A spinel-type high-entropy oxide and its preparation process
Through the preparation process of high-energy ball milling and high-temperature heat treatment, the problem of uneven element distribution of brittle oxides during mechanical alloying is solved, and the uniformity and high magnetization strength of high entropy oxides are achieved. It is suitable for battery electrodes, catalytic degradation and soft magnetic devices.
Patent Information
- Application Number
- CN202310731599.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2023-06-20
- Publication Date
- 2025-07-25
- Estimated Expiration
- 2043-06-20
AI Technical Summary
The prior art is difficult to effectively solve the problem of uneven element distribution and high second phase content during mechanical alloying, resulting in low efficiency and high cost of high entropy oxide preparation, making it difficult to achieve mass production.
The preparation process of high-energy ball milling combined with high-temperature heat treatment is adopted to achieve the elemental diffusion and mutual dissolution of the oxide raw materials through mechanical alloying, forming Zn0.5Mn0.5CrFeO4 high-entropy oxide with spinel structure, including two processes: direct method and indirect method.
The uniform element distribution of high-entropy oxides and significantly increase the particle surface area are achieved, and the magnetization strength is improved. The process is simple, the cost is low, and the efficiency is high, which is suitable for mass production.
Smart Images
Figure CN116768277B_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of preparation of multi-component advanced ceramic materials, and in particular to a spinel-type high-entropy oxide and a preparation process thereof. Background Art
[0002] High-entropy oxides are novel single-phase, multi-principal-element ceramic materials composed of four or more oxides. Their high-entropy effect expands the composition design range and significantly improves the material properties.
[0003] Currently, the preparation methods of high-entropy oxides mainly include gas-phase method, liquid-phase method, and solid-phase method. The gas-phase method is a method for synthesizing coatings or nanomaterials by the reaction of chemical gases, vapors, or plasmas on the substrate surface, and is commonly used for preparing high-entropy thin film materials. The gas-phase method generally refers to chemical vapor deposition, but also includes pulsed laser deposition and magnetron sputtering deposition. The liquid-phase method can be used to synthesize high-entropy powder materials. Using a metal cation solution as a precursor, by selecting a suitable precipitating agent or using methods such as evaporation, sublimation, and hydrolysis, the metal ions are uniformly precipitated, and high-entropy oxides are obtained after heating and drying. The liquid-phase method mainly includes spray pyrolysis, flame pyrolysis, reverse co-precipitation method, hydrothermal method, co-precipitation method, sol-gel method, liquid-phase combustion synthesis, etc. However, the gas-phase method and the liquid-phase method have disadvantages such as complex process flow and high cost, and cannot effectively achieve mass production.
[0004] The solid-phase method is a synthesis method based on solid-phase reactions or solid-state phase transformations, which only involves solid-state reactant substances or solid-state parent-phase materials, and can synthesize bulk and powder high-entropy materials. It mainly includes high-temperature reaction method, reduction reaction method, mechanical alloying, etc. Mechanical alloying was initially used to synthesize oxide dispersion-strengthened superalloys, and later was applied to amorphous nanocrystalline alloys and functional ceramic composites. It is a solid-state phase transformation (or solid-phase reaction) technology capable of preparing non-equilibrium powder materials. The basic principle of mechanical alloying is that during the mutual impact of grinding balls and the ball mill or between grinding balls, the material sandwiched in the middle is repeatedly extruded, causing it to continuously deform, fracture, and weld, gradually refining the particles and forming a layered diffusion couple, realizing the mutual dissolution of different elements, the formation of compounds, or the amorphization of the structure. Preparing high-entropy oxides by mechanical alloying continues the advantages of the ball milling process such as easy operation, high efficiency, low cost, and strong mass production ability, and is a typical solid-phase method preparation process.
[0005] Oxides belong to brittle materials and are in a brittle ball-milling system during high-energy ball milling. The plastic deformation amount is small, and it is difficult to form a lamellar diffusion couple, which is not conducive to the alloying process. However, mechanical ball milling can significantly reduce the particle size (micrometer scale) and grain size (nanometer scale) of brittle oxides, greatly shortening the atomic diffusion distance of the constituent elements. Since mechanical alloying only has local high temperature (~500 °C), the atomic diffusion ability is insufficient and the diffusion range is not wide, resulting in more second phases in high-entropy oxides. High-temperature heat treatment and elemental sublattice diffusion are effective ways to solve this problem, and the key lies in not changing the crystal structure of high-entropy materials.
[0006] Therefore, it is very necessary and urgent to research and develop a high-efficiency and low-cost preparation process for high-entropy oxides to effectively regulate the material composition and crystal structure, such as Zn 0.5 Mn 0.5 CrFeO4 spinel-type high-entropy ferrite, in order to solve the problems of uneven element distribution and relatively high second-phase content existing in the mechanical alloying process of brittle oxide systems.
[0007] In view of this, the present invention is specifically proposed. Summary of the Invention
[0008] The purpose of the present invention is to provide a high-entropy oxide with a composition of Zn 0.5 Mn 0.5 CrFeO4 and having a spinel structure, to establish a preparation process based on mechanical alloying, high-temperature heat treatment, and elemental sublattice diffusion, and then to achieve effective alloying of brittle oxide systems, form single-phase or a large amount of high-entropy oxides, and solve the bottleneck problem of preparing high-entropy oxides by mechanical alloying.
[0009] To achieve the above purpose, the present application specifically proposes the following technical solutions:
[0010] A high-entropy oxide provided by the present invention, the composition of the high-entropy oxide is Zn 0.5 Mn 0.5 CrFeO4 and having a spinel structure;
[0011] The atomic ratio of Zn, Mn, Cr, and Fe in the high-entropy oxide is 1:1:2:2.
[0012] Furthermore, the Zn 0.5 Mn 0.5 CrFeO4 high-entropy oxide has a uniform element distribution and a ferromagnetic spinel lattice, greatly improving the magnetization intensity compared with the oxide raw materials, and its particle surface is covered with micro-nano-sized clusters, significantly increasing the surface area of the particles.
[0013] The magnetization intensity of the spinel-type high-entropy oxide is 2.7 to 2.8 A·m 2 / kg.
[0014] A preparation process of a high-entropy oxide provided by the present invention includes: subjecting raw materials to mechanical alloying by high-energy ball milling and supplemented by high-temperature heat treatment for element diffusion and mutual dissolution to obtain the high-entropy oxide.
[0015] Preferably, the preparation process includes a direct method and an indirect method.
[0016] The direct method includes the following steps:
[0017] Using high-energy ball milling to perform mechanical alloying on a mixture of raw material powders of ZnO, MnO, Cr2O3, and Fe2O3, and supplemented by high-temperature heat treatment to achieve the diffusion and mutual dissolution of different elements, forming a single-phase spinel-type Zn 0.5 Mn 0.5 CrFeO4 high-entropy oxide.
[0018] Further, the ball milling parameters of the mechanical alloying are as follows:
[0019] The grinding ball combination is 10 mm: 8 mm: 5 mm = 5 pieces: 10 pieces: 10 pieces (≈40 g); the ball-to-material ratio is 10:1.
[0020] Preferably, the mechanical alloying is dry intermittent ball milling for 8 hours.
[0021] Furthermore, the dry intermittent ball milling is interrupted for 5 minutes every 30 minutes.
[0022] Further, the temperature of the high-temperature heat treatment is 930 °C to 1030 °C, the isothermal holding time is 1 hour, the atmosphere is air and there is no special atmosphere requirement.
[0023] The indirect method includes the following steps:
[0024] First, in the way of mixing two-component combinations of ZnO and Fe2O3, MnO and Fe2O3, ZnO and Cr2O3, and MnO and Cr2O3, spinel-type precursors of ZnFe2O4, MnFe2O4, ZnCr2O4, and MnCr2O4 are prepared by mechanical alloying supplemented by high-temperature heat treatment. Then, the precursor powder mixture is alloyed step by step to successively obtain Zn 0.5 Mn 0.5 Fe2O4 precursor, Zn 0.5 Mn 0.5 Cr2O4 precursor, high-entropy oxide Zn 0.5 Mn 0.5 FeCrO4, gradually realizing the mutual dissolution and occupancy of different elements in the spinel structure sublattice, and forming a large number of spinel-type high-entropy ferrites.
[0025] Furthermore, the ball milling parameters of the mechanical alloying are as follows:
[0026] The combination of grinding balls is 10 mm: 8 mm: 5 mm = 5 pieces: 10 pieces: 10 pieces (≈40 g); the ball-to-material ratio is 10:1.
[0027] Preferably, in the indirect method, the mechanical alloying is dry intermittent ball milling for 4 hours or 8 hours.
[0028] Furthermore, the dry intermittent ball milling is interrupted for 5 minutes every 30 minutes.
[0029] Furthermore, the temperature of the high-temperature heat treatment is 930 °C to 1030 °C, the isothermal holding time is 1 hour, the atmosphere is air and there is no special atmosphere requirement.
[0030] The present invention provides an application of a high-entropy oxide in battery electrodes, catalytic degradation, and soft magnetic devices.
[0031] Compared with the prior art, the beneficial effects of the present invention are as follows:
[0032] The present invention provides a high-entropy oxide with a composition of Zn 0.5 Mn 0.5 CrFeO4. In this high-entropy oxide, the atomic ratio of Zn, Mn, Cr, and Fe is 1:1:2:2, and it has a spinel crystal structure. The high-entropy oxide has uniform element distribution, a significantly increased magnetization intensity, and a significantly increased particle surface area.
[0033] The present invention provides a preparation process for a high-entropy oxide, including a direct method and an indirect method. It mainly realizes the diffusion and mutual solution of different elements in the oxide raw materials and forms a Zn 0.5 Mn 0.5 CrFeO4 high-entropy ferrite with a spinel crystal structure based on mechanical alloying supplemented by high-temperature heat treatment or precursor sublattice diffusion respectively. The above process has the advantages of easy operation, low cost, high efficiency, and strong mass production. BRIEF DESCRIPTION OF THE DRAWINGS
[0034] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. Obviously, the following drawings are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.
[0035] Figure 1 XRD diffraction pattern of the high-entropy oxide provided in Example 1;
[0036] Figure 2 The hysteresis loop of the high-entropy oxide provided for Example 1;
[0037] Figure 3(a) is the SEM-EDS characterization diagram of the high-entropy oxide provided for Example 1 at a magnification of 100X;
[0038] Figure 3(b) is the SEM-EDS characterization diagram of the high-entropy oxide provided for Example 1 at a magnification of 500X;
[0039] Figure 3(c) is the SEM-EDS characterization diagram of the high-entropy oxide provided for Example 1 at a magnification of 2000X;
[0040] Figure 3(d) is the SEM-EDS characterization diagram of the high-entropy oxide provided for Example 1 at a magnification of 4000X;
[0041] Figure 4 The element distribution diagram of the high-entropy oxide provided for Example 1;
[0042] Figure 5 The XRD diffraction pattern of the high-entropy oxide provided for Example 2;
[0043] Figure 6 The hysteresis loop of the high-entropy oxide provided for Example 2;
[0044] Figure 7 The magnetic property characterization diagram of each high-entropy oxide of the present application provided for Example 2;
[0045] Figure 8(a) is the SEM-EDS characterization diagram of the high-entropy oxide provided for Example 2 at a magnification of 100X;
[0046] Figure 8(b) is the SEM-EDS characterization diagram of the high-entropy oxide provided for Example 2 at a magnification of 500X;
[0047] Figure 8(c) is the SEM-EDS characterization diagram of the high-entropy oxide provided for Example 2 at a magnification of 2000X;
[0048] Figure 8(d) is the SEM-EDS characterization diagram of the high-entropy oxide provided for Example 2 at a magnification of 4000X;
[0049] Figure 9 The element distribution diagram of the high-entropy oxide provided for Example 2;
[0050] Figure 10 The XRD diffraction pattern of the high-entropy oxide prepared without high-temperature heat treatment in Comparative Example 1;
[0051] Figure 11 The XRD diffraction pattern of the high-entropy oxide prepared by high-temperature heat treatment at 930 °C in Comparative Example 2. Detailed implementation manners
[0052] The technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.
[0053] According to one aspect of the present invention, a high-entropy oxide, the composition of the high-entropy oxide is Zn 0.5 Mn 0.5 CrFeO4 and has a spinel crystal structure;
[0054] In the high-entropy oxide, the atomic ratio of Zn, Mn, Cr, and Fe is 1:1:2:2.
[0055] The present invention provides a high-entropy oxide with a composition of Zn 0.5 Mn 0.5 CrFeO4. In this high-entropy oxide, the atomic ratio of Zn, Mn, Cr, and Fe is 1:1:2:2, and it has a spinel structure. The high-entropy oxide has a uniform element distribution and a ferromagnetic spinel lattice, significantly improving the magnetization intensity compared with the oxide raw materials. Its particle surface is covered with micro-nano-sized clusters, significantly increasing the surface area of the particles.
[0056] According to one aspect of the present invention, a preparation process of a high-entropy oxide, the preparation process includes a direct method and an indirect method.
[0057] The steps of the direct method are as follows:
[0058] Use high-energy ball milling to mechanically alloy the powder mixture of ZnO, MnO, Cr2O3, and Fe2O3 raw materials, and supplement it with high-temperature heat treatment to achieve the diffusion and mutual solution of different elements, forming a single-phase spinel-type Zn 0.5 Mn 0.5 CrFeO4 high-entropy oxide. (Volume percentage 100%)
[0059] The steps of the indirect method are as follows:
[0060] First, adopt the method of mixing two components of ZnO and Fe2O3, MnO and Fe2O3, ZnO and Cr2O3, and MnO and Cr2O3, and prepare spinel-type precursors of ZnFe2O4, MnFe2O4, ZnCr2O4, and MnCr2O4 through mechanical alloying supplemented by high-temperature heat treatment. Then, alloy the precursor powder mixture step by step to obtain Zn 0.5 Mn 0.5 Fe2O4 precursor, Zn0.5 Mn 0.5 Cr2O4 precursor, high-entropy oxide Zn 0.5 Mn 0.5 FeCrO4, gradually realizing the mutual solubility and occupation of different elements in the spinel structure sublattice, forming a large number of spinel-type high-entropy ferrites. (Volume percentage greater than 60%)
[0061] It should be noted that the advantage of the above indirect method of the present application compared with the direct method for preparing high-entropy oxides is that: the indirect method introduces a spinel structure precursor in the process of preparing spinel-type high-entropy oxides. Compared with the direct method, it can regulate the mutual solubility and occupation of each element in the spinel sublattice, reduce the energy barrier for the formation of high-entropy oxides by solid-state reaction, and get rid of the dependence on high-temperature heat treatment; while the process of preparing by the direct method is uncontrollable and relies on high-temperature heat treatment.
[0062] A preparation process of high-entropy oxides provided by the present invention is mainly based on mechanical alloying supplemented by high-temperature heat treatment or precursor sublattice diffusion respectively, realizing the diffusion and mutual solubility of different elements in the oxide raw materials, and forming Zn 0.5 Mn 0.5 CrFeO4 high-entropy ferrite. The above process has the advantages of easy operation, low cost, high efficiency and strong mass production.
[0063] In a preferred embodiment of the present invention, the ball milling parameters of the mechanical alloying are as follows:
[0064] The ball combination is 10mm: 8mm: 5mm = 5 pieces: 10 pieces: 10 pieces (≈40g); the ball-to-material ratio is 10:1.
[0065] Preferably, the mechanical alloying in the direct method is dry intermittent ball milling for 8 hours.
[0066] Preferably, the mechanical alloying in the indirect method is dry intermittent ball milling for 4 hours or 8 hours.
[0067] As a preferred embodiment, the ball milling parameters of the above mechanical alloying can significantly reduce the particle size and grain size of brittle oxides in a short time, and to a certain extent reduce the heat treatment temperature for full element diffusion, which helps to reduce costs and increase efficiency.
[0068] In the above preferred embodiment, the dry intermittent ball milling is interrupted for 5 minutes every 30 minutes.
[0069] In a preferred embodiment of the present invention, the high-temperature heat treatment parameters are as follows:
[0070] The heat treatment atmosphere is air, and there is no special gas requirement; the isothermal holding time of the heat treatment is 1 hour; the heat treatment temperature needs to be higher than 500 °C to improve the diffusion ability of the constituent elements.
[0071] Preferably, the temperature of the high-temperature heat treatment in the direct method and the indirect method is 930 °C to 1030 °C.
[0072] As a preferred embodiment, the above high-temperature heat treatment parameters can generate a single-phase or a large amount of spinel crystal phase (volume percentage greater than 60%), which is helpful for the preparation of Zn 0.5 Mn 0.5 CrFeO4 high-entropy ferrite.
[0073] According to one aspect of the present invention, a high-entropy oxide powder material has a uniform element distribution, a significantly increased magnetization intensity, and a significantly increased particle surface area.
[0074] The high-entropy oxide provided by the present invention can be widely applied to battery electrodes, catalytic degradation, and soft magnetic devices.
[0075] The technical solution of the present invention will be further described below in conjunction with embodiments.
[0076] Example 1 Direct method
[0077] A preparation method of a high-entropy oxide Zn 0.5 Mn 0.5 CrFeO4 is as follows:
[0078] (1) Determine the ball milling parameters:
[0079] The total mass of the stainless steel grinding balls is about 40 grams, including 5 grinding balls with a diameter of 10 mm, 10 grinding balls with a diameter of 8 mm, and 5 grinding balls with a diameter of 5 mm; the ball-to-material ratio used is 10:1;
[0080] (2) Calculate the raw material dosage:
[0081] Calculate the total mass of the ball-milled powder according to the ball-to-material ratio, and then calculate the dosages of the four oxide raw material powders of ZnO, MnO, Fe2O3, and Cr2O3 according to the atomic ratio of Zn:Mn:Fe:Cr of 1:1:2:2, and weigh the corresponding masses;
[0082] (3) Mechanical alloying:
[0083] Put the weighed powder into a stainless steel ball milling tank, and then put the tank filled with the powder into a ball mill for dry intermittent ball milling (intermittent for 5 minutes every 30 minutes). After ball milling for 8 hours, turn off the instrument and take out the powder;
[0084] (4) High-temperature heat treatment:
[0085] The ball-milled powder after 8 hours of mechanical alloying was placed in a tube furnace, heated to 1030 °C in an air atmosphere, isothermally held for 1 hour, and then cooled to room temperature in the furnace. The high-entropy oxide sample was taken out.
[0086] Subsequently, the high-entropy oxide sample prepared in Example 1 above was tested as follows:
[0087] Figure 1 is the XRD diffraction pattern of the high-entropy oxide prepared in Example 1 above;
[0088] Figure 2 is the hysteresis loop of the high-entropy oxide prepared in Example 1 above;
[0089] Figure 3(a) is the SEM-EDS characterization diagram of the high-entropy oxide prepared in Example 1 with a magnification of 100X;
[0090] Figure 3(b) is the SEM-EDS characterization diagram of the high-entropy oxide prepared in Example 1 with a magnification of 500X;
[0091] Figure 3(c) is the SEM-EDS characterization diagram of the high-entropy oxide prepared in Example 1 with a magnification of 2000X;
[0092] Figure 3(d) is the SEM-EDS characterization diagram of the high-entropy oxide prepared in Example 1 with a magnification of 4000X;
[0093] Figure 4 is the element distribution diagram of the high-entropy oxide prepared in Example 1 above.
[0094] Example 2 Indirect method
[0095] A preparation method of a high-entropy oxide Zn 0.5 Mn 0.5 CrFeO4 is as follows:
[0096] (1) Determine the ball-milling parameters:
[0097] The total mass of the stainless steel grinding balls is about 40 grams, including 5 grinding balls with a diameter of 10 mm, 10 grinding balls with a diameter of 8 mm, and 5 grinding balls with a diameter of 5 mm; the ball-to-powder ratio used is 10:1;
[0098] (2) Calculate the raw material dosage:
[0099] Calculate the total mass of the ball-milled powder according to the ball-to-material ratio, and then calculate the raw material powder dosages of the two-component oxides of ZnO and Fe2O3, MnO and Fe2O3, ZnO and Cr2O3, and MnO and Cr2O3 respectively according to the atomic ratios of Zn:Fe, Mn:Fe, Zn:Cr, and Mn:Cr (all 1:2) in the four precursors of ZnFe2O4, MnFe2O4, ZnCr2O4, and MnCr2O4, and weigh the corresponding masses;
[0100] (3) Mechanical alloying of raw materials:
[0101] Put the weighed ZnO and Fe2O3 powders, and MnO and Fe2O3 powders into stainless steel ball milling jars respectively, then put the jars filled with powders into a ball mill for dry intermittent ball milling (intermittent for 5 minutes every 30 minutes). After ball milling for 4 hours, turn off the instrument and take out the powders respectively as the ZnFe2O4 spinel precursor and the MnFe2O4 spinel precursor;
[0102] Put the weighed ZnO and Cr2O3 powders, and MnO and Cr2O3 powders into stainless steel ball milling jars respectively, then put the jars filled with powders into a ball mill for dry intermittent ball milling (intermittent for 5 minutes every 30 minutes). After ball milling for 8 hours, turn off the instrument and take out the powders respectively;
[0103] (4) High-temperature heat treatment:
[0104] Put the ZnO and Cr2O3 mixed powders and MnO and Cr2O3 mixed powders that have undergone 8 hours of mechanical alloying into a tube furnace respectively, heat them to 930 °C in an air atmosphere, isothermally hold for 1 hour, and then cool them to room temperature with the furnace. Take out the powders respectively as the ZnCr2O4 spinel precursor and the MnCr2O4 spinel precursor.
[0105] (5) Calculate the precursor dosages:
[0106] Calculate the total mass of the ball-milled powder according to the ball-to-material ratio, and then according to Zn 0.5 Mn 0.5 Fe2O4, Zn 0.5 Mn 0.5 The atomic ratio of Zn:Mn in the two precursors of Cr2O4 is 1:1. Calculate the powder dosages of the two-component precursors of ZnFe2O4 and MnFe2O4, and ZnCr2O4 and MnCr2O4 respectively, and weigh the corresponding masses;
[0107] (6) Primary mechanical alloying of the precursors:
[0108] Weigh the ZnFe2O4 and MnFe2O4 powders and put them into a stainless-steel ball-milling jar. Then, put the jar filled with the powders into a ball mill for dry intermittent ball milling (intermittent for 5 minutes every 30 minutes). After ball milling for 4 hours, turn off the instrument and take out the powders to be used as the Zn 0.5 Mn 0.5 Fe2O4 spinel precursor;
[0109] Weigh the ZnCr2O4 and MnCr2O4 powders and put them into a stainless-steel ball-milling jar. Then, put the jar filled with the powders into a ball mill for dry intermittent ball milling (intermittent for 5 minutes every 30 minutes). After ball milling for 8 hours, turn off the instrument and take out the powders to be used as the Zn 0.5 Mn 0.5 Cr2O4 spinel precursor;
[0110] (7) Secondary mechanical alloying of the precursor:
[0111] According to the atomic ratio of Zn:Mn:Fe:Cr being 1:1:2:2, calculate and weigh the powder masses of the two precursors of Zn 0.5 Mn 0.5 Fe2O4 and Zn 0.5 Mn 0.5 Cr2O4; Put the mixed precursor powders into a stainless-steel ball-milling jar and carry out dry intermittent ball milling (intermittent for 5 minutes every 30 minutes) in a ball mill. After ball milling for 4 hours, turn off the instrument and take out the Zn 0.5 Mn 0.5 CrFeO4 high-entropy oxide sample.
[0112] Subsequently, the high-entropy oxide samples prepared in Example 2 above were tested as follows:
[0113] Figure 5 is the XRD diffraction pattern of the high-entropy oxide prepared in Example 2 above;
[0114] Figure 6 is the hysteresis loop of the high-entropy oxide prepared in Example 2 above;
[0115] Figure 7 is the magnetic property characterization diagram of each high-entropy oxide provided in Example 2 above;
[0116] Among them: Figure 7 (a) in is the hysteresis loop of the sample prepared by the direct method (the sample prepared in Example 1); Figure 7 (b) in is the hysteresis loop of the sample prepared by the indirect method (the sample prepared in Example 2); Figure 7 (c) in is the hysteresis loop of the oxide raw material Fe2O3; Figure 7 (d) in is the hysteresis loop of the oxide raw material MnO; Figure 7In (e) is the hysteresis loop of the oxide raw material Cr2O3; Figure 7 In (f) is the hysteresis loop of the oxide raw material ZnO;
[0117] Figure 8(a) is the SEM-EDS characterization diagram of the high-entropy oxide prepared in Example 2 at a magnification of 100X;
[0118] Figure 8(b) is the SEM-EDS characterization diagram of the high-entropy oxide prepared in Example 2 at a magnification of 500X;
[0119] Figure 8(c) is the SEM-EDS characterization diagram of the high-entropy oxide prepared in Example 2 at a magnification of 2000X;
[0120] Figure 8(d) is the SEM-EDS characterization diagram of the high-entropy oxide prepared in Example 2 at a magnification of 4000X;
[0121] Figure 9 is the element distribution diagram of the high-entropy oxide prepared in the above Example 2.
[0122] Experimental Example 1
[0123] To show that the high-entropy oxide prepared in this application has better magnetization intensity, the magnetization intensities of the oxide raw materials, precursors in the indirect method, and high-entropy oxides in Examples 1 and 2 above were detected (the external magnetic field was 400 kA / m), and the specific results are as follows:
[0124]
[0125]
[0126] Comparative Example 1
[0127] A preparation method of a high-entropy oxide Zn 0.5 Mn 0.5 CrFeO4 is as follows:
[0128] (1) Determine the ball milling parameters:
[0129] The total mass of the stainless steel grinding balls is about 40 grams, including 5 grinding balls with a diameter of 10 mm, 10 grinding balls with a diameter of 8 mm, and 5 grinding balls with a diameter of 5 mm; the ball-to-material ratio used is 10:1;
[0130] (2) Calculate the raw material dosage:
[0131] Calculate the total mass of the ball-milled powder according to the ball-to-material ratio, and then calculate the dosages of the four oxide raw material powders of ZnO, MnO, Fe2O3, and Cr2O3 according to the atomic ratio of Zn:Mn:Fe:Cr of 1:1:2:2, and weigh the corresponding masses;
[0132] (3) Mechanical alloying:
[0133] Weigh the powder and put it into a stainless steel ball milling tank, then put the tank filled with powder into a ball mill for dry intermittent ball milling (intermittent for 5 minutes every 30 minutes). After ball milling for 8 hours, turn off the instrument and take out the powder sample.
[0134] The difference between this comparative example and Example 1 is that it does not include the step (4) of high-temperature heat treatment.
[0135] Detect the high-entropy oxide sample prepared in the above Comparative Example 1. The powder sample prepared in this comparative example hardly has a spinel phase, and its constituent phases are mainly oxide raw materials. For details, see the appendix Figure 10 .
[0136] Figure 10 It is the XRD diffraction pattern of the high-entropy oxide prepared without high-temperature heat treatment in the above Comparative Example 1.
[0137] Comparative Example 2
[0138] The difference between this comparative example and Example 1 is only that the high-temperature heat treatment temperature in step (4) is 930 °C, and the rest is the same as in Example 1.
[0139] The powder sample prepared in this comparative example has a second phase, and the content of its spinel structure phase is about 80%. For details, see Figure 11 .
[0140] Figure 11 It is the XRD diffraction pattern of the high-entropy oxide prepared by high-temperature heat treatment at 930 °C in the above Comparative Example 2.
[0141] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.
Claims
1. A spinel-type high-entropy oxide, characterized in that, The spinel-type high-entropy oxide has Zn 0.5 Mn 0.5 a CrFeO4 spinel-type crystal structure; The atomic ratio of Zn, Mn, Cr, and Fe in the spinel-type high-entropy oxide is 1:1:2:2; The preparation method of the spinel-type high-entropy oxide includes: Firstly, a two-component mixing method of ZnO and Fe2O3, MnO and Fe2O3, ZnO and Cr2O3, and MnO and Cr2O3 is adopted. Spinel-type precursors such as ZnFe2O4, MnFe2O4, ZnCr2O4, and MnCr2O4 are prepared by mechanical alloying supplemented with high-temperature heat treatment. Then, the precursor powder mixture is alloyed step by step to gradually achieve the mutual solubility and occupation of different elements in the sublattice of the spinel structure, forming a large number of Zn 0.5 Mn 0.5 CrFeO4 high-entropy spinel phase; The mechanical alloying is dry intermittent ball milling for 4 hours or 8 hours; The temperature of the high-temperature heat treatment is 930 °C to 1030 °C, the isothermal holding time is 1 hour, the atmosphere is air and there is no special atmosphere requirement.
2. The spinel-type high-entropy oxide according to claim 1, wherein The spinel-type high-entropy oxide has a uniform element distribution and a spinel lattice with ferrimagnetism, and its particle surface is covered with micro-nano-sized clusters; The magnetization intensity of the spinel-type high-entropy oxide is 2.7 to 2.8 A·m 2 / kg.
3. The spinel-type high-entropy oxide according to claim 1, wherein The ball milling parameters of the mechanical alloying are: The grinding ball combination is 10mm:8mm:5mm = 5 pieces:10 pieces:10 pieces; the ball-to-material ratio is 10:1; The mechanical alloying is dry intermittent ball milling for 8 hours.
4. The spinel-type high-entropy oxide according to claim 3, wherein The dry intermittent ball milling is interrupted for 5 minutes every 30 minutes.
5. Application of the spinel-type high-entropy oxide according to any one of claims 1 to 4 in battery electrodes, catalytic degradation, and soft magnetic devices.