Application of Eu2MnSi2O7 in cold storage material

Abstract

The invention discloses application of Eu2MnSi2O7 in a cold storage material, and belongs to the technical field of cold storage. The invention provides the application of Eu2MnSi2O7 in the cold storage material, the Eu2MnSi2O7 shows excellent specific heat performance in a temperature zone of 5-15K, can supplement the field of cold storage materials in a temperature zone below 10K, and has lower environmental influence and higher economic benefits in production and application, so that new development of low-temperature science and technology and industrial application is promoted.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of cold storage, and in particular to application of Eu2MnSi2O7 in cold storage materials. BACKGROUND

[0002] With the continuous progress of science and technology, low-temperature technology, especially low-temperature refrigeration technology, plays a core role in many advanced scientific research and industrial applications. For example, in the fields of superconducting technology, quantum computing, space exploration and medical imaging, the demand for efficient and reliable low-temperature refrigeration systems is growing. In these systems, the performance of the cold storage material is crucial to the efficiency and performance of the entire refrigeration system. Effective cold storage materials not only need to exhibit high specific heat capacity at the specified operating temperature, but also need to stably exchange heat with the working fluid during the refrigeration cycle, while maintaining environmental friendliness and economic feasibility.

[0003] Traditional cold storage materials such as lead are widely used in low-temperature refrigeration systems due to their high specific heat capacity, and the main application temperature range is 10K to 40K. However, the specific heat of lead drops sharply below 15K, which limits its application at lower temperatures. In addition, due to the fact that lead is a harmful heavy metal, its use is subject to increasingly stringent environmental regulations. Therefore, it is an urgent need to find an environmentally friendly cold storage material that can replace lead.

[0004] In recent years, magnetic cold storage materials have been considered as strong candidates to replace traditional cold storage materials (such as lead) due to their abnormal specific heat characteristics near the magnetic phase transition point. For example, rare earth magnetic compounds such as ErNi series and HoCu2 can exhibit significant specific heat peaks at low temperatures, providing higher efficiency and wider temperature adaptation range for low-temperature refrigeration systems. However, one of the main limitations of these magnetic cold storage materials is that their effectiveness is mostly limited within a narrow temperature range (usually spanning no more than 5K). In addition, there are certain technical challenges in the preparation and processing of many magnetic cold storage materials, such as high cost and complex process, which limit their widespread application.

[0005] At the same time, although magnetic cold storage materials have shown excellent performance in the laboratory, in commercial-scale production and practical application, these materials are often difficult to realize due to cost, processing difficulty and environmental persistence, etc. For example, many magnetic cold storage materials may degrade after long-term operation, which reduces their practicality. In addition, the recycling and reuse of these materials are also important environmental problems that existing technologies have not yet solved.

[0006] Therefore, there is an urgent need to develop a new type of cold storage material that not only provides high thermal performance in a wider temperature range, but also has better environmental stability, economy and processing feasibility. Such a new type of cold storage material will be able to meet the high performance requirements of modern low temperature refrigeration technology, comply with strict environmental regulations, and improve the overall performance and reliability of low temperature systems. SUMMARY

[0007] The present application aims to at least solve one of the technical problems existing in the prior art. To this end, the present application proposes an application of Eu2MnSi2O7 in a cold storage material, which exhibits excellent specific heat performance in the temperature range of 5-15K, can supplement the field of cold storage materials below 10K, and has lower environmental impact and higher economic benefits in production and application, thereby promoting new developments in low temperature science and industrial applications.

[0008] According to an embodiment of the first aspect of the present application, an application of Eu2MnSi2O7 in a cold storage material is provided.

[0009] According to the application of the embodiments of the present application, at least the following beneficial effects are achieved:

[0010] Eu2MnSi2O7 is usually used as a magnetic material, and no research has shown that it can be used as a cold storage material. Creatively using it as a cold storage material makes the cold storage material have good magnetic cold storage performance. Specifically, the specific heat of the cold storage material in the temperature range of 5-15K is ≥0.1J / cm 3 K, and the specific heat of the heat peak position is 0.534J / cm 3 K.

[0011] Further, Eu2MnSi2O7 as a cold storage material has a higher number of refrigeration cycles. And Eu2MnSi2O7 is an oxide, which can be well recycled as a cold storage material without the need for repeated and large-scale synthesis.

[0012] According to some embodiments of the present application, the cold storage material is a magnetic cold storage material. In fact, it is a magnetic oxide.

[0013] According to some embodiments of the present application, the specific heat peak value of the Eu2MnSi2O7 is 10.7-11.1K; for example, it can be specifically 10.8K, 10.9K or 11.0K. This temperature is also the temperature at which the refrigeration material undergoes a magnetic phase transition.

[0014] According to some embodiments of the present application, the half-height width of the specific heat peak of the Eu2MnSi2O7 is 4.5-5.5K; for example, it can be specifically about 5K.

[0015] According to some embodiments of the present application, the specific heat of the Eu2MnSi2O7 at the specific heat peak position is 0.534 J / cm 3 K.

[0016] According to some embodiments of the present application, the specific heat of the Eu2MnSi2O7 in the temperature range of 5-15 K is ≥0.1 J / cm 3 K. The above temperature range is covered by the specific heat peak.

[0017] According to some embodiments of the present application, the space group of the Eu2MnSi2O7 is P-421m (113).

[0018] According to some embodiments of the present application, the cell parameters of the Eu2MnSi2O7 are α = β = γ = 90°.

[0019] According to some embodiments of the present application, the preparation method of the Eu2MnSi2O7 comprises the following steps:

[0020] The Eu compound, the Mn compound and the silicon source are mixed according to the molar ratio of the chemical formula of the cold storage material, and then high-temperature solid-phase reaction is performed.

[0021] The preparation method provided by the present application has simple preparation process and is suitable for large-scale industrial production.

[0022] According to some embodiments of the present application, the Eu compound comprises at least one of Eu2O3 and Eu2(CO3)3.

[0023] According to some embodiments of the present application, the Mn compound comprises at least one of MnO, MnCO3 and MnO2.

[0024] According to some embodiments of the present application, the silicon source comprises SiO2 and Si. In addition to serving as a silicon source, the Si also serves as a reducing agent. The molar ratio of the SiO2 and Si is 1-3:1-1.2; for example, it can be about 2:1, 1:1 or about 3:1.2.

[0025] The molar ratio of Eu, Mn and Si in the Eu compound, the Mn compound and the silicon source is 2:1:2-2.3. For example, it can be about 2:1:2.

[0026] The above raw materials are cheap and easy to obtain, thus significantly reducing the preparation cost of the cold storage material and improving its environmental protection.

[0027] According to some embodiments of the present application, the total reaction time of the high-temperature solid-phase reaction is greater than or equal to 48 hours. For example, it can be about 50 hours. In actual production, considering the economy and the reaction sufficiency, any value in the range of 48-50 hours can be selected.

[0028] According to some embodiments of the present application, the high-temperature solid-phase reaction includes 2-4 sintering processes. For example, it can be 2 or 3 times. In actual production, whether to continue sintering is determined by the reaction sufficiency; after the sintering is sufficient, the material will not be denatured even if the sintering is continued.

[0029] According to some embodiments of the present application, the temperature of each sintering process is 1050-1150℃. For example, it can be about 1100℃.

[0030] According to some embodiments of the present application, the time of each sintering process is 12-24 hours. For example, it can be about 15 hours or about 20 hours.

[0031] According to some embodiments of the present application, before each sintering process, the product of the previous step is mixed, ground, and then pressed into a tablet. In this way, the reaction sufficiency in the sintering process can be improved, and thus the number or time of sintering can be reduced.

[0032] According to some embodiments of the present application, the high-temperature solid-phase reaction is carried out in an air-isolated condition. For example, it can be inert gas protection or vacuum. The inert gas (purity greater than or equal to 99.999%) includes at least one of nitrogen and argon. The method of vacuum includes vacuum sealing tube. The vacuum degree of the vacuum tube is less than or equal to 10 -3 Pa.

[0033] By using the above conditions of the high-temperature solid-phase reaction, including the number of sintering and the time of sintering, the purity and crystallinity of the obtained cold storage material can be ensured.

[0034] According to some embodiments of the present application, the cold storage material is a raw material for preparing a refrigeration device.

[0035] The refrigeration device can be used for low-temperature refrigeration in the range of 5-10K.

[0036] According to some embodiments of the present application, the refrigeration device includes a refrigeration device in the fields of superconducting technology, quantum computing, space exploration, and medical imaging.

[0037] Unless otherwise specified, "about" in the present application actually means that the allowed error is within ±2%, for example, about 100 actually means 100±2%×100.

[0038] Other features and advantages of the present application will be set forth in the following description, and in part will become apparent to those skilled in the art from the description, or can be learned by practice of the present application. Attached Figure Description

[0039] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0040] Figure 1 The XRD pattern and refinement results of the cold storage material obtained in Example 1 of this invention are shown.

[0041] Figure 2 The specific heat measurement results of the cold storage material obtained in Example 1 of this invention are shown. Detailed Implementation

[0042] The following will describe the concept and technical effects of the present invention clearly and completely with reference to embodiments, so as to fully understand the purpose, features and effects of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are all within the scope of protection of the present invention.

[0043] In the description of this invention, the terms "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0044] Example 1

[0045] This example demonstrates the application of Eu2MnSi2O7 in cold storage materials, wherein the preparation method of Eu2MnSi2O7 is as follows:

[0046] The dried raw materials Eu2O3 (99.99%), MnO (99.99%), SiO2 (99.99%) and Si (99.99%) were accurately weighed according to the stoichiometric molar ratio of 2:2:3:1 and thoroughly ground and mixed.

[0047] The initial raw material blocks are compressed into blocks using a tablet press under vacuum conditions (vacuum degree ≤ 10). -3 Pa) Heat at a uniform rate to 1100℃ and hold for 24 hours, then slowly cool to room temperature;

[0048] After grinding again, the mixture is pressed into a block again; the raw material block after the first pre-burning is sintered again at a uniform speed to 1100°C under vacuum conditions for 24h, and finally a pure-phase low-temperature magnetic regenerative material of Eu2MnSi2O7 is obtained.

[0049] Example 2

[0050] The example provides an application of Eu2MnSi2O7 in a regenerative material, wherein the preparation method of Eu2MnSi2O7 is different from that of Example 1.

[0051] The selection of the raw materials is a stoichiometric molar ratio of 2:2:3:1.2 of Eu2O3 (99.99%), MnO (99.99%), SiO2 (99.99%), and Si (99.99%).

[0052] The crucible containing the raw materials has different purities, which can cause different degrees of loss of Si and other raw materials, so the example will add Si in excess. According to this proportion, there will be no excess Si in the product, and the excess Si can be volatilized or react slightly with the container.

[0053] The specific steps of the example are as follows:

[0054] The dry raw materials Eu2O3 (99.99%), MnO (99.99%), SiO2 (99.99%), and Si (99.99%) are accurately weighed according to the stoichiometric molar ratio of 2:2:3:1.2, and are fully ground and mixed;

[0055] The tablet press is used to press the block, and the initial raw material block is uniformly heated to 1100°C under vacuum conditions (vacuum degree ≤10 -3 Pa) and kept for 24h, and slowly cooled to room temperature;

[0056] After grinding again, the mixture is pressed into a block again; the raw material block after the first pre-burning is sintered again at a uniform speed to 1100°C under vacuum conditions for 24h, and finally a pure-phase low-temperature magnetic regenerative material of Eu2MnSi2O7 is obtained.

[0057] Example 3

[0058] The example provides an application of Eu2MnSi2O7 in a regenerative material, wherein the preparation method of Eu2MnSi2O7 is different from that of Example 1.

[0059] The selection of the raw materials is a stoichiometric molar ratio of 2:2:3:1 of Eu2(CO3)3 (99.99%), MnO (99.99%), SiO2 (99.99%), and Si (99.99%).

[0060] The specific steps of this example are as follows:

[0061] The dry raw materials Eu2(CO3)3(99.99%), MnO (99.99%), SiO2(99.99%), and Si (99.99%) are accurately weighed in a stoichiometric molar ratio of 2:2:3:1 and thoroughly mixed by grinding;

[0062] The initial raw material block is pressed into a tablet using a tablet press, and then uniformly heated to 1100°C under vacuum (vacuum degree ≤10 -3 Pa) at a constant speed and kept for 24 hours, and then slowly cooled to room temperature.

[0063] After that, the mixture is again uniformly ground and pressed into a tablet. The raw material block after the first pre-burning is again sintered at 1100°C under vacuum for 24 hours, and then uniformly cooled to room temperature. Finally, a pure-phase low-temperature magnetic regenerative material of Eu2MnSi2O7 is obtained.

[0064] Example 4

[0065] This example provides an application of Eu2MnSi2O7 in regenerative materials, wherein the preparation method of Eu2MnSi2O7 is different from that of Example 1.

[0066] The selection of raw materials is as follows: Eu2(CO3)3(99.99%), MnCO3(99.99%), SiO2(99.99%), and Si (99.99%) in a stoichiometric molar ratio of 2:2:3:1.

[0067] The specific steps of this example are as follows:

[0068] The dry raw materials Eu2(CO3)3(99.99%), MnCO3(99.99%), SiO2(99.99%), and Si (99.99%) are accurately weighed in a stoichiometric molar ratio of 2:2:3:1 and thoroughly mixed by grinding;

[0069] The initial raw material block is pressed into a tablet using a tablet press, and then uniformly heated to 1100°C under vacuum (vacuum degree ≤10 -3 Pa) at a constant speed and kept for 24 hours, and then slowly cooled to room temperature.

[0070] After that, the mixture is again uniformly ground and pressed into a tablet. The raw material block after the first pre-burning is again sintered at 1100°C under vacuum for 24 hours, and then uniformly cooled to room temperature. Finally, a pure-phase low-temperature magnetic regenerative material of Eu2MnSi2O7 is obtained.

[0071] Example 5

[0072] The example provides an application of Eu2MnSi2O7 in a cold storage material, wherein the preparation method of Eu2MnSi2O7 is different from that of the embodiment 1.

[0073] The selection of the raw materials is as follows: Eu2O3 (99.99%), MnO2 (99.99%), SiO2 (99.99%) and Si (99.99%) in a stoichiometric molar ratio of 1:1:1:1.

[0074] The specific steps of the example are as follows:

[0075] The dry raw materials Eu2O3 (99.99%), MnO2 (99.99%), SiO2 (99.99%) and Si (99.99%) are accurately weighed in a stoichiometric molar ratio of 1:1:1:1 and are fully ground and mixed;

[0076] The tablet press is used to press the block, and the initial raw material block is uniformly heated to 1100℃ under vacuum condition (vacuum degree ≤10 -3 Pa) at a constant speed and is kept for 24h, and is slowly cooled to room temperature;

[0077] Then the block is uniformly ground and pressed again; the raw material block after the first pre-burning is again sintered at 1100℃ under vacuum condition for 24h at a constant speed, and finally the low-temperature magnetic cold storage material of Eu2MnSi2O7 is obtained.

[0078] Test example

[0079] The first aspect of the example tests the XRD pattern of the cold storage material obtained in the embodiment, and the Rietveld refinement method is used for analysis, and the specific results are shown in Figure 1 The XRD test results and the refinement fitting results, the test and refinement results prove that the low-temperature magnetic cold storage material of Eu2MnSi2O7 prepared in the embodiment 1 is a pure phase material; and the refinement results also show that the cold storage material prepared in the embodiment 1 has a tetragonal system, belongs to P-421m (113) space group, and the cell parameters are α = β = γ = 90°. The parameters of Eu2MnSi2O7 obtained in other embodiments are the same as those of the embodiment 1.

[0080] The second aspect of the example tests the specific heat performance of the cold storage material obtained in the example, and the testing method is using a Quantum Design PPMS DynaCool comprehensive physical property measurement system, and the specific heat change with temperature is measured by a thermal relaxation method. The results show that, in a temperature range of 2-50K and under a 0T magnetic field, the specific heat of the low-temperature magnetic cold storage material of the chemical formula Eu2MnSi2O7 prepared in the example 1 decreases first, then increases, and then decreases again with the decrease of the temperature, has a relatively high volume specific heat (≥0.1 J / cm 3 K) in a temperature range of 5-15K, and has a wide specific heat peak width (about 5K half width), which is suitable for the magnetic cold storage application in the low-temperature region. The specific heat peak value is at 10.9K, reaches 0.534 J / cm 3 K, and exhibits a significant magnetic cold storage effect, and the test results of each example are almost completely the same. The specific test results are shown in Table 1. Figure 2

[0081] According to the above results, it can be known that, within the scope provided by the application, the types of raw materials for transformation preparation can all obtain cold storage materials with equivalent performance, and the performance of the obtained cold storage materials is excellent. In addition, the cold storage material provided by the application is a magnetic oxide, has excellent structural and chemical stability, and becomes an ideal choice in the low-temperature magnetic refrigeration system. Therefore, the cold storage material provided by the application is expected to have a wide application in the fields of superconducting technology, quantum computing, space exploration and medical imaging.

[0082] The above has made a detailed description of the embodiments of the application in combination with the drawings, but the application is not limited to the above embodiments, and various changes can be made within the knowledge range of the ordinary skill in the art without departing from the purpose of the application. In addition, the embodiments of the application and the features in the embodiments can be combined with each other without conflict.​

Claims

1. Application of Eu2MnSi2O7 in cold storage materials.

2. The application according to claim 1, characterized in that, The peak specific heat of the Eu2MnSi2O7 is 10.7–11.1 K; And / or, The specific heat peak of the Eu2MnSi2O7 has a full width at half maximum (FWHM) of 4.5–5.5 K.

3. The application according to claim 1, characterized in that, The specific heat of the Eu2MnSi2O7 at its specific heat peak position is 0.534 J / cm. 3 K; And / or, The specific heat of the Eu2MnSi2O7 is ≥0.1 J / cm³ in the temperature range of 5–15 K. 3 K.

4. The application according to any one of claims 1 to 3, characterized in that, The preparation method of the Eu2MnSi2O7 includes the following steps: After mixing Eu compound, Mn compound and silicon source according to the molar ratio of the chemical formula of the cold storage material, a high-temperature solid-phase reaction is carried out.

5. The application according to claim 4, characterized in that, The silicon source includes SiO2 and Si.

6. The application according to claim 4, characterized in that, The Eu compound includes at least one of Eu2O3 and Eu2(CO3)3.

7. The application according to claim 4, characterized in that, The Mn compound includes at least one of MnO, MnCO3, and MnO2.

8. The application according to claim 4, characterized in that, The high-temperature solid-state reaction includes 2 to 4 sintering processes; And / or, the sintering temperature for each sintering is 1050–1150 °C; And / or, the duration of each sintering is 12 to 24 hours.

9. The application according to claim 1, characterized in that, The cold storage material is a raw material for the preparation of refrigeration equipment.

10. The application according to claim 9, characterized in that, The cooling equipment includes cooling devices used in the fields of superconducting technology, quantum computing, space exploration, and medical imaging.

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