CN111593249A - Manganese-cobalt-germanium-based alloy room-temperature magnetic refrigeration material and preparation method thereof - Google Patents
Manganese-cobalt-germanium-based alloy room-temperature magnetic refrigeration material and preparation method thereof Download PDFInfo
- Publication number
- CN111593249A CN111593249A CN202010406879.5A CN202010406879A CN111593249A CN 111593249 A CN111593249 A CN 111593249A CN 202010406879 A CN202010406879 A CN 202010406879A CN 111593249 A CN111593249 A CN 111593249A
- Authority
- CN
- China
- Prior art keywords
- alloy
- room
- temperature
- magnetic refrigeration
- refrigeration material
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C30/00—Alloys containing less than 50% by weight of each constituent
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C1/00—Making non-ferrous alloys
- C22C1/02—Making non-ferrous alloys by melting
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22F—CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
- C22F1/00—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
- C22F1/02—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working in inert or controlled atmosphere or vacuum
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
- H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
- H01F1/012—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials adapted for magnetic entropy change by magnetocaloric effect, e.g. used as magnetic refrigerating material
- H01F1/015—Metals or alloys
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C2202/00—Physical properties
- C22C2202/02—Magnetic
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Power Engineering (AREA)
- Hard Magnetic Materials (AREA)
Abstract
The invention relates to a manganese-cobalt-germanium-based alloy room-temperature magnetic refrigeration material and a preparation method thereof, wherein the general chemical formula of the room-temperature magnetic refrigeration material is Mn x1‑Zr x CoGe, in the formula, 0.04 is less than or equal toxLess than or equal to 0.06, and the preparation method comprises the following steps: weighing the manganese piece, the zirconium piece, the cobalt block and the germanium block according to the molar ratio of each element in the chemical general formula, and smelting into an alloy ingot; the alloy ingot after smelting is processed under the vacuum condition (the vacuum degree is less than or equal to 10)‑2Pa) annealing at 1123-1273K for 75-100 h, and quenching to room temperature after heat preservation. The Mn atoms in the MnCoGe master alloy are partially replaced by Zr atoms, so that the originally separated ferromagnetic phase change and martensite are realizedThe bulk phase change is coupled near the room temperature, so that excellent magnetocaloric performance is obtained, and the bulk phase change is expected to be applied to the field of room-temperature magnetic refrigeration.
Description
Technical Field
The invention relates to a room temperature magnetic refrigeration material, in particular to a manganese-cobalt-germanium-based alloy room temperature magnetic refrigeration material and a preparation method thereof.
Background
Refrigeration technology plays a very important role in modern social life, from household refrigerators, air conditioners and food cold storage cabinets used in daily life to gas liquefaction, central air conditioners and the like in industrial production. The refrigeration technology which is commonly applied at present is the traditional vapor compression refrigeration, and the Freon refrigerant which is widely used in the technology has great damage effect on the atmospheric ozone layer. Although non-fluorine substitute refrigerants (such as halogenated substances of ammonia, carbon dioxide and other light hydrocarbons) have been used, a large amount of greenhouse gases are still emitted, and the environment is polluted. Another key problem of the conventional refrigeration technology is low refrigeration efficiency and high energy consumption. Under the environment of global warming and energy shortage, the seeking of a novel refrigeration technology which is environment-friendly, efficient and energy-saving is particularly urgent.
In recent years, a novel refrigeration technology (i.e. magnetic refrigeration technology) based on the magnetocaloric effect is widely regarded by researchers at home and abroad and the industry because the novel refrigeration technology is efficient and environment-friendly and meets the low-carbon economic requirements. Magnetic refrigeration technology relies on the magnetocaloric effect characteristic of magnetic materials, which results from a strong coupling between the magnetic moment and the crystal lattice in the magnetic material. When an external magnetic field of a certain magnitude is applied to a magnetic material, the magnetic moment arrangement of the magnetic material is changed from disorder to order, namely, the magnetic entropy is reduced. Under adiabatic conditions, since the total entropy of the material is not changed, in order to compensate for the decrease of the magnetic entropy, the lattice entropy of the material is increased, so that the temperature of the material is increased; conversely, if the external magnetic field is removed, the magnetic moments can restore disorganized arrangement, namely the magnetic entropy is increased, and under an adiabatic condition, the lattice entropy is reduced, so that the temperature of the material is reduced. This phenomenon, in which the temperature of the material changes significantly due to the change in the applied magnetic field, is referred to as the magnetocaloric effect. The key to the application of magnetic refrigeration technology lies in the selection and development of suitable magnetic refrigeration materials. Compared with the second-level magnetic phase change material, the first-level magnetic phase change alloy (such as Gd)5(Si,Ge)4, (Mn,Fe)2(P, As) and La (Fe, Si)13Etc.) because the magnetic phase change is accompanied with the crystal structure phase change (namely the magnetic-structure coupling phase change), the inherent latent heat of phase change brings more remarkable magnetocaloric effect, and has great application prospect in the field of room-temperature magnetic refrigeration. It can be seen that in the magnetic materialThe realization of the coupled primary magnetic phase change of a magnetic-structure is an important way for obtaining excellent magnetocaloric performance at present.
The thermal effect brought by the huge lattice volume change of the MnCoGe alloy during phase change makes the MnCoGe alloy become one of strong competitors of room-temperature magnetic cooling materials. However, the MnCoGe alloy generates martensite structure phase transformation at about 430K and generates ferromagnetic phase transformation at about 323K, and the structure phase transformation temperature is far away from the ferromagnetic phase transformation temperature, so that the magnetic-structure phase transformation coupling is difficult to generate. Therefore, it is necessary to provide a way to couple originally separated magnetic-structure phase transitions in the MnCoGe alloy, so as to obtain excellent magnetocaloric properties in the alloy system. Relevant researches show that the phase transition temperature of a martensite structure can be reduced by replacing magnetic atoms Mn or Co with 3d metal atoms such as V, Cu, Zn and the like, so that the phase transition temperature coincides with the ferromagnetic phase transition temperature, and the giant magnetocaloric effect is realized. However, it has been reported that a room temperature magnetic refrigeration material having excellent magnetocaloric properties can be obtained by introducing 4d metal atom Zr into a MnCoGe-based alloy to realize magnetic-structural phase change coupling at around room temperature.
Disclosure of Invention
The invention aims to provide a MnCoGe-based alloy room-temperature magnetic refrigeration material which realizes magnetic-structure phase change coupling near room temperature and obtains excellent magnetocaloric performance and a preparation method thereof.
The purpose of the invention can be realized by the following technical scheme:
a manganese-cobalt-germanium-based alloy room temperature magnetic refrigeration material has a chemical general formula as follows: mn x1-Zr x CoGe, in the formula, 0.04 is less than or equal tox≤0.06。
According to the manganese-cobalt-germanium-based alloy room-temperature magnetic refrigeration material, Zr atoms are used for partially replacing Mn atoms, so that the phase transition temperature of a martensite structure can be quickly reduced, and the ferromagnetic phase transition temperature can be slowly reduced. When the Zr content is less than or equal to 0.04xWhen the temperature is less than or equal to 0.06, the superposition of martensite structure phase transformation and ferromagnetic phase transformation near room temperature can be realized, and the phase transformation temperature zone is reduced along with the increase of Zr content and can be regulated and controlled near room temperature. The magnetocaloric effect is remarkably improved by the magnetic-structure phase change coupling near room temperature, and compared with MnCoGe master alloy without Zr, Mn x1-Zr x CoGe in 1T and 2T magnetic field variationThe maximum entropy change of the cells is improved by more than 2 times.
The preparation method of the manganese-cobalt-germanium-based alloy room-temperature magnetic refrigeration material comprises the following steps:
1) weighing the manganese piece, the zirconium piece, the cobalt block and the germanium block according to the molar ratio of each element in the chemical general formula, and smelting into an alloy ingot;
2) and annealing the smelted alloy ingot under a vacuum condition.
Preferably, the melting in step 1) is melting by a vacuum arc melting furnace.
Preferably, the smelting in step 1) is smelting by a vacuum induction smelting furnace.
Preferably, the vacuum condition in the step 2) is that the vacuum degree is less than or equal to 10-2Pa。
Preferably, the annealing treatment in the step 2) is carried out at an annealing temperature of 1123-1273K, the heat preservation time is 75-100 hours at the annealing temperature, and the steel plate is quenched to room temperature after the heat preservation is finished.
Compared with the prior art, the invention has the following advantages:
1) according to the invention, Zr atoms are used for partially replacing Mn atoms in the MnCoGe master alloy, so that the phase transition temperature of a martensite structure is reduced to be close to room temperature, and magnetic phase transition is coupled with structural phase transition, thereby obviously improving the magnetocaloric effect.
2) The alloy has the characteristics of simple preparation method, easy realization, excellent magnetic refrigeration performance, wide application prospect and the like. Can be applied to the fields of household appliances, medical instruments, high-energy physics, aerospace, precise instruments, petrochemical industry and the like.
Drawings
FIG. 1 shows a Mn room temperature magnetic refrigerant material of the present invention x1-Zr x CoGe (x =0.04,0.05, 0.06) and Zr-free base alloys (i.e. Zr-freexThermal analysis (DSC) curve of =0) and thermomagnetic (C: =0)M-T) Curve line.
FIG. 2 shows Mn as a room temperature magnetic refrigerant material of the present invention x1-Zr x CoGe (x=0.04,0.05, 0.06) and Zr-free raw alloy (i.e. Zr-free raw alloyxRoom temperature X-ray diffraction (XRD) derivatives of =0)And (4) shooting.
FIG. 3 shows Mn as a room temperature magnetic refrigerant material of the present invention x1-Zr x CoGe (x= 0.06) Scanning Electron Microscopy (SEM) and energy spectroscopy (EDS) images.
FIG. 4 shows Mn as a room temperature magnetic refrigerant material of the present invention x1-Zr x CoGe (x=0.04,0.05, 0.06) and Zr-free raw alloy (i.e. Zr-free raw alloyx=0) isothermal entropy curve (cooling process) under 1T and 2T magnetic field variation.
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.
Example 1
(1) Mixing manganese pieces, zirconium pieces, cobalt blocks and germanium blocks according to Mn0.96Zr0.04And weighing the molar ratio of each element in the CoGe alloy, and smelting the CoGe alloy into an alloy ingot in a vacuum induction smelting furnace.
(2) The smelted alloy ingot is put under vacuum environment (the vacuum degree is less than or equal to 10)-2Pa), annealing for 100 hours at the annealing temperature of 1123K, and quenching with tap water after the annealing is finished to obtain the sample.
Example 2
(1) Mixing manganese pieces, zirconium pieces, cobalt blocks and germanium blocks according to Mn0.95Zr0.05And weighing the molar ratio of each element in the CoGe alloy, and smelting the CoGe alloy into an alloy ingot in a vacuum induction smelting furnace.
(2) The smelted alloy ingot is put under vacuum environment (the vacuum degree is less than or equal to 10)-2Pa), annealing for 75 hours at 1273K, and quenching with tap water after annealing to obtain the sample.
Example 3
(1) Mixing manganese pieces, zirconium pieces, cobalt blocks and germanium blocks according to Mn0.94Zr0.06And weighing the molar ratio of each element in the CoGe alloy, and smelting the CoGe alloy into an alloy ingot in a vacuum induction smelting furnace.
(2) The smelted alloy ingotUnder vacuum environment (vacuum degree is less than or equal to 10)-2Pa) and annealing for 85 hours at the annealing temperature of 1173K, and quenching with tap water after the annealing is finished to obtain the sample.
Mn obtained in examples 1 to 3 x1-Zr x CoGe (xAnd the alloy is subjected to analysis of crystal structure, phase transition thermodynamics, micro morphology, element distribution, magnetic performance and the like by an X-ray diffractometer (XRD), a Differential Scanning Calorimeter (DSC), a Scanning Electron Microscope (SEM), an X-ray energy spectrometer (EDS) and a comprehensive Physical Property Measurement System (PPMS).
FIG. 1 shows Mn according to the invention x1-Zr x CoGe (x=0.04,0.05, 0.06) alloy and master alloy containing no Zr element (i.e. Zr element free alloyxDSC curve of =0) andM-Tcurve line. As can be seen from the figure, the MnCoGe master alloy containing no Zr element undergoes martensite → austenite and austenite → martensite structural phase transformations around 430 and 485K, respectively, during the temperature reduction and temperature rise processes, while the reversible ferromagnetic phase transformation occurs around 330K. Thus, in MnCoGe master alloys without Zr, the ferromagnetic transition temperature: (T C ) Below the structural phase transition temperature (T t ) No magnetic-structural coupling occurs. With part of Mn replaced by Zr in the MnCoGe alloy,T t is rapidly lowered, andT C slowly decrease when Mn is present x1-Zr x The Zr content in the CoGe alloy is not more than 0.04xIn the range of not more than 0.06, the martensitic transformation and the ferromagnetic transformation occur simultaneously at about room temperature (T t =T C ) I.e. a magnetically-structurally coupled phase change occurs.
FIG. 2 shows Mn according to the present invention x1-Zr x CoGe (xXRD patterns at room temperature of the =0.04,0.05, 0.06) alloy with Zr-free MnCoGe master alloy (i.e. x = 0).xThe alloys of =0 and 0.04 are in the orthorhombic martensitic phase of the TiNiSi-type at room temperature; as the content of Zr increases, it is,x=0.05 alloy consisting of TiNiSi-type orthorhombic martensite and N at room temperature2In-type hexagonal austenite two-phase composition; with a further increase in the Zr content,x=0alloy 06 from N at room temperature2In-type hexagonal austenite single phase. It can be seen that the martensite phase transformation temperature is gradually reduced after the Mn part in MnCoGe is replaced by Zr, which is similar to DSC and DSC in FIG. 1M-TThe results shown in the graph are identical.
FIG. 3 shows Mn according to the present invention x1-Zr x CoGe (x= 0.06) SEM and EDS images of the alloy. It can be seen from the figure that the Zr element enters into the grains of the MnCoGe main phase instead of forming a new phase or aggregating at grain boundaries.
FIG. 4 shows Mn according to the present invention x1-Zr x CoGe (xAlloys of =0.04,0.05, 0.06) with the original alloy containing no Zr (i.e. Zr-freex=0) isothermal entropy change curves under 1T and 2T magnetic field variation. As can be seen from the figure, Mn of the present invention x1-Zr x CoGe (x=0.04,0.05, 0.06) the maximum entropy change of the magnetic refrigeration material is improved by more than 2 times compared with the mother alloy without Zr, and the phase transition temperature zone is continuously adjustable near the room temperature.
Claims (6)
1. The manganese-cobalt-germanium-based alloy room-temperature magnetic refrigeration material is characterized in that the chemical general formula of the manganese-cobalt-germanium-based alloy room-temperature magnetic refrigeration material is Mn x1-Zr x CoGe, in the formula, 0.04 is less than or equal tox≤ 0.06，x=The alloy is a TiNiSi-type orthogonal martensite phase at room temperature at 0.04 deg.C;xthe alloy consists of TiNiSi-type orthogonal martensite and N at room temperature when the alloy is 0.05 =2In-type hexagonal austenite two-phase composition;xalloy is N at room temperature when the alloy is 0.062An In-type hexagonal austenite phase.
2. The preparation method of the manganese-cobalt-germanium-based alloy room-temperature magnetic refrigeration material as claimed in claim 1, characterized by comprising the following steps:
1) weighing the manganese piece, the zirconium piece, the cobalt block and the germanium block according to the molar ratio of each element in the chemical general formula, and smelting into an alloy ingot;
2) and annealing the smelted alloy ingot under a vacuum condition.
3. The method for preparing a Mn-Co-Ge-based alloy room-temperature magnetic refrigeration material according to claim 2, wherein the melting in step 1) is performed by a vacuum arc melting furnace.
4. The method for preparing the Mn-Co-Ge-based alloy room-temperature magnetic refrigeration material according to claim 2, wherein the melting in step 1) is performed by a vacuum induction melting furnace.
5. The method for preparing the Mn-Co-Ge-based alloy room-temperature magnetic refrigeration material according to claim 2, wherein the vacuum condition in the step 2) is that the vacuum degree is less than or equal to 10-2Pa。
6. The method for preparing the Mn-Co-Ge-based alloy room-temperature magnetic refrigeration material according to claim 2, wherein the annealing treatment in the step 2) is carried out at an annealing temperature of 1123-1273K, the heat preservation time at the annealing temperature is 75-100 hours, and the Mn-Co-Ge-based alloy room-temperature magnetic refrigeration material is quenched to room temperature after the heat preservation.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010406879.5A CN111593249B (en) | 2020-05-14 | 2020-05-14 | Manganese-cobalt-germanium-based alloy room-temperature magnetic refrigeration material and preparation method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010406879.5A CN111593249B (en) | 2020-05-14 | 2020-05-14 | Manganese-cobalt-germanium-based alloy room-temperature magnetic refrigeration material and preparation method thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN111593249A true CN111593249A (en) | 2020-08-28 |
| CN111593249B CN111593249B (en) | 2021-11-02 |
Family
ID=72187375
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202010406879.5A Active CN111593249B (en) | 2020-05-14 | 2020-05-14 | Manganese-cobalt-germanium-based alloy room-temperature magnetic refrigeration material and preparation method thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN111593249B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112430757A (en) * | 2020-10-19 | 2021-03-02 | 北京工业大学 | MnCoGe-based magnetic alloy capable of being used as magnetic refrigeration material |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2009126835A2 (en) * | 2008-04-09 | 2009-10-15 | University Of Washington Techtransfer Invention Licensing | Magnetic nanoparticle and method for imaging t cells |
| CN103710605A (en) * | 2012-09-28 | 2014-04-09 | 中国科学院物理研究所 | MnCoGe based martensite phase change material with large entropy change, and preparation method and application thereof |
-
2020
- 2020-05-14 CN CN202010406879.5A patent/CN111593249B/en active Active
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2009126835A2 (en) * | 2008-04-09 | 2009-10-15 | University Of Washington Techtransfer Invention Licensing | Magnetic nanoparticle and method for imaging t cells |
| CN103710605A (en) * | 2012-09-28 | 2014-04-09 | 中国科学院物理研究所 | MnCoGe based martensite phase change material with large entropy change, and preparation method and application thereof |
Non-Patent Citations (1)
| Title |
|---|
| PIOTR GEBARA ET AL: ""Structure, magnetocaloric properties and thermodynamic modeling of enthalpies of formation of (Mn,X)-Co-Ge (X=Zr,Pd) alloys", 《JOURNAL OF ALLOYS AND COMPOUNDS》 * |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112430757A (en) * | 2020-10-19 | 2021-03-02 | 北京工业大学 | MnCoGe-based magnetic alloy capable of being used as magnetic refrigeration material |
Also Published As
| Publication number | Publication date |
|---|---|
| CN111593249B (en) | 2021-11-02 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US20130200293A1 (en) | La(fe,si)13-based multi-interstitial atom hydride magnetic refrigeration material with high temperature stability and large magnetic entropy change and preparation method thereof | |
| CN102881393B (en) | A kind of MnFePSi basal cell temperature magnetic refrigerating material and preparation method thereof | |
| CN103710605B (en) | A kind of ferromagnetic Martensitic Transformation Materials of MnCoGe base with big Entropy Changes and preparation method and purposes | |
| CN108300882B (en) | Method for realizing magnetic structure coupling phase change in MnCoGe base alloy | |
| CN100501882C (en) | High temperature low magnetic field large magnetic entropy material and its preparation method | |
| CN111593249B (en) | Manganese-cobalt-germanium-based alloy room-temperature magnetic refrigeration material and preparation method thereof | |
| CN103502497A (en) | Magnetic refrigeration material | |
| JP6009994B2 (en) | Magnetic refrigeration material | |
| CN103668008B (en) | Thulium base metal glass, preparation method and application | |
| CN104630568B (en) | A kind of ferromagnetic Martensitic Transformation Materials of MnCoGe bases and its production and use | |
| KR101921220B1 (en) | Magnetic refrigeration material and magnetic refrigeration device | |
| CN102513536A (en) | Process for preparing magnetic cooling material | |
| CN103334043B (en) | Magnetic alloy serving as magnetic refrigeration material | |
| CN105986177B (en) | Room temperature magnetic refrigerating situ composite material, its preparation method and the application of high heat conduction | |
| CN108642355B (en) | A kind of iron-based room temperature magnetic refrigerating material of manganese and preparation method thereof | |
| CN100489137C (en) | Rare earth-iron-silicon base compound having primary magnetic phase change characteristics and its preparation method | |
| CN109295400B (en) | High-entropy amorphous alloy, and preparation method and application thereof | |
| CN103205590B (en) | Preparation process of magnetic refrigeration material | |
| JP5850318B2 (en) | Magnetic refrigeration material, magnetic refrigeration device and magnetic refrigeration system | |
| CN110172631B (en) | Cobalt-manganese-tin-based alloy material and preparation method thereof | |
| Yildirim et al. | Magnetocaloric Effect with Very Small Magnetic Hysteresis Losses of CoMn 1− x Ti x Ge Alloys | |
| CN109378148B (en) | Lanthanum-iron-silicon-based magnetic refrigeration material and preparation method thereof | |
| CN110453132B (en) | Ni-Mn-Sn-Co-Si magnetic refrigeration material | |
| CN102087899A (en) | La (Fe, al)13-based hydride magnetic refrigerating material and its preparation method and application | |
| CN107760962B (en) | Magnetic refrigeration alloy material and preparation method thereof |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |