阅读说明：本技术 Mo掺杂的Mn-Fe-P-Si基磁制冷材料及其制备方法 (Mo-doped Mn-Fe-P-Si-based magnetic refrigeration material and preparation method thereof ) 是由 缪雪飞 王文尧 徐锋 胡述圆 张玉晶 李琳 查嘉驹 地胡玛尔·艾合买提 于 2019-07-24 设计创作，主要内容包括：本发明公开了一种Mo掺杂的MnFePSi基合金磁制冷材料及其制备方法,属于磁制冷材料技术领域,该材料成分为Mn<Sub>1.1</Sub>Fe<Sub>0.9-X</Sub>Mo<Sub>X</Sub>P<Sub>0.43</Sub>Si<Sub>0.57</Sub>,0.02≤X≤0.04,其制备步骤为：在氩气气氛保护下,将锰片、铁粉、钼粉、磷块、硅块按化学式中各元素的摩尔比进行球磨；将球磨后的粉末压制成试样；将试样封入充有氩气保护的石英管中,退火处理后冷水淬火处理。本发明通过向MnFePSi材料中掺入适量的Mo,使相变温度在室温附近连续可调,大大减小热滞,同时保持较大磁熵变,有利于材料在室温磁制冷领域中的应用。(The invention discloses a Mo-doped MnFePSi-based alloy magnetic refrigeration material and a preparation method thereof, belonging to the technical field of magnetic refrigeration materials 1.1 Fe 0.9‑X Mo X P 0.43 Si 0.57 X is more than or equal to 0.02 and less than or equal to 0.04, and the preparation steps are as follows: under the protection of argon atmosphere, carrying out ball milling on manganese sheets, iron powder, molybdenum powder, phosphorus blocks and silicon blocks according to the molar ratio of each element in the chemical formula; pressing the ball-milled powder into a sample; sealing the samplePutting the quartz tube into a quartz tube filled with argon protection, and carrying out cold water quenching treatment after annealing treatment. According to the invention, by doping a proper amount of Mo into the MnFePSi material, the phase change temperature is continuously adjustable near the room temperature, so that the thermal hysteresis is greatly reduced, and meanwhile, the large magnetic entropy change is kept, thereby being beneficial to the application of the material in the field of room temperature magnetic refrigeration.)

1. A Mo-doped MnFePSi-based alloy magnetic refrigeration material is characterized by comprising the following chemical general formula: mn_1.1Fe_{0.9- X}Mo_XP_0.43Si_0.57Wherein X is more than or equal to 0.02 and less than or equal to 0.04.

2. The MnFePSi-based alloy magnetic refrigeration material as claimed in claim 1, wherein X = 0.04.

3. The method for producing a MnFePSi-based alloy magnetic refrigeration material as claimed in claim 1 or 2, characterized by comprising the steps of:

(1) under the protection of argon atmosphere, carrying out ball milling on manganese sheets, iron powder, molybdenum powder, phosphorus blocks and silicon blocks according to the molar ratio of each element in the chemical formula;

(2) pressing the ball-milled powder into a sample;

(3) and under the protection of argon, carrying out cold water quenching treatment after annealing treatment.

4. The method of claim 3, wherein the ball milling process conditions are: the mass ratio of the steel balls to the raw materials is 6:1, the ball milling time is 10 hours, and the frequency is 30 Hz.

5. The method of claim 3, wherein the ball milled powder is loaded into a 10mm diameter die and pressed at 750MPa to form a 10mm x 5mm wafer sample for 5 min.

6. The method according to claim 3, wherein the sample is sealed in a quartz tube filled with argon gas, annealed at 1100 ℃ for 40 hours, and then quenched with cold water.

Technical Field

The invention relates to the field of room temperature magnetic refrigeration, in particular to a Mo-doped MnFePSi-based alloy magnetic refrigeration material and a preparation method thereof.

Background

The magnetic refrigeration technology is a brand new refrigeration technology which takes a magnetic material as a working medium and utilizes the change of the magnetic entropy of the material in the process of applying a magnetic field to remove the magnetic field to realize refrigeration. Compared with the traditional gas compression refrigeration and the like, the magnetic refrigeration technology has the advantages of no pollution, low noise, small occupied area and high energy conversion efficiency, and is considered to be a novel green refrigeration technology which is expected to solve the problems of human energy and environmental pollution. The key point of the application of the magnetic refrigeration technology is to select and develop a proper magnetic refrigeration working medium. The room temperature magnetic refrigeration materials found so far mainly include rare earth magnetic refrigeration materials, LaFeSi series alloys, perovskite-like manganese oxides, Heusler type alloys, MnFePSi series alloys, and the like. Among them, the MnFePSi series alloy is considered as the most promising magnetic refrigeration material due to its large entropy change, rich raw materials and low cost. However, the MnFePSi material has a primary magnetoelastic phase change, so that the phase change process is accompanied by large thermal hysteresis, and the MnFePSi material has poor and fragile mechanical stability and is not beneficial to the practical application of the material. Earlier researches show that the Curie temperature Tc and the thermal hysteresis of the material can be adjusted by changing the Mn/Fe ratio and the P/Si ratio, but the mixed magnetism of the material is weakened, and the magnetocaloric effect is adversely affected; it has also been found that the doping of boron atoms can significantly increase the Curie temperature Tc of the material, and at the same time, the thermal hysteresis is significantly reduced, but the adjustment is only to increase Tc unidirectionally and is not easy to control.

Disclosure of Invention

The invention aims to provide a continuous adjustable-Curie temperature control device which has the working temperature near room temperature; the magnetic refrigeration material has small thermal hysteresis, has large magnetic entropy change in a magnetic field range which can be provided by the permanent magnet, and can be widely applied to a magnetic refrigeration technology and a preparation method thereof.

The chemical general formula of the magnetic refrigeration material is as follows: mn_1.1Fe_0.9-XMo_XP_0.43Si_0.57Wherein X is more than or equal to 0.02 and less than or equal to 0.04.

The invention also provides a method for preparing the Mn-Fe-P-Si-based magnetic refrigeration material, which comprises the following steps:

(1) under the protection of argon atmosphere, carrying out ball milling on manganese sheets, iron powder, molybdenum powder, phosphorus blocks and silicon blocks according to the molar ratio of each element in the chemical formula;

(2) pressing the ball-milled powder into a sample;

(3) the sample was sealed in a quartz tube filled with argon gas, sintered at 1100 ℃ for 40 hours, and then quenched with cold water.

Further, the ball milling process conditions are as follows: the mass ratio of the steel balls to the raw materials (namely the ball-material ratio) is 6:1, the ball milling time is 10 hours, and the frequency is 30 Hz.

Further, the ball-milled powder was put into a die having a diameter of 10mm and pressed under a pressure of 750MPa to prepareThe pressing time of the disc-shaped test piece was 5 min.

Compared with the prior art, the invention has the following remarkable advantages:

1) according to the invention, trace Mo is doped at the Fe position of the MnFePSi base alloy, so that the Curie temperature and the magnetocaloric effect of the magnetic material are effectively optimized; and the thermal stagnation of the alloy is obviously reduced, and the refrigeration efficiency is improved.

2) The material system has the characteristics of abundant raw material reserves, simple preparation method, easy realization, low manufacturing cost, wide application prospect and the like. Can be applied to various fields relating to refrigeration and low-temperature technology, such as high-energy physics, low-temperature engineering, aerospace, precise instruments, petrochemical industry, superconducting technology, medical appliances and the like.

Drawings

FIG. 1 shows a magnetic refrigerant Mn of the present invention_1.1Fe_0.9-XMo_XP_0.43Si_0.57(X ═ 0.02,0.04,0.06) and the room temperature XRD diffractogram of the material containing no Mo component.

FIG. 2 shows a magnetic refrigerant Mn of the present invention_1.1Fe_0.9-XMo_XP_0.43Si_0.57(X ═ 0.02,0.04,0.06) and M-T curves at an external field of 0.01T for materials containing no Mo component.

FIG. 3 shows a magnetic refrigerant Mn of the present invention_1.1Fe_0.86Mo_0.04P_0.43Si_0.57(b) M-H curves at different temperatures from the material (a) containing no Mo component.

FIG. 4 shows a magnetic refrigerant Mn of the present invention_1.1Fe_0.9-XMo_XP_0.43Si_0.57(X ═ 0.02,0.04) versus isothermal entropy change curve for material without Mo component under 1T magnetic field change.

Detailed Description

The following examples are given for the detailed implementation and specific operation of the present invention, but the scope of the present invention is not limited to the following examples.

The inventor finds that the doping of Mo element is used for partially replacing Fe element, so that the Curie temperature Tc of the material can be reduced, and the Curie temperature can be continuously adjusted near the room temperature; meanwhile, as the content of the Mo element is increased, the thermal hysteresis is obviously reduced, and the larger magnetic entropy change is kept, so that the method can be used in the magnetic refrigeration technology.