KR101574843B1 - Method for classifying articles and method for fabricating a magnetocalorically active working component for magnetic heat exchange - Google Patents

Abstract

The present invention relates to a method of sorting articles and a method of manufacturing a magnetorheological active workpiece for magnetic heat exchange, the method comprising the steps of providing a source of articles to be sorted, the source being a magnet having a different magnetic transition temperature An article comprising a thermally active material; Sequentially applying a magnetic field to the source at different temperatures, wherein the magnetic field is sufficient to cause a magnetic force greater than the inertia of the portion of the article to act on the source to move the portion of the article to produce the article portion; And collecting the article portion at each temperature to provide a plurality of discrete article portions having different magnetic transition temperatures to classify the article comprising the thermo-volatile active material according to the magnetic transition temperature.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of classifying articles and a method of manufacturing magnetically active workpieces for magnetic heat exchange,

The present application relates to a method of classifying articles, in particular to a method of classifying particles comprising a magnetocalorically active material, and to a method of producing a magnetocalorically active working component for magnetic heat exchange.

The magnetocaloric effect describes magnetically induced entropy changes to heat release or adiabatic conversion to absorption. Thus, by applying a magnetic field to a magnetocaloric material, an entropy change that results in the release or absorption of heat can be induced. This effect is utilized in magnetic heat exchangers to provide refrigeration and / or heating.

Materials such as Gd ₅ (Si ₅ Ge) ₄ , Mn (As, Sb) and MnFe (P ₅ , As) having a magnetic transition temperature or Curie temperature at room temperature or near room temperature Has come. The magnetic transition temperature shifts to the working temperature of the material in a magnetic heat exchange system. Thus, these materials are suitable for use in applications such as building room thermostats, domestic and industrial refrigerators and freezers as well as automotive room thermostats.

Magnetic heat exchange technology is important as a magnetic heat exchanger and is, in principle, more energy efficient than a gas compression / expansion cycle system. In addition, magnetic heat exchangers are eco-friendly because ozone-depleting chemicals such as CFC are not used.

WO 2009/090442 discloses a composite article comprising a plurality of layers each comprising a magnetocalorically active material. Each layer has a different magnetic transition temperature and the layers are arranged such that the magnetic transition temperature increases from one end of the composite article to the other end to provide a layered workpiece for magnetic heat exchange. The layered arrangement of increased or decreased magnetic transition temperatures can allow the working range of the working parts to increase as compared to a workpiece comprising a magnetocalorically active material having a single magnetic transition temperature.

To produce such a layered workpiece, a plurality of magnetocalorically active materials in powder form may be used. Each magnetocalorically active material has a different Curie temperature. Therefore, a method of producing a plurality of magnetocalorically active materials having different magnetic transition temperatures is desirable.

A method of classifying an article comprising a magnetocalorically active material according to a magnetic transition temperature includes the following. A source comprising a plurality of articles to be sorted is provided. The source includes an article comprising a magnetocalorically active material having a different magnetic transition temperature. The magnetic field is applied sequentially to the source at different temperatures. The magnetic field is sufficient to act on the source of magnetic force greater than the inertia of the fraction of the article. The magnetic force causes a portion of the article to move, creating an article portion. Collecting article parts at each temperature provides a plurality of separate article parts with different magnetic transition temperatures. Therefore, articles containing a magnetocalorically active substance are classified according to the magnetic transition temperature.

The method produces a plurality of distinct article portions each comprising a magnetocalorically active material having a different average magnetic transition temperature. The plurality of distinct article portions are obtained from a single source comprising a mixture of articles comprising a magnetocalorically active material having a different magnetic transition temperature. Thus, the method classifies articles containing the thermo-volatile active material according to the magnetic transition temperature since each article part has a different average magnetic transition temperature. The method may be described as a thermomagnetic separation method.

A magnetocalorically active material is defined herein as a material that undergoes an entropy change when subjected to a magnetic field. The change in entropy can be a result, for example, from a ferromagnetic behavior to a paramagnetic behavior. The temperature at which magnetic transition from ferromagnetic to paramagnetic behavior takes place is also known as the Curie temperature. Entropy changes may also be the result of changes from antiferromagnetic to ferromagnetic behavior. This may also be the result from any kind of magnetic reorientation spin reorientation.

An article can have many forms. For example, in some embodiments, the article includes powder particles and has a diameter of less than 2 mm (millimeters). In some embodiments, the article can be regarded as a fragment or component and can have at least one dimension greater than 2 mm (millimeters).

In one embodiment, the magnetocalorically active material has a magnetic transition temperature in the range of 220K to 345K. The operating temperature of the magnetocalorically active material when used in a magnetic heat exchange system is approximately its magnetic transition temperature. Magnetorheological active materials with a magnetic transition temperature in the range of 220K to 345K are suitable for applications such as domestic and commercial refrigerator systems, cooling, air conditioning or room temperature control systems depending on the desired working temperature and operating temperature range.

The self-heat active substance is _{Gd, La (Fe 1 - b} Si b) 3 - based phase _{(-based phase), Gd 5 (} Si, Ge) 4 - based phase, Mn (As, Sb) - based 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, Ni (Mn , Co, Fe) (Sn, In, Ge) -type phase and Pr ₂ (Fe, Co) ₁₇ -type phase. These basic compositions may further include other chemical elements that may be partially or wholly replaceable with respect to the listed elements. These phases may also contain an element, such as hydrogen, which is accommodated in at least some of the gaps in the crystal structure. These phases may also contain small amounts of elements such as impurity elements and oxygen.

In the case where the magnetic transition is a transition from a ferromagnetic state to a paramagnetic state, the method is characterized in that the saturation magnetization of the article comprising the magnetocalorically active material is maintained at a temperature below the magnetic transition temperature Use big features. Thus, by applying a magnetic field at different temperatures, an article within a source having a magnetic transition temperature at or near the applied temperature will be magnetized to a greater extent than the article within the source having a magnetic transition temperature that is lower than the applied temperature . Thus, the more magnetized the articles are processed and moved to a larger magnetic force, allowing these articles to be separated from the rest of the articles.

The more magnetized article has a magnetic transition temperature around the temperature applied to the source. Thus, an article having a particular magnetic transition temperature can be separated from a source comprising an article having a different plurality of magnetic transition temperatures by applying a magnetic field gradient at a temperature relative to the source of supply that approximates the desired magnetic transition temperature of the removed article. have.

When the saturation magnetization increases with increasing temperature during magnetic transfer, for example from an antiferromagnetic to a ferromagnetic transition, an article with a transition temperature lower than the actual separation temperature will be attracted by the magnetic field.

The method enables production of article portions having a smaller magnetic transition temperature range than the article portion by, for example, creating a batch of magnetically thermally activated powder having a composition designed to produce a specific magnetic transition temperature .

The narrow range of the magnetic transition temperature of the article portion can be used to produce a layered article in which each layer has a more clearly defined magnetic transition temperature. This arrangement increases the efficiency of the workpiece comprising layers of different magnetic transition temperatures, thus increasing the efficiency of the magnetic heat exchanger.

In one embodiment, the temperature of the source is set at a temperature T1 corresponding to a first desired magnetic transition temperature T _trans1 . A magnetic field is applied to the source while the source is at temperature T1 such that the first article portion within the source having a magnetic transition temperature of T _trans1 +/- 3 DEG C is magnetically attracted to the magnet and removed from the source. And then collects the first article part.

In order to remove the article portion from the source, the strength of the magnetic field applied to the source relative to the particular geometry of the article at a particular temperature is chosen such that the article is ideally magnetically saturated.

The first article portion comprises an article of a magnetocalorically active material having a magnetic transition temperature within < RTI ID = 0.0 > 3 C < / RTI > of the desired magnetic transition temperature T _trans1 to be removed from the source.

Preferably, the first article portion has a magnetic transition temperature within +/- 1 DEG C of the desired magnetic transition temperature T _trans1 .

In another embodiment, the temperature of the source is changed to a temperature T2 corresponding to a second desired magnetic transition temperature T _trans2 , wherein T _trans2 ≠ T _trans1 And T2? T1. Since the source is at temperature T2 while the magnetic field is applied to the source, the second article portion within the source having a magnetic transition temperature of T _trans2 + - 3 DEG C is magnetically attracted to the magnet and removed from the source. And collects the second article portion.

The second article portion has an average magnetic transition temperature that is different from the average magnetic transition temperature of the first article portion because the second article portion is collected at a temperature T2 that is different from the temperature T1.

Preferably, the second article part has a magnetic transition temperature within +/- 1 DEG C of the desired magnetic transition temperature T _trans2 .

To classify one or more other article parts from a source having a different average magnetic transition temperature, the temperature applied to the source may be varied at different temperatures and at each different temperature, the magnetic field is applied and the temperature at which the source is maintained An article having a magnetic transition temperature within about 3 DEG C can be attracted by the magnetic field, resulting in movement and removal from the source.

The difference between the mean magnetic transition temperatures of the various article parts can be determined by an appropriate choice of the temperature applied to the source. For example, the difference between temperatures T _{1 and} T ₂ may be in the range of 0.5 ° C. to 5 ° C., ie, 0.5 ° C. ≦ T ₂ - T ₁ ≦ 5 ° C.

In one embodiment, the source is disposed in a thermally conductive container. The temperature of the vessel may be varied to change the temperature of the source by heat conduction. In one embodiment, the vessel is thermally connected to a bath, e.g., by a heating and / or cooling circuit. The temperature of the bath is changed to change the temperature of the source by heat conduction between the heating / cooling circuit and the source.

The source is sequentially maintained at a plurality of different temperatures. At each temperature, a portion of the article with a magnetic field and a magnetic transition temperature close to the temperature of the source is removed. Such a method can be described by a static method.

In another embodiment, a continuous process can be used. In these embodiments, the source is subjected to a temperature gradient and the source moves along a temperature gradient to change the temperature of the source by thermal conduction. The article portion is removed from the source at different temperatures along different points and temperature gradients. The method can be used for a continuously supplied source moving continuously through a temperature gradient.

Two or more means for applying a magnetic field at intervals along the temperature gradient may be arranged to apply a magnetic field to the source at different points along the temperature gradient and thus at different temperatures. This method causes the article portion of different magnetic transition temperatures to be removed from the moving source as the source moves along the temperature gradient sequentially.

In one embodiment, the source moves from a higher temperature to a lower temperature along a temperature gradient. This embodiment can be used for articles that exhibit magnetization from high magnetization to low magnetization to increase the temperature. Examples of these materials are LaFeSi- and MnFePAs-based materials. This arrangement also utilizes unique heat dissipation when the high temperature is above ambient temperature. This can simplify the manufacture of the temperature gradient as the source moves along the temperature gradient.

In another embodiment, the source moves along an error gradient from a lower temperature to a higher temperature. This embodiment can be used for articles that exhibit magnetic transfer from low magnetization to high magnetization in order to increase the temperature. Examples of these materials are CoMnSi- and NiMnGa-based systems.

In one embodiment, the source is located on a band that carries the source through a temperature gradient. This band may have the form of a drive belt having a direction of movement corresponding to the temperature gradient direction. Alternatively, or in addition, the source can move along the band by oscillation of the band.

The source can be moved continuously along the band by vibration or alternatively the magnetic field can be applied at a distance or spacing along the band such that the source has a different temperature at each distance or interval at which the magnetic field is applied.

The magnetic field may be applied perpendicular to the surface of the band supporting the source and perpendicular to the direction of movement of the source. In terms of Cartesian coordinates, if the movement direction of the band and the movement direction of the source are indicated in the x direction, the width of the band will extend in the y direction and the magnetic field can be applied in the z direction.

In some embodiments, the temperature gradient is in the range of 10 占 폚 / m to 200 占 폚 / m. In one particular embodiment, the temperature at one end of the band is -10 占 폚 and the temperature at the opposite end of the band is +60 占 폚. The temperature gradient is 175 ° C / m. In this embodiment the temperature gradient is applied over a distance of about 40 cm.

The magnetic field can be applied to the source by applying current to the electromagnet. Alternatively, a magnetic field can be applied using a permanent magnet.

The field strength applied to the source can be increased to a threshold that the article is sufficiently magnetized to move by increasing the magnetic field gradient applied to the source. This can be done, for example, by reducing the distance between the permanent magnet and the source or by increasing the current flowing through the coils of the electromagnet.

The magnetic field may be generated by disposing the first magnet adjacent the first side of the source. In other embodiments, other magnets may be disposed adjacent opposite sides of the source. The combination of the two magnets can be used not only to regulate the intensity of the magnetic field applied to the source but also to adjust the gradient of the magnetic field. The applied magnetic field may range from 0.003T to 0.3T or 0.01T or 0.1T. The magnetic gradient may be from 0.5 T / m to 10 T / m.

As discussed above, the method utilizes a higher feature in the case of an article in which the magnetization of the article comprises a magnetocalorically active material having a magnetic transition temperature around the temperature applied to the source. This degree of magnetization can be further optimized by applying a magnetic field having a strength depending on the magnetic polarization of the article having a specific shape. In the case of isotropic articles, for example spherical articles, the magnetic field B applied to the source may be at least J _S / 3 to saturate the article at the applied temperature.

After the article is removed from the source, the removed article portion may be secured to the surface of the removal surface, e.g., the magnet, before being transferred to the collection container.

The present application also relates to the use of magnetic separation at a plurality of different temperatures to produce a plurality of particle portions having different magnetic transition temperatures from a source comprising a plurality of particles of different magnetic transition temperatures. The particles may comprise a La (Fe, Si) ₁₃ -based phase. In another embodiment, the particles comprise at least one of the following phases: a Gd ₅ (Si, Ge) ₄ -phase, an Mn (As, Sb) -crystalline phase, a MnFe (P, Gd- based phase, (La, Ca, Pr, Nd, Sr) MnO 3 - based phase, Co-Mn- (Si, Ge ) - based phase and _{Pr 2 (Fe, Co) 17} - based phase.

A method of manufacturing a magnetically thermally active workpiece for magnetic heat exchange is also provided. The method includes obtaining a plurality of particle portions each having a different magnetic transition temperature using a method according to one of the embodiments described above. These particle portions are arranged in the order of increasing or decreasing the magnetic transfer temperature to produce a magnetorheological active workpiece for magnetic heat exchange.

The particle portions may be arranged to produce a layered structure in which the average magnetic transition temperature of the layer is increased or decreased in the working direction of the magnetocalorically active workpiece.

The average magnetic transition temperature of the partial particles is within a smaller range of the average magnetic transition temperature of the particles of the part due to the use of thermo-magnetic separation to separate the particles from the source. This increases the efficiency of the workpiece relative to one in which the magnetic transition temperature of the particles is larger in the particle part or in the case of the layer part.

The first particle portion can be compressed before other particle portions having different magnetic transition temperatures are arranged on the first particle portion. Other particle portions can then be compressed. This method can be used to form a layered workpiece with each layer having a different mean magnetic transition temperature.

In some embodiments, after the particles have been arranged in the order of increasing or decreasing the magnetic transition temperature, the arrangement is heat treated to produce a sintered magnetocalorically active workpiece for magnetic heat exchange. This heat treatment can be used to increase the mechanical integrity of the workpiece.

Suitable heat treatment conditions for producing sintered workpieces can be, for example, from 2 hours to 10 hours in the range of 300 ° C to 1200 ° C for the case of La (Fe, Si) ₁₃ -system. Compression to form a green body may be carried out at a pressure in the range of 10 MPa to 300 MPa and optionally in a temperature other than room temperature such as 30 DEG C to 250 DEG C.

In another embodiment, the particles of the particle portion are mixed with the adhesive before compression. After compressing the particle / adhesive mixture, the adhesive can be cured. The method of curing the adhesive depends on the composition of the adhesive. The adhesive can be cured, for example, by heat treatment at a temperature in the range of 0 占 폚 to 200 占 폚. The adhesive may be cured, for example, by treatment with UV light.

Embodiments will be described in detail with reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 shows an apparatus according to a first embodiment for sorting magnetically thermally active articles using thermo-magnetic separation.
Figure 2 shows an apparatus according to a second embodiment for sorting magnetically thermally active articles using thermo-magnetic separation.
Figure 3 shows a calorimetric entropy graph as a function of temperature for the first source.
Figure 4 shows a calorimetric entropy graph as a function of temperature for the second source.
Figure 5 shows a calorimetric entropy graph as a function of temperature for a third source.
Figure 6 shows a graph of the calorimetric entropy as a function of temperature for a fourth source treated to different thermo-magnetic separation conditions.
Figure 7 shows a graph of the calorimetric entropy as a function of temperature for a fourth source treated to different thermo-magnetic separation conditions.
Figure 8 shows a saturation magnetization graph for temperature.
Figure 9 shows a workpiece made using a magnetocalorically active material classified according to the present invention.
Figure 10 shows the forces acting on an individual article in a non-uniform magnetic field.
Figure 11 shows the magnetization behavior of magnetocaloric particles with different demagnetization factors.
Figure 12 shows the effect of alpha Fe on thermomagnetic separation.
Figure 13 shows chain formation of magnetized particles.
Figure 14 shows a diagram of the calculated saturation magnetization required for lift off of the particles.
Figure 15 shows a diagram of the calculated saturation magnetization required for lift-off of the particles.

In the following embodiments, the articles separated by their magnetic separation are particles separated from the powder source. The particles have an average particle size of 50 mu m to 750 mu m determined by sieving. However, the described method can be used to separate larger or smaller articles from the source by adjusting the magnetic field strength and magnetic field gradient in accordance with the size, shape and magnetic polarization of the article.

Figure 1 shows a device 10 according to a first embodiment for sorting magnetocalorically active particles using thermo-magnetic separation.

The apparatus 10 is designed to control the temperature of the vessel 11 in the form of a bath 13 that can be heated or cooled to control the temperature of the vessel 11, the magnet 12 and the vessel 11, And adjusting means. The container (11) is opened upward and can also include copper.

The source 14 of the magnetocalorically active particles 15 to be sorted is placed in the thermally conductive container 11. The source 14 comprises a plurality of particles 15 comprising a magnetocalorically active material having a different magnetic transition temperature. In this embodiment, the majority of the particles 15 comprise a magnetocalorically active material. However, some impurity particles not containing the magnetocalorically active material may also be present.

In one particular embodiment, the magnetocalorically active material of the particle is a La (FeSi) ₁₃ -based phase. The impurity particles may comprise, for example, alpha-iron.

The source 14 is disposed in a container 11 and the container 11 is closed by a non-magnetic lid 16. [ A magnet 12 is disposed over the lid 16 and is movable relative to the source 14 to regulate the magnetic field strength and magnetic gradient applied across the source 14. The movement of the magnet 12 and the lid 16 is indicated by the arrow 17. In one particular embodiment, the magnetic field is 0.03 T and the magnetic field gradient is 2.2 T / m.

The temperature of the vessel 11 can be adjusted by providing the base 19 of the vessel 11 with a channel 18 in flow communication with the cooling and heating bath 13. The temperature of the bath 13 can be adjusted and the liquid is allowed to flow through the channel 18 in the base 19 of the vessel 11. The circuit 20 coupling the channel 18, bath 13 and channel 18 in the base 19 to the bath 13 provides the heating / cooling circuit 21 for the source 14. The temperature of the container 11 and the supply source 14 is regulated by the heat conduction of heat from the liquid flowing in the heating / cooling circuit 21 or of the liquid. The temperature of the vessel 11 and the source 14 can be measured by a thermocouple 22 attached to the inner surface 23 of the base 19 of the vessel 11.

Also shown in Figure 1 is any second magnet 24 disposed adjacent the bottom surface 25 of the base 19 of the vessel 11. The second magnet 24 may be used to regulate the magnetic field strength and magnetic field gradient across the source 14.

In certain embodiments, the magnets 12, 24 are permanent magnets and the particles 15 of the source 14 have a diameter in the range of 400 [mu] m to 500 [mu] m. Once the temperature of the bath 13 has been adjusted and the temperature of the vessel 11 has been monitored and the temperature of the thermocouple 22 has reached the desired temperature, ). ≪ / RTI >

The lid 16 is installed on the open side of the container 11 and the temperature is stabilized. The magnet 12 is directed toward the lid 16 to increase the magnetic field gradient across the source 14. Portions of the particles 26 are attracted to the interior of the lid 16 due to the increased magnetic field provided by the magnets 12. These particles adhere to the inside of the lid 16.

The removed particles 26 are still attracted by the magnet 12 while removing the lid 16 with the magnet 12 from the container 11 to remove the first particle portion 27. [ Finally, the magnet 12 is removed from the lid 16 and the removed particles 26 can be collected in the vessel.

These removed particles 26 form a first particle portion 27 that is sorted from the source 14. The first particle portion (27)

 And has a magnetic transition temperature corresponding to the material having the maximum magnetization polarization at the temperature. The magnetic transition temperature of the first particle portion 27 corresponds to the temperature applied to the source.

The temperature of the source 14 is changed by changing the temperature of the heating and cooling bath 13. After reaching the new temperature, the method described above is repeated to remove the second particle portion from the source 14. The particles of the second particle portion have an average magnetic transition temperature corresponding to the second temperature applied to the source 14. The average magnetic transition temperature of the second particle portion is different from the average magnetic transition temperature of the first particle portion 27.

The apparatus can be used to perform a static or batch thermal demagnetization process.

Figure 2 shows an apparatus 30 according to a second embodiment used to sort magnetocalorically active particles.

The device 30 includes a band 31 and a temperature gradient 32. A source 33 containing particles 34 of the classified magnetocalorically active material is transported through the temperature gradient 32 by movement of the band 31. In this particular embodiment, the band 31 vibrates in order to move the source 33 in the direction of the arrow 35 through the temperature gradient 32.

In another embodiment, the band 31 can move the source 33 in the direction of the temperature gradient 32 along the temperature gradient 32 by movement of the band 31. The band 31 may be, for example, a conveyor belt.

The device 30 also includes a plurality of magnets 36, 37, 38, 39 spaced along the length of the band 31. Each of the plurality of magnets (36, 37, 38, 39) is placed on the band (31) at different temperatures due to the temperature gradient (32). The majority of the particles 34 of the source 33 comprise a magnetocalorically active material. The magnetic transition temperature of the particles 34 is different due to the difference in the composition of the magnetocalorically active material.

The band 31 is also connected to a source 33 (not shown) under a plurality of magnets 36, 37, 38, 39 through a temperature gradient 32 at a speed suitable for the temperature of the source 33 to correspond to the temperature gradient 32 Lt; / RTI > Thus, as the source 33 reaches the magnet 36, it has a temperature T1. Particles magnetically magnetized at temperature T1 by the magnetic field generated by the magnet 36 are attracted to the magnet 36 and removed from the source 33 on the band 31 producing the first particle portion 40 .

As the source 33 progresses through the temperature gradient 32, it has a temperature T2 that is lower than T1 because it is disposed below the magnet 37. [ It is highly magnetized due to the presence of the magnetic field provided by the magnet 37 and, preferably, particles saturated at the temperature T2 are attracted, so that these particles are separated from the source 33 to produce the second particle portion 41. [

The source 33 can be continuously fed to the beginning of the band and the particle portion is removed from the source 33 at intervals along the band 31 due to the arrangement of the magnets. The four magnets 36, 37, 38, 39 are shown in FIG. 2 and are arranged to sequentially remove particles from the source at a decreasing temperature. However, the number of magnets and the particle portion classified from the source are not limited to four. The number of particle portions sorted from the source 33 can be adjusted by adjusting the number of magnets and the temperature range over which the temperature gradient is provided.

The magnets 36, 37, 38 and 39 are merged to form a single extended magnet, which in principle allows continuous separation. The magnets 36, 37, 38, 39 may be oriented in the magnetization direction perpendicular to the major surface of the band 31 as shown in Fig. However, they can be oriented parallel to the band. In this parallel arrangement, the magnet can rotate about an axis perpendicular to the band surface. The steering effect created within the source 33 supports the extraction of individual particles from the source.

The apparatus 30 according to the second embodiment comprises a plurality of particles comprising a magnetocalorically active material having a different magnetic transition temperature and a continuous thermo-magnetic separation Process. ≪ / RTI >

In another embodiment, the particles are separated from the source with the aid of other magnet systems that determine the passage. For example, as the horizontal band moves across the cylindrical magnet system, particles with a high saturation magnetization are directed along a lower parabolic path than particles with a lower saturation magnetization. Thus, the two types of particles can be separated from each other.

FIG. 3 shows a graph of the adiabatic temperature change which can be termed a magnetic calorimetric effect (MCE) as a function of temperature for a sample according to the first embodiment. The source includes particles having a nominal composition of LaFe _{11 .42} Mn _{0 .32} Si _{1 .26} H _{1 .53} with a diameter of from 400 μm to 500 μm. A single permanent magnet is placed at a distance of about 20 mm from the source to provide a magnetic field of 0.03 T and a magnetic field gradient of 2.2 T / m.

The starting powder not separated by the thermomagnetic separation process is indicated by the dotted line in Fig. The magnetic transition temperature of the starting powder is about 24 캜 as indicated by the peak position in the curve. The starting powder is subjected to a magnetic field at a plurality of different temperatures and one particle portion is removed from the source at each of these temperatures. The interval between the applied temperatures is 2K.

Fig. 3 shows the curve of the magnetic calorie effect on the temperature for each of these powder portions. Figure 3 shows that, except for the first and last portions, the peak width for the particle portion is narrower than the peak width of the starting powder, indicating that the uniformity of the individual particle portions is better than the starting powder. The magnetic calorimetric effect of these particle parts is also greater than that of the starting mixture. The first part and the last part are those removed at the highest and lowest temperatures.

Removal of the portion of the particles having much higher and much lower peak temperatures relative to the peak temperature of the starting powder can improve the uniformity of the remaining powder. Thus, the method can be used to remove particles that have a magnetic transition temperature outside the desired peak width. The remaining powder that can be classified as other particle portions can be left in the mixture because the mixture has a suitably uniform property for the particular application.

Figure 4 shows a graph of the caloric effect on temperature for a sample with a slightly different composition of LaFe _{11 .39} Mn _{0 .35} Si _{1 .26} H _{1 .53} and a low magnetic transition temperature of 17 ° C. The particle size of the powder is 400 탆 to 500 탆. The starting powder was subjected to a thermomagnetic separation process in which a 0.03 T magnetic field having a gradient of 2.2 T / m was applied to the powder at a plurality of temperatures. The distance between the temperatures is about 2 ° C.

A plurality of particle portions having different peak temperatures are obtained. Particles of the particles having a peak temperature close to the peak temperature of the starting powder have a higher magnetic calorie effect than the starting powder. These results indicate that the thermomagnetic separation process can be successfully performed on starting powders having different mean magnetic transition temperatures.

Fig. 5 is a graph showing the composition corresponding to the composition of Fig. 4: LaFe _{11 .39} Mn _{0 .35} Si _{1 .26} H _{1 .53} , the temperature at a temperature of 17 ° C. and a mean particle size of less than 250 μm A graph of the magnetocaloric effect is shown.

The powder is magnetically treated at a plurality of different temperatures, and the interval between the temperatures is about 2K. The magnetic calorimetric effect was observed to increase in the part of the particles having a magnetic transition temperature around the average magnetic transition temperature of 17 DEG C of the starting powder. These results indicate that thermo-magnetic separation can be used for starting powders of different particle sizes.

Fig. 6 shows the results of the experiment with different manganese contents: LaFe _{11 .74} Mn _y Si _{1 .26} H _{1 .53} , where y is 0.32, 0.34, 0.36, 0.37, 0.39 in a 1: 1: Graphs of the effect of magnetocaloric effect on temperature in a sample having the same portion of powder containing La (FeSi) ₁₃ phase are shown. The particle size is 400 탆 to 500 탆. The starting powder was subjected to a thermomagnetic separation process in which a magnetic field 0.03T with a gradient of 2.2 T / m was applied to the powder at a plurality of temperatures. The distance between the temperatures is about 2 ° C.

The curve of the magnetocaloric effect (MCE) versus temperature in the starting powder is indicated by the dashed line in Fig. This curve contains the phase with a different magnetic transition temperature and is not uniform due to the very large width of the peaks and the presence of sub-peaks.

The powder may be classified into various particle portions having a larger caloric effect than the starting powder. In some cases, the caloric effect is more than double. These results indicate that the powder mixture can be classified as a separate particle fraction with good uniformity as shown by the increased MCE value.

FIG. 7 shows a graph of the caloric effect on temperature, illustrating the classification of the powder used in the embodiment shown in FIG. However, in the embodiment illustrated in Figure 7, a second magnet was used during thermo-magnetic separation. The second magnet is disposed on the opposite side of the source of the starting powder. In this embodiment, a magnetic field of 0.08 T and a magnetic field gradient of 1 T / m are used. In this embodiment, the interval between the temperatures at which the magnetic field is applied is reduced to 1K. The plurality of particle portions were removed from the starting powder at different temperatures. Each particle portion has a different peak temperature. This indicates that the thermo-magnetic separation can be performed even in a high magnetic field.

Without being bound by any theory, it is believed that the method of thermomagnetic separation according to the embodiments described above is based on one or more of the following concepts.

Some magnetocalorically active materials generally exhibit a large temperature dependence of saturation magnetization in the region of the working temperature corresponding to the magnetic transition temperature or Curie temperature. The magnetic transition temperature can strongly depend on the composition of the magnetocalorically active phase. For example, the Curie temperature on La (Fe, Si) ₁₃ can be controlled by substituting elements such as Mn and H. The Curie temperature decreases by -26 K with respect to 1 wt% of Mn and increases by +700 K with respect to 1 wt% of hydrogen.

If the Curie temperature is strongly dependent on the composition of the particles, magnetic particles may be separated from the mixture using magnetic separation at different temperatures. The particle portions have a narrow composition range, because the composition outside the narrow range is because their saturation magnetization is too small at the set temperature to attract magnetically.

When a magnetic field large enough to saturate the particles is applied, the particles with different magnetic transition temperatures are magnetized to different degrees. Figure 8 shows a graph of saturation magnetization as a function of temperature for two magnetocalorically active materials A and B having different compositions and different magnetic transition temperatures.

Figure 8 shows that at a given separation temperature, T _separation , the magnetic polarization is greater in the case of sample A than in sample B. When these particles are subjected to a magnetic field gradient in addition to a magnetic field, they are subjected to magnetic force in addition to gravity. The magnetic force depends on the saturation magnetization and therefore depends on the Curie temperature of the particles. If the magnetic force generated by the magnetic field gradient direction is selected so as to oppose gravity and the value of the magnetic field gradient is selected so that the magnetic force for the particle A is larger than the gravity but the magnetic force for the particle B is smaller than the gravity for the particle B, Can be moved and separated from the mixture.

The above principles can be used to separate a plurality of particle portions from a single source by appropriate selection of temperature, magnetic field and magnetic gradient, so that the particle portions have different Curie temperatures.

FIG. 9 shows a workpiece 100 for a magnetic heat exchanger fabricated from a plurality of particle portions 101, 102, 103, respectively, which are classified using thermo-magnetic separation comprising a magnetocalorically active material.

The workpiece 100 has a layered structure comprising three layers 104, 105, 106 having different magnetic transition temperatures that increase or decrease along the working direction 107 of the workpiece 100. However, the working part 100 is not limited to having only three layers. Temperatures less than or greater than three layers and less than or greater than three different magnetic transition temperatures may be used for the workpiece.

The working part 100 can be manufactured as follows. The particle portions 101, 102, and 103 are mixed with an adhesive to obtain three separate pastes. The paste comprising the first particle portion 101 is compressed in a mold and the second particle portion 102 is placed on the compressed first particle portion 101 and self-compressed. A third particle portion (103) is placed on the second particle portion (102) and compressed to create a green body.

The green body is heat treated at a temperature in the range of 30 캜 to 200 캜 to cure the adhesive to produce the workpiece 100. The adhesive can be used to increase the mechanical integrity of the workpiece 100 as compared to a workpiece that acts as a binder and includes only compressed particles. The amount of binder is selected to form open pores in the workpiece. The open pores allow the heat transfer fluid to flow through the workpiece. The heat transfer fluid may be pumped through the open pores of the workpiece. In another embodiment, an adhesive may not be used.

In another non-limiting embodiment, the workpiece 100 is fabricated as follows. The particle portions 101, 102 and 103 are arranged in a laminating manner in the molds, respectively, as in the embodiments described above, and the lamellar structure is compressed to produce a green body. The layer can be compressed sequentially so that a layered structure is formed in the mold. The green body is heat treated at a temperature to sinter the particles to produce a sintered workpiece 100.

Suitable heat treatment conditions may be, for example, from 2 hours to 10 hours in the range of 300 ° C to 1200 ° C in the case of the La (FeSi) ₁₃ -based phase. The compression to form the green body can be carried out at pressures in the range from 10 MPa to 300 MPa and, occasionally, at temperatures other than room temperature, such as 30 DEG C to 250 DEG C.

Without being bound by theory, thermo-magnetic separation (TMS) can utilize one or more of the following concepts.

the forces acting on the individual particles in a non-uniform magnetic field oriented vertically in the z direction can be calculated. The conditions to be considered are shown in Fig. 10 where B _z is the magnetic induction applied from the outside, dB _z / dz is the gradient (T / m), J is the polarization (T) and m is the mass ), Ρ is the density (kg / m ³ ), and finally F _G is the weight force (N).

Point of action

Magnetic force and gravity act on the particles:

By making the two forces equal, an equilibrium condition is created that describes the point of action of the thermomagnetic separation:

The left side of the equation describes the effect of gravity and the right side of the equation describes the influence of magnetic force. As long as the gradient of the magnetic field can be assumed to be constant over the volume of the particles, the equilibrium condition does not depend on the mass or volume of the particles. The strength of the magnetic field is not explicitly included in the condition.

Saturating condition

To create a thermomagnetic separation function, the magnetic field must be strong enough to magnetize, that is, to magnetically magnetize the magnetocalorically active phase of the particle to be removed from the source.

In order to calculate the saturation field strength required, it is assumed that the magnetocaloric particles can be easily magnetized in their magnetic transition temperature region and that the magnetization behavior is essentially determined by the magnetic self-elimination field of the particles themselves. This estimate is considered acceptable for the case of tetragonal symmetric La (FeSi) ₁₃ -based materials. In this case, the permeability effective in terms of magnetocalorically depends only on the geometry and orientation of the particles, and the following formula applies:

H _ext is the external magnetic field acting on the particle and N is the magnetorheological factor acting in the direction of the magnetic field. B _z is the magnetic induction acting in the z direction at the position of the particle in the particular case considered here. The different particle groups result in different magnetization curves as can be seen in Fig.

Where the saturation field strength H ₁ depends on the magnetic removal factor of the particle under consideration. Because the particles can move freely, they are always rotated in their longest axis so that they are oriented parallel to the applied magnetic field. As a result, in the case of spherical particles having N = 1/3, the largest expected electric field intensity required to saturate the particles is generated. In addition to equation (3), the following conditions are the best for thermomechanical separation:

If the above conditions are not met, the particles that can be magnetized most easily due to their shape along their longest axis will tend to further lift off. In this case, the particles will be classified by shape rather than by the desired Curie temperature.

Intermediate phase  Condition

The LaFeSi alloy powder may contain a small percentage of alpha Fe phase. The αFe phase may be undesirable sintered residues that were not completely dissolved during manufacture or may be due to metal compositions pushed to the Fe-rich side by increased oxygen uptake during the powder metallurgy process employed in the manufacture. However, it is possible to produce off-stoichiometric alloy powders, especially to prevent intentional formation of the corrosive LaFeSi ₁₃ phase. Fe incorporation reacts naturally with the applied magnetic field, resulting in undesirable force involvement for thermo - magnetic separation.

The αFe phase is generally present in the structure in spherical incorporation form and on average contains N _Fe = 1/3 can be estimated. Since alpha Fe has a saturation polarization of about 2.16 T at room temperature, it will not saturate sufficiently until the field strength of about 0.7 T has been reached, and the effective polarization is described as follows:

This results in an indication of the force component on the particle surface resulting from the? Fe content:

In the formula, α is a part by volume of αFe.

To produce thermo-magnetic separation, F _Fe must be less than the weight force acting on the particles, resulting in the following intermediate phase conditions:

Generally, it can be considered that the upper portion of the magnetocalorically active phase beta is less than 100%. This leads to the following conditions for the ease of thermo-magnetic separation:

Figure 12 shows the effect of alpha Fe on thermomagnetic separation, with 1:13 phase with J _S = J _S (T), beta and alpha Fe with phase component: J _S = 2.16 T, phase component: alpha. J _S is the saturation polarization on the magnetic calorie at the temperature at which the TMS is performed. In order to achieve clean separation, βJ _S should be as large as possible compared to 3αB _z . Figure 12 shows the requirements for B _z selected slightly larger than J _S / 3. Conditions suitable for use in thermomechanical separation are indicated by gray areas in FIG.

Referring to Fig. 12, in one embodiment, the saturation magnetization on the magnetic calorie amount at which the lift-off condition 9 is satisfied is placed in the region where the temperature dependence of the saturation magnetization is greatest to achieve the largest separation sharpness. The gradient selected in equation (9) should be low enough and B _z selected in equation (10) to be high enough not to lift off the particles until a relatively high desired saturation polarization of about 0.5 T is reached. This method can be used for individual particles. However, in practice, bulk powder is used and such a high degree of magnetization causes significant interactions between the powder particles, resulting in deterioration in separation sharpness. The following describes the calculation of the degree of polarization that can be expected in the case of this type of destructive interaction.

Particle interaction

In order to calculate the interaction between two adjacent particles, their dipole moments mu ₁ And μ ₂ A first approximation that briefly describes the particle is sufficient. The use of letters in dark colors indicates vector values. The magnetostatic dipole interaction energies are generally as follows:

Where r is the position vector between the midpoints of the two particles. μ ₁ And μ ₂ The arrangement of the room smell preferably the (perpendicular to μ with respect to r) instead of each other particles back along (parallel to μ with respect to r) z-axis, the side contralateral Considering the special case in the problem of matching the z-axis in a more energetically Is easy to understand with the help of equation (12). This results in the known formation of a powder chain in the field strength direction and rejection of the chains perpendicular thereto.

When the electric field strength direction is parallel to gravity gravity, one particle is lifted by the diameter of each other to form the first element of the powder chain as shown in Fig.

If the work required to do this is less than the gain in the magnetostatic energy, the powder chain is formed once it is properly activated. Figure 13 shows the necessary conditions for the simplest case of spherical particles of the same size.

D is the particle diameter. The polarization J is forced in the z direction by the magnetic field, and B _z , which satisfies the saturation condition 10, makes the polarization independent of the relative position of the particles. Let R be the radius of the particle:

In the particular case considered here, including equation (13) in equation (12) results in a powder chain consisting of two spheres in accordance with the following static magnetic energy:

The reduction of the magnetostatic energy in the boundary case must compensate for the increase in energy that can be present as the powder chain is formed, so that the following equilibrium condition is created:

If J ₁ = J ₂ , the formation of the powder chain occurs according to D, so that the boundary polarization can be calculated. A typical LaFeMnSiH _sat density of about 7.1 g / cm < ³ > results in a boundary polarization of about 0.033T at a particle diameter of 1 mm and also results in a boundary polarization of only about 0.010T at a particle diameter of 100 mu m. In order to form a longer chain, the newly binding particles have to overcome the ever increasing height difference and as a result the required degree of magnetization increases with the root of the chain length according to the above equation (15).

If the powder chains are made up of uniform particles having the same magnetic transition temperature, thermo-magnetic separation can be carried out. As soon as the falling temperature is high enough for the saturation magnetization to meet the lift-off condition (9), the entire chain is lifted out of the bulk material. According to equation (15), this is a particle with the highest saturation magnetization and highest magnetic transition temperature, which strictly form the initial chain.

However, the attractive forces between intragranular particles can be greater than gravity gravity and as a result, particles that are not sufficiently magnetically saturated can be "torn off" on particles with sufficiently high Curie temperatures, piggy-backed "). The force between two particle contacts as shown in Figure 13 can be calculated by differentiating 14 against z:

Making the force equal to gravity acting on low particles results in a condition for continued adhesion of the particles in a manner similar to equation (15) above:

Therefore, the average polarization moving away from the adjacent particles is lower than the polarization required to form the powder chain, about 僚 3 factor. In order to minimize the effect of powder particle interactions, the saturation polarization for particles with a diameter of several hundred micrometers should be significantly lower than 0.1T. Further, it is appropriate to keep the bulk powder relatively thin and to suppress agglomeration of the powder particles by mechanical vibration. This can be done by transporting the powder to an oscillating conveyor and combining the use of a minimal magnetic field to effect thermo-magnetic separation.

Calculated examples and tasks Diagram

The inferred condition from above is best discussed with the aid of a diagram that plots the saturation magnetization required to lift off the particles according to equation (9) as a magnetic field gradient function. This is shown in Fig. 14 for a series of field strengths Bz, alpha Fe portion alpha and fraction of magnetocalorically active 1:13 phase beta. A typical LaFeMnSiH _sat density value of 7.1 g / cm < ³ > was used.

The black curve of the solid line represents a case of a sample which is 100% 1:13 phase and does not contain? Fe. In the case of the equation (9), the bias point does not depend on the electric field intensity but depends only on the gradient. However, saturation condition 10 still needs to be met. Is 0.03T in B _z was estimated, the calculated black line. As a result of the saturation condition, the line ends at a saturation polarization of 0.09T at about 1 T / m dB _z / dz. This means that at an electric field strength of 0.03 T the gradient should be at least about 1 T / m if thermomembrane works. The embodiment described above is based on the assumption that B _z = 0.03 T and 2.2 T / m. In this electric field structure, when 1:13 particles from the temperature above the Curie temperature are slowly cooled, their saturation magnetization increases until the particles are lifted out of the bulk powder at a value of about 0.04T.

14, the dotted line shows the effect of increasing the? Fe content at 0.03T electric field intensity. The αFe content of 5% has only a slight effect on the path of the working curve (see solid line and dotted line). However, the saturation polarization of 1:13 on the higher gradient required to lift off the particles at 10% (short dashed line) and 20% (long dashed line) is significantly reduced. Was negative from a gradient of 20% αFe to about 5 T / m J _s (1:13). This means that under these conditions the force acting on the? Fe content alone is sufficient to lift off the particles. This corresponds to an intermediate phase condition (11) which can be rewritten as J _s (1:13)> 0 if included in (9).

At a slope of 2.2 T / m, the 20% αFe content causes a decrease in J _s (1:13) from about 0.04 to about 0.03 T. This reduces the separation sharpness of the thermo-magnetic separation by the different? Fe content. FIG. 14 also shows that the lower the gradient, the lower the sensitivity to the? Fe content. B _z = 0.03T, the line for the various alpha Fe contents at a minimum gradient that is acceptable for an electric field strength of about 1 T / m is substantially converged.

Finally, dark black (B _z = 0.01 T), a short dashed line (B _z = 0.03 T) and the long dashed line (B _z = 0.08 T), Figure 15 shows the effect of the magnetic field strength on typical LaFeMnSiH _sat at 5% alpha Fe and 90% 1:13. B _z = 0.08 T and about 1 T / m, reasonable thermomagnetic separation can still be carried out. However, the relatively high J _s of about 0.085 T (1:13) results in a significantly increased tendency towards chain formation.

As expected from equation (9), the effect of αFe decreases with B _z , and for B _z = 0.01 T, the working curve is almost the same as the non-αFe ideal curve. Considering the results deduced above, we suggest that a B _z of about 0.01 T at a gradient of about 4-5 T / m is a particularly desirable bias point for thermomagnetic separation. The expected αFe effect in this region is low and the expected interaction between particles is also low due to the relatively low 1:13 phase saturation polarization of about 0.02 T.

Claims (34)

Providing a source of articles to be classified, wherein the source comprises articles comprising a magnetocalorically active material having a different magnetic transition temperature, said articles comprising at least one La (Fe _1-b Si _b ) ₁₃ -system (La, Ca, Pr, Nd, Pd) phase, Gd ₅ (Si, Ge) ₄ -phase, Mn (As, Sb) Sr) MnO ₃ - based phase, Co-Mn- (Si, Ge ) - based phase and _{Pr 2 (Fe, Co) 17} - including the type phase and;
Sequentially applying a magnetic field to the source at different temperatures, wherein the magnetic field is sufficient to act on the source of a magnetic force greater than the inertia of some of the article, ; And
Collecting a portion of the article at each temperature to provide portions of the separated article having different magnetic transition temperatures, thereby sorting the articles comprising the thermally activated magnetic material according to the magnetic transition temperature;
A method of sorting an article comprising a magnetocalorically active material according to a magnetic transition temperature. The method according to claim 1,
The temperature of the source is set at a temperature T ₁ corresponding to a first desired magnetic transition temperature T _trans1 ,
_{Applying a} magnetic field to the source to magnetically magnetically _attract a portion of the first article within the source having a magnetic transition temperature of T _trans1 +/- 3 DEG C to be removed from the source, A method of sorting an article comprising a magnetocalorically active material according to a magnetic transition temperature. 3. The method of claim 2,
The temperature of the source changes to a temperature T ₂ corresponding to a second desired magnetic transition temperature T _trans2, where T _trans2 ≠ T _trans1 ,
_{Applying a} magnetic field to said source to magnetically magnetically attract a portion of a second article within said source having a magnetic transition temperature of T _trans2 +/- 3 DEG C to be removed from said source, A method of sorting an article comprising a magnetocalorically active material according to a magnetic transition temperature. The method of claim 3,
0.5 ° C ≤ ≤T ₂ -T ₁ ≤ 5 ° C according to the magnetic transition temperature. 5. The method of any one of claims 1 to 4, wherein the source is disposed in a thermally conductive container, the temperature of the container being adapted to change to a temperature of the source by heat conduction, A method of classifying an article comprising an active substance. The method of claim 1, wherein the source is moving along a temperature gradient, and wherein a portion of the article is removed from the source at a different temperature along the temperature gradient, the article comprising a magnetocalorically active material Way. 7. The article of claim 6, wherein the source is adapted to move from a higher temperature to a lower temperature along the temperature gradient, or move from a lower temperature to a higher temperature, wherein the article comprises a magnetocalorically active material Lt; / RTI > 7. The method of claim 6, wherein the source is located on a band that carries the source through the temperature gradient, wherein the source comprises a magnetocalorically active material according to a magnetic transition temperature. 9. The method of claim 8, wherein the source moves along the temperature gradient by the oscillation of the band, wherein the source comprises a magnetocalorically active material according to a magnetic transition temperature. 7. The method of claim 6, wherein the source is continuously moving through the temperature gradient and a magnetic field is applied spaced along the band, the source having a different temperature at each interval, A method of classifying an article comprising a substance. The method of claim 1, wherein the source is supported on a surface and the magnetic field is applied perpendicularly to the surface. 12. The method according to claim 11, wherein the source is supported on a surface, and a magnetic field is applied parallel to the surface, wherein the magnetic field is applied parallel to the surface. 13. The method of claim 12, wherein the magnetic field is rotated about an axis perpendicular to the surface, wherein the article comprises a magnetocalorically active material according to a magnetic transition temperature. The method according to claim 6, wherein the temperature gradient is in the range of 10 占 폚 / m to 200 占 폚 / m, wherein the article comprises the magnetocalorically active substance according to the magnetic transition temperature. The method according to claim 1, wherein the magnetic field is applied by applying a current to the electromagnet or by a permanent magnet. The method of claim 1, wherein the first magnet is disposed adjacent the first side of the source, and wherein the article comprises a magnetocalorically active material according to a magnetic transition temperature. 17. The method of claim 16, wherein the other magnet is disposed near the opposite surface of the source. 17. A method of sorting articles comprising a magnetocalorically active material according to a magnetic transition temperature. The method according to claim 1, wherein a magnetic field of 0.003T to 0.3T is applied, and the article comprising the magnetocalorically active material is classified according to the magnetic transition temperature. The method of claim 1, wherein the magnetic field gradient is applied to the source. 20. The method according to claim 19, wherein the magnetic gradient is between 0.5 T / m and 10 T / m. The method according to claim 1, wherein the magnetic field B is J _S / 3 or more. The method according to claim 1, wherein the articles have a maximum diameter of 2 mm, wherein the article comprises a magnetocalorically active material according to a magnetic transition temperature. The method according to claim 1, wherein the articles are particles having a diameter in the range of from 50 탆 to 750 탆, comprising a magnetocalorically active substance according to a magnetic transition temperature. The method according to claim 1, wherein the articles removed from the source are immobilized on a removal surface, the article comprising a magnetocalorically active material according to a magnetic transition temperature. Applying the source to a magnetic field at a plurality of different temperatures to produce a plurality of discrete particle portions having different magnetic transition temperatures from a source comprising a plurality of particles of different magnetic transition temperatures,
The particles may be at least one of La (Fe _1-b Si _b ) ₁₃ -phase, Gd ₅ (Si, Ge) ₄ -phase, Mn (As, Sb) , Tb-Gd- based phase, (La, Ca, Pr, Nd, Sr) MnO 3 - the total phase-phase-based, Co-Mn- (Si, Ge ) - based phase and Pr ₂ (Fe, Co) ₁₇ Including,
A method for sorting particles containing a magnetocalorically active material according to a magnetic transition temperature. delete Performing a method according to claim 1 to produce a plurality of particle portions having different magnetic transition temperatures, and
And arranging the particle portions in the order of increasing or decreasing the magnetic transfer temperature to produce a magnetocalorically active workpiece for magnetic heat exchange.
Method of manufacturing magnetic calorimetric active workpieces for magnetic heat exchange. 28. The method of claim 27, further comprising compressing the first particle portion before arranging other particle portions on the first particle portion. 29. The method of claim 28, further comprising compressing the other particle portion. 30. The method of any one of claims 27 to 29, wherein the particle portions are arranged in order of increasing or decreasing the magnetic transition temperature, and then the particle portions are heat-treated to form a sintered magnetocalorically active operation Wherein the component is manufactured by a method comprising the steps of: 29. The method of claim 27 or 28, wherein particles of the particle portion are mixed with the adhesive prior to compression. 31. The method of claim 30, wherein the adhesive after curing is cured. 32. The method of claim 31, wherein the adhesive is cured at a temperature of 0 ° C <T _cure <200 ° C, T _cure . 19. The method according to claim 18, wherein a magnetic field of 0.01T to 0.1T is applied, and the article comprises a magnetocalorically active substance according to a magnetic transition temperature.

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