KR20100007854A - Article for magnetic heat exchange and methods for manufacturing an article for magnetic heat exchange - Google Patents

Abstract

An article (1) for magnetic heat exchange extends in a first direction (3) and in a second direction (5) generally axially perpendicular to said first direction (3). The article (1) comprises at least one magnetocalorically active phase (2). The average thermal conductivity of the article (1) is anisotropic.

Description

ARTICLE FOR MAGNETIC HEAT EXCHANGE AND METHODS FOR MANUFACTURING AN ARTICLE FOR MAGNETIC HEAT EXCHANGE}

The present invention relates to a method for producing an article for magnetic heat exchange and an article for magnetic heat exchange.

The magnetocaloric effect accounts for the adiabatic conversion of the magnetic induced entropy change leading to the release or absorption of heat. Therefore, applying a magnetic field to the magnetocaloric material can induce a change in entropy leading to the release or absorption of heat. This magnetocaloric effect can be used to perform freezing and / or heating.

Recently developed materials such as La (Fe _1-a Si _a ) ₁₃ , Gd ₅ (Si, Ge) ₄ , Mn (As, Sb) and MnFe (P, As) are at or near room temperature Curie temperature (Tc) Has Curie temperature is interpreted as the operating temperature of a material in a magnetic heat exchange system. As a result, these materials are suitable for use in applications such as building climate control, household and industrial refrigerators and freezers, as well as automotive climate control.

Magnetic heat exchange technology has the advantage that magnetic heat exchangers are in principle more energy efficient than gas compression / expansion stroke systems. Magnetic heat exchangers are also environmentally friendly because they do not use ozone depleting chemicals such as CFCs.

As a result, a magnetic heat exchanger system has been developed to actually realize the advantages of the newly developed magnetocaloric material. Magnetic heat exchangers, such as those disclosed in US Pat. No. 6,676,772, typically include a pumped recirculation system and a chamber filled with particles of magnetic refrigerant agent that exhibit a magnetocaloric effect and heat exchange medium such as a fluid refrigerant and means for applying a magnetic field to the chamber. .

However, further improvements are needed to make the magnetic heat exchange technology more widely available.

It is an object of the present invention to provide an article for magnetic heat exchange which can be manufactured reliably and cost effectively. Another object is to provide a method of making the article.

These objects are solved by the subject matter of the independent claims. Another advantageous improvement is the subject matter of the dependent claims.

The present invention provides an article for magnetic heat exchange. The article extends in a first direction and in a second direction approximately axially perpendicular to the first direction and includes at least one phase that is magnetocalorically active (hereinafter referred to as the 'magnetocaloric active phase'). . According to the invention, the average thermal conductivity of the article is anisotropic.

The article can be used as a magnetic refrigerant or magnetically acting medium of a magnetic heat exchange system. The provision of an article with an anisotropic average thermal conductivity has the advantage that heat generated in the article due to the magnetocaloric effect can be transferred by anisotropic conduction to the article surface. Heat exchange between the article and the refrigerant surrounding the article may also be anisotropic.

The article may be arranged in a magnetic heat exchange system such that the most efficient heat transfer occurs in a direction perpendicular to the direction of the refrigerant stream and the most inefficient heat transfer occurs in the direction of the refrigerant stream. This arrangement allows for more efficient heat exchange. Heat generated in the article by the magnetocaloric effect can be efficiently conducted to the article surface in a direction perpendicular to the refrigerant flow, at which heat is transferred to the refrigerant and transferred from the article to the refrigerant flow direction by the refrigerant.

The lower the thermal conductivity of the article along the refrigerant flow direction, the more heat that was initially conducted from the article is prevented from being transferred back to the article in the opposite direction of the refrigerant stream. Overall, the cooling efficiency of the article for magnetic heat exchange is improved through the provision of an article having an anisotropic average thermal conductivity.

In the present specification, a magnetocalorically active material (hereinafter referred to as a 'magnetocaloric active material') is defined as a material that undergoes entropy change under a magnetic field. The entropy change may be the result of a change from ferromagnetic behavior to paramagnetic behavior, for example. The magnetocaloric active material may exhibit an inflection point at which the second derivative of the magnetization curve for the applied magnetic field changes only from positive to negative in some temperature range.

As used herein, a magnetocalorically passive material (hereinafter referred to as a 'magnet calorific floating material') is defined as a material in which entropy change is not significant under a magnetic field.

In one embodiment, the average thermal conductivity along the first direction of the article is lower than the average thermal conductivity along the second direction of the article. In operation, the article has the most efficient heat transfer with the first direction arranged substantially parallel to the refrigerant stream.

In one embodiment, the article has a first length extending in a first direction and a cross-sectional area extending in a second direction, wherein the cross-sectional area has a second length. The average thermal conductivity measured over the first length of the article is less than the average thermal conductivity measured over the second length of the article, ie in the plane of the cross-sectional area. In other words, in operation the first length of the article is arranged substantially parallel, and the second direction is generally perpendicular to the flow direction of the refrigerant.

Anisotropic average thermal conductivity of an article can be provided in a variety of ways. In some embodiments, the article also includes a magnetocalorically floating phase (hereinafter referred to as a 'magnetic calorific floating phase') having a thermal conductivity greater than that of the magnetocaloric active phase.

The anisotropic average thermal conductivity of the article can be provided by various arrangements of the magnetocaloric active phase and the magnetocaloric floating phase in the article. Thermal anisotropy is characterized by the arrangement of individual grains or particles or microscopic anisotropy, i.e., a magnetocaloric floating phase and / or a magnetocaloric active phase, or an arrangement of elements of which macromolecularity, i.e., a magnetocaloric active phase and a floating phase, is essential. It can be formed by macroscopic anisotropy resulting.

In one embodiment, the magnetocaloric floating phase has a plurality of grains having, on average, preferred orientation. Firstly orientation is used to describe the anisotropic arrangement and / or distribution of grains in the article. For example, individual grains may be generally spherical in shape, and therefore do not have orientation first. However, spherical grains may be arranged in a matrix of one row or more columns or a matrix of many columns and rows and thus have a preferential, ie physically anisotropic, arrangement within the article.

This anisotropic arrangement provides an article having an average anisotropic thermal conductivity when the magnetocaloric floating phases have different thermal conductivity, even when the magnetocaloric active phases are randomly arranged in the article. If the thermal conductivity of the magnetocaloric floating phase is greater than the thermal conductivity of the magnetocaloric active phase, the average thermal conductivity in the long direction along the rows of the grains of the magnetocaloric floating phase or in the matrix plane is determined by the magnetocaloric floating phase crystal grains. Is greater than the average thermal conductivity in the direction perpendicular to the longitudinal direction along the matrix plane or the rows of grains. As a result, the article has an anisotropic average thermal conductivity.

In one embodiment, the magnetocaloric floating phase has a plurality of elongated crystal grains each having a long direction and a short direction approximately perpendicular to the long direction.

In order to produce thermal anisotropy at the microscopic level, the grains of the magnetocaloric immobilized phase may be arranged in the article with preferential orientation and / or preferred texture.

Firstly orientation is used to describe the physical arrangement of grains in the article. Preferred tissue is used to describe grains arranged in an article to have a preferential crystal orientation on average. Thus, grains may have both preferential orientation and preferential tissue.

First, in the case of long grains arranged in tissue, the average thermal conductivity of the article along the long direction of the grains is higher than the average thermal conductivity of the article along the unidirectional direction of the grains.

A thermally anisotropic article may be provided by arranging a plurality of long grains in the article having a magnetocaloric floating phase such that on average the long direction of the grains extends substantially perpendicular to the first direction of the article. The plurality of elongated grains having a magnetocaloric floating phase can be arranged so that on average the unidirectional direction of the article extends substantially parallel to the first direction of the article. These arrangements provide articles having a high average thermal conductivity in a direction perpendicular to the first direction and low in a direction parallel to the first direction.

In operation, the article is arranged such that the long direction of the grains is oriented generally perpendicular to the refrigerant flow direction and the unidirectional direction of the grains is oriented generally parallel to the refrigerant stream. This arrangement prevents heat flow through the article in the direction opposite to the coolant flow.

In one embodiment, the magnetocaloric active phase has a plurality of grains arranged in an article with an average orientation first. In this case, firstly orientation is also used to indicate an anisotropic arrangement of the grains in the article.

In another embodiment, the magnetocaloric active phase has a plurality of grains arranged first in an article having a structure, and in another embodiment also having a orientation. In one embodiment, the magnetocaloric active phase has a plurality of long grains having a long direction and a short direction approximately perpendicular to the long direction. These grains may be fibrous or plate-like, for example.

To produce an article that is thermally anisotropic at the microscopic level, the grains of the magnetocaloric active phase can be arranged so that on average the longitudinal direction of the grains in the article extends in a direction approximately perpendicular to the first length of the article. The grains of the magnetocaloric active phase may be arranged such that on average the unidirectional direction of the article extends approximately parallel to the first length of the article.

This arrangement provides an article having a high average thermal conductivity in the direction of the article parallel to the long direction of the grains and low in the unidirectional direction of the grains.

In some embodiments, the magnetocaloric floating and active phases are arranged in a preferred orientation and / or preferential tissue in the article. The grains of the two phases may be tightly mixed to provide thermal anisotropy at the microscopic level.

In another embodiment, only the magnetocaloric active phase has preferential orientation and / or preferred tissue or elongated grains to provide an article with anisotropic average thermal conductivity. The article may first have a magnetocaloric floating phase without tissue. The magnetocaloric active phase may be distributed in the preferred orientation and / or preferential tissue among the grains of the magnetocaloric floating phase. As an alternative, the magnetocaloric active phase can be distributed free of preferential orientation and / or tissue among the grains of the magnetocaloric floating phase having preferential orientation and / or preferential tissue. The magnetocaloric floating phase can provide a matrix in which grains of the magnetocaloric active phase are arranged. The article can be described as a composite.

Articles for magnetic heat exchange can have anisotropic average thermal conductivity through an array of materials having different thermal conductivity at the macroscopic level. In one embodiment, the article includes a plurality of first layers having an essential configuration of a magnetocaloric active layer interposed with a plurality of second layers that basically include a magnetocaloric floating phase.

In one embodiment, the article includes only the magnetocaloric active phase and substantially no magnetocaloric floating phase. In this respect, phase is used to refer to solids and exclude gases and air. Substantially free is defined as less than 10% by volume.

In this embodiment, the average anisotropic thermal conductivity is achieved by the anisotropic distribution of the article density. In particular, the density of the article varies macroscopically. This is an at least one first layer having a magnetocaloric active phase as an essential configuration and having at least one first layer having a first density and a magnetocaloric active phase having a second density less than the first density, according to one embodiment. Provided by a second layer.

The relatively high density first layer has a higher thermal conductivity than the low density second layer. Thus, the average thermal conductivity of the article along the direction perpendicular to the plane of the layer is less than the average thermal conductivity in the direction parallel to the plane of the layer. Thus, the article has an anisotropic average thermal conductivity.

The density of at least one first layer and at least one second layer can be adjusted to a desired average value by adjusting the porosity of each layer. At least one first layer may have a first average porosity and at least one second layer may have a second average porosity, and the second average porosity is greater than the first average porosity. This provides an article having a first layer that is denser than the second layer and anisotropic average thermal conductivity.

In another embodiment, at least one first layer and at least one second layer are arranged in a stack in which adjacent layers are in physical contact with each other. Adjacent layers may be directly connected to one another, for example by means of an adhesive layer or directly by sintering the material of the adjacent layers.

The first and second layers have a thickness extending substantially parallel to the first direction of the article and a cross-sectional area extending substantially in the second direction of the article. Each layer consists of a plurality of layers of grains or particles in each phase.

In operation, the article is arranged such that the lateral region of the plane of the layer extends approximately perpendicular to the refrigerant flow direction and the thickness of the layer extends approximately parallel to the refrigerant flow direction. The thermal conductivity of the magnetocaloric floating phase is preferably such that the magnetocaloric activity in the articles of the arrangement is such that the average thermal conductivity of the article along the refrigerant flow direction is less than the average thermal conductivity of the article along the direction perpendicular to the refrigerant flow direction. It is larger than the thermal conductivity of the phase.

In another embodiment, the article includes a plurality of active layers, each active layer comprising a magnetocaloric active material having a Tc different from the Tc of the magnetocaloric active material of the adjacent layer. In another embodiment, the magnetocaloric active material of each layer is selected with the order in which the materials are arranged so that the Tc gradually increases from one end of the article to the other end.

The use of articles having a plurality of magnetocaloric active materials with different Tc has the advantage that the operating range of the heat exchanger in which the articles are used is increased. The Curie temperature Tc is interpreted as the operating temperature, and since the range of Tc is provided, the operating range of the heat exchanger is increased. This allows the heat exchanger to perform cooling and / or heating over a wide operating temperature range and to cooling and / or to the lowest / highest temperatures lower / higher than possible when using magnetocaloric active materials having a single Tc from the starting temperature. Allow heating to take place.

In another embodiment, the article further comprises at least one heat barrier having a thermal conductivity less than that of the magnetocaloric active phase.

The heat barrier prevents heat transfer from the article region on one side of the thermal barrier to the article region on the other side. The heat barrier may be arranged so that heat transfer in the refrigerant flow direction is hindered to further improve the efficiency of the magnetic heat exchange.

In another embodiment, the article includes a plurality of thermal barriers arranged at intervals along the first direction of the article. If a plurality of parts with different Tc are provided, the heat barrier may be arranged between adjacent parts.

The magnetocaloric active phase is Gd, La (Fe _1-b Si _b ) ₁₃ phase, Gd ₅ (Si, Ge) ₄ phase, Mn (As, Sb) phase, MnFe (P, As) phase, Tb- One or more of a Gd based phase, a (La, Ca, Pr, Nd, Sr) MnO ₃ based phase, a Co-Mn- (Si, Ge) -based phase and a Pr ₂ (Fe, Co) ₁₇ based phase. These base compositions may further comprise additional chemical components which may partially or wholly replace these listed components. These phases may also comprise components which are at least partially entrained in the crystal structure, for example hydrogen. These phases may also comprise trace components such as impurity components and oxygen.

In another embodiment, the grains of the magnetocaloric active phase comprise an anticorrosive coating. This anticorrosive coating may comprise one or more metals, alloys, polymers, ceramics or inorganic components. The metal may be Al, Cu, or Sn, and the alloy may include one or more of Al, Cu, and Sn. Inorganic anticorrosive coatings may be provided by phosphates such as zinc phosphate. The anticorrosive coating can extend the operating life of the magnetocaloric active phase upon application, which at least slows or even the operation of the magnetocaloric active material by corrosion protection of the magnetocaloric active material to the non-magnetic caloric active phase by anticorrosive coating. This is because they are completely prevented over their lifetime.

The article also has effective pores. Effective porosity is used herein to describe the porosity of an article that has a significant effect on magnetic heat exchange.

The effective pores include at least one channel extending from the first side to the second side of the article in the body of the article. Porosity can range from 10% to 60% by volume.

The effective pores may be provided in the form of a series of interconnecting channels in communication with each other to form a hollow network of skeletal structure within the body of the article. The heat exchange fluid or refrigerant may flow from one side to the other side of the article through its hollow network.

Effective pores may be formed by compacting or weak powder compaction followed by sintering to form compacts having a density of less than 100% in each case so that the unoccupied portion provides an interconnected hollow network through which the heat exchange medium can flow. have.

The articles of these embodiments have the advantage that the surface area of the articles is increased. The coolant is in contact with the entire outer surface of the article as well as the inner surface that provides pores located within the body of the article, ie the surface of the channel. Thus, the contact area between the article and the heat exchange fluid is increased. As a result, the efficiency of the magnetic heat exchange can be further improved.

The article may further comprise at least one channel. The channel may be provided in the form of a through-hole enclosed by the article or in the form of a channel on the outer surface of the article. One or more channels have the advantage of increasing the surface area of the article, which can further improve the heat exchange efficiency between the article and the refrigerant. The channel can be formed, for example, by extrusion or profile rolling.

In another embodiment, the channel is configured to advance the flow of the refrigerant. The position of the channel is determined by the design of the heat exchange system in which the article is to operate. The channel may be configured to reduce or optionally minimize the flow of the refrigerant to increase the heat exchange efficiency.

The article may be a component of a heat exchanger, a cooling system, a building or vehicle, in particular an automotive air conditioner, or a climate control device for a building or a differential vehicle. The climate control device can be used as a heater in winter and as a cooler in summer by reversing the direction of the fluid refrigerant or heat exchanger medium. This is particularly advantageous for automobiles or other vehicles, since the useful space in the body which houses the climate control device is limited depending on the design of the vehicle.

The article may also include an outer protective coating. The outer protective coating can be made of metal, alloy or polymer. The material of the outer protective coating can be selected to be mechanically and chemically stable in the heat exchange medium during the operational life of the article. Once the coating is applied to the final finished article, it does not become hot, for example, during sintering or during operation of the article. In this case, a polymer having a relatively low decomposition temperature or a melting temperature can be used.

The heat exchange medium may comprise ethanol or glycol, water, a mixture of ethanol or glycol, or other materials of high thermal conductivity to improve the heat exchange efficiency between the article and the heat exchange medium. The heat exchange medium may be corrosive to the magnetocaloric active material and / or magnetocaloric antifreeze material of the matrix. Thus, an additional outer protective coating can be applied for additional protection.

The article according to one of the embodiments may be used as a component of a heat exchanger, a cooling system, a climate control device, an air conditioner, or a refrigerator of industrial, commercial or domestic use. The article is arranged such that in operation its first direction is approximately parallel to the direction of the heat flow.

The present invention also provides a method for producing an article for magnetic heat exchange. In one embodiment, a magnetocaloric active phase is provided and a magnetocaloric floating phase consisting of a plurality of particles is provided. The magnetocaloric active phase and magnetocaloric floating phase are coalesced and compacted to form an article. On average the preferred orientation of the at least a plurality of crystal grains, ie the physical arrangement, is produced in the magnetocaloric floating phase.

In one embodiment, a precursor of a magnetocaloric floating phase consisting of a magnetocaloric active phase and a plurality of particles is provided. The precursors of the magnetocaloric active phase and the magnetocaloric floating phase are coalesced and compacted to form an article. Preferred orientation of the plurality of crystal grains of the magnetocaloric floating phase is generated. In this embodiment, the article forms a magnetocaloric active phase from the precursor by reactive sintering.

The article has anisotropic thermal conductivity due to the preferential orientation of the magnetocaloric floating phase because the thermal conductivity of the plurality of crystal grains of the magnetocaloric floating phase is higher along the long direction than the unidirectional direction of the crystal grains. As mentioned above, the grains may, on average, also have crystal orientation of the preferential tissue.

The orientation can first be formed at least in part by a compression process or in a separate method step which can be carried out partially or entirely before or after the compression.

In one embodiment, the compaction is performed to induce orientation first in grains of at least the magnetocaloric floating phase and / or at least grains of the magnetocaloric active phase.

In one embodiment, the average preferred orientation of the at least a plurality of grains of the magnetocaloric floating phase is formed at least in part by application of a magnetic field. This method can be used when the magnetocaloric floating phase is ferromagnetic, for example made of Fe or FeSi.

The magnetic field can be applied to provide preferential orientation to the particles of the magnetocaloric active phase when the magnetocaloric active phase is in a ferromagnetic state. If the magnetocaloric active phase is ferromagnetic at a temperature below its Curie temperature, the magnetic field can be applied at a temperature lower than the Curie temperature of the magnetocaloric active phase for self-alignment of the particles.

The magnetic field may be applied prior to the compression operation to provide preferential orientation to the particles of the magnetocaloric floating phase and / or magnetocaloric active phase. The orientation is first maintained in the article being compressed and the article being compressed.

Compression may be performed to induce tissue first, at least in the magnetocaloric floating phase. When the particles of the magnetocaloric floating phase have dimensions of anisotropy, the pressing may be performed by arranging the pressing directions approximately perpendicular to the long direction of the grains, or in the case of plate-shaped grains, approximately perpendicular to the planar region. First, the degree of orientation can be provided by rocking the powder in a direction perpendicular to the pressing direction prior to the pressing operation. This encourages the plate grains to take a layered structure prior to compression.

Compression is performed such that the grains of the magnetocaloric floating phase are oriented on average so that their long direction is perpendicular to the first direction of the article. This provides an article having a high average thermal conductivity in a direction perpendicular to the first direction and a low average thermal conductivity in the first direction.

In one embodiment, the average preferential orientation of the at least a plurality of crystal grains of the magnetocaloric floating phase and / or magnetocaloric active phase is formed at least in part by mechanical deformation of the article after compression. The mechanical deformation can be done by one or more of rolling, swaging, drawing or extrusion.

In one embodiment, the magnetocaloric active phase and magnetocaloric floating phase are combined by intimately mixing them with each other. This method forms an anisotropic thermally conductive article formed on a microscopic scale.

In another embodiment, the magnetocaloric active phase and the magnetocaloric floating phase are combined by cross-aligning the layers of the magnetocaloric active phase with the layers of the magnetocaloric active phase as the essential configuration. This method forms an article of anisotropic average thermal conductivity on a macro scale.

In one embodiment, one or more of a lubricant, an organic binder and a dispersant may be further added to the combined magnetocaloric active phase and magnetocaloric floating phase. These additives can help increase the density of the article.

The coalesced magnetocaloric active phase and magnetocaloric floating phase can be compressed by one or more of rolling and pressing. Rolling can be used to form long shaped articles that follow the length of the article and whose thermal conductivity along the width is greater than that of the article. Such articles may be arranged in layered laminates. Pressing can be used to form an article whose thermal conductivity is greater along the width than the length of the article because the long direction of the magnetocaloric floating phase is oriented generally perpendicular to the length of the article.

In another embodiment, the article is heated during compression. Heat treatment may be used to sinter the grains together as well as further press the article. When using the precursor, the heat treatment is performed under conditions selected such that the magnetocaloric active phase is formed from the precursor.

The heat treatment during compression may also be applied to further enhance the degree of grain organization due to grain growth as well as grain growth along the preferred direction of the grains, advantageously the long direction of the grains.

In another embodiment, a magnetic field is applied during compression to magnetically orient the grains of the magnetocaloric floating and / or active phase on average so that its long direction is oriented approximately perpendicular to the first direction of the article. At the same time, heating can also be done. The method can be used when the magnetocaloric floating phase consists of a soft magnetic material such as Fe or FeSi, or the magnetocaloric active phase is already formed and ferromagnetic during the pressing process.

Also provided is a method of making an article in which there is no magnetocaloric floating phase and has anisotropic average thermal conductivity. In this method, at least one first plate having the magnetocaloric active phase as an essential configuration and having a first density and at least one second plate having the magnetocaloric active phase as an essential configuration and having a second density is provided. The first density of the first plate is greater than the second density of the second plate. The first and second plates are stacked to provide an article for magnetic heat exchange.

The first and second plates have different average thermal conductivity due to their different densities. High density provides high average thermal conductivity. Therefore, the average thermal conductivity in the stacking direction, that is, the direction perpendicular to the plate plane, is smaller than the average thermal conductivity of the plate plane.

In one embodiment, the first and second plates are arranged to be in physical contact with each other.

In another embodiment, the first plate has a first pore and the second plate has a second pore, wherein the second pore is larger than the first pore. This provides a first plate of greater density than the second plate.

The first plate and / or the second plate may be formed by pressing particles of a precursor of the magnetocaloric active phase or the magnetocaloric active phase.

Compression conditions are adjusted to form lower porosity in the first plate than in the second plate. For example, the compression pressure and, if applied, the temperature can be elevated through elevated pressure to lower porosity and increase plate density. In contrast, the pressing pressure and, if applied, the temperature can increase the porosity and lower the density of the plate through reduced pressure reduction.

In another embodiment, a plurality of first plates and a plurality of second plates are provided. The plurality of first plates and the plurality of second plates are interposed with each other in the stacking direction of the article. The article thus produced has a multilayer or layered structure.

An outer protective coating may be applied to the article after compression of the article or after completion of the manufacture of the article. The outer protective coating can be applied by dipping, spraying or electrolytic deposition.

1 is a side view of an article for magnetic heat exchange.

2 is a cross-sectional view of the article of FIG. 1.

3 is a cross-sectional view of an article for magnetic heat exchange having a fine structure according to the first embodiment.

4 is a cross-sectional view of an article for magnetic heat exchange having a microstructure according to a second embodiment.

Fig. 5 is a sectional view of an article for magnetic heat exchange having a fine structure according to the third embodiment.

6 is a cross-sectional view of an article for magnetic heat exchange having a fine structure according to a fourth embodiment.

Fig. 7 is a sectional view of an article for magnetic heat exchange having a fine structure according to the fifth embodiment.

* Explanation of Drawings *

1: Item for magnetic heat exchange 2: Magnetocaloric active phase

3: refrigerant flow direction 4: channel

5: second direction 6: outer surface of article

7: cold end of article 8: hot end of article

9: first active part 10: second active part

11: third active part 12: heat barrier

13: magnetocaloric floating phase 14: crystal grains of magnetocaloric floating phase

15: Long direction of grains 16: Unidirectional of grains

17: Grain of magnetocaloric active phase 18: Layer of magnetocaloric active phase

19: layer of magnetocaloric floating phase 20: outer protective coating

21: grains of the magnetocaloric active phase 22: long direction of the grains

23: Unidirectional of grains 24: Chain

25: first layer 26: second layer

27: pore 28: lamination direction

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a side view of the article 1 for magnetic heat exchange, and the article has a magnetocaloric value having a La (Fe _1-ab Co _a Si _b ) ₁₃ phase phase having a Curie temperature Tc of 20 ° C. in this embodiment. Active phase (2). The article 1 provides a magnetic refrigerant operating component of an unillustrated magnetic heat exchange system further comprising a pumped recirculation system, a heat exchange medium such as a fluid refrigerant and means for applying a magnetic field to the chamber.

The article 1 has a first length l and a second length b extending approximately perpendicular to the first length l. The direction of the coolant flow is indicated by arrow 3 in FIG. Depending on whether the heat exchange system is used for recooling or heating, the refrigerant may flow in opposite directions. In operation, the first length l of the article 1 is arranged to extend in the refrigerant flow direction 3, and the second length b is arranged to extend approximately perpendicular to the refrigerant flow direction 3. In the drawing shown in Fig. 1, the refrigerant direction is from the top to the bottom side. The article 1 also has a plurality of channels 4 extending on the outer surface in the refrigerant flow direction 3 and increasing the surface area of the article 1 to improve the efficiency of heat transfer from the article 1 to the refrigerant. Equipped.

According to the invention, the article 1 has an anisotropic average thermal conductivity. In particular, the average thermal conductivity of the article along the refrigerant flow direction 3 is determined by the direction along the direction perpendicular to the cooling stream 3 indicated by the arrow 5 in which the second length b of the article 1 extends ( It is smaller than the average thermal conductivity of 1).

This arrangement allows the magnetic induction heat generated by the magnetocaloric active phase 2 in the article 1 to be efficiently conducted to the outer surface of the article 1 in the direction of the arrow 5 and from there to the refrigerant. The magnetic induction heat in (1) is prevented from conducting in the direction opposite to the refrigerant flow direction (3). This is a kind of internal phenomenon in which heat transferred from the cold end 7 to the hot end 8 by the refrigerant is reversed back to the cold end 7 only by the article 1 itself. Prevents short circuits from occurring in the article 1.

2 is a cross-sectional view of the article 1 of FIG. The cross-sectional view of FIG. 2 shows that the article 1 has a layered structure and includes three active portions 9, 10, 11 each comprising a magnetocaloric active phase 2. Each of the three active portions 9, 10, 11 includes a magnetocaloric active phase having a different Tc, and the Tc of each active portion rises in the refrigerant flow direction 3. Each active portion 9, 10, 11 is separated from its adjacent portion by a heat barrier 12, which further prevents thermal conduction between adjacent portions 9, 10, 11 of the article 1. .

Each active portion 9, 10, 11 further includes a magnetocaloric floating phase 13 having a thermal conductivity greater than that of the magnetocaloric active phase 2. The anisotropic average thermal conductivity of the article 1 is provided by arranging the crystal grains 14 of the magnetocaloric floating phase 13 in a layered manner. The layered arrangement may be provided microscopically as shown in FIGS. 3 and 5 or macroscopically as shown in FIGS. 2 and 4. Arrangements comprising a combination of microscopic and macroscopic hierarchies can also be used.

In the embodiment shown in Fig. 3, the magnetocaloric floating phase 13 comprises a plurality of grains 14 which are generally in the form of plates. The plate crystal grains 14 have a longitudinal direction 15 and a unidirectional 16 arranged approximately perpendicular to the longitudinal direction 15. The plate-shaped grains 14 are on average such that their longitudinal direction 15 extends in a direction parallel to the second length b of the article 1 and in a direction substantially perpendicular to the refrigerant flow direction 3. Arranged within. The unidirectional direction of the crystal grains 14 averagely extends parallel to the first length 1 of the article 1 and parallel to the refrigerant flow direction 3.

The plurality of crystal grains 14 of the magnetocaloric floating phase 13 are arranged in the article such that these grains have preferential orientation and / or preferential texture. Firstly orientation is used to indicate the physical arrangement of grains and firstly tissue is used to indicate the crystal orientation of the grains. Due to this preferential orientation and / or preferential structure, the average thermal conductivity of the article 1 along the direction perpendicular to the refrigerant flow direction 3 is greater than the average thermal conductivity of the article 1 along the refrigerant flow direction 3. Big.

The crystal grains 17 of the magnetocaloric active phase 2 are generally isotropic in comparison with the crystal grains 14 of the magnetocaloric floating phase 13 in the present embodiment. The crystal grains 17 of the magnetocaloric active phase 2 are distributed between the crystal grains 14 of the magnetocaloric floating phase 13. The magnetocaloric floating phase 13 provides a matrix of the article 1 and can act as a binder of the crystal grains 17 of the magnetocaloric active phase 2. The embodiment shown in FIG. 3 provides an article 1 having anisotropic mean thermal conductivity due to the distribution of grains 14 of the microscale magnetocaloric floating phase 13.

In the second embodiment shown in Fig. 4, the crystal grains 14 of the magnetocaloric floating phase 13 also have a generally plate shape. The crystal grains 14 are firstly oriented so that their long direction 15 extends in a direction substantially parallel to the second length b of the article 1 and in a direction substantially perpendicular to the refrigerant flow direction 3. 1) arranged in.

In the second embodiment of FIG. 4, as in the embodiment of FIG. 2, the anisotropic thermal conductivity of the article 1 is characterized by the magnetocaloric floating phase 13 in the layer 18, which essentially consists of the magnetocaloric active phase 2. Is provided by a layered structure interposed therebetween. In the embodiment shown in FIG. 4, the anisotropic average thermal conductivity of the article 1 is provided macroscopically.

4 shows a single layer of magnetocaloric floating phase 13 interposed between two layers of magnetocaloric active phases 2, however, the number of layers may be provided arbitrarily. The stacking arrangement of layers 18, 19 consists in the direction of the first length l of the article 1.

The magnetocaloric floating phase 13 may be metal and in some embodiments is magnetic. The magnetic magnetocaloric floating phase 13 has the advantage that the crystal grains 14 can be magnetically aligned to firstly form an orientation.

The article 1 may comprise an outer coating 20 to protect the article 1, in particular the magnetocaloric active phase 2, from corrosion by the environment and in particular by refrigerant.

The article 1 of FIG. 3 can be made by intimately mixing the powder of the magnetocaloric active phase 2 and the magnetocaloric floating phase 13 and pressing the mixture. The preferential orientation of the grains 14 of the magnetocaloric floating phase 13 can be at least partially formed by anchoring the powder in a mold into which the powder mixture is pressed. The preferential orientation of the grains 14 can also be induced by the compaction process. Since the direction of the pressure applied during the pressing process is substantially perpendicular to the longitudinal direction 16 of the plate-shaped grains 14, the plate-shaped grains 14 are encouraged so that their longitudinal direction is perpendicular to the direction of the pressing. In addition, the plate crystal grains 14 may be slid relative to each other to first double the degree of orientation.

First, the degree of orientation can be doubled by heating during the pressing process. Such heating can promote sintering of the grains, which can further double the anisotropy and preferential orientation of the plate crystal grains when given the growth direction first.

The preferred orientation of the grains may be formed at least in part by an alignment process performed before or after compaction. First of all, the orientation may be substantially obtained separately from the pressing process.

In another embodiment, the magnetocaloric floating phase can be provided by a magnetic field applied in the magnetic material and article 1 to induce preferential orientation in the desired direction. The magnetic field may be applied before and / or during compression. In addition, the heat treatment can be performed simultaneously with the application of the magnetic field.

The article 1 can also be produced by reactive sintering. In this embodiment, a precursor of the magnetocaloric active phase is provided. The precursor consists entirely of non-magnetic caloric active phases and forms a magnetocaloric active phase when they react with each other. The precursor can be tightly mixed with the magnetocaloric floating phase to form an article with anisotropic thermal conductivity at the microscopic scale. The precursors of the magnetocaloric active phase may be provided as individual layers or multilayers in an array of macroscopic layered structures similar to those shown in FIG. 4. After or during compression, the article is heated to reactive sinter the precursor to form a magnetocaloric active phase.

Preferred orientation of the magnetocaloric floating phase can also be obtained by other known methods. For example, the magnetocaloric floating phase can be rolled or provided as a thin layer with preferential orientation.

If an outer coating is provided, the coating may be applied to the article after pressing and predetermined heat treatment. The coating can be applied by dipping, spraying or electroplating.

In another embodiment shown in FIG. 5, the magnetocaloric active phase 2 also comprises an elongated crystal grain 21. For example, the crystal grains 21 of the magnetocaloric active phase 2 are displayed in black, and the crystal grains 14 of the magnetocaloric floating phase 13 are displayed in white. In this embodiment, the magnetocaloric active phase 2 extends in the longitudinal direction 22 of the crystal grains 21 substantially perpendicular to the refrigerant flow direction 3, and the unidirectional 23 of the crystal grains 21 forms the refrigerant flow 3. It may also be arranged in the article 1 to have a preferential orientation extending in the) direction.

Figure 6 shows an article 1 used as an operating component of a magnetic heat exchange system according to the fourth embodiment.

The article 1 of the fourth embodiment includes a plurality of crystal grains 17 of the magnetocaloric active phase 2 and a plurality of crystal grains 14 of the magnetocaloric floating phase 14. On average, each grain 17 has a generally isotropic shape. In this embodiment, the article 1 has anisotropic thermal conductivity due to the preferential orientation of the isotropic shaped crystal grains 14 of the magnetocaloric floating phase 13.

The crystal grains 14 of the substantially spherical magnetocaloric floating phase 13 are made of ferromagnetic material, and in this embodiment, iron. The crystal grains 14 are arranged in a plurality of rows or chains 24 having a long direction that is substantially parallel to the second direction 5 of the article 1 and extends perpendicular to the refrigerant flow direction 3. The chains 24 are arranged in a series of layers superimposed and arranged in a stacking direction 28 parallel to the refrigerant flow direction 3. The crystal grains 17 of the magnetocaloric active phase 2 are arranged between the chains 24 of the magnetocaloric floating phase 13 and have some degree of preferential orientation. The preferred orientation of the magnetocaloric active phase 2 is produced by first forming the orientation in the magnetocaloric floating phase 13 in advance.

The thermal conductivity of the magnetocaloric floating phase 13 is greater than that of the magnetocaloric active phase 2. Therefore, the article 1 has an anisotropic thermal conductivity on average, and in particular, the thermal conductivity of the article 1 is larger in the second direction 5 than in the refrigerant flow direction 3.

The article 1 of the fourth embodiment shown in FIG. 6 is produced by intimate mixing of particles of the magnetocaloric active phase 2 and particles of the magnetocaloric floating phase 13 and placing the mixture in a compression vessel such as a die. . When the magnetic field is applied in the second direction, the plurality of chains 24 are formed by self-aligning the ferromagnetic particles of the magnetocaloric floating phase 13 in the direction of the applied magnetic field.

The preferential orientation of the crystal grains 17 of the magnetocaloric active phase 2 preforms an ordered chain 24 consisting of particles of the magnetocaloric floating phase 13, thereby causing the magnetocaloric active phase ( This is caused by the limited movement of the particles in 2).

In another embodiment, the magnetocaloric active phase 2 is ferromagnetic at a temperature below its Curie temperature. Therefore, when a magnetic field is applied to the powder mixture at a temperature below the Curie temperature of the magnetocaloric active phase 2, the preferred orientation of the particles of the magnetocaloric active phase 2 along the direction of the applied magnetic field can be obtained.

Fig. 7 shows an article 1 'used as an operating component of a magnetic heat exchange system according to the fifth embodiment.

The article 1 ′ of the fifth embodiment has at least one magnetocaloric active phase 2 as an essential construction. The article 1 ′ of the fifth embodiment does not include a magnetocaloric floating phase. In this embodiment the article 1 'has anisotropic average thermal conductivity due to the anisotropic distribution of the density of the article 1' and in particular the anisotropic distribution of the pores of the article 1 '.

The article 1 ′ of the fifth embodiment comprises a plurality of layers, in which five layers are shown. Three first layers 25 have a low porosity, and two second layers 26 arranged between adjacent first layers 25 have a higher porosity than the first layer 25. In Fig. 7, the pores 27 are indicated by black regions.

The pores have a lower thermal conductivity than the magnetocaloric active phase 2. Thus, the second layer 26 has a lower average thermal conductivity than the first layer 25. This provides an article 1 ′ having an average thermal conductivity measured from end to end of the article 1 ′ along the refrigerant flow direction 3, which average thermal conductivity is measured along the second direction 5. 1 ') is smaller than the average thermal conductivity measured from side to side.

The article 1 'of the multilayer or layered structure of the fifth embodiment can be produced by laminating together a plurality of layers of different densities or porosities. In particular, the low-density layer 26 is interposed in the high-density layer 25. Layers 25 and 26 are stacked superimposed on one another in the stacking direction 28 such that each layer is in close physical contact. Layers 25 and 26 may be adhered to the adjacent layer with an adhesive.

The article 1 ′ of the fifth embodiment may be manufactured by primary manufacturing a plurality of first layers 25 of plate or foil shape of a first density. A plurality of second layers 26 of plate or foil shape of a second density less than the first density may be produced.

The first plate layer 25 and the second plate layer 26 are alternately stacked on top of each other such that each layer 25, 26 is bonded to its underlying layer to produce the article 1 ′.

Plate or foil layers 25 and 26 can be prepared by pressing particles of the magnetocaloric active phase 2 '. The density of the plate or foil can be adjusted by adjusting the compression conditions. For example, pressing pressure and heat treatment can be used to increase the heat treatment temperature and time to induce high density in the plate or foil.

The article 1 ′ of the fifth embodiment may further comprise an anticorrosion coating, an outer coating, a heat barrier layer covering the grains of the magnetocaloric active phase as described in connection with the previous embodiment.

Claims (64)

In an article (1) for a magnetic heat exchanger (1) comprising at least one magnetocaloric active phase (2) extending in a first direction (3) and in a second direction (5) approximately perpendicular to the first direction (3), The article (1) for magnetic heat exchange, characterized in that the average thermal conductivity of the article (1) is anisotropic. 2. The magnetic heat exchange of claim 1, wherein the average thermal conductivity in the first direction 3 of the article 1 is lower than the average thermal conductivity in the second direction 5 of the article 1. Article (1). 3. The article according to claim 1, wherein the article 1 has a first length extending in the first direction 3 and a cross-sectional area extending in the second direction 5, wherein the cross-sectional area is a second length. And wherein the average thermal conductivity measured over the first length of the article is less than the average thermal conductivity measured over the second length of the article. The article for magnetic heat exchange according to one of the preceding claims, wherein the article (1) further comprises a magnetocaloric floating phase (13) having a thermal conductivity greater than that of the magnetocaloric active phase (2). (One). 5. An article (1) according to claim 4, characterized in that the magnetocaloric floating phase (13) comprises a plurality of crystal grains (14) having, on average, preferential orientation. The elongated shape according to claim 4 or 5, wherein the plurality of crystal grains 14 of the magnetocaloric floating phase 13 have a longitudinal direction 15 and a unidirectional 16 substantially perpendicular to the longitudinal direction 15. Magnetic heat exchange article (1) characterized in that. The article (1) according to one of claims 4 to 6, characterized in that the grains (14) of the magnetocaloric floating phase (13) are first arranged in tissue in the article (1). 8. The article 1 according to claim 4, wherein the plurality of crystal grains 14 of the magnetocaloric floating phase 13 have an average length thereof 15 in the article 1. An article (1), characterized in that it is arranged to extend substantially perpendicular to the first direction (3) of the. 9. The plurality of crystal grains (14) of the magnetocaloric floating phase (13) has an average unidirectional direction (16) of the article (1) in the article (1). An article for magnetic heat exchange, characterized in that it is arranged to extend approximately parallel to the first direction (3). The article for magnetic heat exchange according to one of the preceding claims, characterized in that the magnetocaloric active phase (2) comprises a plurality of crystal grains (17) which are arranged with average orientation in the article (1) on average. One). The article (1) according to claim 10, characterized in that the plurality of crystal grains (17) of the magnetocaloric active phase (2) have a preferential texture on average. 12. The magnetocaloric active phase (2) according to claim 10 or 11, wherein the magnetocaloric active phase (2) comprises a plurality of elongated crystal grains (21) having a long direction (22) and a short direction (23) substantially perpendicular to the long direction (22). Magnetic heat exchange article (1) comprising a. 13. The article according to one of claims 10 to 12, wherein the grains 21 of the magnetocaloric active phase 2 have an average length 22 of the grains 21 in the article 1 on average. An article for magnetic heat exchange, characterized in that it is arranged to extend in a direction substantially perpendicular to the first length (3) of (1). 14. The article of claim 10, wherein the grains 21 of the magnetocaloric active phase 2 are unidirectional 23 of the grains 21 on average in the article 1. An article (1) for magnetic heat exchange, characterized in that it is arranged to extend substantially parallel to the first length of (1). 15. The article (1) according to one of claims 10 to 14, characterized in that the grains (17) of the magnetocaloric active phase (2) further comprise an anticorrosive coating. 16. The article (1) according to claim 15, wherein the anticorrosive coating comprises a metal, an alloy, a polymer, a ceramic or an inorganic compound. 16. The article (1) according to claim 15, wherein the anticorrosive coating comprises Al, Cu, Sn or phosphate. The article (1) according to one of the preceding claims, wherein the article (1) is interposed therebetween with a plurality of second layers (19) having the magnetocaloric floating phase (13) as an essential component and the magnetocaloric active phase (2) as essential. An article (1) for magnetic heat exchange comprising a plurality of first layers (18) in a configuration. 19. The article (1) according to any one of claims 1 to 3 or 10 to 18, wherein the article (1) has at least one first of which the magnetocaloric active phase (2) is of essential construction and has a first density. At least one second layer 26 having a layer 25 and the magnetocaloric active phase 2 as essential components and having a second density, wherein the first density is greater than the second density. Magnetic heat exchange article (1). 20. The method of claim 19, wherein the at least one first layer 25 has a first average porosity and the at least one second layer 26 has a second average porosity, wherein the second average porosity is An article for magnetic heat exchange, characterized in that greater than said first average porosity. 21. The method according to any one of claims 18 to 20, wherein the at least one first layer 25 and the at least one second layer 26 are arranged in a stack and adjacent layers of the layers are in physical contact with each other. Magnetic heat exchange article (1) characterized in that. 22. The method of claim 18, wherein the first layers 18, 25 and the second layers 19, 26 extend approximately parallel to the first direction 3 of the article 1. An article for magnetic heat exchange, characterized in that it has a thickness that is approximately and a cross-sectional area extending in a second direction (5) of said article (1). The article (1) according to one of the preceding claims, wherein the article (1) comprises at least two active parts (9, 10, 11) arranged along the first direction (3), and the active parts (9, 10, 11). ) Each of which comprises a magnetocaloric active phase (2) having a different Curie temperature (Tc). The article (1) according to claim 23, characterized in that the Tc of the active part (9, 10, 11) increases in the first direction of the article (1). The magnetic heat exchanger of claim 1, wherein the article 1 further comprises at least one heat barrier 12 having a thermal conductivity less than that of the magnetocaloric active phase 2. Article (1). 26. The article according to claim 25, characterized in that the article (1) comprises a plurality of heat barriers (12) arranged at intervals along the first direction (3) of the article (1). One). 27. The article (1) according to claim 25 or 26, characterized in that the heat barrier (12) is arranged between adjacent active parts (9, 10, 11). The magnetocaloric active phase (2) according to any one of the preceding claims is a Gd, La (Fe _1-b Si _b ) ₁₃ phase, a Gd ₅ (Si, Ge) ₄ phase, a Mn (As, Sb) system Phase, MnFe (P, As) based phase, Tb-Gd based phase, (La, Ca, Pr, Nd, Sr) MnO ₃ based phase, Co-Mn- (Si, Ge) based phase and Pr ₂ (Fe, Co) Articles for magnetic heat exchange, characterized in that at least one of the ₁₇ system phases. The article (1) according to one of the preceding claims, characterized in that the magnetocaloric floating phase (13) comprises at least one element of Al, Cu, Ti, Mg, Zn, Sn, Bi and Pb. . The article (1) according to one of the preceding claims, characterized in that the magnetocaloric floating phase (13) comprises a soft magnetic material. 31. The article (1) according to claim 30, wherein the soft magnetic material comprises at least one of Fe, FeSi, Co, Ni. The article (1) according to one of the preceding claims, characterized in that the article (1) further comprises at least one channel (4) on the surface (6). 33. The article (1) according to claim 32, wherein the channel (4) is configured to advance the flow of the heat exchange medium. The article (1) according to one of the preceding claims, further comprising an outer protective coating (20). 35. The article according to claim 34, wherein the outer protective coating (20) comprises a polymer, a metal or an alloy. Use of an article (1) according to any of the preceding claims for use as a component of a heat exchanger, cooling system, climate control, air conditioner, or industrial, commercial or domestic refrigerator. As a component of a heat exchanger, a cooling system, a climate control device, an air conditioner, or an industrial, commercial or household refrigerator, the article 1 has a heat flow direction during which the first direction 3 of the article 1 is in operation. Use of an article (1) according to any one of the preceding claims, arranged substantially parallel to. Heat exchanger system comprising an article (1) according to one of the preceding claims. Providing a magnetocaloric active phase (2) or a precursor of a magnetocaloric active phase, Providing a magnetocaloric floating phase 13 comprising a plurality of crystal grains 14, Incorporating the magnetocaloric active phase (2) or the precursor of the magnetocaloric active phase and the magnetocaloric floating phase (13), Pressing the magnetocaloric active phase (2) or precursor of the magnetocaloric active phase and the magnetocaloric floating phase (13) to form an article (1); Forming an average preferred orientation for at least a plurality of crystal grains (14) of said magnetocaloric floating phase (13). 40. The method of claim 39, wherein said pressing step is performed to induce preferential orientation of at least a plurality of crystal grains (14) of said magnetocaloric floating phase (13). 41. The article (1) according to claim 39 or 40, wherein said pressing step is performed to induce preferential orientation of at least said plurality of crystal grains (17) of said magnetocaloric active phase (2). Method of preparation. The average of at least a plurality of crystal grains 14 of the magnetocaloric floating phase 13 and / or of at least a plurality of crystal grains 17 of the magnetocaloric active phase 2. First of all, the orientation is formed at least in part by application of a magnetic field. 43. A method according to claim 42, wherein the magnetic field is applied before the pressing step. 44. The method of claim 42 or 43, wherein the magnetic field is applied at a temperature below the Curie temperature of the magnetocalorically active phase. 45. The method of any one of claims 39 to 44, wherein the particles of the magnetocaloric floating phase (13) have an anisotropic dimension on average, and the pressing step is such that the grains (14) of the magnetocaloric floating phase (13) are averaged. And the long direction (15) is oriented perpendicular to the first direction (3) of the article (1). 40. The magnetic heat exchanger of claim 39, wherein the average preferred orientation of the at least a plurality of crystal grains 14 of the magnetocaloric floating phase 13 is formed at least in part by mechanical deformation of the article after the pressing step. Method of making the article (1). 47. A method according to claim 46, wherein the mechanical deformation is carried out by at least one of rolling, swaging, drawing and extrusion. 48. The magnetocaloric active phase (2) and the magnetocaloric floating phase (13) comprise the magnetocaloric active phase (2) and the magnetocaloric floating phase (13). A method for producing an article for magnetic heat exchange, characterized in that it is coalesced by intimate mixing. The magnetocaloric active phase (2) and the magnetocaloric floating phase (13) comprise a layer (18) having the magnetocaloric active phase (2) as essential components and A method of manufacturing an article for magnetic heat exchange (1), characterized in that it is coalesced by alternately arranging layers (19) having a magnetocaloric floating phase (13) as an essential configuration. 50. The article according to any one of claims 39 to 49, wherein the magnetocaloric active phase (2) and the magnetocaloric floating phase (13) are compressed by one of rolling and pressing. ) Manufacturing method. 51. The long direction 15 of the crystal grains 14 of the magnetocaloric floating phase 13, on average during the compression, means that the first direction 3 of the article 1 is on average. A magnetic field is applied to self-orient the crystal grains (14) of the magnetocaloric floating phase (13) approximately perpendicular to the magnetic field. 52. The method according to any one of claims 39 to 51, wherein during the pressing, the long direction 15 of the crystal grains 17 of the magnetocaloric active phase 2 is on average the first direction 3 of the article 1. A magnetic field is applied to magnetically orient the crystal grains (17) of the magnetocaloric active phase (2) approximately perpendicular to the magnetic field. Providing at least one first plate 25 having an essential configuration of a magnetocaloric active phase 2 having a first density, Providing at least one second plate 26 having an essential configuration of a magnetocaloric active phase 2 having a second density less than the first density; Arranging the first plate (25) and the second plate (26) in a laminate. 54. The method of claim 53, wherein the first plate and the second plate are arranged to be in physical contact with each other. 55. The method of claim 53 or 54, wherein the first plate 25 has a first porosity and the second plate 26 has a second porosity, wherein the second porosity is the first porosity. A method for producing an article for magnetic heat exchange, characterized in that it is larger. The article of claim 53, wherein the first plate 25 is formed by pressing particles of the magnetocaloric active phase or precursors of the magnetocaloric active phase. The manufacturing method of (1). 57. The article of claim 53, wherein the second plate 26 is formed by pressing particles of the magnetocaloric active phase or precursors of the magnetocaloric active phase. The manufacturing method of (1). 58. The magnetic heat exchange according to any one of claims 53 to 57, wherein the conditions of the pressing step are adjusted to form a lower porosity in the first plate 25 than in the second plate 26. Method of making the article (1). 59. The method according to one of claims 53 to 58, characterized in that a plurality of first plates 25 and a plurality of second plates 26 are provided which are interposed with each other in the stacking direction 28 of the article 1. The manufacturing method of the article (1) for magnetic heat exchange. 60. The method of any one of claims 39 to 59, wherein at least one of a lubricant, an organic binder, and a dispersant is further added to the coalesced magnetocaloric active phase (2) and / or magnetocaloric floating phase (13). The manufacturing method of the article (1) for magnetic heat exchange. 61. A method according to any one of claims 39 to 60, wherein said article (1) is heated during compression. 63. A method according to any one of claims 39 to 61, wherein the article 1 is heated to form the magnetocaloric active phase 2 from the precursor. . 63. A method according to any one of claims 39 to 62, further comprising applying an outer protective coating (20) to the article (1). 64. A method according to claim 63, wherein the outer protective coating (20) is applied by dipping, spraying or electrolytic deposition.

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