeration composite material that contains a hydrogenated magnetic refrigeration material with excellent magnetocaloric effect, has excellent formability and processability into a desired shape, and is effective in heat exchange ability.
• the object of the present invention is to provide a manufacturing method thereof.
• Another object of the present invention is to provide a magnetic refrigeration device including the magnetic refrigeration composite material.
• the plate surface of the plate-shaped magnetic refrigeration composite material of the present invention may be flat, or may have an uneven shape, a protrusion shape, or the like.
• the present inventors have discovered a plate-shaped mixed material containing a hydrogenated magnetic refrigeration material having a specific elemental composition having a NaZn 13 type crystal structure and a resin binder, and a plate-shaped mixed material containing a resin binder.
• a plate-shaped magnetic refrigeration composite material that includes metal foils on both the front and back sides of the material, and have completed the present invention.
• a plate-shaped composite material comprising a plate-shaped mixed material containing a hydrogenated magnetic refrigeration material and a resin binder, and metal foils on both the front and back surfaces of the plate-shaped mixed material
• the hydrogenated magnetic refrigeration material is a hydrogenated LaFeSi-based material having a composition represented by formula (1)
• a magnetic refrigeration composite material wherein the metal foil has a thickness of 1 ⁇ m or more and 50 ⁇ m or less.
• RE represents one or more elements selected from the group consisting of rare earth elements excluding La
• M represents one or more elements selected from the group consisting of Mn, Co, Ni, and Cr
• T represents one or more elements selected from the group consisting of Al, B, and C.
• x, a, b, c, y, and z are 0.00 ⁇ x ⁇ 0.50, 0.00 ⁇ a ⁇ 0.20, 0.03 ⁇ b ⁇ 0.17, 0.00 ⁇ c ⁇ 0.05, 12.50 ⁇ y ⁇ 13.50, and 0.30 ⁇ z ⁇ 3.00.
• a method for manufacturing the above magnetic refrigeration composite material there is provided a method for manufacturing the above magnetic refrigeration composite material.
• a magnetic refrigeration device including the above magnetic refrigeration composite material is provided.
• the magnetic refrigeration composite material of the present invention is a plate-shaped composite material comprising metal foil on both the front and back surfaces of a plate-shaped mixed material containing a hydrogenated magnetic refrigeration material having the above-described specific elemental composition and a resin binder. , exhibits excellent heat exchangeability, high strength, and excellent formability.
• the production method of the present invention can produce the magnetic refrigeration composite material of the present invention that exhibits excellent heat exchange properties, high strength, and excellent formability.
• 1 is an external photographic diagram of a magnetic refrigeration composite material of the present invention, which has a rib shape on its surface.
• 1 is an external photographic diagram of a magnetic refrigeration composite material of the present invention having cylindrical protrusions on its surface.
• 1 is a schematic cross-sectional view of an embodiment of a magnetic refrigeration device according to the present invention.
• the magnetic refrigeration composite material of the present invention is a plate-shaped composite material comprising a plate-shaped mixed material containing a hydrogenated magnetic refrigeration material and a resin binder, and metal foils on both the front and back surfaces of the plate-shaped mixed material.
• the magnetic refrigeration composite material of the present invention has a specific hydrogenated magnetic refrigeration material, a specific resin binder, and a specific metal foil. Further, it may contain magnetic refrigeration materials other than the hydrogenated magnetic refrigeration material of the present invention. Hereinafter, the magnetic refrigeration composite material may be simply referred to as a composite material.
• compositional formula of the hydrogenated magnetic refrigeration material constituting the present invention is expressed by the following formula (1), and has a NaZn 13 type crystal structure, mainly consisting of La(Fe,Si) 13 phase (also referred to as 1-13 phase).
• the phase is a hydrogenated LaFeSi-based material.
• RE represents one or more elements selected from the group consisting of rare earth elements excluding La
• M represents one or more elements selected from the group consisting of Mn, Co, Ni, and Cr
• T represents one or more elements selected from the group consisting of Al, B, and C.
• x, a, b, c, y, and z are numerical values representing the content ratio of each element, and are respectively 0.00 ⁇ x ⁇ 0.50, 0.00 ⁇ a ⁇ 0.20, and 0.03 ⁇ b. ⁇ 0.17, 0.00 ⁇ c ⁇ 0.05, 12.50 ⁇ y ⁇ 13.50, and 0.30 ⁇ z ⁇ 3.00.
• x, a, b, c, and z represent the content of each element in molar ratio, and the details are as follows.
• the content ratio may be referred to as “content” or “amount”.
• y represents the content ratio (total number of moles) of (Fe 1-ab-c M a Si b T c ) with respect to (La 1-x RE x ) (1 mole in total).
• the hydrogenated magnetic refrigeration material contains La.
• 1-x represents the content ratio of La.
• 1-x is 0.50 ⁇ 1-x ⁇ 1.00, preferably 0.60 ⁇ 1-x ⁇ 1.00.
• RE represents one or more elements selected from rare earth elements other than La.
• Rare earth elements other than La include Sc, Y, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu.
• x represents the content rate of RE. x is 0.00 ⁇ x ⁇ 0.50, preferably 0.00 ⁇ x ⁇ 0.40.
• the magnetic transition temperature (Tc) of the hydrogenated magnetic refrigeration material can be adjusted by adjusting the content ratio of RE.
• Ce it is possible to lower the magnetic transition temperature of the hydrogenated magnetic refrigeration material and to increase the magnetocaloric effect of the material.
• recycled raw materials can be used, which is advantageous in terms of material availability and reduces material costs. be able to.
• the hydrogenated magnetic refrigeration material contains Fe.
• 1-a-b-c represents the content ratio of Fe.
• 1-a-b-c is 0.58 ⁇ 1-a-b-c ⁇ 0.97, preferably 0.60 ⁇ 1-a-b-c ⁇ 0.95, more preferably 0 .63 ⁇ 1-a-b-c ⁇ 0.94.
• Fe affects the generation efficiency of the 1-13 phases. If the Fe content is high, the magnetocaloric effect may be reduced.
• M represents one or more elements selected from the group consisting of Mn, Co, Ni, and Cr.
• M is one or more elements selected from the group consisting of Mn and Co.
• a represents the content ratio of M. a is 0.00 ⁇ a ⁇ 0.20, preferably 0.00 ⁇ a ⁇ 0.18.
• M is not an essential element for the hydrogenated magnetic refrigeration material, the inclusion of M widens the adjustment temperature range of the magnetic transition temperature of the hydrogenated magnetic refrigeration material. In particular, when Mn is used, it is possible to lower the magnetic transition temperature in proportion to the Mn content without causing a large drop in thermomagnetic properties. Furthermore, when using Co, it is possible to increase the magnetic transition temperature in proportion to the Co content.
• the hydrogenated magnetic refrigeration material contains Si.
• b represents the content ratio of Si.
• b is 0.03 ⁇ b ⁇ 0.17, preferably 0.06 ⁇ b ⁇ 0.14.
• Si acts as a stabilizer for the 1-13 phase, and by using Si, it becomes possible to form the 1-13 phase by heat treatment.
• T represents one or more elements selected from the group consisting of Al, B, and C.
• c represents the content ratio of T. c is 0.00 ⁇ c ⁇ 0.05, preferably 0.00 ⁇ c ⁇ 0.04. By using T, the magnetic transition temperature of the hydrogenated magnetic refrigeration material can be adjusted.
• y represents the ratio of (Fe 1-abc M a Si b T c ) to (La 1-x RE x ) as described above.
• y is 12.50 ⁇ y ⁇ 13.50, preferably 12.70 ⁇ y ⁇ 13.30. Even if the homogenization heat treatment described below is performed, if y exceeds 13.50, a large amount of ⁇ -Fe remains, and if y is less than 12.50, a rare earth-rich phase (hereinafter sometimes referred to as R-rich phase). ) remains, there is a possibility that an alloy having the 1-13 phase as the main phase cannot be obtained.
• R-rich phase a rare earth-rich phase
• the hydrogenated magnetic refrigeration material contains H (hydrogen).
• z represents the content rate of H. z is 0.30 ⁇ z ⁇ 3.00, preferably 0.30 ⁇ z ⁇ 2.00.
• the hydrogenated magnetic refrigeration material may substantially contain inevitable impurities such as oxygen, nitrogen, and raw material-derived impurities.
• composition of the hydrogenated magnetic refrigeration material used in the composite material of the present invention can be measured by ICP (Inductively Coupled Plasma) emission spectrometry.
• the hydrogenated magnetic refrigeration material is obtained by hydrogenating a LaFeSi alloy having a NaZn 13 type crystal structure.
• the method for producing the LaFeSi alloy is not particularly limited and can be selected from known methods, such as a strip casting method such as a single roll method, a twin roll method, or a disk method, and a die casting method.
• the phase diagram of the LaFeSi alloy shows that the 1-13 phase exhibits a peritectic reaction, and when an alloy with the desired composition is cast, grain boundaries containing more rare earth elements than the main phase form around the ⁇ -Fe main phase.
• a peritectic structure having a phase (R-rich phase) is formed.
• the starting alloy has a predetermined composition in consideration of the melting yield, etc., and is then made into a microstructure using a rapidly solidified alloy manufacturing method such as a strip casting method. It is possible to maintain an alloy with this fine structure in vacuum or in an inert gas atmosphere at a temperature where the 1-13 phase is stable for an appropriate processing time (more than 0 seconds and less than 480 hours after reaching the processing temperature). desirable. Since the stable temperature varies depending on the alloy composition, it is maintained at a temperature of, for example, 900° C. to 5° C. lower than the melting point, depending on the composition.
• the obtained LaFeSi-based alloy is subjected to hydrogenation treatment using a hydrogenation treatment apparatus (hydrogenation container) capable of applying hydrogen to obtain a hydrogenated magnetic refrigeration material.
• Hydrogenation treatment makes it possible to adjust Tc.
• a hydrogenation activation treatment may be performed as necessary.
• the hydrogenation activation process is a process of performing evacuation at room temperature or higher and applying a predetermined hydrogen pressure. The process may be repeated multiple times.
• alloy will refer to the LaFeSi alloy.
• the specific hydrogenation treatment is performed by applying a hydrogen pressure of 0.01 MPa or more at room temperature or higher to the alloy (or hydrogenation activated alloy) sealed in the hydrogenation treatment apparatus.
• the hydrogenation treatment may be performed at a high temperature if necessary. Thereafter, the applied hydrogen pressure is removed from the processing apparatus, and after replacement with inert gas or air as necessary, the produced hydrogenated magnetic refrigeration material is taken out.
• the hydrogenated magnetic refrigeration material obtained as described above is formed into the composite material of the present invention by the method described below. If a temperature higher than the hydrogen release temperature of the hydrogenated magnetic refrigeration material is applied to the refrigeration material during the molding, hydrogen will be released and the magnetocaloric performance of the refrigeration material will be significantly reduced. Therefore, when molding the hydrogenated magnetic refrigeration material into the composite material of the present invention, it is necessary to mold at a temperature lower than the hydrogen release temperature, so it is important to know the hydrogen release temperature in advance.
• the hydrogen release temperature of the hydrogenated magnetic refrigeration material can be determined as follows. Heat treatment is applied to the hydrogenated magnetic refrigeration material at a specific temperature, and the magnetic transition temperature (Tc) is measured before and after the heat treatment temperature to confirm the change in Tc. Specifically, the heat treatment temperature is increased stepwise, and the change in Tc before and after each heat treatment temperature is confirmed each time. If there is no change in Tc even after heat treatment, it can be determined that hydrogen in the hydrogenated magnetic refrigeration material has not been released. If Tc decreases before and after the heat treatment, it can be determined that hydrogen has been released from the material, and the heat treatment temperature is taken as the hydrogen release temperature.
• Tc magnetic transition temperature
• Other methods include determining the hydrogen release temperature by measuring the endothermic reaction accompanying hydrogen release during the temperature rise process using differential scanning calorimetry (DSC), and determining the hydrogen release temperature using TG-DTA, etc.
• DSC differential scanning calorimetry
• TG-DTA TG-DTA
• PPMS Physical Property Measurement System
• a preferred shape of the magnetic refrigeration material will be explained.
• a shape that makes the magnetic refrigeration material advantageous in heat exchange with the heat transport medium, which also contributes to improving the performance of magnetic refrigeration equipment It is desirable to have a shape that This point will be explained below.
• a plate-shaped molded body is an example of a molded body shape of a magnetic refrigeration material that satisfies these requirements.
• shaping may be added to the surface of the plate-shaped magnetic refrigeration material so that it has an uneven shape, a protrusion shape, or a rib shape.
• the hydrogenated magnetic refrigeration material constituting the present invention undergoes volumetric expansion, fine cracks, etc. due to the introduction of hydrogen, and therefore has extremely poor machinability, and is a brittle material with poor ductility. Therefore, in the present invention, the problem of machinability is solved by making the hydrogenated magnetic refrigeration material into powder form, using a resin binder and metal foil, and combining these to form a desired molded object such as a plate shape. can be obtained.
• the resin binder used in the present invention preferably has good handling properties in order to facilitate mixing of raw materials before forming a molded body. Furthermore, a resin binder having appropriate ductility is preferable so that a plate-shaped mixed material that can exhibit good moldability can be obtained. Further, in the present invention, the pasting of the metal foil and the forming into a plate-shaped mixed material are performed almost simultaneously, but the details will be described later.
• the magnetic refrigeration performance per unit volume of the composite material of the present invention containing a hydrogenated magnetic refrigeration material is approximately proportional to the filling rate of the hydrogenated magnetic refrigeration material in the composite material.
• it is effective to form the hydrogenated magnetic refrigeration material into powder particles having an average particle size suitable for a high filling rate.
• the LaFeSi-based alloy is an iron-based alloy, it has relatively high hardness.
• a hydrogenated magnetic refrigeration material obtained by hydrogenating this alloy is brittle, and some degree of pulverization occurs due to volume expansion accompanying hydrogenation.
• Desirable methods of pulverization include mechanical pulverization in the presence of an inert gas (using a hammer mill, etc.), jet mill pulverization using an inert gas, and the like.
• the average particle size of the obtained hydrogenated magnetic refrigeration material powder can be adjusted.
• a hydrogenated magnetic refrigeration material powder having a predetermined particle size can be obtained by performing crushing and sieving continuously or batchwise using a device such as a vibrating sieve.
• a method for confirming the average particle size a dynamic light scattering method, a laser diffraction method, a gravitational sedimentation method, an image imaging method, etc. can be used.
• the hydrogenated magnetic refrigeration material powder obtained as described above is mixed with a resin binder to obtain a raw material mixture for preparing a plate-shaped mixed material.
• the raw material mixture may further contain an organic solvent. The organic solvent is removed after molding, and this point will be discussed later.
• the mixing ratio of the hydrogenated magnetic refrigeration material powder and the resin binder is such that the mass ratio of "hydrogenated magnetic refrigeration material: resin binder" is preferably 99.9:0.1 to 85.0:15.0, and 99. More preferably 9:0.1 to 90.0:10.0.
• the raw material mixture of the present invention may be in any form as long as it can be formed into a plate shape using a press molding machine or a press mold.
• it may be in a prepreg-like state in which a resin binder and/or an organic solvent is impregnated into a hydrogenated magnetic refrigeration material powder, or in a slurry state in which a hydrogenated magnetic refrigeration material powder is dispersed in a resin binder and/or an organic solvent.
• it may be clay-like, in which a resin binder and/or an organic solvent serve as a binder for the hydrogenated magnetic refrigeration material powder. That is, the raw material mixture of the present invention can be plastically deformed into a plate shape by press molding or the like, and can maintain the shape while solidifying the obtained plate-shaped molded product.
• thermoplastic resin as a binder.
• a hydrogenated magnetic refrigeration material and a thermoplastic resin are mixed and then heated above the melting point of the resin to form a clay-like raw material mixture.
• the clay-like raw material mixture is sandwiched between two sheets of metal foil, and pressed using a press machine or a press die so that the metal foils are attached to both the front and back surfaces to form a plate-like shape.
• projections or the like may be simultaneously provided on the surface of the plate-shaped molded body by using a specific press mold.
• the magnetic refrigeration composite material of the present invention which includes metal foils on both the front and back surfaces of the plate-shaped mixed material, can be prepared. That is, the preparation of the plate-shaped mixed material in which the raw material mixture is solidified and the application of the metal foil are performed almost simultaneously.
• This preparation method is just one example, and after preparing the plate-shaped mixed material, metal foils may be attached to both the front and back surfaces.
• the above prepreg-like raw material mixture can also be prepared using a thermosetting or UV-curing liquid resin as a binder precursor.
• a prepreg-like raw material mixture is formed into a plate shape by pressing, and then a magnetic cryocomposite material is prepared by heating or UV irradiation. That is, a thermosetting or UV-curing liquid resin is cured by heating or UV irradiation after molding, and becomes a resin binder in the plate-shaped mixed material.
• an organic solvent may be added together with the hydrogenated magnetic refrigeration material and the resin binder to form a slurry-like or clay-like raw material mixture.
• Use of an organic solvent has the advantage that moldability is improved and further, molding can be performed at room temperature without the need for heating.
• a raw material mixture containing an organic solvent and a metal foil are similarly formed into a plate shape using a press or the like, and then the organic solvent is evaporated off to prepare a magnetic refrigeration composite material.
• any binder that can be uniformly dissolved or mixed in the organic solvent may be a thermoplastic resin or a thermosetting resin.
• the resin serving as a binder examples include polyethylene, polypropylene, polystyrene, (meth)acrylic resin, fluororesin, epoxy resin, phenol resin, and melamine resin.
• a resin having a melting point lower than the hydrogen release temperature of the hydrogenated magnetic refrigeration material and having good water resistance is preferred.
• a thermosetting or UV curing liquid resin is preferable.
• the curing temperature is preferably lower than the hydrogen release temperature of the hydrogenated magnetic refrigeration material.
• the magnetic refrigeration composite material has appropriate formability so that it can be plastically deformed to finely adjust its shape by matching the installation location in the refrigerator and the method of contact with the heat transport medium.
• resin binders that can be applied to magnetic refrigeration composites.
• thermosetting resins and UV curable resins function as binders after a curing reaction, but in this specification, they are also referred to as resin binders even before curing. That is, the raw material resin that functions as a binder in the magnetic refrigeration composite material of the present invention will be referred to as a resin binder.
• resins preferable as binders include fluororesins, thermosetting epoxy resins, thermosetting (meth)acrylic resins, UV-curing epoxy resins, and UV-curing (meth)acrylic resins. This is because, in the production of the magnetic refrigeration composite material of the present invention, treatment at a temperature higher than the hydrogen release temperature of the hydrogenated magnetic refrigeration material can be made unnecessary.
• fluororesin examples include polytetrafluoroethylene resin (PTFE resin), polyvinylidene fluoride resin (PVDF resin), polyvinyl fluoride resin (PVF resin), and the like.
• PTFE resin polytetrafluoroethylene resin
• PVDF resin polyvinylidene fluoride resin
• PVF resin polyvinyl fluoride resin
• polyvinylidene fluoride resin is preferred because it has excellent water resistance.
• the molecular weight (Mw) of the resin is preferably 100,000 to 1,200,000, and 300,000 to 300,000. More preferably, it is between 1,200,000 and 1,200,000.
• thermosetting resin has a curing temperature of 120° C. or lower. This is because the hydrogenated magnetic refrigeration material of the present invention releases hydrogen and changes in performance due to high temperatures starting at about 130°C, so the plate-shaped molded product is solidified below that temperature.
• Thermosetting epoxy resins are particularly preferred because they have excellent water resistance.
• a raw material mixture containing an organic solvent may be prepared.
• an organic solvent for example, when polyvinylidene fluoride resin is used, N-methylpyrrolidone, ketones such as methylethylketone and acetone, etc. can be used as the solvent, and N-methylpyrrolidone and methylethylketone are particularly preferred. Alcohol or the like may be used as an auxiliary solvent.
• An organic solvent may also be used when thermosetting resin or UV curable resin is used. Alcohol-based solvents and the like can be used as the solvent.
• the amount of organic solvent used is a suitable amount that allows the raw material mixture to be prepared to be easily molded into a plate shape.
• the organic solvent in addition to dissolving the resin binder in an organic solvent and mixing it with the hydrogenated magnetic refrigeration material, the organic solvent may be added after mixing the hydrogenated magnetic refrigeration material and the resin binder. may be mixed at the same time.
• the organic solvent is used for the purpose of making it easier to mold the raw material mixture into a plate shape, and is removed by evaporation after the plate-shaped molded product with the metal foil attached is prepared. Therefore, when a raw material mixture that can be easily molded into a plate shape can be obtained only by using a resin binder melted by heating, a thermosetting liquid resin, or a UV curable liquid resin, it is preferable not to use an organic solvent.
• the magnetic refrigeration composite material of the present invention is a plate-shaped composite material in which metal foil is pasted on both the front and back surfaces of a plate-shaped mixed material.
• the magnetic refrigeration composite material preferably has a thin plate shape, and specifically, the average thickness is preferably 1.0 mm or less, and 0.5 mm or less. is more preferable. In terms of strength, the thickness is preferably 0.1 mm or more.
• the magnetic refrigeration composite material of the present invention may be used by forming the surface to have an uneven shape such as a dimple shape. Therefore, the metal foil should preferably have good toughness.
• copper (Cu) foil, aluminum (Al) foil, brass foil, and stainless steel foil are preferable.
• the stainless steel foil is preferably non-magnetic, such as SUS304 series or SUS316 series.
• the metal foils on both the front and back sides may be the same or different.
• the thickness of the metal foil is 1 ⁇ m or more and 50 ⁇ m or less.
• the strength of the magnetic refrigeration composite material can be improved.
• the hydrogenated magnetic refrigeration material may fall off when bending and deforming it into a desired shape when incorporating it into a magnetic refrigeration device.
• there is a risk that the hydrogenated magnetic refrigeration material may fall off due to deterioration due to long-term use. By providing metal foil, this falling off can be prevented.
• undulations may be formed on the surface.
• the undulations include an uneven shape such as a dimple shape, a protrusion shape, a rib shape, a corrugated plate shape, and the like.
• FIG. 1 An example of a magnetic refrigeration composite material provided with a rib shape is shown in FIG. 1, and an example of a magnetic refrigeration composite material provided with a cylindrical projection shape is shown in FIG.
• All shown in Figure 1 are thin plates with a thickness of 0.3 mm including rib shapes, respectively: left: rib width 0.1 mm, rib spacing 0.3 mm, center: rib width 0.15 mm, rib spacing 1.5 mm.
• Each of the plates shown in FIG. 2 is a thin plate with a thickness of 0.3 mm and includes a cylindrical protrusion shape, and the diameter of the protrusion is 0.15 mm on the left and 0.25 mm on the right.
• the manufacturing method includes a step of preparing a raw material mixture containing a hydrogenated magnetic refrigeration material represented by formula (1) and a resin binder, a step of installing a metal foil on both the front and back surfaces of the raw material mixture, and a step of disposing the metal foil on both sides of the raw material mixture.
• the step of preparing the raw material mixture is performed by the above-mentioned method of heating the resin binder to a temperature higher than its melting point, using an organic solvent, or using a thermosetting or UV-curing liquid resin.
• a partial solidification step may be performed in which a part of the liquid resin is subjected to a curing reaction. Partial solidification is preferably performed at a temperature lower than the temperature for solidifying the plate-shaped molded body, for example, preferably at 70° C. to 100° C. for 1 to 30 hours. Due to partial solidification, the raw material mixture becomes granular, and adhesive force between the particles occurs when pressure is applied, making it easy to install metal foil and to form a plate-shaped body using a press or the like in the next step.
• the raw materials in the step of preparing the raw material mixture can be mixed using a mixer such as a rocking mixer, a planetary mixer, a tumbler mixer, a Henschel mixer, or various kneaders, kneaders, and other devices. Since the mixing needs to be carried out at a temperature at which no hydrogen is released from the hydrogenated magnetic refrigeration material, a mixing (kneading) container provided with a cooling means is used, if necessary.
• a mixer such as a rocking mixer, a planetary mixer, a tumbler mixer, a Henschel mixer, or various kneaders, kneaders, and other devices. Since the mixing needs to be carried out at a temperature at which no hydrogen is released from the hydrogenated magnetic refrigeration material, a mixing (kneading) container provided with a cooling means is used, if necessary.
• the following method can be exemplified as a method for installing metal foil in the process of installing metal foil.
• the raw material mixture is applied onto the metal foil to a substantially uniform thickness.
• An example of the coating method is a method using a coater such as a blade coater.
• the granular raw material mixture prepared by the above-mentioned partial solidification it can be fed onto the metal foil using a powder feeder or the like.
• Other methods may be used as long as the raw material mixture can be coated or supplied onto the metal foil to a substantially uniform thickness.
• metal foil is pasted on one side of the coated raw material mixture.
• metal foil is pasted on the other side of the applied raw material mixture.
• metal foils are placed on both the front and back surfaces of the raw material mixture.
• the following methods can be exemplified as the molding method in the step of obtaining a plate-shaped molded body.
• a raw material mixture with metal foil installed (affixed) on both the front and back sides is rolled, extruded, pressed, etc. using equipment such as an extrusion molding machine, a compression molding machine, a tableting machine, etc. to form a plate-shaped molded product in the desired shape. do.
• a heating device may be used during molding. However, it should be noted that the heating is below the hydrogen release temperature of the hydrogenated magnetic refrigeration material.
• lubricants such as various metal soaps such as magnesium stearate are applied to the surface of the mold.
• a mold release agent such as a fluorine-based mold release agent may be sprayed or applied.
• the magnetic refrigeration composite material of the present invention may have undulations such as an uneven shape on the surface of the metal foil.
• the following method can be exemplified as a method for forming the undulations.
• a press molding machine or the like capable of imparting uneven shapes such as grooves and ribs or protruding shapes is used to prepare a plate-shaped molded body having these shapes on the surface.
• the method for solidifying the plate-shaped compact in the process of obtaining the magnetic refrigeration composite material is as follows.
• a thermoplastic resin binder to prepare a plate-shaped molded body at a temperature higher than the melting point of the resin binder, by cooling the plate-shaped molded body to a temperature below the melting point, the plate-shaped molded body solidifies and undergoes magnetic refrigeration.
• a composite material is obtained.
• the plate-shaped molded body solidifies and becomes a magnetic refrigeration composite. Materials are obtained.
• the plate-shaped molded body When preparing a plate-shaped molded body using a thermosetting liquid resin, by heating the plate-shaped molded body above the curing reaction temperature of the liquid resin, the plate-shaped molded body solidifies and becomes a magnetic refrigeration composite material. is obtained.
• the heating temperature at this time is preferably lower than the hydrogen release temperature of the hydrogenated magnetic refrigeration material, for example, preferably room temperature or higher and lower than 130°C. Therefore, a thermosetting liquid resin whose curing reaction proceeds within this temperature range is preferred.
• the heating time is matched with the curing time of the thermosetting liquid resin, and is, for example, more than 0 seconds and less than 30 hours after reaching the heating (curing) temperature.
• the plate-shaped molded body When preparing a plate-shaped molded body using a UV-curable liquid resin, the plate-shaped molded body can be solidified by irradiating the plate-shaped molded body with UV at a temperature lower than the hydrogen release temperature of the hydrogenated magnetic refrigeration material. A magnetic refrigeration composite material is obtained.
• the UV irradiation time is matched with the curing time of the UV curable liquid resin, and is, for example, more than 0 seconds and less than 2 hours.
• the process of obtaining a plate-shaped molded body and the process of obtaining a magnetic refrigeration composite material may be performed at the same time. That is, the magnetic refrigeration composite material may be prepared by performing cooling, organic solvent removal, thermosetting reaction, or UV curing reaction while forming the plate-shaped compact to solidify the plate-shaped compact.
• the magnetic refrigeration composite material of the present invention preferably has a thin plate shape with an average thickness of 1.0 mm or less, more preferably a thickness of 0.5 mm or less, particularly preferably 0.40 mm or less. In terms of strength, the thickness is preferably 0.1 mm or more, more preferably 0.15 mm or more. By forming the plate into a thin plate shape, good heat exchange performance can be obtained while suppressing pressure loss. It also has the advantage of improving the accuracy of punching, surface shaping, etc. of magnetic refrigeration composite materials.
• the magnetic refrigeration composite material produced by the production method of the present invention can be further processed into a desired shape and used as a part of a refrigeration device or the like.
• processing include cutting, punching, and processing for forming undulations on the surface such as the uneven shape described above. That is, a magnetic refrigeration composite material having undulations on its surface may be given undulations in the process of obtaining a plate-shaped compact as explained above, and after preparing the magnetic refrigeration composite material, it may be further subjected to surface processing such as compression. It is also possible to add undulations.
• the magnetic refrigeration composite material of the present invention exhibits high heat exchangeability due to its high strength and excellent formability, so by using it as a component of a refrigeration system, a magnetic refrigeration system with excellent refrigeration effects can be obtained.
• the magnetic refrigeration composite material of the present invention has higher heat exchange efficiency when built into a refrigeration device than the powder of hydrogenated magnetic refrigeration material, so the magnetic refrigeration device of the present invention has higher performance than conventional magnetic refrigeration devices. be.
• the magnetic refrigeration device of the present invention is equipped with the magnetic refrigeration composite material of the present invention, and other known configurations can be used.
• a schematic diagram of the magnetic refrigeration system is shown in Figure 3.
• the main components of the magnetic refrigeration device include a magnetic refrigeration composite material (1), a magnetic field (for example, a rotating magnet: 2), a means for applying and removing the magnetic field (for example, a motor that rotates the magnet: not shown), and a magnetic refrigeration composite material.
• a heat transport system heat transport medium transfer pump: 4, heat transport medium: 8, heat transport medium flow path: 9, etc.
• Examples include means such as a rotary valve (rotary valve: 5, or the direction of operation of the transfer pump may be switched).
• Example 1 The raw material elements were weighed so that the composition of the LaFeSi-based alloy before hydrogenation was the composition shown in Table 1 excluding the hydrogen portion, and melted in an argon gas (Ar) atmosphere in a high-frequency melting furnace to obtain a melted alloy. Subsequently, this melt was rapidly cooled and solidified at a pouring temperature of 1550° C. by a strip casting method using a single roll casting device using a water-cooled copper roll to obtain an alloy slab. Next, the obtained alloy slab was subjected to a homogenization treatment at 1100° C. for 80 hours in an Ar atmosphere, and then rapidly cooled to obtain an alloy slab having a NaZn 13 type crystal structure as a main phase.
• Ar argon gas
• the alloy slab was hydrogenated in a hydrogenation furnace to obtain a hydrogenated magnetic refrigeration material.
• the hydrogenation conditions were as follows: After loading the slab into a hydrogenation furnace, vacuum evacuation and Ar substitution were repeated, and then the temperature was raised to 200°C while applying hydrogen (0.1 MPa). Hydrogen is supplied to the storage so that the hydrogen pressure is constant. After sufficient hydrogenation, the mixture was cooled to room temperature, hydrogen gas removed, and replaced with air to obtain a hydrogenated magnetic refrigeration material.
• the obtained magnetic refrigeration material was pulverized using a hammer mill under an Ar gas flow to obtain a hydrogenated magnetic refrigeration material powder having an average particle size (D50) of about 80 ⁇ m.
• D50 was measured using a laser diffraction/scattering particle size distribution analyzer, Partica LA-960 (manufactured by Horiba, Ltd.).
• the composition of the hydrogenated magnetic refrigeration material powder was analyzed by ICP emission spectroscopy and was found to be (La 0.70 Ce 0.30 ) (Fe 0.89 Si 0.11 ) 13 H 1.5 .
• a raw material mixture was prepared by mixing 24.975 g of hydrogenated magnetic refrigeration material powder and 0.025 g of EP160 (one-component low-temperature curable epoxy resin: manufactured by Cemedine Co., Ltd.) in a mortar for 5 minutes. Approximately 0.5 g of the raw material mixture was applied onto a 9 ⁇ m thick aluminum foil, and a similar aluminum foil was further placed on top of the mixture. The raw material mixture with aluminum foil placed on both the front and back surfaces was filled into a circular die with a diameter of 20 mm for press processing, and press compression molding was performed for 5 minutes at a surface pressure of 1.6 t/cm 2 to form a plate-shaped molded product. Obtained. The obtained plate-shaped molded body was heat-treated at 110° C. for 30 minutes to solidify it, thereby producing a thin plate-shaped magnetic refrigeration composite material with a diameter of 20 mm and a thickness of 0.3 mm.
• EP160 one-component low-temperature curable epoxy resin: manufactured by Cemedine Co., Ltd
• Example 2-5, 17-22 A magnetic refrigeration composite material was produced in the same manner as in Example 1, except that the composition of the hydrogenated magnetic refrigeration material and the mixing ratio of the hydrogenated magnetic refrigeration material and EP160 were as shown in Table 1.
• Table 1 shows the results of the punching test and simple bending test of the magnetic refrigeration composite materials of each example.
• Example 6 A magnetic refrigeration composite material was produced in the same manner as in Example 5, except that the composition of the hydrogenated magnetic refrigeration material and the metal foil used were as shown in Table 1. Table 1 shows the results of the punching test and simple bending test of the magnetic refrigeration composite materials of each example.
• Example 11-12 A magnetic refrigeration composite material was produced in the same manner as in Example 6, except that the composition of the hydrogenated magnetic refrigeration material was as shown in Table 1 and partial solidification was performed. Partial solidification was performed after preparing a raw material mixture by mixing the hydrogenated magnetic refrigeration material powder and EP160 and before applying it to metal foil, and was performed at 80° C. for 20 hours. Table 1 shows the results of the punching test and simple bending test of the magnetic refrigeration composite materials of each example.
• Example 13 The magnetic refrigeration process was carried out in the same manner as in Example 6, except that the composition of the hydrogenated magnetic refrigeration material was as shown in Table 1, and that the forming into a plate-shaped compact and the preparation of the magnetic refrigeration composite material by solidifying the plate-shaped compact were carried out simultaneously.
• a frozen composite material was prepared. Specifically, a raw material mixture with aluminum foil placed on both the front and back surfaces was filled into a circular die with a diameter of 20 mm for press processing, and hot pressed at 120°C for 5 minutes with a surface pressure of 1.6 t/cm 2 .
• a magnetic refrigeration composite material was produced by compression molding. Table 1 shows the results of the punching test and simple bending test of the magnetic refrigeration composite material of Example 13.
• Example 14 A magnetic refrigeration composite material was prepared in the same manner as in Example 6, except that the resin binder was changed to ThreeBond 2087 (two-component mixed epoxy resin: manufactured by Three Bond Co., Ltd.), and the composition and solidification conditions of the hydrogenated magnetic refrigeration material were changed as shown in Table 1. was prepared. Table 1 shows the results of the punching test and simple bending test of the magnetic refrigeration composite material of Example 14.
• Example 15 A magnetic refrigeration composite material was prepared in the same manner as in Example 7, except that the resin binder was changed to Epifine EX-0427 (one-component modified epoxy resin: manufactured by Fine Polymers Co., Ltd.) and the thickness of the aluminum foil was changed as shown in Table 1. was prepared. Table 1 shows the results of the punching test and simple bending test of the magnetic refrigeration composite material of Example 15.
• Example 16 Magnetic refrigeration was carried out in the same manner as in Example 7, except that the resin binder was changed to XM-5866 TYPE E3 (one-component heat-curing epoxy resin: manufactured by Pernox Co., Ltd.) and the thickness of the aluminum foil was changed as shown in Table 1. A composite material was created. Table 1 shows the results of the punching test and simple bending test of the magnetic refrigeration composite material of Example 16.
• Comparative magnetic refrigeration composite materials were prepared in the same manner as in Example 1, except that no metal foil was used and the mixing ratio of the hydrogenated magnetic refrigeration material and EP160 was changed as shown in Table 1.
• Table 1 shows the results of the punching test and simple bending test of the magnetic refrigeration composite materials of each comparative example.
• Comparative magnetic refrigeration composite materials were prepared in the same manner as in Example 1, except that the composition and the mixing ratio of the hydrogenated magnetic refrigeration material and EP160 were as shown in Table 1. Table 1 shows the results of the punching test and simple bending test of the magnetic refrigeration composite materials of each comparative example.
• Example 15 A magnetic refrigeration composite material was produced in the same manner as in Example 3, except that the thickness of the aluminum foil was changed as shown in Table 1, and the aluminum foil was attached only to one side of the magnetic refrigeration composite material.
• Table 1 shows the results of the punching test and simple bending test of the magnetic refrigeration composite material of Comparative Example 15.
• Comparative magnetic refrigeration composite materials were produced in the same manner as in Example 1, except that the mixing ratio of the hydrogenated magnetic refrigeration material and EP160 was changed as shown in Table 1.
• Table 1 shows the results of the punching test and simple bending test of the magnetic refrigeration composite materials of each comparative example.
• the magnetic refrigeration composite materials of each example have superior strength and formability compared to the magnetic refrigeration composite materials of each comparative example.

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