A magnetic high-entropy ceramic with a spinel structure and a preparation method thereof

Abstract

The present invention provides a magnetic high-entropy ceramic with a spinel structure and a preparation method thereof, relating to the technical field of magnetic materials. The chemical formula of the magnetic high-entropy ceramic with a spinel structure is CoFe(Ti0.2Cr0.2Mn0.2Al0.2Me0.2)O4, where Me represents a divalent metal element, and the preparation method is to ball-mill the weighed drugs and then perform two-step pressureless sintering to prepare the target magnetic high-entropy ceramic. The present invention overcomes the deficiencies of the prior art, makes innovations in the design concept of common high-entropy spinel materials, and the overall preparation has the characteristics of short cycle, safety, high efficiency, simple and economical operation, etc. Moreover, the high-entropy spinel material obtained according to the present invention has good application prospects in the field of magnetism, and provides a new idea for the design of high-entropy materials.

Description

Technical Field

[0001] The present invention relates to the technical field of ceramic materials, and particularly relates to a magnetic high-entropy ceramic with a spinel structure and a preparation method thereof. Background Art

[0002] In recent years, the field of entropy-stabilized oxides has developed rapidly. In entropy-stabilized materials, the contribution of configurational entropy (Sconfig) to the Gibbs free energy drives entropy-stabilized oxides to become single-phase solid solutions. This high configurational entropy mainly comes from the disordered arrangement of elements. Generally, when five metal cations with equimolar ratios simultaneously occupy one or more Wyckoff sites (S configuration = 1.61R), this kind of oxide is called high-entropy oxide (HEOs). Entropy has a great influence on the stability of materials, so HEOs can contain more elements. Due to their flexible composition, these materials can provide some amazing properties. In summary, the properties of HEOs can be adjusted to different structures by selecting different combinations of cations. Rost et al. first reported single-phase HEOs synthesized by solid-state reaction in 2015. Compared with traditional oxides, HEOs have complex elemental compositions and interesting physical and chemical properties. Therefore, HEOs have attracted people's attention in the fields of optics, magnetism, catalysis, energy storage, and electricity. However, there is a lack of research on the design of new high-entropy disorder mechanisms and magnetic properties in the field of HEOs.

[0003] Based on the above research foundation, the present unit further studies the magnetic high-entropy ceramic with a spinel structure, and previously authorized "A High-Entropy Ceramic with a Spinel Structure, Its Preparation Method and Application" disclosed in CN115594497A. This patent is mainly based on the combination of four metal elements and Zn, and the magnetic properties of the material can be effectively adjusted by adjusting the content of Zn. With further research, this adjustment method has limitations. In the field of high-entropy ceramics, different materials are needed to obtain different properties, that is, different ion designs are required for this research direction to enrich material selection, providing more possibilities for understanding and applying multi-component functional ceramics and HEOs. Summary of the Invention

[0004] Aiming at the deficiencies of the prior art, the present invention provides a magnetic high-entropy ceramic with a spinel structure and a preparation method thereof. By adopting a new ion composition design idea, a new type of high-entropy material is synthesized, so that the designed magnetic high-entropy ceramic material can be effectively applied in the magnetic field, and the synthesis convenience of the material is ensured and the cost is reduced.

[0005] To achieve the above objectives, the technical solution of the present invention is realized through the following technical solutions:

[0006] A magnetic high entropy ceramic with a spinel structure, wherein the chemical formula of the magnetic high entropy ceramic with a spinel structure is: CoFe(M) 0.2 O4; wherein M is five metal ions replacing Fe in CoFe2O4, and M is specifically five metal ions of Ti, Cr, Mn, Al, and Me with an atomic ratio of 1:1:1:1, and Me is a metal ion with a valence of +2.

[0007] Preferably, the content of M accounts for 33.3333% of the total metal ions in the chemical formula.

[0008] The preparation method of a magnetic high-entropy ceramic having a spinel structure comprises the following steps:

[0009] (1) Raw material processing: Take metal oxide powder according to the metal ion ratio in the chemical formula, ball mill and mix into slurry, and then dry to obtain a uniform mixed powder;

[0010] (2) Calcination: The mixed powder is placed in a muffle furnace for calcination to obtain a primary calcined powder;

[0011] (3) Grinding and crushing: The primary calcined powder is placed in a mortar and fully crushed and ground to obtain a pre-made powder;

[0012] (4) Secondary calcination: The preformed powder is placed in a muffle furnace for a second calcination to obtain a magnetic high-entropy ceramic powder with a spinel structure.

[0013] Preferably, the ball milling in step (1) is specifically performed by placing the metal oxide powder into a metal ball mill jar filled with distilled water and fully mixing the metal oxide powder at a rotation speed of 130-330 r / min for 2-10 hours.

[0014] Preferably, the calcination in step (2) is carried out by heating to 790° C.-1470° C. and then calcining at this temperature for 2-6 hours.

[0015] Preferably, in step (3), the crushing and grinding is performed through a 80-mesh sieve.

[0016] Preferably, the calcination temperature in step (4) is 800° C.-1570° C., and the calcination time is 5-20 h.

[0017] Preferably, the calcination atmosphere in step (2) and step (4) is air atmosphere.

[0018] The present invention provides a magnetic high-entropy ceramic with a spinel structure and a preparation method thereof, which has the following advantages over the prior art:

[0019] The present invention adopts a new design concept of ion composition to synthesize a new type of high-entropy material. Moreover, the present invention provides a method for synthesizing magnetic high-entropy ceramics with economy, high efficiency and convenience, enabling the magnetic high-entropy ceramic material designed by the present invention to be effectively applied in the fields of magnetism and microwave absorption. Description of the Drawings

[0020] Figure 1 XRD diagrams of the magnetic high-entropy ceramics in the embodiments of the present invention, where (a) is the XRD diagram of the magnetic high-entropy ceramics in Embodiment 1 of the present invention; (b) is the XRD diagram of the magnetic high-entropy ceramics in Embodiment 2 of the present invention; (c) is the XRD diagram of the magnetic high-entropy ceramics in Embodiment 3 of the present invention; (d) is the XRD diagram of the magnetic high-entropy ceramics in Embodiment 4 of the present invention; (e) is the XRD diagram of the magnetic high-entropy ceramics in Embodiment 5 of the present invention;

[0021] Figure 2 SEM diagram of the high-entropy ceramics in Embodiment 1 of the present invention;

[0022] Figure 3 M-H diagram of the high-entropy ceramics in Embodiment 1 of the present invention;

[0023] Figure 4 SEM diagram of the high-entropy ceramics in Embodiment 2 of the present invention;

[0024] Figure 5 M-H diagram of the high-entropy ceramics in Embodiment 2 of the present invention;

[0025] Figure 6 SEM diagram of the high-entropy ceramics in Embodiment 3 of the present invention;

[0026] Figure 7 M-H diagram of the high-entropy ceramics in Embodiment 3 of the present invention;

[0027] Figure 8 SEM diagram of the high-entropy ceramics in Embodiment 4 of the present invention;

[0028] Figure 9 M-H diagram of the high-entropy ceramics in Embodiment 4 of the present invention;

[0029] Figure 10 SEM diagram of the high-entropy ceramics in Embodiment 5 of the present invention;

[0030] Figure 11 M-H diagram of the high-entropy ceramics in Embodiment 5 of the present invention. Detailed Embodiments

[0031] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Apparently, the described embodiments are some, but not all, of the embodiments of the present invention. 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.

[0032] Example 1:

[0033] Prepare a magnetic high-entropy ceramic with the chemical formula CoFe(Ti 0.2 Cr 0.2 Mn 0.2 Al 0.2 Mg 0.2 )O4:

[0034] (1) Select Co3O4, Fe2O3, TiO2, Cr2O3, Mn3O4, Al2O3, MgO as the original powders. Weigh the above original powders according to the proportions in the chemical formula. Using a ball milling jar as a container, disperse them in 100 ml of distilled water.

[0035] (2) Add steel balls to the ball milling jar for ball milling; mix thoroughly at a speed of 230 r / min for 3 hours, and obtain the ball-milled material after drying.

[0036] (3) Heat the above ball-milled material to 950 °C in an air atmosphere for the first calcination, and the heat treatment time is 2 hours.

[0037] (4) Take out the calcined powder and crush it with a mortar. After passing the crushed powder through an 80-mesh sieve, obtain the preform.

[0038] (5) Re-put the above preform into a muffle furnace, heat it to 1180 °C in an air atmosphere, keep it warm for 10 hours, take it out and crush it to obtain the magnetic high-entropy ceramic.

[0039] Example 2:

[0040] Prepare a magnetic high-entropy ceramic with the chemical formula CoFe(Ti 0.2 Cr 0.2 Mn 0.2 Al 0.2 Fe 0.2 )O4:

[0041] (1) Select Co3O4, Fe2O3, TiO2, Cr2O3, Mn3O4, Al2O3, Fe2O3 as the original powders. Weigh the above original powders according to the proportions in the chemical formula. Using a ball milling jar as a container, disperse them in 100 ml of distilled water.

[0042] (2) Add steel balls to the ball milling tank for ball milling; mix thoroughly at a speed of 230 r / min for 3 hours, and dry it to obtain ball-milled material.

[0043] (3) Heat the above ball-milled material to 950 °C in an air atmosphere for the first calcination, and the heat treatment time is 2 hours.

[0044] (4) Take out the powder after the above calcination and crush it with a mortar. After passing the crushed powder through an 80-mesh sieve, obtain the preform.

[0045] (5) Re-put the above preform into a muffle furnace, heat it to 1180 °C in an air atmosphere, keep it warm for 10 hours, take it out and crush it to obtain the magnetic high-entropy ceramic.

[0046] Example 3:

[0047] Prepare a magnetic high-entropy ceramic with the chemical formula CoFe(Ti 0.2 Cr 0.2 Mn 0.2 Al 0.2 Ni 0.2 )O4:

[0048] (1) Select Co3O4, Fe2O3, TiO2, Cr2O3, Mn3O4, Al2O3, NiO as the original powders. Weigh the above original powders according to the proportions in the chemical formula, and use the ball milling tank as the container to disperse them in 100 ml of distilled water.

[0049] (2) Add steel balls to the ball milling tank for ball milling; mix thoroughly at a speed of 230 r / min for 3 hours, and dry it to obtain ball-milled material.

[0050] (3) Heat the above ball-milled material to 950 °C in an air atmosphere for the first calcination, and the heat treatment time is 2 hours.

[0051] (4) Take out the powder after the above calcination and crush it with a mortar. After passing the crushed powder through an 80-mesh sieve, obtain the preform.

[0052] (5) Re-put the above preform into a muffle furnace, heat it to 1180 °C in an air atmosphere, keep it warm for 10 hours, take it out and crush it to obtain the magnetic high-entropy ceramic.

[0053] Example 4:

[0054] Prepare a magnetic high-entropy ceramic with the chemical formula CoFe(Ti 0.2 Cr 0.2 Mn 0.2 Al 0.2 Cu 0.2 )O4:

[0055] (1) Select Co3O4, Fe2O3, TiO2, Cr2O3, Mn3O4, Al2O3, CuO as the raw powders. Weigh the above raw powders according to the proportions in the chemical formula. Using a ball milling jar as the container, disperse them in 100 ml of distilled water.

[0056] (2) Add steel balls to the ball milling jar for ball milling; mix thoroughly at a speed of 230 r / min for 3 hours, and dry it to obtain the ball milled material.

[0057] (3) Heat the above ball milled material to 950 °C in an air atmosphere for the first calcination, and the heat treatment time is 2 hours.

[0058] (4) Take out the powder after the above calcination and crush it with a mortar. After passing the crushed powder through an 80-mesh sieve, obtain the preform.

[0059] (5) Re-put the above preform into a muffle furnace, heat it to 1180 °C in an air atmosphere, and keep it warm for 10 hours. Take it out and crush it to obtain the magnetic high-entropy ceramic.

[0060] Example 5:

[0061] Prepare a magnetic high-entropy ceramic with the chemical formula CoFe(Ti 0.2 Cr 0.2 Mn 0.2 Al 0.2 Zn 0.2 )O4:

[0062] (1) Select Co3O4, Fe2O3, TiO2, Cr2O3, Mn3O4, Al2O3, ZnO as the raw powders. Weigh the above raw powders according to the proportions in the chemical formula. Using a ball milling jar as the container, disperse them in 100 ml of distilled water.

[0063] (2) Add steel balls to the ball milling jar for ball milling; mix thoroughly at a speed of 230 r / min for 3 hours, and dry it to obtain the ball milled material.

[0064] (3) Heat the above ball milled material to 790 °C - 1470 °C in an air atmosphere for the first calcination, and the heat treatment time is 2 hours.

[0065] (4) Take out the powder after the above calcination and crush it with a mortar. After passing the crushed powder through an 80-mesh sieve, obtain the preform.

[0066] (5) Re-put the above preform into a muffle furnace, heat it to 1180 °C in an air atmosphere, and keep it warm for 10 hours. Take it out and crush it to obtain the magnetic high-entropy ceramic.

[0067] Detection:

[0068] 1. Phase detection:

[0069] The phases of the magnetic high-entropy ceramics prepared in Examples 1-5 above were analyzed by X-ray diffraction (XRD), and the results are as Figure 1 shown: Figure 1 Among them, (a) is the XRD pattern of the magnetic high-entropy ceramic sample of Example 1, (b) is the XRD pattern of the magnetic high-entropy ceramic sample of Example 2, (c) is the XRD pattern of the magnetic high-entropy ceramic sample of Example 3, (d) is the XRD pattern of the magnetic high-entropy ceramic sample of Example 4, and (e) is the XRD pattern of the magnetic high-entropy ceramic sample of Example 5. From Figure 1 the XRD test results in it, it can be seen that Examples 1-5 above all have a spinel structure (Fd3 _ m).

[0070] 2. Morphology detection:

[0071] The morphologies of the magnetic high-entropy ceramic samples prepared in Examples 1-5 above were observed using a scanning electron microscope. The morphology of the magnetic high-entropy ceramic sample of Example 1 is as Figure 2 shown, the morphology of the magnetic high-entropy ceramic sample of Example 2 is as Figure 4 shown, the morphology of the magnetic high-entropy ceramic sample of Example 3 is as Figure 6 shown, the morphology of the magnetic high-entropy ceramic sample of Example 4 is as Figure 8 shown, and the morphology of the magnetic high-entropy ceramic sample of Example 5 is as Figure 10 shown.

[0072] Most of the sintered powders are closely connected polyhedral particles. The average particle size fluctuates with the substitution of Me cations.

[0073] 3. Magnetic property detection:

[0074] The magnetic properties of the magnetic high-entropy ceramic samples prepared in Examples 1-5 above were measured using a vibrating sample magnetometer: among them Figure 3 , Figure 5 , Figure 7 , Figure 9 , Figure 11 are the M-H diagrams of the magnetic high-entropy ceramic samples of Example 1, Example 2, Example 3, Example 4, and Example 5 respectively. The specific magnetic property measurement performances are shown in the following table:

[0075]

[0076] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; 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 recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A magnetic high-entropy ceramic with a spinel structure, characterized in that, The chemical general formula of the magnetic high-entropy ceramic with a spinel structure is: CoFe(Ti 0.2 Cr 0.2 Mn 0.2 Al 0.2 Me 0.2 )O4; where Me is any one of divalent metal ions of Mg, Fe, Ni, Cu or Zn.

2. A preparation method of a magnetic high-entropy ceramic with a spinel structure as described in claim 1, characterized in that, The preparation method comprises the following steps: (1) Raw material processing: Take metal oxide powder according to the metal ion ratio in the chemical formula, ball mill and mix into slurry, and then dry to obtain a uniform mixed powder; (2) Calcination: The mixed powder is placed in a muffle furnace for calcination to obtain a primary calcined powder; (3) Grinding and crushing: Place the primary calcined powder in a mortar and grind it thoroughly to obtain pre-made powder; (4) Secondary calcination: The preformed powder is placed in a muffle furnace for a second calcination to obtain a magnetic high-entropy ceramic powder with a spinel structure.

3. The preparation method of a magnetic high-entropy ceramic with a spinel structure according to claim 2, characterized in that: The ball milling method in step (1) is specifically to place the metal oxide powder into a metal ball mill jar filled with distilled water and mix it thoroughly at a speed of 130-330 r / min for 2-10 hours.

4. The preparation method of a magnetic high-entropy ceramic with a spinel structure according to claim 2, characterized in that: The calcination method in step (2) is to heat to 790°C-1470°C and then keep the temperature to calcine for 2-6 hours.

5. The preparation method of a magnetic high-entropy ceramic with a spinel structure according to claim 2, characterized in that: In the step (3), the powder is crushed and ground through a 80-mesh sieve.

6. The preparation method of a magnetic high-entropy ceramic with a spinel structure according to claim 2, characterized in that: The calcination temperature in step (4) is 800° C.-1570° C., and the calcination time is 5-20 hours.

7. The preparation method of a magnetic high-entropy ceramic with a spinel structure according to claim 2, characterized in that: The calcination atmosphere in step (2) and step (4) is both air atmosphere.

Images