Ten-membered fergusonite structure high-entropy oxide ceramic and preparation method thereof

Abstract

Disclosed are a ten-membered fergusonite structure high-entropy oxide ceramic and a preparation method thereof, where the high-entropy oxide ceramic has a monoclinic structure, with a chemical formula of RENbO.sub.4, and the RE is any ten rare-earth cations selected from a group consisting of La.sup.3+, Ce.sup.3+, Pr.sup.3+, Nd.sup.3+, Sm.sup.3+, Eu.sup.3+, Gd.sup.3+, Dy.sup.3+, Ho.sup.3+, Er.sup.3+, Tm.sup.3+, Yb.sup.3+, Lu.sup.3+ and Y.sup.3+. The ten rare-earth cations have a molar ratio of 1:1:1:1:1:1:1:1:1:1 and equal share of RE position. According to the application, by adopting solid state reaction, the fergusonite structure high-entropy oxide ceramic with single-phase structure, uniform element distribution and stable phase is obtained. The high-entropy oxide ceramic prepared by the application is simple in process, uniform in chemical composition and microstructure, and convenient to realize on-demand regulation on properties through a combination of different elements.

Claims

1. A ten-membered fergusonite structure high-entropy oxide ceramic, comprising a chemical structural formula of RENbO.sub.4, wherein the RE is any ten rare-earth cations selected from a group consisting of La.sup.3+, Ce.sup.3+, Pr.sup.3+, Nd.sup.3+, Sm.sup.3+, Eu.sup.3+, Gd.sup.3+, Dy.sup.3+, Ho.sup.3+, Er.sup.3+, Tm.sup.3+, Yb.sup.3+, Lu.sup.3+ and y.sup.3+ and occupying an RE position in an equal molar ratio, and the ten-membered fergusonite structure high-entropy oxide ceramic has a single homogeneous structure.

2. A preparation method of the ten-membered fergusonite structure high-entropy oxide ceramic according to claim 1, comprising following steps: (1) adding rare-earth cations in a form of rare-earth oxides, and weighing and proportioning raw material powders of the rare-earth oxides RE.sub.2O.sub.3 and Nb.sub.2O.sub.5 with a purity over 99.9% according to a composition of the RENbO.sub.4; (2) mixing the raw materials in step (1) by wet ball milling, drying and pre-sintering at atmospheric atmosphere of 1225-1250° C. for 6-10 hours to obtain powders; and (3) adding binder to the powders prepared in step (2) for granulation and dry pressing and molding, and finally sintering for 2-6 hours at atmospheric atmosphere of 1350-1400° C. to obtain the ten-membered fergusonite structure high-entropy oxide ceramic.

3. The preparation method according to claim 2, wherein in the step (2), a ball milling duration is 6 hours, and ball milling mediums are absolute ethanols.

4. The preparation method according to claim 2, wherein in the step (3), the binder accounts for 3 percent (%) of a total mass of the powders prepared in the step (2).

5. The preparation method according to claim 4, wherein the binder is a polyvinyl alcohol solution with a mass concentration of 5%.

6. The preparation method according to claim 2, wherein equipment for the dry pressing and molding is a uniaxial hydraulic press, and a molding pressure is 50-80 megapascal (MPa).

7. The preparation method according to claim 2, wherein the pre-sintering in the step (2 ) and the sintering in the step (3) are both carried out in a muffle furnace.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) In order to more clearly explain the embodiments of the present application or the technical solutions in the prior art, the following will briefly introduce the drawings needed in the embodiments. Obviously, the drawings in the following description are only some implementations of the present application. For those of ordinary skill in this field, other drawings may be obtained according to these drawings without creative labor.

(2) FIG. 1 is an X-ray diffraction (XRD) pattern of (La, Nd, Sm, Eu, Gd, Dy, Ho, Y, Yb, Lu)NbO.sub.4 high-entropy oxide ceramic material in embodiment 1.

(3) FIG. 2 shows a scanning electron microscope (SEM) morphology and elemental energy spectrum analysis results of (La, Nd, Sm, Eu, Gd, Dy, Ho, Y, Yb, Lu)NbO.sub.4 high-entropy oxide ceramic material in embodiment 1.

(4) FIG. 3 is an XRD pattern of (La, Nd, Sm, Eu, Gd, Dy, Ho, Y, Yb, Lu)NbO.sub.4 high-entropy oxide ceramic material in embodiment 2.

(5) FIG. 4 is an XRD pattern of comparative example 1 (La, Nd, Sm, Eu, Gd, Dy, Ho, Y, Yb, Lu)NbO.sub.4 high-entropy oxide material.

(6) FIG. 5 is an XRD pattern of comparative example 2 (La, Nd, Sm, Eu, Gd, Dy, Ho, Y, Yb, Lu)NbO.sub.4 high-entropy oxide material.

(7) FIG. 6 is an XRD pattern of comparative example 3 (La, Nd, Sm, Eu, Gd, Dy, Ho, Y, Yb, Lu)NbO.sub.4 high-entropy oxide material.

DETAILED DESCRIPTION OF THE EMBODIMENTS

(8) Now various exemplary embodiments of the present application will be described in detail. This detailed description should not be considered as a limitation of the present application, but should be understood as a more detailed description of some aspects, characteristics and embodiments of the present application.

(9) It should be understood that the terms described in the present application are only used to describe specific embodiments, and are not used to limit the application. In addition, for the numerical range in the present application, it should be understood that each intermediate value between the upper limit and the lower limit of the range is also specifically disclosed. Any stated value or intermediate value within the stated range, and any other stated value or intermediate value within the stated range are also included in the present application. The upper and lower limits of these smaller ranges can be independently included or excluded from the range.

(10) Unless otherwise stated, all technical and scientific terms used herein have the same meanings commonly understood by those of ordinary skill in the field to which this application relates. Although the present application only describes preferred methods and materials, any methods and materials similar or equivalent to those described herein may be used in the practice or testing of the present application. All references mentioned in this specification are incorporated by reference to disclose and describe the methods and/or materials related to the references. In case of conflict with any incorporated references, the contents of this specification shall prevail.

(11) Without departing from the scope or spirit of the present application, it is obvious to those skilled in the art that many modifications and changes may be made to the specific embodiments of the present specification. Other practical ways obtained from the description of the present application are obvious to the skilled person. The description and embodiment of the present application are only exemplary.

(12) As used in this paper, the terms “comprising”, “including”, “having” and “containing” are all open terms, meaning including but not limited to.

(13) Embodiment 1

(14) A-site ten-membered high-entropy fergusonite high-entropy oxide ceramic material, with a chemical formula of (La, Nd, Sm, Eu, Gd, Dy, Ho, Y, Yb, Lu)NbO.sub.4, and a preparation method thereof, including following steps:

(15) (1) weighing and proportioning raw material of La.sub.2O.sub.3, Nd.sub.2O.sub.3, Sm.sub.2O.sub.3, Eu.sub.2O.sub.3, Gd.sub.2O.sub.3, Dy.sub.2O.sub.3, Ho.sub.2O.sub.3, Y.sub.2O.sub.3, Yb.sub.2O.sub.3, Lu.sub.2O.sub.3 and Nb.sub.2O.sub.5 with a purity of over 99.9% according to a composition of (La, Nd, Sm, Eu, Gd, Dy, Ho, Y, Yb, Lu)NbO.sub.4, where a molar ratio of La.sub.2O.sub.3, Nd.sub.2O.sub.3, Sm.sub.2O.sub.3, Eu.sub.2O.sub.3, Gd.sub.2O.sub.3, Dy.sub.2O.sub.3, Ho.sub.2O.sub.3, Y.sub.2O.sub.3, Yb.sub.2O.sub.3, Lu.sub.2O.sub.3 is 1:1:1:1:1:1:1:1:1:1;

(16) (2) mixing the raw materials in step (1) by wet ball milling for 6 hours, with absolute ethanol as a ball milling medium, drying and pre-sintering for 8 hours at atmospheric atmosphere 1250° C. to obtain powders; and

(17) (3) adding binder to the powders prepared in step (2) for granulation and dry pressing and molding, and finally sintering at the atmospheric atmosphere of 1350° C. for 4 hours, where the binder is a polyvinyl alcohol solution with a mass concentration of 5%, and an addition amount of the polyvinyl alcohol accounts for 3% of a total mass of the powders.

(18) An X-ray diffraction (XRD) pattern of (La, Nd, Sm, Eu, Gd, Dy, Ho, Y, Yb, Lu)NbO.sub.4 high-entropy oxide ceramic material prepared in embodiment 1 is shown in FIG. 1, and FIG. 1 shows a synthesized (La, Nd, Sm, Eu, Gd, Dy, Ho, Y, Yb, Lu)NbO.sub.4 phase. Results of scanning electron microscope (SEM) morphology and elemental energy spectrum analysis are shown in FIG. 2 and FIG. 2 shows good crystalline state and uniform element distribution of ceramics.

(19) Embodiment 2

(20) A-site ten-membered high-entropy fergusonite high-entropy oxide ceramic material, with a chemical formula of (La, Nd, Sm, Eu, Gd, Dy, Ho, Y, Yb, Lu)NbO.sub.4, and a preparation method thereof, including following steps:

(21) (1) weighing and proportioning raw material of La.sub.2O.sub.3, Nd.sub.2O.sub.3, Sm.sub.2O.sub.3, Eu.sub.2O.sub.3, Gd2O.sub.3, Dy.sub.2O.sub.3, Ho.sub.2O.sub.3, Y.sub.2O.sub.3, Yb.sub.2O.sub.3, Lu.sub.2O.sub.3 and Nb.sub.2O.sub.5 with a purity of over 99.9% according to a composition of (La, Nd, Sm, Eu, Gd, Dy, Ho, Y, Yb, Lu)NbO.sub.4, where a molar ratio of La.sub.2O.sub.3, Nd.sub.2O.sub.3, Sm.sub.2O.sub.3, Eu.sub.2O.sub.3, Gd.sub.2O.sub.3, Dy.sub.2O.sub.3, Ho.sub.2O.sub.3, Y.sub.2O.sub.3, Yb.sub.2O.sub.3, Lu.sub.2O.sub.3 is 1:1:1:1:1:1:1:1:1:1;

(22) (2) mixing the raw materials in the step (1) by wet ball milling for 6 hours, with absolute ethanol as a ball milling medium, drying and pre-sintering for 8 hours at atmospheric atmosphere of 1225° C. to obtain powders; and

(23) (3) adding binder into the powders prepared in the step (2) for granulation and dry pressing and molding, and finally sintering at atmospheric atmosphere of 1350° C. for 4 hours, where the binder is a polyvinyl alcohol solution with a mass concentration of 5%, and an addition amount of the polyvinyl alcohol accounts for 3% of a total mass of the powders.

(24) The XRD pattern of (La, Nd, Sm, Eu, Gd, Dy, Ho, Y, Yb, Lu)NbO.sub.4 high-entropy oxide ceramic material prepared in embodiment 2 is shown in FIG. 3, and FIG. 3 shows a synthesized (La, Nd, Sm, Eu, Gd, Dy, Ho, Y, Yb, Lu)NbO.sub.4 phase.

(25) Comparative Example 1

(26) A-site ten-membered fergusonite high-entropy oxide ceramic material and a preparation method thereof, including following steps:

(27) (1) weighing and proportioning raw material of La.sub.2O.sub.3, Nd.sub.2O.sub.3, Sm.sub.2O.sub.3, Eu.sub.2O.sub.3, Gd.sub.2O.sub.3, Dy.sub.2O.sub.3, Ho.sub.2O.sub.3, Y.sub.2O.sub.3, Yb.sub.2O.sub.3, Lu.sub.2O.sub.3 and Nb.sub.2O.sub.5 with a purity of over 99.9% according to a composition of (La, Nd, Sm, Eu, Gd, Dy, Ho, Y, Yb, Lu)NbO.sub.4, where a molar ratio of La.sub.2O.sub.3, Nd.sub.2O.sub.3, Sm.sub.2O.sub.3, Eu.sub.2O.sub.3, Gd.sub.2O.sub.3, Dy.sub.2O.sub.3, Ho.sub.2O.sub.3, Y.sub.2O.sub.3, Yb.sub.2O.sub.3, Lu.sub.2O.sub.3 is 1:1:1:1:1:1:1:1:1:1;

(28) (2) mixing the raw materials in the step (1) by wet ball milling for 6 hours, with absolute ethanol as a ball milling medium, drying and pre-sintering at atmospheric atmosphere of 1200° C.

(29) The XRD pattern of (La, Nd, Sm, Eu, Gd, Dy, Ho, Y, Yb, Lu)NbO.sub.4 high-entropy oxide ceramic material prepared in comparative example 1 is shown in FIG. 4, and FIG. 4 shows a single-phase (La, Nd, Sm, Eu, Gd, Dy, Ho, Y, Yb, Lu)NbO.sub.4 is not obtained by sintering at 1200° C.

(30) Comparative Example 2

(31) A-site ten-membered fergusonite high-entropy oxide ceramic material and a preparation method thereof, including following steps:

(32) (1) weighing and proportioning raw material of La.sub.2O.sub.3, Nd.sub.2O.sub.3, Sm.sub.2O.sub.3, Eu.sub.2O.sub.3, Gd.sub.2O.sub.3, Dy.sub.2O.sub.3, Ho.sub.2O.sub.3, Y.sub.2O.sub.3, Yb.sub.2O.sub.3, Lu.sub.2O.sub.3 and Nb.sub.2O.sub.5 with a purity of over 99.9% according to a composition of (La, Nd, Sm, Eu, Gd, Dy, Ho, Y, Yb, Lu)NbO.sub.4, where a molar ratio of La.sub.2O.sub.3, Nd.sub.2O.sub.3, Sm.sub.2O.sub.3, Eu.sub.2O.sub.3, Gd.sub.2O.sub.3, Dy.sub.2O.sub.3, Ho.sub.2O.sub.3, Y.sub.2O.sub.3, Yb.sub.2O.sub.3, Lu.sub.2O.sub.3 is 1:1:1:1:1:1:1:1:1:1;

(33) (2) mixing the raw materials in step (1) by wet ball milling for 6 hours, with absolute ethanol as a ball milling medium, drying and pre-sintering at atmospheric atmosphere of 1300° C.

(34) The XRD pattern of (La, Nd, Sm, Eu, Gd, Dy, Ho, Y, Yb, Lu)NbO.sub.4 high-entropy oxide ceramic material prepared in comparative example 2 is shown in FIG. 5, and FIG. 5 shows a single-phase (La, Nd, Sm, Eu, Gd, Dy, Ho, Y, Yb, Lu)NbO.sub.4 is not obtained by sintering at 1300° C.

(35) Comparative Example 3

(36) A-site ten-membered fergusonite high-entropy oxide ceramic material and a preparation method thereof, including following steps:

(37) (1) weighing and proportioning raw material of La.sub.2O.sub.3, Nd.sub.2O.sub.3, Sm.sub.2O.sub.3, Eu.sub.2O.sub.3, Gd.sub.2O.sub.3, Dy.sub.2O.sub.3, Ho.sub.2O.sub.3, Y.sub.2O.sub.3, Yb.sub.2O.sub.3, Lu.sub.2O.sub.3 and Nb.sub.2O.sub.5 with a purity of over 99.9% according to a composition of (La, Nd, Sm, Eu, Gd, Dy, Ho, Y, Yb, Lu)NbO.sub.4, where a molar ratio of La.sub.2O.sub.3, Nd.sub.2O.sub.3, Sm.sub.2O.sub.3, Eu.sub.2O.sub.3, Gd.sub.2O.sub.3, Dy.sub.2O.sub.3, Ho.sub.2O.sub.3, Y.sub.2O.sub.3, Yb.sub.2O.sub.3, Lu.sub.2O.sub.3 is 1.5:1:1:1:1:1:1:1:1:0.5;

(38) (2) mixing the raw materials in the step (1) by wet ball milling for 6 hours, with absolute ethanol as a ball milling medium, drying and pre-sintering at atmospheric atmosphere of 1250° C.

(39) The XRD pattern of (La, Nd, Sm, Eu, Gd, Dy, Ho, Y, Yb, Lu)NbO.sub.4 high-entropy oxide ceramic material prepared in comparative example 3 is shown in FIG. 6, and FIG. 6 shows the solid solubility of non-molar ratio high-entropy oxide decreases and a single-phase (La, Nd, Sm, Eu, Gd, Dy, Ho, Y, Yb, Lu)NbO.sub.4 is not obtained.

(40) The above-mentioned embodiments only describe the preferred mode of the present application, but do not limit the scope of the present application. On the premise of not departing from the design spirit of the present application, all kinds of modifications and improvements on technical schemes of the present application made by ordinary technicians in the field should fall within the scope of protection defined in the claims of the present application.