High-entropy oxide ceramic material, method of making and use thereof

Abstract

This invention provides a high-entropy oxide ceramic material, its preparation method, and its application. The chemical composition of the high-entropy oxide ceramic material is (Y0...). 0.25‑0.25x Ho 0.25‑0.25x Er 0.25‑ 0.25x Yb 0.25‑0.25x Hf x )2O 3+x ,0< x <1. This invention utilizes rare earth oxides (Y) 0.25 Ho 0.25 Er 0.25 Yb 0.25 Doping HfO2 into O2O3 reduces the thermal conductivity of the material (2.6~3.0 W·m at room temperature). ‑1 ·K ‑1 At the same time, it has a low coefficient of thermal expansion (7.8~8.0×10⁻⁶ in the range of 300~900℃). ‑6 K ‑1 Its excellent high-temperature phase stability (no phase change after annealing at 1600℃ for 100 hours) and other characteristics enable it to meet the service requirements of thermal / environmental barrier coatings.

Description

Technical Field

[0001] This invention belongs to the field of ceramic materials technology, specifically relating to a high-entropy oxide ceramic material, its preparation method, and its application. Background Technology

[0002] With the increasingly harsh service environment of aero-engines, the materials of hot-end components and their protective coatings—thermal / environmental barrier coatings (T / EBCs)—are facing more severe challenges. In recent years, high-entropy rare earth oxides have attracted widespread attention as a new generation of thermal / environmental barrier coating materials due to their excellent high-temperature performance and corrosion resistance. Compared with single-component ceramic materials, the unique properties of high-entropy ceramics stem from the synergistic effect between their multiple components. The inherent crystal structure of rare earth oxides can accommodate significant variations in cation radii, a characteristic that makes them particularly suitable for stabilizing high-entropy systems. Sun et al. successfully prepared two high-entropy rare earth oxides (Eu... 0.2 Er 0.2 Lu 0.2 Y 0.2 Yb 0.2 )2O3 and (Sm 0.2 Er 0.2 Lu 0.2 Y 0.2 Yb 0.2 Both materials, ₂O₃ and ₂O₃, exhibit low coefficients of thermal expansion in the temperature range from room temperature to 1400℃, at 8.09 × 10⁻⁶ and 8.09 × 10⁻⁶, respectively. -6 K -1 and 7.95×10 -6 K -1 However, they have high thermal conductivity (5.1 W·m⁻¹, respectively). -1 ·K -1 and 4.6 W·m -1 ·K -1 This limits its application in thermal / environmental barrier coatings. Although increasing the amount of rare earth elements is expected to further reduce the thermal conductivity of the material, it also causes problems such as an increased coefficient of thermal expansion and difficulty in single-phase formation.

[0003] Therefore, how to effectively reduce thermal conductivity while maintaining a low coefficient of thermal expansion has become the key to promoting the practical application of such materials. Summary of the Invention

[0004] This invention aims to provide a (Y) 0.25-0.25x Ho 0.25-0.25x Er 0.25-0.25x Yb 0.25-0.25x Hf x )2O 3+xHigh-entropy oxide ceramic materials, their preparation methods, and applications. These materials possess excellent high-temperature phase stability, low coefficient of thermal expansion, and low thermal conductivity, meeting the application requirements of thermal / environmental barrier coatings.

[0005] To meet the application requirements of thermal / environmental barrier coatings, this invention provides a high-entropy oxide ceramic material (Y). 0.25-0.25x Ho 0.25-0.25x Er 0.25-0.25x Yb 0.25-0.25x Hf x )2O 3+x The ceramic powder and its bulk preparation methods are described. The ceramic powder is prepared by a two-step solid-state synthesis method, while the ceramic bulk is prepared by a hot-pressing sintering process.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] This invention provides a high-entropy oxide ceramic material, wherein the chemical composition of the high-entropy oxide ceramic material is (Y 0.25-0.25x Ho 0.25-0.25x Er 0.25-0.25x Yb 0.25-0.25x Hf x )2O 3+x ,0< x <1.

[0008] Furthermore, the high-entropy oxide ceramic material has a single-phase ferromanganese structure with space group [missing information]. I a-3.

[0009] Furthermore, the high-entropy oxide ceramic material has a thermal conductivity of 2.6 ~ 3.0 W·m at room temperature. -1 ·K -1 The coefficient of thermal expansion in the range of 300 ~ 900℃ is 7.8 ~ 8.0 × 10⁻⁶. -6 K -1 Furthermore, no phase transformation occurred after annealing at 1600℃ for 100 hours.

[0010] The present invention also provides a method for preparing the above-mentioned high-entropy oxide ceramic material, the method comprising the following steps: (1) mixing Y2O3, Ho2O3, Er2O3 and Yb2O3 powders in a molar ratio of 1:1:1:1 and then ball milling them to obtain a Y2O3-Ho2O3-Er2O3-Yb2O3 mixed powder; (2) subjecting the Y2O3-Ho2O3-Er2O3-Yb2O3 mixed powder to a solid-state reaction at a temperature T1 for t1 hours to obtain (Y 0.25 Ho 0.25 Er 0.25 Yb 0.25)2O3 ceramic sintered powder; wherein, the solid-phase reaction temperature T1 is 1400~1600℃, and the solid-phase reaction time t1 is 10~50 hours; (3) the molar ratio is as described (0.5-0.5 x ): x of(Y 0.25 Ho 0.25 Er 0.25 Yb 0.25 The sintered powder of 2O3 ceramic and the powder of HfO2 were mixed and then ball-milled to obtain (Y) 0.25 Ho 0.25 Er 0.25 Yb 0.25 (4) Mixed powder of 2O3-HfO2; 0.25 Ho 0.25 Er 0.25 Yb 0.25 The 2O3-HfO2 mixed powder was subjected to a solid-state reaction at temperature T2 for t2 hours to obtain (Y) 0.25-0.25x Ho 0.25-0.25x Er 0.25-0.25x Yb 0.25-0.25x Hf x )2O 3+x High-entropy ceramic sintering powder; wherein, the solid-phase reaction temperature T2 is 1450 ~ 1650℃, and the solid-phase reaction time t2 is 10 ~ 50 hours; (5) the (Y) 0.25-0.25x Ho 0.25-0.25x Er 0.25-0.25x Yb 0.25-0.25x Hf x )2O 3+x High-entropy ceramic sintered powder is ball-milled to obtain the aforementioned high-entropy oxide ceramic material. After ball milling, the high-entropy oxide ceramic material is a powder with a uniform particle size distribution, hereinafter referred to as high-entropy ceramic powder or ceramic powder.

[0011] Furthermore, the atmosphere for the solid-phase reaction in steps (2) and (4) is air, and the heating and cooling rates are both 5 ~ 10℃ / min.

[0012] Furthermore, the ball milling process in steps (1), (3) and (5) specifically includes: using anhydrous ethanol as a medium and placing it in a planetary ball mill for processing, wherein the mass ratio of powder to anhydrous ethanol is between 1:1 and 1:1.5, the mass ratio of ball to material is between 2:1 and 4:1, the ball milling speed is 160 to 350 rpm, and the mixing time is 24 to 48 h.

[0013] Furthermore, the method further includes: (6) sintering the high-entropy oxide ceramic material at a temperature T3 for t3 hours; wherein the sintering temperature T3 is 1700 ~ 1900℃, the sintering time t3 is 1 ~ 3 hours, the sintering pressure is 20 ~ 30MPa, and the sintering atmosphere is argon. The high-entropy oxide ceramic material is prepared into a bulk material by hot pressing sintering, hereinafter referred to as high-entropy ceramic bulk or ceramic bulk.

[0014] Furthermore, step (6) specifically involves placing the high-entropy oxide ceramic material into a graphite mold and then sintering it in a hot press furnace or a spark plasma sintering furnace.

[0015] Furthermore, the particle size of the high-entropy oxide ceramic material after step (5) is all below 2.0 μm; the density of the high-entropy oxide ceramic material after step (6) exceeds 98.5%, and the grain size is 1.5 ~ 2.0 μm.

[0016] The present invention also provides an application of the above-mentioned high-entropy oxide ceramic material in the fields of hot-end component materials and thermal / environmental barrier coatings.

[0017] Compared with the prior art, the technical solution provided by the present invention has at least the following advantages:

[0018] 1. In terms of material design, this invention utilizes rare earth oxides (Y) 0.25 Ho 0.25 Er 0.25 Yb 0.25 Doping HfO2 into O2O3 reduces the thermal conductivity of the material (2.6 ~ 3.0 W·m at room temperature). -1 ·K -1 At the same time, it has a low coefficient of thermal expansion (7.8 ~ 8.0 × 10⁻⁶ in the range of 300 ~ 900℃). -6 K -1 Its excellent high-temperature phase stability (no phase change after annealing at 1600℃ for 100 hours) and other characteristics enable it to meet the service requirements of thermal / environmental barrier coatings.

[0019] 2. This invention utilizes a two-step solid-state reaction method to dope hafnium ions with significant size differences and different valence states into rare earth oxides, thereby preparing (Y) 0.25-0.25x Ho 0.25-0.25x Er 0.25-0.25x Yb 0.25-0.25x Hf x )2O 3+x High-entropy ceramic powder.

[0020] 3. This invention prepares (Y) by hot pressing and sintering. 0.25-0.25x Ho0.25-0.25x Er 0.25-0.25x Yb 0.25- 0.25x Hf x )2O 3+x High-entropy ceramic bulk with a density exceeding 98.5% and a grain size of 1.5 ~ 2.0 μm. Attached Figure Description

[0021] Figure 1 The X-ray diffraction patterns of high-entropy ceramic powders in (a) comparative example, (b) Example 1, and (c) Example 2 of this invention are shown below.

[0022] Figure 2 The surface morphology of the high-entropy ceramic powder in Embodiments (a) and (b) 2 of the present invention is shown.

[0023] Figure 3 The X-ray diffraction patterns of the high-entropy ceramic powder after annealing at 1600°C for 100 hours in Examples (a) and (b) 2 of the present invention are shown.

[0024] Figure 4 The surface morphology of the high-entropy ceramic block in Embodiment 3 of the present invention;

[0025] Figure 5 The elongation of the high-entropy ceramic block in Example 3 of this invention ( ΔL / L The curve showing how temperature changes. Detailed Implementation

[0026] In view of the technical problems existing in the background art, the present invention addresses the application requirements of thermal / environmental barrier coatings for hot-end components of next-generation aero-engines, and provides a high-entropy oxide ceramic material with the chemical composition (Y 0.25- 0.25x Ho 0.25-0.25x Er 0.25-0.25x Yb 0.25-0.25x Hf x )2O 3+x Given that the radius of hafnium ions is significantly smaller than that of rare earth ions, introducing hafnium ions into rare earth oxides leads to significant lattice distortion. Furthermore, the substitution of trivalent rare earth ions with tetravalent hafnium ions generates additional point defects. The combined effect of these lattice distortions and point defects is expected to enhance phonon scattering, thereby improving the thermal insulation performance of the material. However, the differences in size and valence state also pose challenges to hafnium ion doping. This invention successfully prepared a single-phase ferromanganese oxide structure (Y2)2. 0.25-0.25x Ho 0.25-0.25x Er 0.25-0.25x Yb 0.25-0.25x Hf x )2O 3+xHigh-entropy ceramic powder was obtained, and corresponding high-entropy ceramic blocks were prepared by hot pressing sintering, and relevant performance tests were completed.

[0027] The present invention will now be described in detail with reference to specific embodiments.

[0028] The performance test information in the following examples is as follows:

[0029] (1) Morphological observation:

[0030] The morphology of the powder and bulk material was observed using field emission scanning electron microscopy (Clara, Tescan, Czech Republic).

[0031] (2) X-ray diffraction analysis:

[0032] Phase analysis was performed using an X-ray diffractometer (D8 Advance, Bruker, Germany);

[0033] (3) Density measurement:

[0034] The apparent density of the bulk sample was measured using the Archimedes displacement method.

[0035] (4) High-temperature phase stability test:

[0036] (Y) 0.25-0.25x Ho 0.25-0.25x Er 0.25-0.25x Yb 0.25-0.25x Hf x )2O 3+x High-entropy ceramics were placed in a muffle furnace and annealed at 1600℃ for 100 hours. The phase composition before and after annealing was compared.

[0037] (5) Measurement of thermal diffusivity and calculation of thermal conductivity:

[0038] The thermal diffusivity of the sintered bulk material was measured using a Netzsch LFA427 laser thermal conductivity meter, and the thermal conductivity was calculated according to formula (1).

[0039] κ = αC p ρ (1)

[0040] in, κ For thermal conductivity, α For thermal diffusivity, C p For thermal melting (obtained by Neumann-Kopp rule calculation), ρ The density is the bulk density.

[0041] (6) The coefficient of thermal expansion of the sintered block was measured using a Misura ODHT 1600-50 optical dilatometer manufactured by Expert System Solutions Srl.

[0042] The present invention will be further described in detail below through embodiments.

[0043] Comparative Example

[0044] In this comparative example, (Y) 0.25 Ho 0.25 Er 0.25 Yb 0.25 The preparation method of 2O3 powder is as follows:

[0045] (1) Using Y2O3, Ho2O3, Er2O3 and Yb2O3 powders as raw materials (where the molar ratio of Y2O3, Ho2O3, Er2O3 and Yb2O3 is 1:1:1:1), and anhydrous ethanol as the medium, the raw materials and anhydrous ethanol are placed in a silicon nitride ball mill jar at a mass ratio of 1:1.2 and ball-milled in a planetary ball mill. The ball-to-material mass ratio is 2:1, the rotation speed is 300 rpm, and the ball milling time is 24 h. After drying and sieving, a Y2O3-Ho2O3-Er2O3-Yb2O3 mixed powder is obtained;

[0046] (2) The mixed powder of Y2O3-Ho2O3-Er2O3-Yb2O3 was placed in a zirconia crucible and then placed in a muffle furnace. The temperature was increased to 1500℃ at a rate of 5℃ / min under air atmosphere and held for 10 hours to carry out a complete solid-phase reaction. Then it was cooled to room temperature at a rate of 5℃ / min to obtain (Y 0.25 Ho 0.25 Er 0.25 Yb 0.25 )2O3 ceramic sintered powder.

[0047] For (Y) 0.25 Ho 0.25 Er 0.25 Yb 0.25 The performance of the O2 powder was tested, and the results are as follows:

[0048] like Figure 1 As shown in (a), (Y) 0.25 Ho 0.25 Er 0.25 Yb 0.25 The X-ray diffraction pattern of the 2O3 powder shows that it has a single-phase ferromanganese structure, with space group [missing information]. I a-3.

[0049] Example 1

[0050] In this embodiment, (Y) 0.225 Ho 0.225 Er 0.225 Yb 0.225 Hf 0.1 )2O 3.1 The specific steps for preparing high-entropy ceramic powder are as follows:

[0051] Steps (1) and (2) are completely consistent with steps (1) and (2) in the comparative example;

[0052] (3) with (Y) 0.25 Ho 0.25 Er 0.25 Yb 0.25 )2O3 sintered powder and HfO2 powder are used as raw materials (of which (Y 0.25 Ho 0.25 Er 0.25 Yb 0.25 Using a silicon nitride ball mill jar with a molar ratio of 0.45:0.1 for 2O3 and HfO2, and anhydrous ethanol as the medium, the raw materials and anhydrous ethanol were placed in the jar at a mass ratio of 1:1.2 and ball milled in a planetary ball mill. The ball-to-material mass ratio was 2:1, the milling speed was 300 rpm, and the milling time was 24 h. After drying and sieving, (Y) was obtained. 0.25 Ho 0.25 Er 0.25 Yb 0.25 )2O3-HfO2 mixed powder;

[0053] (4) (Y) 0.25 Ho 0.25 Er 0.25 Yb 0.25 The 2O3-HfO2 mixed powder was loaded into a zirconia crucible and placed in a muffle furnace. The temperature was increased to 1600℃ at a rate of 5℃ / min under air atmosphere and held for 10 hours to allow for a complete solid-phase reaction. Subsequently, it was cooled to room temperature at a rate of 5℃ / min to obtain (Y). 0.225 Ho 0.225 Er 0.225 Yb 0.225 Hf 0.1 )2O 3.1 Ceramic sintered powder;

[0054] (5) with (Y) 0.225 Ho 0.225 Er 0.225 Yb 0.225 Hf 0.1 )2O 3.1Using ceramic sintered powder as raw material and anhydrous ethanol as the medium, the raw material and anhydrous ethanol were placed in a silicon nitride ball mill jar at a mass ratio of 1:1.2 and ball-milled in a planetary ball mill. The ball-to-powder mass ratio was 2:1, the rotation speed was 300 rpm, and the milling time was 24 h. Subsequently, the powder was dried and sieved to obtain uniformly sized (Y) particles. 0.225 Ho 0.225 Er 0.225 Yb 0.225 Hf 0.1 )2O 3.1 High-entropy ceramic powder.

[0055] For (Y) 0.225 Ho 0.225 Er 0.225 Yb 0.225 Hf 0.1 )2O 3.1 The performance of high-entropy ceramic powder was tested, and the results are as follows:

[0056] like Figure 1 As shown in (b), (Y) 0.225 Ho 0.225 Er 0.225 Yb 0.225 Hf 0.1 )2O 3.1 The X-ray diffraction pattern of the high-entropy ceramic powder shows that the powder has a single-phase ferromanganese structure with space group [missing information]. I a-3. This result indicates that a certain amount of HfO2 can be completely dissolved into (Y). 0.25 Ho 0.25 Er 0.25 Yb 0.25 In 2O3.

[0057] like Figure 2 As shown in (a), (Y) 0.225 Ho 0.225 Er 0.225 Yb 0.225 Hf 0.1 )2O 3.1 The scanning electron microscope image of the high-entropy ceramic powder shows that the powder has a uniform particle size distribution and the particle size is below 2.0 μm.

[0058] like Figure 3 As shown in (a), (Y) 0.225 Ho 0.225 Er 0.225 Yb 0.225 Hf 0.1 )2O 3.1The X-ray diffraction pattern of high-entropy ceramic powder after annealing at 1600℃ for 100 hours shows that the powder still maintains a single-phase ferromanganese structure after annealing, exhibiting excellent high-temperature phase stability.

[0059] Example 2

[0060] In this embodiment, (Y) 0.2 Ho 0.2 Er 0.2 Yb 0.2 Hf 0.2 )2O 3.2 The preparation method of high-entropy ceramic powder is basically the same as that in Example 1, except that:

[0061] In step (3) (Y) 0.25 Ho 0.25 Er 0.25 Yb 0.25 The molar ratio of 2O3 to HfO2 is 0.4:0.2;

[0062] In steps (4) and (5), “(Y)” 0.225 Ho 0.225 Er 0.225 Yb 0.225 Hf 0.1 )2O 3.1 “Change to “(Y”) 0.2 Ho 0.2 Er 0.2 Yb 0.2 Hf 0.2 )2O 3.2 ".

[0063] The performance of hafnium oxide modified high-entropy rare earth oxide powder 3 for thermal spraying was tested, and the results are as follows:

[0064] like Figure 1 As shown in (c), (Y) 0.2 Ho 0.2 Er 0.2 Yb 0.2 Hf 0.2 )2O 3.2 The X-ray diffraction pattern of the high-entropy ceramic powder shows that the main phase is a ferromanganese-structured product with space group [space group missing]. I a-3; also contains a small amount of fluorite structural products, space group: F m-3m. This result indicates that excess HfO2 cannot be completely dissolved into (Y). 0.25 Ho 0.25 Er 0.25 Yb 0.25 In 2O3, it affects the formation of single-phase structure.

[0065] like Figure 2 As shown in (b), (Y) 0.2 Ho 0.2 Er 0.2 Yb 0.2 Hf 0.2 )2O 3.2 The scanning electron microscope image of the high-entropy ceramic powder shows that the powder has a uniform particle size distribution and the particle size is below 2.0 μm.

[0066] like Figure 3 As shown in (b), (Y) 0.2 Ho 0.2 Er 0.2 Yb 0.2 Hf 0.2 )2O 3.2 The X-ray diffraction pattern of high-entropy ceramic powder after annealing at 1600℃ for 100 hours shows that the annealed powder still consists of two phases: ferromanganese structure and fluorite structure products, which can maintain the stability of the two phases at high temperature.

[0067] Example 3

[0068] In this embodiment, (Y) 0.225 Ho 0.225 Er 0.225 Yb 0.225 Hf 0.1 )2O 3.1 The specific steps for preparing high-entropy ceramic bulk materials are as follows:

[0069] Among them, steps (1), (2), (3), (4) and (5) are completely consistent with steps (1), (2), (3), (4) and (5) in Example 1;

[0070] (6) (Y) 0.225 Ho 0.225 Er 0.225 Yb 0.225 Hf 0.1 )2O 3.1 High-entropy ceramic powder was loaded into a 50 mm diameter graphite mold and placed in a hot-press sintering furnace. Under an argon protective atmosphere, the temperature was increased to 1800 °C at a rate of 10 °C / min, and sintered at 30 MPa for 2 hours. The powder was then cooled to room temperature at a rate of 10 °C / min to obtain dense (Y) ceramic powder. 0.225 Ho 0.225 Er 0.225 Yb 0.225 Hf 0.1 )2O 3.1 High-entropy ceramic bulk.

[0071] (Y) 0.225 Ho0.225 Er 0.225 Yb 0.225 Hf 0.1 )2O 3.1 The performance of the high-entropy ceramic bulk was tested, and the results are as follows:

[0072] like Figure 4 As shown, (Y) 0.2 Ho 0.2 Er 0.2 Yb 0.2 Hf 0.2 )2O 3.2 Scanning electron microscopy images of high-entropy ceramic bulk bodies show that no obvious pores were observed, indicating high density; the grains are uniform in size, ranging from 1.5 to 2.0 μm.

[0073] Table 1. Apparent density, theoretical density, and compacted density of the high-entropy ceramic bulk material in Example 3 of this invention.

[0074]

[0075] As shown in Table 1, (Y 0.2 Ho 0.2 Er 0.2 Yb 0.2 Hf 0.2 )2O 3.2 The apparent density of the high-entropy ceramic bulk is 7.94 g / cm³. 3 The density exceeds 98.5%.

[0076] Table 2. Comparison of thermal conductivity of the high-entropy ceramic bulk in Example 3 of the present invention with that of two reported high-entropy rare earth oxides.

[0077]

[0078] As shown in Table 2, (Y 0.2 Ho 0.2 Er 0.2 Yb 0.2 Hf 0.2 )2O 3.2 The thermal diffusivity of the high-entropy ceramic bulk at room temperature is 1.2 mm. 2 / s, thermal conductivity 2.6 ~ 3.0 W·m -1 ·K -1 Compared to the two reported high-entropy rare earth oxides, it is reduced by about 40 to 45%.

[0079] like Figure 5 As shown, (Y) 0.2 Ho 0.2 Er 0.2 Yb 0.2 Hf0.2 )2O 3.2 Elongation of high-entropy ceramic bulk materials ( ΔL / L The curve shows that the linear expansion coefficient of this block is approximately 7.8 to 8.0 × 10⁻⁶ in the temperature range of 300 to 900℃. -6 K -1 .

[0080] In summary and in combination Figures 1 to 5 It can be seen that the present invention successfully prepared (Y) via a two-step solid-state reaction method. 0.25-0.25x Ho 0.25-0.25x Er 0.25-0.25x Yb 0.25-0.25x Hf x )2O 3+x High-entropy ceramic powder was successfully prepared by hot pressing sintering (Y) 0.25-0.25x Ho 0.25-0.25x Er 0.25-0.25x Yb 0.25-0.25x Hf x )2O 3+x High-entropy ceramic bulk. This ceramic material has a low thermal conductivity (2.6 ~ 3.0 W·m at room temperature). -1 ·K -1 Compared to the two reported high-entropy rare earth oxide materials, this represents a reduction of approximately 40-45%, and a decrease in the coefficient of thermal expansion (7.8-8.0×10⁻⁶ in the 300-900℃ range). -6 K -1 It has excellent high-temperature phase stability (no phase change after annealing at 1600℃ for 100 hours), making it a potential thermal / environmental barrier coating surface material.

[0081] Those skilled in the art will understand that the above embodiments are specific examples of implementing the present invention, and in practical applications, various changes in form and detail can be made without departing from the spirit and scope of the present invention. Any person skilled in the art can make their own modifications and alterations without departing from the spirit and scope of the present invention; therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

Claims

1. A high-entropy oxide ceramic material, characterized in that, The chemical composition of the high-entropy oxide ceramic material is (Y 0.25-0.25x Ho 0.25-0.25x Er 0.25-0.25x Yb 0.25-0.25x Hf x )2O 3+x 0 < x < 1.

2. The high-entropy oxide ceramic material according to claim 1, characterized in that, The high-entropy oxide ceramic material has a single-phase ferromanganese oxide structure with space group [space group number missing]. I a-3.

3. The high-entropy oxide ceramic material according to claim 1, characterized in that, The high-entropy oxide ceramic material has a thermal conductivity of 2.6 ~ 3.0 W·m at room temperature. -1 ·K -1 The coefficient of thermal expansion in the range of 300 ~ 900℃ is 7.8 ~ 8.0 × 10⁻⁶. -6 K -1 Furthermore, no phase transformation occurred after annealing at 1600℃ for 100 hours.

4. A method for preparing a high-entropy oxide ceramic material according to any one of claims 1 to 3, characterized in that, The method includes the following steps: (1) Y2O3, Ho2O3, Er2O3 and Yb2O3 powders with a molar ratio of 1:1:1:1 were mixed and then ball-milled to obtain Y2O3-Ho2O3-Er2O3-Yb2O3 mixed powder; (2) The Y2O3-Ho2O3-Er2O3-Yb2O3 mixed powder was subjected to a solid-state reaction at temperature T1 for t1 hours to obtain (Y 0.25 Ho 0.25 Er 0.25 Yb 0.25 )2O3 ceramic sintered powder; wherein, the solid-phase reaction temperature T1 is 1400 ~ 1600℃, and the solid-phase reaction time t1 is 10 ~ 50 hours; (3) Set the molar ratio to (0.5-0.5) x ): x of(Y 0.25 Ho 0.25 Er 0.25 Yb 0.25 The sintered powder of 2O3 ceramic and the powder of HfO2 were mixed and then ball-milled to obtain (Y) 0.25 Ho 0.25 Er 0.25 Yb 0.25 )2O3-HfO2 mixed powder; (4) The (Y) 0.25 Ho 0.25 Er 0.25 Yb 0.25 The 2O3-HfO2 mixed powder was subjected to a solid-state reaction at temperature T2 for t2 hours to obtain (Y) 0.25-0.25x Ho 0.25-0.25x Er 0.25-0.25x Yb 0.25-0.25x Hf x )2O 3+x High-entropy ceramic sintered powder; wherein the solid-phase reaction temperature T2 is 1450 ~ 1650℃, and the solid-phase reaction time t2 is 10 ~ 50 hours; (5) The (Y) 0.25-0.25x Ho 0.25-0.25x Er 0.25-0.25x Yb 0.25-0.25x Hf x )2O 3+x High-entropy ceramic sintered powder is ball-milled to obtain the high-entropy oxide ceramic material.

5. The method for preparing high-entropy oxide ceramic materials according to claim 4, characterized in that, The atmosphere for the solid-phase reaction in steps (2) and (4) is air, and the heating and cooling rates are both 5 ~ 10℃ / min.

6. The method for preparing high-entropy oxide ceramic materials according to claim 4, characterized in that, The ball milling process in steps (1), (3) and (5) specifically includes: using anhydrous ethanol as a medium and placing it in a planetary ball mill for processing, wherein the mass ratio of powder to anhydrous ethanol is between 1:1 and 1:1.5, the mass ratio of ball to material is between 2:1 and 4:1, the ball milling speed is 160 to 350 rpm, and the mixing time is 24 to 48 h.

7. The method for preparing high-entropy oxide ceramic materials according to claim 4, characterized in that, The method also includes: (6) The high-entropy oxide ceramic material is sintered at a temperature of T3 for t3 hours; wherein the sintering temperature T3 is 1700~1900℃, the sintering time t3 is 1~3 hours, the sintering pressure is 20~30 MPa, and the sintering atmosphere is argon.

8. The method for preparing high-entropy oxide ceramic materials according to claim 7, characterized in that, In step (6), the high-entropy oxide ceramic material is placed into a graphite mold and then sintered in a hot press furnace or a spark plasma sintering furnace.

9. The method for preparing high-entropy oxide ceramic materials according to claim 7, characterized in that, The particle size of the high-entropy oxide ceramic material after step (5) is below 2.0 μm; the density of the high-entropy oxide ceramic material after step (6) exceeds 98.5%, and the grain size is 1.5 ~ 2.0 μm.

10. The application of a high-entropy oxide ceramic material according to claim 1 or 2 in the field of thermal / environmental barrier coatings.

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