Magnetic refrigeration LaFe13-xSix-based alloy material and preparation method thereof

Abstract

The invention discloses a magnetic refrigeration LaFe < 13-x > Si < x >-based alloy material and a preparation method thereof, the chemical formula of the alloy material is LaFe < 11.6-x > Co < x > Si < 1.4 >, and x is greater than or equal to 0.5 and less than or equal to 0.9. The preparation method comprises the following steps: 1, preparing raw materials according to the chemical formula of the alloy material, and smelting to obtain a cast ingot sample; and 2, after the ingot casting sample is subjected to high-temperature annealing, the ingot casting sample is cooled to the room temperature along with a furnace, and the LaFe < 11.6-x > CoxSi < 1.4 > alloy is obtained. The alloy material is the room-temperature secondary phase-change magnetic refrigeration alloy with the Curie temperature close to the room temperature, large magnetocaloric performance and hysteresis approaching to zero, the preparation time is greatly shortened, and the problems that an existing primary phase-change magnetic refrigeration material LaFe13-xSix alloy is low in Curie temperature, large in hysteresis, low in preparation efficiency and the like are solved.

Description

Technical Field

[0001] The present invention relates to the field of magnetic refrigeration technology, and in particular to a magnetic refrigeration LaFe 13-x Si x Base alloy material and preparation method thereof. Background Art

[0002] Magnetic refrigeration relies on the magnetocaloric effect of materials, and has the characteristics of high efficiency and environmental protection. It is an ideal alternative technology to traditional compression refrigeration. The size of the magnetocaloric effect of the magnetic refrigeration medium is the key to the cooling capacity and efficiency. The development of materials with giant magnetocaloric effect plays a decisive role in the application of room temperature magnetic refrigeration technology. At the same time, it is also of great significance to the thermal conductivity, magnetic permeability, strong corrosion resistance, and processing type of the medium.

[0003] LaFe 13-x Si x The alloy has a magnetic field-induced first-order magnetic phase transition during the isothermal magnetization process, and is accompanied by a giant magnetocaloric effect near the Curie temperature. Because the raw materials are cheap, this series of alloys is a very promising magnetic refrigeration material. However, the Curie temperature of this series of alloys is around 200K, which is not suitable for the field of room temperature magnetic refrigeration, resulting in significant restrictions on its application and promotion. In addition, since this series of alloys is a typical first-order phase change material, there is obvious thermal hysteresis in the magnetic cycle, which affects the refrigeration efficiency. Therefore, a new solution is sought to obtain LaFe2+ with its Curie temperature raised to near room temperature while maintaining good magnetocaloric properties. 13-x Si x Alloy materials, for LaFe 13-x Si x The industrial application of alloys is of great significance. 13-x Si x The 1:13 phase in the alloy directly contributes to refrigeration. It is formed by the reaction of the high-temperature primary γ-Fe phase and the liquid phase. During the preparation process, several weeks of heat treatment are required to obtain a sample with a high main phase content, resulting in a long preparation cycle and low efficiency.

[0004] In view of this, this patent application is filed. Summary of the invention

[0005] In order to solve the above mentioned LaFe 13-x Si x The alloy material is not suitable for the field of room temperature magnetic refrigeration, has limited application, and has obvious thermal hysteresis in the magnetic cycle and low preparation efficiency. The present application provides a magnetic refrigeration LaFe 13-x Si xA base alloy material, a preparation method thereof and a magnetic refrigeration device are also provided, and a room temperature secondary phase change magnetic refrigeration alloy with a Curie temperature near room temperature, large magnetocaloric performance, and magnetic hysteresis approaching zero is obtained.

[0006] The present invention is achieved through the following technical solutions:

[0007] The first object of the present invention is to provide a magnetic refrigeration LaFe 13-x Si x Base alloy material, the chemical formula of the alloy material is LaFe 11.6-x Co x Si 1.4 , where 0.5≤x≤0.9.

[0008] In the present invention, the chemical formula of the alloy material is rationally designed. 13-x Si xAdding element Co to the alloy and increasing the content of element Co have a good regulating effect on the Curie temperature. When x=0.1, 0.3, 0.5, 0.7, and 0.9, the Curie temperatures of the temperature rise measurement are 207.34K, 225.50K, 250.02K, 275.75K, and 298.15K, and the temperature of the temperature drop measurement are 202.29K, 224.38K, 249.93K, 275.42K, and 298.20K, respectively. The corresponding thermal hysteresis is 5.05K, 1.12K, 0.09K, 0.33K, 0.22K, and 0.05K, respectively. With the increase of x, the thermal hysteresis of the alloy gradually decreases. When x>0.3, the thermal hysteresis of the alloy can be ignored. Secondly, due to the addition of Co, the hysteresis of the alloy is also significantly reduced. When x = 0.1, 0.3, 0.5, 0.7, and 0.9, the hysteresis is 26.24 J / kg, 4.25 J / kg, 2.08 J / kg, 0.21 J / kg, and 0.03 J / kg, respectively. Like thermal hysteresis, when x > 0.3, the hysteresis of the alloy can also be ignored. In addition, the alloy with the addition of Co can also maintain good magnetocaloric properties. When x = 0.1, 0.3, 0.5, 0.7, and 0.9, the maximum magnetic entropy change of the alloy under a 2T magnetic field is 12.50 J / kg·K, 8.10 J / kg·K, 7.40 J / kg·K, 6.57 J / kg·K, and 5.90 J / kg·K, respectively, and the relative cooling capacity is 139.59 J / kg, 125.00 J / kg, 123.93 J / kg, 116.41 J / kg, and 171.24 J / kg, respectively. The value of the relative cooling capacity does not decrease with the increase of the Co content. On the contrary, due to the addition of Co, the magnetic phase transition temperature range of the alloy increases, and the relative cooling capacity also increases, especially when x = 0.9, its relative cooling capacity reaches the maximum. Therefore, when x is between 0.5 and 0.9, it has the best performance. Finally, since the addition of Co does not reduce the content of the 1:13 main phase in the alloy, LaFe 11.6-x Co x Si 1.4 The mass percentage of the main phase in the alloy is above 95%, and the organizational composition is uniform. In summary, LaFe 11.6-x Co x Si 1.4 (0.5≤x≤0.9) alloy has the characteristics of almost zero thermal hysteresis and magnetic hysteresis, high main phase content, uniform structure, and large magnetic entropy change. 10.7 Co 0.9 Si 1.4 The Curie temperature of the alloy is around 300K and it has good magnetocaloric properties. Therefore, the alloy is a room-temperature secondary phase change magnetic refrigeration material with great application prospects.

[0009] As a preferred design, the mass percentage of the 1:13 phase of the alloy material is greater than or equal to 95% to ensure that the material per unit mass has good magnetocaloric efficiency.

[0010] As a preferred design, the alloy material has a uniform organizational structure.

[0011] As a preferred design, the alloy material is a room temperature secondary phase change material, and the Curie temperature of the alloy material can be adjusted to room temperature; preferably, LaFe 10.7 Co 0.9 Si 1.4 The Curie temperature of the alloy is 298.15K±0.50K.

[0012] The alloy material of the present invention is a room temperature secondary phase change material. Compared with the current LaFe 13-x Si x The alloy is a primary phase change magnetic refrigeration material. The secondary phase change material of the present invention enables the magnetic refrigeration technology to have a wider temperature range (the Curie temperature is raised to near room temperature) and better refrigeration capacity, and has a secondary magnetic phase change behavior that is more advantageous in the prototype cycle, and thus has broad application prospects.

[0013] As a preferred design, when x = 0.9, LaFe 10.7 Co 0.9 Si 1.4 The maximum entropy change of the alloy is 5.90 J / kg·K.

[0014] The maximum entropy change of the alloy material of the present invention under a 2T magnetic field reaches 5.9 J / kg·K, which is comparable to the high-purity Gd of a typical secondary phase change magnetic refrigeration medium, but the price of its raw materials is less than 10% of that of Gd. 13-x Si x It provides important core technologies and related parameters for the industrial production of alloys.

[0015] The second object of the present invention is to provide any of the above-mentioned magnetic refrigeration LaFe 13-x Si x The method for preparing the base alloy material comprises the following steps:

[0016] Step 1: preparing raw materials according to the chemical formula of the alloy material, and smelting to obtain an ingot sample;

[0017] Step 2: After the ingot sample is annealed at high temperature, it is cooled to room temperature to obtain LaFe 11.6-x Co x Si 1.4 alloy.

[0018] As a preferred design, the purity of the raw materials is respectively: La>99.8%, Fe>99.4%, Co>99.9%, Si>99.99%, and all of them can be obtained through commercial channels.

[0019] As a preferred design, in step 1, the smelting is performed by remelting in a tungsten electrode non-consumable arc furnace filled with high-purity inert gas to obtain an ingot sample;

[0020] And / or, the inert gas is argon;

[0021] And / or, the number of remelting in a non-consumable arc furnace is greater than or equal to 6 times.

[0022] As a preferred design, in step 2, the temperature of high temperature annealing of the ingot sample is (1250±20)°C, and the holding time is (4±1) hours;

[0023] And / or in step 2, the ingot sample is placed in a corundum crucible during high-temperature annealing in a high-vacuum molybdenum wire furnace.

[0024] Preferably, the high temperature annealing temperature is 1250°C.

[0025] In the present invention, Co element is added to the alloy, and the components of the alloy material are reasonably designed. During preparation, the high-temperature annealing temperature can be increased to (1250±20)°C, and the temperature can be kept at a temperature for (4±1) hours to obtain a room-temperature secondary magnetic phase change material with uniform magnetocaloric properties. Compared with the current preparation process that requires several weeks of heat treatment, the present invention significantly shortens the preparation cycle and improves the preparation efficiency.

[0026] The best heat treatment temperature in the present invention is 1250°C. 11.6-x Co x Si 1.4 The component x=0 in the alloy, i.e. LaFe 11.6 Si 1.4 The alloy was heat treated at different temperatures for 5 hours and the results showed that the content of impurities in the alloy was very high after heat treatment at 1200℃ and below and 1300℃ and above. Considering the uncertainty of the temperature sensor is 20℃, the optimal heat treatment temperature is determined to be (1250±20)℃. In addition, the SEM analysis of the x=0.5, 0.7, and 0.9 alloys after heat treatment at 1250℃ for 5 hours showed that the content of the 1:13 phase in the three alloys was very high and the microstructure was evenly distributed.

[0027] As a preferred design, in step 2, the ingot sample is placed in a corundum crucible for high-temperature annealing in a high-vacuum molybdenum wire furnace.

[0028] The third object of the present invention is to provide a magnetic refrigeration device, comprising the alloy material as described in any one of the above items or the alloy material obtained by any one of the above preparation methods.

[0029] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0030] (1) In the present invention, the chemical formula of the alloy material is rationally designed. 13-x Si x Adding the element Co to the alloy and increasing the content of the element Co has a good regulating effect on the Curie temperature. At the same time, due to the addition of Co and the reasonable design of the content of each element, the obtained alloy material has greater magnetocaloric properties, and the hysteresis is close to zero. It is a secondary phase change magnetic refrigeration material with high main phase content, uniform organizational composition, stable performance, and large magnetic entropy change. It solves the technical problems of low Curie temperature and large hysteresis of the current primary phase change magnetic refrigeration material.

[0031] (2) The maximum entropy change of the alloy material of the present invention under a 2T magnetic field is 5.9 J / kg·K, which can promote the LaFe 13-x Si x It provides important core technologies and related parameters for the industrial production of alloys.

[0032] (3) The alloy material of the present invention has a temperature of 1250°C during high temperature annealing, and the heat preservation time is only 3 to 5 hours, which greatly shortens the preparation time and improves the preparation efficiency. This solves the technical problem that the current primary phase change magnetic refrigeration material requires several weeks of processing and has low preparation efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and should not be regarded as limiting the scope. For those of ordinary skill in the art, other relevant drawings can be obtained based on these drawings without creative work. In the drawings:

[0034] Figure 1 LaFe 11.6 Si 1.4 SEM images of the alloys heat treated at different temperatures for 5 hours.

[0035] Figure 2 LaFe 10.7 Co 0.9 Si 1.4 SEM images of the alloys heat treated at 1250°C for different times.

[0036] Figure 3 LaFe 10.7Co 0.9 Si 1.4 X-ray powder diffraction pattern of alloy.

[0037] Figure 4 is LaFe in 0.01T magnetic field 11.6-x Co x Si 1.4 MT diagrams of the alloy measured in ZFC and FC modes.

[0038] Figure 5 LaFe 10.7 Co 0.9 Si 1.4 Isothermal magnetization curve (MH) of the alloy in the temperature range of 260K-320K and the external magnetic field of 0-2T.

[0039] Figure 6 For Figure 3 The corresponding Arrott diagram after scaling theory optimization.

[0040] Figure 7 LaFe 10.7 Co 0.9 Si 1.4 Isothermal magnetic entropy change curves of alloy under different magnetic fields (ΔS M -T). DETAILED DESCRIPTION

[0041] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with embodiments. The illustrative embodiments of the present invention and their description are only used to explain the present invention and are not intended to limit the present invention.

[0042] The "range" disclosed in the present application is defined in the form of a lower limit and an upper limit, and a given range is defined by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundaries of the particular range. The range defined in this way can be inclusive or exclusive of the end values, and can be arbitrarily combined, that is, any lower limit can be combined with any upper limit to form a range. For example, if a range of 60 to 120 and 80 to 110 is listed for a particular parameter, it is understood that a range of 60 to 110 and 80 to 120 is also expected. In addition, if the minimum range values ​​1 and 2 are listed, and if the maximum range values ​​3, 4 and 5 are listed, the following ranges can all be expected: 1 to 3, 1 to 4, 1 to 5, 2 to 3, 2 to 4 and 2 to 5. In the present application, unless otherwise specified, the numerical range "a to b" represents an abbreviation of any real number combination between a and b, where a and b are both real numbers. For example, the numerical range "0-5" means that all real numbers between "0-5" are listed in this document, and "0-5" is just an abbreviation of these numerical combinations. In addition, when a parameter is expressed as an integer ≥ 2, it is equivalent to disclosing that the parameter is, for example, an integer of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0043] Unless otherwise specified, all embodiments and optional embodiments of the present application can be combined with each other to form a new technical solution.

[0044] Unless otherwise specified, all technical features and optional technical features of this application can be combined with each other to form a new technical solution.

[0045] If there is no special explanation, all steps of the present application can be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), which means that the method may include steps (a) and (b) performed sequentially, or may include steps (b) and (a) performed sequentially. For example, the method may further include step (c), which means that step (c) may be added to the method in any order. For example, the method may include steps (a), (b) and (c), or may include steps (a), (c) and (b), or may include steps (c), (a) and (b), etc.

[0046] If there is no special explanation, the "include" and "comprising" mentioned in this application are open-ended or closed-ended. For example, the "include" and "comprising" may mean that other components not listed may also be included or only the listed components may be included or only the listed components may be included.

[0047] If not specifically stated, in this application, the term "or" is inclusive. For example, the phrase "A or B" means "A, B, or both A and B". More specifically, any of the following conditions satisfies the condition "A or B": A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist).

[0048] Embodiment 1:

[0049] A magnetic refrigeration LaFe 13-x Si x The base alloy material is prepared according to the following method:

[0050] Step 1: Prepare the raw materials with purity of La (>99.8%), Fe (>99.4%), Co (>99.9%) and Si (>99.99%) according to the chemical formula LaFe 11.6-x Co x Si 1.4 The raw materials were mixed according to the design, and then each raw material was melted six times in a tungsten electrode non-consumable arc furnace filled with high-purity argon to obtain an ingot sample;

[0051] Step 2: Place the ingot sample in a corundum crucible, keep it at 1250°C in a high vacuum molybdenum wire furnace for 5 hours, and then cool it to room temperature to obtain LaFe 11.6-x Co x Si 1.4 Alloy. Where x is 0.5, 0.7, and 0.9 respectively.

[0052] Embodiment 2:

[0053] According to the method of Example 1, x=0.9 is set, and the ingot samples are kept at 1250° C. in a high vacuum molybdenum wire furnace for 3 and 4 hours respectively. The rest is the same as Example 1.

[0054] The tungsten electrode non-consumable arc furnace and high vacuum molybdenum wire furnace used in the present invention can be obtained from the market. Of course, those skilled in the art can also use other existing equipment with the same function.

[0055] Comparative Example 1:

[0056] As a comparison, the inventors studied the LaFe 11.6 Si 1.4 The heat preservation performance of alloy materials varies at different temperatures.

[0057] Specifically, design x = 0, mix the obtained LaFe 11.6 Si 1.4The ingot sample was placed in a corundum crucible and kept at 1100°C, 1150°C, 1200°C, 1250°C, 1300°C and 1350°C in a high vacuum molybdenum wire furnace for 5 hours, respectively, and then cooled to room temperature with the furnace.

[0058] Comparative Example 2:

[0059] For comparison, the inventors also studied the performance differences of the alloy materials obtained when x=0.0, 0.1, and 0.3.

[0060] Specifically, x is designed to be 0.0, 0.1, and 0.3 respectively, and the ingredients are prepared according to the chemical formula. The obtained ingot samples are placed in corundum crucibles, kept at 1250℃ in a high vacuum molybdenum wire furnace for 5 hours, and then cooled to room temperature with the furnace to obtain LaFe 11.6- x Co x Si 1.4 Alloy. Where x is 0.0, 0.1, and 0.3 respectively.

[0061] Step 3: Perform scanning electron microscopy test on the samples in the above embodiments and comparative examples to characterize their phase distribution and structural characteristics.

[0062] Characterization process:

[0063] The performance of the obtained alloy material was characterized and studied according to the following process.

[0064] Step 4: Test and obtain the scanning electron microscope photos of the alloy to determine the phase composition and microstructure distribution of the alloy. 11.6 Si 1.4 From the SEM photos after being kept at 1100℃, 1150℃, 1200℃, 1250℃, 1300℃, and 1350℃ for 5 hours, it can be observed that the impurity content in the alloy is very high after heat treatment at 1200℃ and below and 1300℃ and above. Considering that the uncertainty of the temperature sensor is 20℃, the optimal heat treatment temperature is determined to be (1250±20)℃, see Figure 1 .

[0065] Specifically, the powdered phenolic resin (common bakelite powder) used in the experiment was used, and the block sample was hot-mounted by ordinary method, and then ground and polished by sandpaper. The sample was tested by JSM-6490LV scanning electron microscope (SEM) without corrosion, see Figure 1 .

[0066] Step 5: Test and obtain the scanning electron microscope photos of the alloy to determine the phase composition and organizational distribution of the alloy. 10.7 Co 0.9 Si 1.4In the SEM images after heat treatment at 1250℃ for different times, it can be seen that after heat treatment for 3, 4, and 5 hours, the alloy has uniform structure and no significant difference in impurity content. Therefore, the optimal heat treatment time is determined to be (4±1) hours, see Figure 2 The best time is 5 hours.

[0067] Step 6: Test and obtain the room temperature X-ray powder diffraction pattern (XRD) of the alloy to determine the content of 1:13 phase and α-Fe in the sample. The room temperature X-ray powder diffraction pattern obtained is shown in Figure 3 as shown in .

[0068] Specifically, a DX-2700 diffractometer was used to perform diffraction scanning on the powder sample, and the radiation source was Cu-K α1 X-ray, scanning angle 2θ = 10° ~ 80°, step 0.03°. Based on the room temperature X-ray powder diffraction data of the sample, the phase structure and purity of the sample were analyzed using Jade6.0 software, and the magnetic properties of the sample were measured using a vibrating sample magnetometer. The results showed that the content of 1:13 phase in the sample was above 95% (mass percentage), see Figure 3 .

[0069] Step 7: Test the alloy magnetization intensity (M) versus temperature (T) curves in ZFC (zero field cooling) and FC (additional field cooling) modes, i.e., MT diagrams. 11.6-x Co x Si 1.4 The relationship between the Curie temperature of the alloy and the Co content is used to determine the optimal ratio of the Curie temperature near room temperature and the thermal hysteresis of the alloy. Figure 4 .

[0070] Specifically, a Lakeshore 7410 vibrating sample magnetometer was used for magnetic measurement. In the MT curve measurement, the temperature was first dropped to 100°C in zero field, then a 0.01T magnetic field was added, the temperature was raised to 350°C, and the magnetization intensity was collected; then, the temperature was dropped from 350°C to 100°C in a 0.01T magnetic field.

[0071] from Figure 4It can be seen that when x = 0.1, 0.3, 0.5, 0.7, 0.9, the Curie temperatures of the temperature rise measurement are 207.34K, 225.50K, 250.02K, 275.75K, 298.15K, and the temperature of the temperature drop measurement distance is 202.29K, 224.38K, 249.93K, 275.42K, 298.20K, respectively, and the corresponding thermal hysteresis is 5.05K, 1.12K, 0.09K, 0.33K, 0.22K, 0.05K, respectively. As x increases, the thermal hysteresis of the alloy gradually decreases. When x>0.3, the thermal hysteresis of the alloy can be ignored. When x is 0.5, 0.7, 0.9 (as an example), LaFe 11.6-x Co x Si 1.4 The Curie temperature of the alloy reaches near room temperature, especially when x = 0.9, which is the optimal ratio. At this time, LaFe 10.7 Co 0.9 Si 1.4 When x is 0.1 or 0.3, the Curie temperature cannot reach the room temperature. Therefore, the LaFe alloy obtained by selecting x in the range of 0.5 to 0.9 is 11.6- x Co x Si 1.4 With a wider temperature range, the Curie temperature can be as high as room temperature.

[0072] Step 8. The isothermal magnetization curve (MH) of the alloy in the temperature range of 260K-320K and the external magnetic field of 0-2T. Figure 5 LaFe 10.7 Co 0.9 Si 1.4 Isothermal magnetization curve (MH) of the alloy (a sample heat-treated at 1250°C and kept warm for 5 hours) in the temperature range of 260K-320K and an external magnetic field of 0-2T.

[0073] Specifically, a Lakeshore 7410 vibrating sample magnetometer was used for magnetic measurement. The temperature was first dropped to 260 K in zero field, then the magnetization intensity was measured from 260 K to 320 K with a temperature interval of 2 K and 0 to 2 T.

[0074] Depend on Figure 5 It can be determined that LaFe 10.7 Co 0.9 Si 1.4 There is no step-like change in the isothermal magnetization curve of the alloy, and the hysteresis is almost negligible, so it is preliminarily determined that the alloy has secondary phase transition properties.

[0075] Step 9: Based on the data from step 8, a variety of scaling theoretical models are used to obtain the critical parameters of the magnetic phase transition and draw the corresponding Arrott diagram. Figure 6 The Figure 5 The corresponding Arrott diagram after scaling theory optimization.

[0076] Specifically: Based on the isothermal magnetization curve data in step 8, the Arrott-Noakes state equation and Kouvel–Fisher (KF) relationship are used to calculate the LaFe 10.7 Co 0.9 Si 1.4 The alloy (a sample heat treated at 1250℃ and kept at this temperature for 5 hours) was scaled with theoretical phase transformation parameters and the optimized Arrott diagram was plotted. Figure 6 It shows that it has a linear characteristic, and the extension line of the curve at the Curie temperature passes through the origin of the coordinate system, which further confirms that the alloy has a secondary phase transition characteristic.

[0077] Step 10: Based on the isothermal magnetization curve obtained in step 8, combined with the discretized Maxwell equations, calculate LaFe 10.7 Co 0.9 Si 1.4 Isothermal magnetic entropy change curve of the alloy (a sample heat treated at 1250℃ and kept at this temperature for 5 hours). Figure 7 Given LaFe 10.7 Co 0.9 Si 1.4 Isothermal magnetic entropy change curves of alloy under different magnetic fields (ΔS M -T). The results show that under a 2T magnetic field, the maximum entropy change of the alloy material of the present invention reaches 5.9J / kg·K. Figure 7 .

[0078] The magnetic refrigeration alloy material of the present invention is LaFe 13-x-y Co y Si x Based on the alloy, by optimizing the ratio and coordinating high-temperature short-time heat treatment, a room-temperature secondary phase change material is obtained. The Curie temperature of the material is near room temperature, it has large magnetocaloric properties, and the hysteresis is close to zero. The main phase content is high, the structure composition is uniform, and the performance is stable. The present invention can promote the development of LaFe 13-x Si x It provides important core technologies and related parameters for the industrial production of alloys.

[0079] The present invention also provides a magnetic refrigeration device, which comprises the LaFe prepared in the embodiment of the present invention. 11.6- x Co x Si 1.4 Alloy material.

[0080] The above specific implementation methods further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above are only specific implementation methods of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A magnetic refrigeration LaFe 13-x Si x Base alloy material, characterized in that The chemical formula of the alloy material is LaFe 11.6- x Co x Si 1.4 , where 0.5≤x≤0.

9.

2. A magnetic refrigeration LaFe according to claim 1 13-x Si x Base alloy material, characterized in that The mass percentage of the 1:13 phase of the alloy material is greater than or equal to 95%.

3. A magnetic refrigeration LaFe according to claim 1 13-x Si x Base alloy material, characterized in that The alloy material has a uniform organizational structure.

4. A magnetic refrigeration LaFe according to claim 1 13-x Si x Base alloy material, characterized in that The alloy material is a room temperature secondary phase change material, and the Curie temperature of the alloy material can be adjusted to room temperature; Preferably, LaFe 10.7 Co 0.9 Si 1.4 The Curie temperature of the alloy is 298.15K±0.50K.

5. A magnetic refrigeration LaFe according to claim 1 13-x Si x Base alloy material, characterized in that When x = 0.9, LaFe 10.7 Co 0.9 Si 1.4 The maximum entropy change of the alloy is 5.90 J / kg·K.

6. A magnetic refrigeration LaFe according to any one of claims 1 to 5 13-x Si x A method for preparing a base alloy material, characterized in that: The following steps are involved: Step 1: preparing raw materials according to the chemical formula of the alloy material, and smelting to obtain an ingot sample; Step 2: After the ingot sample is annealed at high temperature, it is cooled to room temperature to obtain LaFe 11.6-x Co x Si 1.4 alloy.

7. A magnetic refrigeration LaFe according to claim 6 13-x Si x A method for preparing a base alloy material, characterized in that: The purities of the raw materials are respectively: La>99.8%, Fe>99.4%, Co>99.9%, Si>99.99%.

8. A magnetic refrigeration LaFe according to claim 6 13-x Si x A method for preparing a base alloy material, characterized in that: In step 1, the smelting is performed by remelting in a tungsten electrode non-consumable arc furnace filled with high-purity inert gas to obtain an ingot sample; And / or, the inert gas is argon; And / or, the number of remelting in a non-consumable arc furnace is greater than or equal to 6 times.

9. A magnetic refrigeration LaFe according to claim 7 13-x Si x A method for preparing a base alloy material, characterized in that: In step 2, the temperature of high-temperature annealing of the ingot sample is (1250±20)°C, and the insulation time is 3 to 5 hours and / or in step 2, the ingot sample is placed in a corundum crucible during high-temperature annealing in a high vacuum molybdenum wire furnace.

10. A magnetic refrigeration device, characterized in that: The invention comprises an alloy material prepared by the method according to any one of claims 1 to 5 or claims 6 to 9.

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