A high-entropy magnetic phase change alloy material, preparation method and application

Abstract

The present invention discloses a high-entropy magnetic phase change alloy material with a chemical general formula of Mn a Fe b Ni c Co d Ge e Si f X z ; wherein X is one or more of Cu, Ti, Zr, Ag, Nb, Zn, La, Y, Ce, Pr, Nd, Ga, B, C, and a, b, c, d, e, f, z represent the atomic molar contents, a + b + c + d + e + f + z = 100, and 15 ≤ a ≤ 25, 8 ≤ b ≤ 18, 15 ≤ c ≤ 30, 5 ≤ d ≤ 20, 8 ≤ e ≤ 18, 15 ≤ f ≤ 25, 0 ≤ z ≤ 6. The present invention also discloses a preparation method of the high-entropy magnetic phase change alloy material. The prepared high-entropy magnetic phase change alloy material has strong magnetocrystalline coupling characteristics in the temperature range of 260K - 360K. The high-entropy phase change alloy material is applied in magnetic refrigeration, magnetic drive, phase change sensing, and thermomagnetic power generation. By adopting the above high-entropy magnetic phase change alloy material, preparation method and application, the present invention can solve the problems of few existing magnetic phase change material systems, narrow working temperature ranges, and insufficient magnetic structure coupling, and has the advantage of a simple preparation method.

Description

Technical Field

[0001] The present invention relates to the technical field of magnetic materials, and particularly relates to a high-entropy magnetic phase change alloy material, a preparation method and an application thereof. Background Art

[0002] In recent years, high-entropy alloy materials (HEAs) or multi-principal element alloy materials have been rapidly developed in basic research and engineering technology applications due to their excellent physical properties and application backgrounds in many fields. High-entropy alloys refer to alloy materials composed of five or more main elements, and the content of each main element is 5%-35%. High-entropy alloy materials tend to have the characteristics of long-range order in crystal structure and long-range disorder in chemical composition due to their composition of multiple main elements. Different high-entropy alloy materials will show different characteristics with the change of composition. These high-entropy alloy materials have great value in theoretical research and also have huge development potential in industrial production.

[0003] Under the single or combined action of external temperature, pressure or magnetic field, some materials will undergo crystal structure transformation and be accompanied by magnetic changes. Materials with such phenomena are generally called magnetic phase change materials. Through appropriate material design, the structural phase change and magnetic change of the material can occur when the physical external conditions change. This phenomenon is called the magneto-structural coupling phenomenon. Magnetic phase change materials with strong magneto-structural coupling often have excellent physical properties and have good application prospects in magnetic refrigeration, magnetic drive components, phase change sensing, thermomagnetic power generation and other fields. Currently, the known magnetic phase change material systems are relatively few, and have the deficiencies of narrow working temperature range, insufficient magneto-structural coupling characteristics, insignificant related performance and complex preparation process. Summary of the Invention

[0004] The purpose of the present invention is to provide a high-entropy magnetic phase change alloy material to solve the problems of few existing magnetic phase change material systems, narrow working temperature range and insufficient magneto-structural coupling. Another purpose of the present invention is to provide a preparation method and an application of a high-entropy magnetic phase change alloy material.

[0005] To achieve the above purpose, the present invention provides a high-entropy magnetic phase change alloy material with a chemical general formula of Mn a Fe b Ni c Co d Ge e Si f X z; wherein X is one or more of Cu, Ti, Zr, Ag, Nb, Zn, La, Y, Ce, Pr, Nd, Ga, B, and C; a, b, c, d, e, f, and z represent the atomic molar content; a+b+c+d+e+f+z=100; and 15≤a≤25, 8≤b≤18, 15≤c≤30, 5≤d≤20, 8≤e≤18, 15≤f≤25, and 0≤z≤6.

[0006] Preferably, 18≤a≤22, 10≤b≤16, 18≤c≤26, 8≤d≤18, 10≤e≤15, 18≤f≤22, 0≤z≤3.

[0007] The method for preparing the high entropy magnetic phase change alloy material comprises the following steps:

[0008] S1. Weigh the metals Mn, Fe, Ni, Co, Ge, Si and X according to the molar ratio in the molecular formula;

[0009] S2, heating the raw material obtained in step S1 under argon protection until the raw material is completely melted and maintaining for 5-30 seconds and then cooling to obtain a block mixture;

[0010] S3, after inverting the block mixture obtained in step S2, heating it again under argon protection until it is completely melted, keeping it for 10-60 seconds and then cooling it again, repeating this step 2-4 times to obtain an alloy ingot;

[0011] S4, after removing the oxide scale from the alloy ingot obtained in step S3, heating it in a vacuum for annealing to obtain high entropy Mn a Fe b Ni c Co d Ge e Si f X z Magnetic phase change alloy materials.

[0012] Preferably, in S4, the annealing temperature is 740° C.-960° C., and the annealing time is 40 h-90 h.

[0013] Preferably, the prepared high entropy magnetic phase change alloy material has strong magnetocrystalline coupling characteristics within the temperature range of 260K-360K.

[0014] The above-mentioned high entropy phase change alloy materials are used in magnetic refrigeration, magnetic drive, phase change sensing, and thermomagnetic power generation.

[0015] The advantages and positive effects of the high entropy magnetic phase change alloy material, preparation method and application described in the present invention are:

[0016] 1. Through a reasonable composition ratio, a new type of high entropy magnetic phase change alloy material is prepared. The high entropy magnetic phase change alloy material has strong magnetocrystalline coupling characteristics in the temperature range of 260K-360K. It broadens the system of high entropy magnetic phase change alloy materials, broadens the working temperature range of magnetic phase change alloy materials, and solves the problem of insufficient magnetic structure coupling.

[0017] 2. The preparation method of the present invention can obtain a magnetic phase change alloy material through multiple smelting and annealing treatments. The preparation method is simple and easier to promote and apply in industry.

[0018] The technical solution of the present invention is further described in detail below through embodiments. DETAILED DESCRIPTION

[0019] The technical solution of the present invention is further illustrated by the following examples.

[0020] Example 1 High Entropy Mn 20 Fe 13 Ni 22 Co 12 Ge 13 Si 20 Magnetic phase change alloy materials

[0021] S1. Weigh Mn, Fe, Ni, Co, Ge and Si metals according to the molar ratio in the molecular formula;

[0022] S2, heating the raw material obtained in step S1 under argon protection until the raw material is completely melted and maintaining for 20 seconds and then cooling to obtain a block mixture;

[0023] S3, after inverting the block mixture obtained in step S2, heating it again under argon protection until it is completely melted, keeping it for 40 seconds and then cooling it again, repeating this step 4 times to obtain an alloy ingot;

[0024] S4, after removing the oxide scale from the alloy ingot obtained in step S3, heating it to 820°C in a vacuum and annealing it for 52 hours to obtain high entropy Mn 20 Fe 13 Ni 22 Co 12 Ge 13 Si 20 Magnetic phase change alloys.

[0025] Tests have shown that the above material has strong magnetic coupling characteristics at 254-288K, and the maximum magnetic entropy change is 41.8J / kgK under 0-5T magnetic field changes.

[0026] Example 2 High Entropy Mn 19 Fe 14 Ni 23 Co 11 Ge14 Si 19 Magnetic phase change alloy material

[0027] S1. Weigh the metals of Mn, Fe, Ni, Co, Ge, and Si according to the molar ratio in the molecular formula;

[0028] S2. Heat the raw materials obtained in step S1 under argon protection until they are completely melted and keep for 15 seconds, then cool to obtain a massive mixture;

[0029] S3. After reversing the massive mixture obtained in step S2, heat it again under argon protection until it is completely melted and keep for 40 seconds, then cool again. Repeat this step 3 times to obtain an alloy ingot;

[0030] S4. After removing the oxide scale from the alloy ingot prepared in step S3, heat it in vacuum to 930 °C and anneal for 48 hours to obtain a high-entropy Mn 19 Fe 14 Ni 23 Co 11 Ge 14 Si 19 Magnetic phase change alloy.

[0031] Tests show that the above materials have strong magnetocrystalline coupling characteristics at 322 - 353 K, and the maximum reversible magnetic entropy change is 39.4 J / kgK under the magnetic field change of 0 - 5 T.

[0032] Example 3 High-entropy Mn 19 Fe 13 Ni 23 Co 11 Ge 14 Si 18 Cu₂ magnetic phase change alloy material

[0033] S1. Weigh the metals of Mn, Fe, Ni, Co, Ge, Si, and Cu according to the molar ratio in the molecular formula;

[0034] S2. Heat the raw materials obtained in step S1 under argon protection until they are completely melted and keep for 10 seconds, then cool to obtain a massive mixture;

[0035] S3. After reversing the massive mixture obtained in step S2, heat it again under argon protection until it is completely melted and keep for 50 seconds, then cool again. Repeat this step 4 times to obtain an alloy ingot;

[0036] S4. After removing the oxide scale from the alloy ingot prepared in step S3, heat it in vacuum to 900 °C and anneal for 64 hours to obtain a high-entropy Mn 19 Fe 13 Ni 23 Co 11 Ge 14 Si18 Cu₂ magnetic phase transition alloy.

[0037] Tests show that the above material has strong magnetocrystalline coupling characteristics at 282 - 314K, and the maximum reversible magnetic entropy change is 38.2 J / kgK under a magnetic field change of 0 - 5T.

[0038] Example 4: High-entropy Mn 20 Fe 14 Ni 22 Co 11 Ge 14 Si 17 Zn₁Pr₁ magnetic phase transition alloy material

[0039] S1. Weigh the metals Mn, Fe, Ni, Co, Ge, Si, Zn, and Pr according to the molar ratios in the chemical formula.

[0040] S2. Heat the raw materials obtained in step S1 under argon protection until they are completely melted and keep for 8 seconds, then cool to obtain a massive mixture.

[0041] S3. After reversing the massive mixture obtained in step S2, heat it again under argon protection until it is completely melted and keep for 35 seconds, then cool again. Repeat this step 4 times to obtain an alloy ingot.

[0042] S4. After removing the oxide scale from the alloy ingot prepared in step S3, heat it in vacuum to 880 °C and anneal for 80 hours to obtain high-entropy Mn 20 Fe 14 Ni 22 Co 11 Ge 14 Si 17 Zn₁Pr₁ magnetic phase transition alloy.

[0043] Tests show that the above material has strong magnetocrystalline coupling characteristics at 292 - 318K, and the maximum reversible magnetic entropy change is 36.4 J / kgK under a magnetic field change of 0 - 5T.

[0044] Example 5: High-entropy Mn 19 Fe 15 Ni 21 Co 12 Ge 13 Si 17 Ag₁Y₁B₁ magnetic phase transition alloy material

[0045] S1. Weigh the metals Mn, Fe, Ni, Co, Ge, Si, Ag, Y, and B according to the molar ratios in the chemical formula.

[0046] S2. Heat the raw materials obtained in step S1 under argon protection until they are completely melted and keep for 20 seconds, then cool to obtain a massive mixture.

[0047] S3, after inverting the block mixture obtained in step S2, heating it again under argon protection until it is completely melted, keeping it for 50 seconds and then cooling it again, repeating this step 3 times to obtain an alloy ingot;

[0048] S4, after removing the oxide scale from the alloy ingot obtained in step S3, heating it to 850°C in a vacuum and annealing it for 72 hours to obtain high entropy Mn 19 Fe 15 Ni 21 Co 12 Ge 13 Si 17 Ag1Y1B1 magnetic phase change alloy.

[0049] Tests have shown that the above material has strong magnetocrystalline coupling characteristics at 264-303K, and the maximum reversible magnetic entropy change is 33.8J / kgK under 0-5T magnetic field changes.

[0050] Therefore, the present invention adopts the above-mentioned high entropy magnetic phase change alloy material, preparation method and application, which can solve the problems of few existing magnetic phase change material systems, narrow working temperature range, and insufficient magnetic structure coupling, and has the advantage of simple preparation method.

[0051] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A high-entropy magnetic phase change alloy material, characterized in that: The chemical general formula is Mn a Fe b Ni c Co d Ge e Si f X z ; where X is one or more of Cu, Ti, Zr, Ag, Nb, Zn, La, Y, Ce, Pr, Nd, Ga, B, C, a, b, c, d, e, f, z represent the atomic molar contents, a + b + c + d + e + f + z = 100, and 18 ≤ a ≤ 22, 10 ≤ b ≤ 16, 18 ≤ c ≤ 26, 8 ≤ d ≤ 18, 10 ≤ e ≤ 15, 18 ≤ f ≤ 22, 0 ≤ z ≤ 3; High entropy magnetic phase change alloy materials have strong magnetocrystalline coupling characteristics in the temperature range of 260K-360K.

2. A preparation method of a high-entropy magnetic phase change alloy material as described in claim 1, characterized in that, The following steps are involved: S1. Weigh the metals Mn, Fe, Ni, Co, Ge, Si and X according to the molar ratio in the molecular formula; S2, heating the raw material obtained in step S1 under argon protection until the raw material is completely melted and maintaining for 5-30 seconds and then cooling to obtain a block mixture; S3, after inverting the block mixture obtained in step S2, heating it again under argon protection until it is completely melted, keeping it for 10-60 seconds and then cooling it again, repeating this step 2-4 times to obtain an alloy ingot; S4. After removing the oxide scale from the alloy ingot obtained in step S3, heat it in a vacuum for annealing treatment to obtain a high-entropy Mn a Fe b Ni c Co d Ge e Si f X z magnetic phase change alloy material.

3. The preparation method of a high-entropy magnetic phase change alloy material according to claim 2, wherein: In the above S4, the annealing temperature is 740°C-960°C, and the annealing time is 40h-90h.

4. The high entropy phase change alloy material according to claim 1 is used in magnetic refrigeration, magnetic drive, phase change sensing, and thermomagnetic power generation.