KR102069770B1 - Magneto-caloric alloy and preparing method thereof - Google Patents

Abstract

The present invention is a magnetocaloric alloy represented by the formula Mn _2-ab Fe _a X _b P _1-c Y _c , X is Zr or Hf, Y is at least one selected from Ge, Si, 0.8≤a + It relates to a magnetocaloric alloy with b ≦ 1.0, 0 <b ≦ 0.1, and 0.4 ≦ c ≦ 0.6.
The magnetocaloric alloy according to the present invention can provide an alloy composition of high cooling ability having a high entropy change amount ΔS _M. In addition, the manufacturing method of the magnetocaloric alloy has the advantage of producing a homogeneous alloy at the same time to produce a phase having excellent magnetocaloric effect.

Description

Magnetocaloric alloy and its manufacturing method {MAGNETO-CALORIC ALLOY AND PREPARING METHOD THEREOF}

The technical idea of the present invention relates to a magnetocaloric alloy, and more particularly, to a highly cooling magnetocaloric alloy having a high ΔS _M (entropy change) value and a manufacturing method thereof.

Magnetic cooling material is a material that can be cooled without freon gas refrigerant (CFC, chlorofluorocarbon) used in conventional refrigerators and air conditioners by using a magnetocaloric effect (MCE) that is heated when magnetized and cooled when demagnetized.

1 is a view showing the cooling and heat generation according to the magnetic arrangement. Systems that use the magnetocaloric effect include a system in which heat is used to convert heat energy from a low temperature source into a hot sink (or vice versa) from a thermomagnetic device that converts thermal energy into magnetic work. Up to the pump can be applied. It generally corresponds to thermomagnetic, thermoelectric and thermomagnetic generators, magnetic refrigerators, heat exchangers, heat pumps or air conditioning systems.

These MCEs can be quantified as entropy change (ΔS _M ) or temperature change (ΔTad), respectively, depending on whether the magnetic field application is performed at isothermal or adiabatic conditions.

In addition, the general magnetocaloric alloy is a situation that the mechanical stability is not excellent because the strain generated from the change in volume during the thermal or magnetic field circulation caused the bulk fragments, there is a problem of low cooling capacity below 10J / kg . In order to apply MCE in a large scale or various applications, it is necessary to have a homogeneous, high mechanical stability and a magnetocaloric alloy having excellent magnetocaloric effect and a manufacturing method thereof.

1. Republic of Korea Patent Publication No. 10-2013-0051440 2. Republic of Korea Patent Publication No. 10-2012-0135233

The technical problem to be achieved by the technical idea of the present invention is to provide a high-cooling magnetocaloric alloy having a high ΔS _M (entropy change) value.

The technical problem to be achieved by the technical idea of the present invention is to provide a method for producing a magnetocaloric alloy capable of producing a homogeneous alloy while producing a phase having excellent magnetocaloric effect.

However, these problems are exemplary, and the technical idea of the present invention is not limited thereto.

The magnetocaloric alloy according to the technical idea of the present invention for achieving the above technical problem is represented by the formula Mn _2-ab Fe _a X _b P _1-c Y _c , X is Zr or Hf, Y is Ge, Si At least one selected, and may be 0.8≤a + b≤1.0, 0 <b≤0.1, 0.4≤c≤0.6.

In some embodiments of the present invention, Y is Ge, 0.7 ≦ a ≦ 0.8, 0 <b <0.1, 0.4 ≦ c <0.5, heat treated at 1000 to 1200 ° C., and T _c ( Curie temperature) is shown, and may have a relative cooling power (RCP) of 40 to 100 J / kg at 210 ± 40K.

In some embodiments of the present invention, X is Zr, 0 <b <0.05, T _c (Curie temperature) appears at 240 ± 10K, and RCP (90-100 J / kg) at 240 ± 10K. Relative cooling power) and a magnetic entropy change amount ΔS _M of 6.5 to 8.5 J / kgK.

In some embodiments of the present invention, X is Hf, 0 <b <0.05, T _c (Curie temperature) appears at 240 ± 10K, and RCP (80-90 J / kg at 240 ± 10K). Relative cooling power) and a magnetic entropy change amount ΔS _M of 6 to 8 J / kgK.

In some embodiments of the present invention, Y is Ge, 0.7 ≦ a ≦ 0.8, 0.5 <c ≦ 0.6, heat treated at 1000 to 1200 ° C., and T _c (Curie temperature) appears at 290 ± 50 K, It may have a relative cooling power (RCP) of 50 to 140 J / kg at 290 ± 50K.

In some embodiments of the present invention, X is Zr, 0.03 <b <0.1, T _c (Curie temperature) appears at 290 ± 10K, and RCP (50-60 J / kg at 290 ± 10K). It may have relative cooling power.

In some embodiments of the present invention, X is Hf, 0.03 <b <0.1, T _c (Curie temperature) appears at 250 ± 10K and 330 ± 10K, and 130-140 J / at 250 ± 10K. It has a relative cooling power (RCP) of kg and may have a relative cooling power (RCP) of 130 to 140 J / kg at 330 ± 10K.

In some embodiments of the present invention, Y is Si, 0.9 ≦ a ≦ 1.0, 0 <b <0.05, 0.5 ≦ c <0.6, heat treated at 1000 to 1200 ° C., and T _c (Curie) at 260 ± 20K. Temperature), and may have a relative cooling power (RCP) of 145 to 160 J / kg and a magnetic entropy change amount ΔS _M of 4 to 6.5 J / kgK at 260 ± 20K.

In some embodiments of the present invention, X is Zr, T _c (Curie temperature) appears at 260 ± 10K, and may have a relative cooling power (RCP) of 150 to 160 J / kg at 260 ± 10K. have.

In some embodiments of the present invention, X is Hf, T _c (Curie temperature) appears at 250 ± 10K, and may have a relative cooling power (RCP) of 145 to 155 J / kg at 250 ± 10K. have.

In some embodiments of the present invention, the magnetocaloric alloy is heat-treated at 900 to 1000 ℃, T _c (Curie temperature) appears at 370 ± 90K, RCP (100 to 220 J / kg at 370 ± 90K) It may have relative cooling power.

In some embodiments of the invention, Y is Ge, 0.7 ≦ a ≦ 0.8, 0.4 ≦ _c <0.5, T _c (Curie temperature) appears at 380 ± 70K, and 100 to 200 at 380 ± 70K It may have a relative cooling power (RCP) of J / kg and a magnetic entropy change amount ΔS _M of 1 to 10 J / kgK.

In some embodiments of the present invention, Y is Si, 0.9 ≦ a ≦ 1.0, 0.5 ≦ c <0.6, T _c (Curie temperature) appears at 320 ± 40K, and 190-220 at 320 ± 40K. It may have a relative cooling power (RCP) of J / kg.

In some embodiments of the present invention, the magnetocaloric alloy may have a ribbon shape.

Method for manufacturing a magnetocaloric alloy according to the technical idea of the present invention for achieving the above technical problem is to prepare a master alloy of a magnetocaloric alloy material of the composition represented by Mn _2-ab Fe _a X _b P _1-c Y _c Preparing a ribbon by melt spinning the prepared master alloy; and heat treating the ribbon to prepare and homogenize a phase having excellent magnetocaloric effect, wherein X is Zr or Hf. , Y is at least one selected from Ge and Si, and may be 0.8≤a + b≤1.0, 0 <b≤0.1, 0.4≤c≤0.6.

In some embodiments of the present invention, the step of preparing the ribbon may be manufactured at a speed of 30 to 50 m / s through melt spinning.

In some embodiments of the present invention, the heat treatment step may be a heat treatment at 900 to 1200 ℃.

The magnetocaloric alloy according to the technical idea of the present invention may provide a high cooling magnetocaloric alloy composition having a high ΔS _M (entropy change) value.

In addition, the method for producing a magnetocaloric alloy according to the present invention can produce a homogeneous alloy while preparing a phase having excellent magnetocaloric effect.

The effects of the present invention described above have been described by way of example, and the scope of the present invention is not limited by these effects.

1 is a schematic diagram showing cooling and heat generation according to self-arrangement.
Figure 2 is a photograph showing the Arc button and Melt spinning ribbon prepared according to an embodiment of the present invention.
3 is a magnetization graph according to temperature and a magnetic entropy change graph according to temperature.
4 is a magnetization graph according to (a) temperature and (b) graph of magnetic entropy change according to temperature of the magnetocaloric alloy Mn _1.2 Fe _0.79 Zr _0.01 P _0.6 Ge _0.4 prepared according to an embodiment of the present invention.
5 is a magnetization graph according to (a) temperature of the magnetocaloric alloy Mn _1.2 Fe _0.79 Hf _0.01 P _0.6 Ge _0.4 prepared according to an embodiment of the present invention and (b) magnetic entropy change graph according to the temperature.
6 is a magnetization graph according to (a) temperature of the magnetocaloric alloy Mn _1.0 Fe _0.99 Zr _0.01 P _0.5 Si _0.5 prepared according to an embodiment of the present invention and (b) graph of magnetic entropy change according to temperature.
7 is a magnetization graph according to (a) temperature of the magnetocaloric alloy Mn _1.0 Fe _0.99 Hf _0.01 P _0.5 Si _0.5 prepared according to an embodiment of the present invention and (b) magnetic entropy change graph according to the temperature.
8 is a graph showing the magnetocaloric effect according to the addition element of the magnetocaloric alloy prepared according to an embodiment of the present invention.
9 is a graph showing the magnetocaloric effect according to the heat treatment temperature change of the magnetocaloric alloy prepared according to an embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. Embodiments of the present invention are provided to more fully explain the technical idea of the present invention to those skilled in the art, and the following embodiments may be modified in various other forms, and The scope of the technical idea is not limited to the following examples. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the inventive concept to those skilled in the art. As used herein, the term "and / or" includes any and all combinations of one or more of the listed items. Like numbers refer to like elements all the time. Furthermore, various elements and regions in the drawings are schematically drawn. Therefore, the technical idea of the present invention is not limited by the relative size or spacing drawn in the accompanying drawings.

The magnetocaloric alloy according to the present invention is represented by the formula Mn _2-ab Fe _a X _b P _1-c Y _c , X is Zr or Hf, Y is at least one selected from Ge, Si, 0.8≤a + b ≦ 1.0, 0 <b ≦ 0.1, and 0.4 ≦ c ≦ 0.6. The magnetocaloric effect can be improved by including Mn, Fe, P, Ge, or Si as the main constituent elements and partially substituting Fe by adding Zr and Hf elements.

In addition, the magnetocaloric alloy may have a ribbon shape. Ribbon-shaped magnetocaloric alloys can reduce the heat treatment time to obtain a homogeneous phase than the bulk manufacturing method.

Curie temperature (T _c ) is the temperature that occurs when a phase transition occurs in a magnetocaloric material.As the temperature decreases, a transition from the austenite phase to the martensite phase occurs near the Curie temperature (T _c ). The magnetization value is increased. In addition, since it is a section that changes from paramagnetic to ferromagnetic, the range in which the magnetic cooling technology such as refrigerator, air conditioner, etc. can be applied is the product operated at room temperature, and thus the temperature range in which the magnetocaloric effect, which is the principle of the magnetic cooling technology, appears is room temperature. It is advantageous to appear in the vicinity.

The wider the temperature range (ΔTad) in which the magnetocaloric effect occurs, the better the cooling capacity. Therefore, the cooling capacity can be improved by using several materials having different Curie temperatures (T _c ) together (layered MCMs). The temperature range is not very low temperature, so it can be introduced into the applications to be applied, and the combination of materials can be used to improve cooling capacity.

Figure 2 is a photograph showing the arc button, Melt spinning equipment and Melt spinning ribbon manufactured according to an embodiment of the present invention. The method of manufacturing a magnetocaloric alloy according to the present invention includes a step of manufacturing a master alloy, a step of manufacturing a ribbon and a heat treatment.

The step of preparing the master alloy is to prepare a master alloy of the magnetocaloric alloy material of the composition represented by Mn _2-ab Fe _a X _b P _1-c Y _c , for example by arc melting method (arc melting) The master alloy can be produced. X is Zr or Hf, and Y is at least one selected from Ge and Si, and may be 0.8 ≦ a + b ≦ 1.0, 0 <b ≦ 0.1, and 0.4 ≦ c ≦ 0.6.

In the preparing of the ribbon, the ribbon may be manufactured at a speed of 30 to 50 m / s by preparing a ribbon through melt spinning of the prepared master alloy.

The melt spinning is solidified by instantaneous solidification while contacting the rapidly rotating Cu wheels of the liquid sprayed through the nozzle to produce a ribbon-shaped alloy. Alloys produced by melt spinning can produce fine microstructures and increase solute solubility. It also has the advantage of reducing macro-segregation or micro-segregation and forming metastable phases. And it is possible to reduce the heat treatment time to obtain a homogeneous phase than the manufacturing method in bulk.

Alloys fabricated using the arc melting and melt spinning methods overcome the limitations in terms of mechanical stability during which thermal or magnetic field cycling, resulting from strains caused by volume changes, causes the breakage of bulk operations. Can be.

The heat treatment step is a step of heat-treating the ribbon for the production and homogenization of the phase having excellent magnetocaloric effect. The heat treatment step may be a heat treatment for 24 hours at 900 to 1200 ℃ in a vacuum state of 10 ^-5 Torr through a high vacuum heat treatment furnace.

Hereinafter, the details of the process of the present invention will be described through examples.

Table 1 is a table showing the magnetocaloric alloy and its magnetocaloric characteristics according to the present invention, Curie temperature (T _c ), magnetic entropy change (ΔS _M ) and Contains a measure of relative cooling power (RCP).

No. alloy T _C (K) | △ S _m | (J / kg
(△ H = 2T) RCP (J / kg) Example 1 Mn _1.2 Fe _0.79 Zr _0.01 P _0.6 Ge _0.4 242 7.52 94.84 Example 2 Mn _1.2 Fe _0.75 Zr _0.05 P _0.6 Ge _0.4 227 6.14 69.64 Example 3 Mn _1.2 Fe _0.7 Zr _0.1 P _0.6 Ge _0.4 187 0.15 5.91 Example 4 Mn _1.2 Fe _0.79 Hf _0.01 P _0.6 Ge _0.4 237 6.99 86.89 Example 5 Mn _1.2 Fe _0.75 Hf _0.05 P _0.6 Ge _0.4 177 1.91 40.59 Example 6 Mn _1.2 Fe _0.7 Hf _0.1 P _0.6 Ge _0.4 402 0.007 0.16 Example 7 Mn _1.2 Fe _0.75 Zr _0.05 P _0.4 Ge _0.6 292 3.76 56.71 Example 8 Mn _1.2 Fe _0.75 Hf _0.05 P _0.4 Ge _0.6 252
332 0.59
0.60 132.73 Example 9 Mn _1.0 Fe _0.99 Zr _0.01 P _0.5 Si _0.5 262 5.58 154.71 Example 10 Mn _1.0 Fe _0.99 Hf _0.01 P _0.5 Si _0.5 252 5.09 151.42 Example 11 Mn _1.0 Fe _0.95 Zr _0.05 P _0.5 Si _0.5 232 0.94 41.68 Example 12 Mn _1.0 Fe _0.9 Zr _0.1 P _0.5 Si _0.5 182 0.11 10.15

In Table 1, Examples 1 to 8 in the high-cooling magnetocaloric alloy is an alloy in which Fe is partially substituted by adding Zr and Hf elements to an alloy containing Mn, Fe, P, and Ge as main constituent elements. Examples 9 to 12 are alloys in which Fe is partially substituted by adding Zr and Hf elements to an alloy containing Mn, Fe, P, and Si as main constituent elements.

Mn ₂ P, Fe, Ge, Si, Zr, Hf elements of 2N ~ 3N grade are dissolved in a vacuum arc furnace to prepare a mother alloy, and the prepared mother alloy is melt-spun using 39.3 A ribbon with a width of 3-4 mm was produced at a speed of m / s.

When the ribbon is manufactured by the melt spinning process, the quenching process can reduce defects such as pores or dislocations that may exist inside, thereby improving properties and obtaining a desired phase through heat treatment. Can be.

All processed samples were evaluated for magnetocaloric properties through a Vibrating Sample Magnetometer (VSM). The VSM records the applied magnetic field applied by the Hall probe, and the magnetization value of the sample is measured by recording the electromotive force obtained when vibrating the sample by Faraday's law. Through this, the Curie temperature (T _c ) and the magnetic entropy change amount (ΔS _M ) can be obtained to measure the magnetocaloric effect indirectly.

3 is a magnetization graph according to temperature and a magnetic entropy change graph according to temperature. Indirectly, the magnetocaloric effect can be measured by analyzing the Curie temperature (T _C ) and the magnetic entropy change (ΔS _M ) through the magnetization graph and the magnetic entropy variation graph. The relative cooling power (RCP) is obtained by multiplying the half width of the peak by the height of the peak at the curie temperature T _C.

Table 1 shows the results of confirming the magnetocaloric characteristics of Examples 1 to 12 by performing heat treatment at 1100 ° C. for 24 hours.

As in Examples 1 to 2 and Examples 4 to 5, Y is Ge, and a magnetocaloric alloy Mn _2-ab Fe _a X _b P _{1 having} 0.7 ≦ a ≦ 0.8, 0 <b <0.1, 0.4 ≦ c <0.5 _-c Y _c is heat-treated at 1000 to 1200 ° C. to show T _c (Curie temperature) at 210 ± 40K, and has a relative cooling power (RCP) of 40 to 100 J / kg at 210 ± 40K.

4 is a magnetization graph according to (a) temperature of the magnetocaloric alloy Mn _1.2 Fe _0.79 Zr _0.01 P _0.6 Ge _0.4 prepared according to Example 1 of the present invention and (b) a graph of magnetic entropy change according to temperature. In the magnetocaloric alloy Mn _2-ab Fe _a X _b P _1-c Y _c , X is Zr, Y is Ge, 240 ± 10K when 0.7≤a≤0.8, 0 <b <0.05, 0.4≤c <0.5 At T _c (Curie temperature) is shown and may have a relative cooling power (RCP) of 90 to 100 J / kg at 240 ± 10K. Especially 6.5 to 8.5 The high magnetic entropy change amount (ΔS _M ) of J / kgK is shown.

5 is a magnetization graph according to (a) temperature of the magnetocaloric alloy Mn _1.2 Fe _0.79 Hf _0.01 P _0.6 Ge _0.4 prepared according to Example 4 of the present invention and (b) graph of magnetic entropy change according to temperature. In the magnetocaloric alloy Mn _2-ab Fe _a X _b P _1-c Y _c , X is Hf, Y is Ge, 240 ± 10K when 0.7≤a≤0.8, 0 <b <0.05, 0.4≤c <0.5 At T _c (Curie temperature) is shown, and may have a relative cooling power (RCP) of 80 to 90 J / kg at 240 ± 10K. Especially 6 to 8 The high magnetic entropy change amount (ΔS _M ) of J / kgK is shown.

In addition, as in Examples 7 to 8, Y is Ge, and the magnetocaloric alloy Mn _2-ab Fe _a X _b P _1-c Y _c having 0.7 ≦ a ≦ 0.8 and 0.5 <c ≦ 0.6 is used at 1000 to 1200 ° C. The heat treatment shows _Tc (Curie temperature) at 290 ± 50K, and has a relative cooling power (RCP) of 50 to 140 J / kg at 290 ± 50K.

In particular, when X, Zc, 0.03 <b <0.1, T _c (Curie temperature) appears at 290 ± 10K and has a relative cooling power (RCP) of 50 to 60 J / kg at 290 ± 10K.

In addition, X exhibits T _c (Curie temperature) at 250 ± 10K and 330 ± 10K when Hf, 0.03 <b <0.1, and has a relative cooling power (RCP) of 125 to 135 J / kg at 250 ± 10K. The relative cooling power (RCP) of 125 to 130 J / kg at 330 ± 10K.

Increasing the content of Ge elements in the Mn _1.2 Fe _0.75 X _0.05 P _0.6 Ge _0.4 alloy of Examples 2 and 5 and the Mn _1.2 Fe _0.75 X _0.05 P _0.4 Ge _0.6 (X = Zr, Hf) alloys of Examples 7-8 In comparison, when the Ge element is increased, the Curie temperature (T _c ) increases in the alloy containing the Zr element, but the magnetic entropy change amount (ΔS _M ) and the magnetic cooling capacity (RCP) decrease. However, in the alloy containing Hf element, Curie temperature (T _c ) and self-cooling capacity (RCP) increase but magnetic entropy change amount (ΔS _M ) decreases.

In the alloy containing Hf element as in Example 8, the self-cooling capacity (RCP) is increased, which means that the S value is repeatedly increased and decreased like the camel's shape. Calculated by the self cooling capacity (RCP) of Therefore, the S value decreases as the content of Ge element increases, but the Curie temperature (T _c ) and its area increase to realize the magnetocaloric effect in a wider area.

As in Examples 9 and 10, Y is Si, 0.9 ≦ a ≦ 1.0, 0 <b <0.05, 0.5 ≦ c <0.6, and the magnetocaloric alloy Mn _2-ab Fe _a X _b P _1-c Y _c is 1000 to Heat treatment at 1200 ° C. shows T _c (Curie temperature) at 260 ± 20K, and has a relative cooling power (RCP) of 145 to 160 J / kg at 260 ± 20K. It also shows a high magnetic entropy change amount (ΔS _M ) of 4 to 6.5 J / kgK.

6 is a magnetization graph according to (a) temperature and a graph of magnetic entropy change according to (b) temperature of the magnetocaloric alloy Mn _1.0 Fe _0.99 Zr _0.01 P _0.5 Si _0.5 prepared according to Example 9 of the present invention. In the magnetocaloric alloy Mn _2-ab Fe _a X _b P _1-c Y _c , X is Zr, Y is Si, 260 ± 10K when 0.9≤a≤1.0, 0 <b <0.05, 0.5≤c <0.6 _Tc (Curie temperature) is shown, and has a high relative cooling power (RCP) of 150 to 160 J / kg and a magnetic entropy change (ΔS _M ) of 4.5 to 6.5 J / kgK at 260 ± 10K.

7 is a magnetization graph according to (a) temperature of the magnetocaloric alloy Mn _1.0 Fe _0.99 Hf _0.01 P _0.5 Si _0.5 prepared according to Example 10 of the present invention and (b) graph of magnetic entropy change according to temperature. In the magnetocaloric alloy Mn _2-ab Fe _a X _b P _1-c Y _c , X is Hf, Y is Si, and at 250 ± 10K when 0.9≤a≤1.0, 0 <b <0.05, 0.5≤c <0.6 T _c (Curie temperature) is shown and has a high relative cooling power (RCP) of 145 to 155 J / kg and a magnetic entropy change (ΔS _M ) of 4 to 6 J / kgK at 250 ± 10K.

As in Examples 9 and 10, in the MnFeXPSi (X = Zr, Hf) alloy, the properties of the two alloys are almost similar, but the alloy to which the Zr element is added has slightly improved properties.

8 is a graph showing the magnetocaloric effect according to the addition element of the magnetocaloric alloy prepared according to an embodiment of the present invention.

Examples 1 to 2 and Examples 4 to 5 in which the content of the additive element Zr or Hf in the MnFeXPGe (X = Zr, Hf) alloy is 0 <b <0.1 are superior to Examples 3 and 6, where b = 0.1. Has characteristics. In addition, as the content of the substitution element Zr or Hf increases, the Curie temperature (T _c ), the change in magnetic entropy (ΔS _M ), and the self-cooling ability (RCP) generally decrease. In addition, when the Zr and Hf elements are added, the magnetocaloric properties are superior to those of the Hf element.

As in Examples 9 to 10, it can be seen that the properties of the two alloys in MnFeXPSi (X = Zr, Hf) alloys are almost similar. However, Example 9, which is an alloy to which Zr element is added, has a slightly improved characteristic than that in the case where Hf element is added. Comparing the magnetocaloric properties of Examples 9 and 11 to 12, the Curie temperature (T _c ), the change in magnetic entropy (ΔS _M ), and the magnetic cooling capacity (RCP) were all increased as the content of the substitution element Zr or Hf increased. It tends to decrease.

Table 2 is a table comparing the magnetocaloric characteristics according to the heat treatment temperature change of the magnetocaloric alloy according to the present invention, Figure 9 is a magnetocaloric effect according to the heat treatment temperature change of the magnetocaloric alloy prepared according to an embodiment of the present invention Is a graph. Curie temperature (T _C ), magnetic entropy change amount (ΔS _M ) of the magnetocaloric alloys of Examples 1 to 6 and Examples 9 to 10, and As a result of RCP (Relative cooling power), the result of 24 hours heat treatment at 1100 ℃ and 12 hours heat treatment at 950 ℃ was analyzed.

No. Magnetocaloric alloy T _c (K) | △ S _M | (J / kgK)
(△ H = 2T) RCP (J / kg) 1100 ℃ 950 ℃ 1100 ℃ 950 ℃ 1100 ℃ 950 ℃ Example 1 Mn _1.2 Fe _0.79 Zr _0.01 P _0.6 Ge _0.4 242 442 7.52 3.42 94.84 150.62 Example 2 Mn _1.2 Fe _0.75 Zr _0.05 P _0.6 Ge _0.4 227 367 6.14 3.67 69.64 108.30 Example 3 Mn _1.2 Fe _0.7 Zr _0.1 P _0.6 Ge _0.4 187 367
397 0.15 1.30
1.31 5.91 122.79 Example 4 Mn _1.2 Fe _0.79 Hf _0.01 P _0.6 Ge _0.4 237 447 6.99 4.57 86.89 197.71 Example 5 Mn _1.2 Fe _0.75 Hf _0.05 P _0.6 Ge _0.4 177 377 1.91 2.62 40.59 140.66 Example 6 Mn _1.2 Fe _0.7 Hf _0.1 P _0.6 Ge _0.4 402 322 0.007 1.71 0.16 105.11 Example 9 Mn _1.0 Fe _0.99 Zr _0.01 P _0.5 Si _0.5 262 287 5.58 2.65 154.71 196.95 Example 10 Mn _1.0 Fe _0.99 Hf _0.01 P _0.5 Si _0.5 252 355 5.09 9.39 151.42 216.21

As in Examples 1 to 6 and Examples 9 to 10, the magnetocaloric alloy Mn _2-ab Fe _a X _b P _1-c Y _c according to the present invention X is Zr or Hf, Y is at least one selected from Ge and Si, and when 0.8 ≦ a + b ≦ 1.0, 0 <b ≦ 0.1, 0.4 ≦ c ≦ 0.6, heat treatment is performed at 900 to 1000 ° C. to 370. T _c (Curie temperature) appears at ± 90K, and has a relative cooling power (RCP) of 100 to 220 J / kg and a magnetic entropy change (ΔS _M ) of 1 to 10 J / kgK at 370 ± 90K.

In particular, as in Examples 1 to 6 of the present invention, Y is Ge, 0.7≤a≤0.8, 0.4≤c <0.5, T _c (Curie temperature) appears at 380 ± 70K, and at 380 ± 70K Relative cooling power (RCP) of 100 to 200 J / kg and magnetic entropy change (ΔS _M ) of 1 to 5 J / kgK.

In addition, as in Examples 9 to 10 of the present invention, Y is Si, 0.9 ≦ a ≦ 1.0, 0.5 ≦ c <0.6, and T _c (Curie temperature) appears at 320 ± 40K, and at 320 ± 40K. Relative cooling power (RCP) of 190 to 220 J / kg and magnetic entropy change (ΔS _M ) of 2 to 10 J / kgK.

As a result of the magnetocaloric alloys of Examples 1 to 6 heat-treated at 900 to 1000 ° C., the Curie temperature (T _c ) and the magnetic entropy change amount were increased as the content of the additive element Hf increased in the magnetocaloric alloys of Examples 4 to 6. (ΔS _M ) and both self cooling capacity (RCP) decrease. This shows a similar trend as when heat treated at 1000 to 1200 ° C.

However, the Curie temperature (T _c ) and the self-cooling capacity (RCP) decrease with increasing Zr content in the magnetocaloric alloys of Examples 1 to 3 heat-treated at 900 to 1000 ° C., but the change in magnetic entropy (△ S _M ) increases and decreases. This shows a different tendency than when heat-treated at 1000 to 1200 ° C.

Compared with the heat treatment temperature, the Curie temperature (T _c ) and the self cooling capacity (RCP) generally increase as the temperature decreases from 1000 to 1200 ° C. to 900 to 1000 ° C. However, the change in magnetic entropy (ΔS _M ) decreases when the Zr content is 0.01, 0.05 and Hf content is 0.01, but increases when the Zr content is 0.1 and Hf content is 0.05 and 0.1.

Compared with the addition elements Zr and Hf in the MnFeXPGe (X = Zr, Hf) alloy, the magnetocaloric properties were generally higher when the Hf element was added in alloys heat-treated at 900 to 1000 ° C than when heat-treated at 1000 to 1200 ° C. You can see that it is better.

Comparing the amount of change in magnetic entropy (ΔS _M ), when a small amount of addition element Zr or Hf was added (0.01), it showed higher magnetic entropy change when the heat treatment temperature was high, but when the addition element content was increased, the heat treatment temperature was lower. Higher magnetic entropy change (ΔS _M ).

The results of the magnetocaloric alloys of Examples 9 to 10 heat-treated at 900 to 1000 ° C. showed different tendencies depending on the elements added in the MnFeXPSi (X = Zr, Hf) alloy. When Zr is added, the values except for the amount of magnetic entropy change (ΔS _M ) increase when the heat treatment temperature decreases, but when the Hf element is added, all characteristic values increase as the heat treatment temperature decreases. These results with the addition of the Hf element show the opposite results to those of (Zr, Hf = 0.01) when the amounts of added elements are the same in the MnFeXPGe (X = Zr, Hf) alloys of Examples 1 and 4.

The magnetocaloric alloys heat-treated at 1000 to 1200 ° C generally have a Curie temperature (T _c ) of less than 300K, so that they can be applied to low temperature magnetic refrigerators, and heat-treated at 900 to 1000 ° C. Since the Curie temperature (T _c ) is higher than that of 1000 to 1200 ° C. heat treatment, it may be used in a high temperature magnetic cooler.

As described above, the magnetocaloric alloy and its manufacturing method according to the present invention provides a high-cooling magnetocaloric alloy composition having a high ΔS _M (entropy change) value, and to produce a phase having excellent magnetocaloric effect by the above manufacturing method Homogeneous alloys can be produced.

The technical spirit of the present invention described above is not limited to the above-described embodiments and the accompanying drawings, and various substitutions, modifications, and changes can be made without departing from the technical spirit of the present invention. It will be apparent to those of ordinary skill in the art.

Claims (15)

Represented by the formula Mn _2-ab Fe _a X _b P _1-c Y _c ,
X is Zr or Hf, Y is at least one selected from Ge and Si,
A magnetocaloric alloy with 0.8 ≦ a + b ≦ 1.0, 0 <b ≦ 0.1, and 0.4 ≦ c ≦ 0.6.
The method of claim 1,
Y is Ge, 0.7 ≦ a ≦ 0.8, 0 <b <0.1, 0.4 ≦ c <0.5,
Heat treatment at 1000 to 1200 ° C,
T _c (Curie temperature) appears at 210 ± 40K,
The magnetocaloric alloy having a relative cooling power (RCP) of 40 to 100 J / kg at 210 ± 40K.
The method of claim 2,
X is Zr, 0 <b <0.05,
T _c (Curie temperature) appears at 240 ± 10K,
The magnetocaloric alloy having a relative cooling power (RCP) of 90 to 100 J / kg and a magnetic entropy change (ΔS _M ) of 6.5 to 8.5 J / kgK at 240 ± 10K.
The method of claim 2,
X is Hf, 0 <b <0.05,
T _c (Curie temperature) appears at 240 ± 10K,
The magnetocaloric alloy having a relative cooling power (RCP) of 80 to 90 J / kg and a magnetic entropy change (ΔS _M ) of 6 to 8 J / kgK at 240 ± 10K.
The method of claim 1,
Y is Ge, 0.7 ≦ a ≦ 0.8, 0.5 <c ≦ 0.6,
Heat treatment at 1000 to 1200 ° C,
T _c (Curie temperature) appears at 290 ± 50 K,
The magnetocaloric alloy having a relative cooling power (RCP) of 50 to 140 J / kg at 290 ± 50K.
The method of claim 5,
X is Zr, 0.03 <b <0.1,
T _c (Curie temperature) appears at 290 ± 10K,
The magnetocaloric alloy having a relative cooling power (RCP) of 50 to 60 J / kg at 290 ± 10K.
The method of claim 5,
X is Hf, 0.03 <b <0.1,
T _c (Curie temperature) appears at 250 ± 10K and 330 ± 10K,
It has a relative cooling power (RCP) of 130 to 140 J / kg at 250 ± 10K
The magnetocaloric alloy having a relative cooling power (RCP) of 130 to 140 J / kg at 330 ± 10K.
The method of claim 1,
Y is Si, 0.9 ≦ a ≦ 1.0, 0 <b <0.05, 0.5 ≦ c <0.6,
Heat treatment at 1000 to 1200 ° C,
T _c (Curie temperature) appears at 260 ± 20K,
The magnetocaloric alloy having a relative cooling power (RCP) of 145 to 160 J / kg and a magnetic entropy change (ΔS _M ) of 4 to 6.5 J / kgK at 260 ± 20K.
The method of claim 8,
X is Zr,
T _c (Curie temperature) appears at 260 ± 10K,
The magnetocaloric alloy having a relative cooling power (RCP) of 150 to 160 J / kg at 260 ± 10K.
The method of claim 8,
X is Hf,
T _c (Curie temperature) appears at 250 ± 10K,
The magnetocaloric alloy having a relative cooling power (RCP) of 145 to 155 J / kg at 250 ± 10K.
The method of claim 1,
Heat-treated at 900 to 1000 ° C,
T _c (Curie temperature) appears at 370 ± 90K,
The magnetocaloric alloy having a relative cooling power (RCP) of 100 to 220 J / kg and a magnetic entropy change (ΔS _M ) of 1 to 10 J / kgK at 370 ± 90K.
The method according to any one of claims 1 to 11,
The magnetocaloric alloy is a magnetocaloric alloy in the shape of a ribbon.
Preparing a master alloy of a magnetocaloric alloy material having a composition represented by Mn _2-ab Fe _a X _b P _{1 -c} Y _c ;
Preparing a ribbon through melt spinning of the prepared mother alloy; and
Heat treating the ribbon to prepare and homogenize a phase having excellent magnetocaloric effect, wherein X is Zr or Hf, and Y is at least one selected from Ge and Si, and 0.8 ≦ a + b ≦ 1.0 And 0 <b ≦ 0.1 and 0.4 ≦ c ≦ 0.6.
The method of claim 13,
The step of preparing the ribbon is a method of producing a magnetocaloric alloy to produce a ribbon at a speed of 30 to 50 m / s through a rapid spinning method (melt spinning).
The method of claim 13,
The heat treatment step is a method of producing a magnetocaloric alloy is heat-treated at 900 to 1200 ℃.

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