Medium-entropy ceramic powder material with multilevel structure and continuous discrete evaporation and preparation method and application of medium-entropy ceramic powder material

Abstract

The invention discloses a multi-stage structure continuous discrete evaporation medium-entropy ceramic powder material and a preparation method and application thereof, and belongs to the technical field of ceramic powder materials. The chemical general formula of the medium-entropy ceramic powder material is (YxYbyGdzLar) 2Zr2O7, the value of at least two of x, y, z and r is larger than 0, x + y + z + r = 1, and the molten sand dust corrosion resistance of the material at the high temperature is improved through the action of multi-element rare earth. According to the preparation method of the medium-entropy ceramic powder material, continuous discrete evaporation is achieved through design and preparation of a three-stage powder structure, the first-stage structure is original ceramic particles with the particle size being 0.2-1 micron, the second-stage structure is agglomerated particles with the particle size being 1-5 microns formed by agglomeration of the first-stage structure, and the third-stage structure is formed by agglomeration of the second-stage structure. The third-level structure is 5-25 [mu] m micron-level agglomerated particles formed by agglomerating the first-level structure and the second-level structure together, and the problem that in an existing thermal barrier coating material, powder evaporation is not uniform is solved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of ceramic powder materials, and particularly relates to a multi-stage structure sustained dispersion evaporation medium-entropy ceramic powder material and a preparation method and application thereof. BACKGROUND

[0002] Thermal barrier coatings (TBCs) are one of the key core technologies of aero-engine turbine blades, which can significantly improve the engine operating temperature and enhance the engine thrust and working efficiency.

[0003] The widely used thermal barrier coating material is yttria-stabilized zirconia (YSZ). YSZ has good thermal insulation performance and mechanical properties, and is an excellent choice as a thermal barrier coating material. However, with the development of technology, the service temperature of the aero-engine gradually increases, causing the blade and its surface TBCs to suffer severe sand and dust corrosion. These sand and dust will deposit on the engine blades and, after melting, penetrate into the coating along the cracks and pores in the coating, causing the coating to delaminate and eventually fail.

[0004] The addition of rare earth elements can effectively improve the high-temperature molten sand and dust corrosion resistance of ceramic materials, which is specifically manifested by the formation of a dense reaction layer, thereby preventing further penetration of high-temperature sand and dust melts. However, different rare earth elements have different contributions in terms of reaction speed and thickness of the dense layer when forming a dense reaction layer due to differences in atomic radius. For example, small ionic radius rare earth elements can quickly form a large amount of dense reaction layer due to their fast diffusion speed, which can quickly block the penetration, but will cause a large amount of coating material loss. Large ionic radius rare earth elements have slow diffusion speed, resulting in slow formation of dense reaction layer, and the sand and dust melts will penetrate severely.

[0005] As a new type of thermal barrier coating preparation technology, plasma physical vapor deposition (PS-PVD) has high input power and low operating pressure, which can control the melting and vaporization degree of the powder material, thereby obtaining various coating structures. However, to achieve powder vaporization, the structure of the powder needs to be specially designed. The existing multi-stage structure powder design can ensure that the powder meets the powder feeding conditions and can be broken down into smaller particles after entering the jet, thereby being more effectively melted and evaporated. However, the particles will concentrate in the same area of the jet after breaking down, causing the local temperature of the jet to decrease, thereby causing uneven melting and evaporation of the powder. SUMMARY

[0006] In order to overcome the problems of insufficient single rare earth element and difficulty in existing powder structure evaporation, the present application aims to provide a multi-level structure continuous dispersion evaporation medium entropy ceramic powder material and a preparation method and application thereof, so as to solve the problems of poor high-temperature molten sand dust corrosion resistance of existing materials and poor coating performance caused by uneven powder evaporation.

[0007] In order to achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0008] The present application provides a multi-level structure continuous dispersion evaporation medium entropy ceramic powder material, the chemical general formula of the medium entropy ceramic powder material is: (Y x Yb y Gd z La r )2Zr2O7, wherein at least two of x, y, z and r are greater than 0, and x+y+z+r=1; the medium entropy ceramic powder material has a pyrochlore structure crystal.

[0009] The present application also provides a preparation method of the above-mentioned multi-level structure continuous dispersion evaporation medium entropy ceramic powder material, comprising the following steps:

[0010] 1) The raw materials are weighed according to the stoichiometric ratio of the corresponding elements in the chemical general formula of the medium entropy ceramic powder material, and after ball milling and mixing, a mixed raw material is formed; the raw materials include ZrO2 powder and at least two of Y2O3, Yb2O3, Gd2O3 and La2O3;

[0011] 2) After low-temperature drying of the mixed raw material, a mixed powder is obtained;

[0012] 3) The mixed powder is subjected to high-temperature solid phase reaction in an inert atmosphere to obtain a powder material;

[0013] 4) The powder material is cooled, crushed and sieved to obtain a first-level structure particle with a particle size of 0.2-1 mu m;

[0014] 5) The first-level structure particle is bonded by phenolic resin to form a second-level structure agglomerated particle with a particle size of 1-5 mu m, and the addition amount of phenolic resin is 8-12% of the mass of dry phenolic resin powder relative to the mass of the first-level structure particle to be bonded;

[0015] 6) The first-level structure particle and the second-level structure agglomerated particle are bonded by modified epoxy resin to form a third-level structure agglomerated particle with a particle size of 5-25 mu m, and the medium entropy ceramic powder material is prepared; the addition amount of epoxy resin is 12-18% of the mass of dry epoxy resin powder relative to the total mass of the first-level structure particle and the second-level structure agglomerated particle to be bonded; the mass fraction of the first-level structure particle in the third-level structure agglomerated particle is 10-30%.

[0016] Preferably, in step 4), the particle size of the primary structure particles is 0.2 μm-1 μm; in step 5), the particle size of the secondary structure agglomerated particles is 1 μm-5 μm; in step 6), the particle size of the tertiary structure agglomerated particles is 5 μm-25 μm.

[0017] Preferably, in step 1), 1%-2% of anhydrous ethanol is added in the ball milling process.

[0018] Preferably, in step 2), the low-temperature drying temperature is 40-60℃.

[0019] In step 3), the inert atmosphere is argon, and the argon flow rate is 200-500 mL / min.

[0020] Preferably, the high-temperature solid-phase reaction conditions include: the reaction temperature is 1400-1600℃, and the reaction time is 6-8 hours.

[0021] Preferably, in step 5), the gasification temperature is 200-250℃; the inlet air temperature is 150-180℃, and the outlet air temperature is 80-90℃.

[0022] Preferably, in step 6), the gasification temperature is 150-200℃; the inlet air temperature is 150-180℃, and the outlet air temperature is 65-100℃.

[0023] The application also provides the application of the above-mentioned multi-level structure continuous dispersion evaporation medium-entropy ceramic powder material in the field of thermal barrier coating materials.

[0024] Compared with the prior art, the application has the following beneficial effects:

[0025] The application provides a multi-level structure continuous dispersion evaporation medium-entropy ceramic powder material. A medium-entropy solid solution formed by multiple rare earth elements (Y, Yb, Gd, La) reduces the atomic diffusion rate, and due to the use of the configuration entropy effect of multiple rare earth cations, the lattice thermal conductivity is significantly reduced, the phase stability is improved, and the coexistence of multiple rare earth elements can reduce the preferential evaporation tendency of a single element, so that the evaporation process is more uniform. The pyrochlore structure provides a stable crystal framework, reduces composition segregation at high temperatures, and improves evaporation consistency. The medium-entropy effect enhances lattice distortion, hinders the penetration of corrosive media (such as CaO-MgO-Al2O3-SiO2 dust), and promotes the formation of a dense oxide layer to block the corrosion reaction.

[0026] The pyrochlore structure of the medium-entropy ceramic powder material realizes evaporation uniformity in two ways: (1) element synergy inhibits preferential evaporation: a single rare earth pyrochlore (such as Y2Zr2O7) will preferentially evaporate Y at high temperatures, and the coexistence of multiple rare earth elements can inhibit the preferential evaporation of a single element. 3+The small ion radius and low binding energy preferentially evaporate, leading to composition deviation. When multiple rare earth elements coexist (such as Y / Yb / Gd / La), different ion radii and binding energies form energy potential wells in the lattice, and higher energy is required to break free from the lattice binding, which overall slows down the evaporation rate and reduces the selective escape of single elements; (2) Configuration entropy increases the diffusion energy barrier: the disordered arrangement of multiple rare earth elements at the A site of the crystallographic position, i.e. the configuration entropy effect, significantly increases the atomic diffusion activation energy, changing the "sudden concentrated escape" of evaporation into "gradual discrete release" (i.e. "continuous discrete evaporation"). Through the above two points, the technical problem of uneven powder evaporation in existing thermal barrier coating materials, which affects the uniformity of the coating, is solved.

[0027] In addition, the multi-level structure continuous discrete evaporation of the entropy ceramic powder material of the present application also solves the technical problem of sand and dust corrosion through chemical activity regulation, specifically including the following two points: (1) Active interception of molten sand and dust: Yb 3 + / Gd 3 Preferentially reacts with SiO2 in sand and dust to generate high-melting-point apatite phase, blocking the corrosion channel; La 3+ Generates perovskite phase with Al2O3, enhancing the permeability resistance. (2) Synergistic passivation effect: The coexistence of multiple elements forms a gradient reaction layer composed of multiple high-melting-point compounds at the corrosion interface, making the entropy ceramic powder material have a wider temperature stability interval, effectively resisting capillary penetration of molten sand and dust.

[0028] The present application also provides a preparation method of the above-mentioned multi-level structure continuous discrete evaporation of the entropy ceramic powder material, which realizes gradient regulation of the evaporation rate through "primary crushing → secondary phenolic bonding → tertiary epoxy bonding" of the three-level structure: the high specific surface of the primary particles provides initial evaporation active sites; during the preparation of the secondary structure particles, the phenolic resin is carbonized and decomposed to form a nanoscale pore network, allowing the primary particles to "discretely escape" through the pores, avoiding concentrated evaporation; during the preparation of the tertiary structure particles, the epoxy resin is decomposed and leaves a rigid skeleton, delaying the disintegration of the secondary particles and realizing continuous evaporation. In the three-level structure, the proportion of primary particles is 10%-30%, which is the optimal evaporation window verified by experiments; if > 30%, the evaporation is too fast and the coating is prone to form pores; if < 10%, the evaporation is discontinuous and the coating density decreases.

[0029] Further, the primary structure particles have high specific surface area, providing a fast evaporation starting power, making the evaporation continuous; the secondary structure particles act as a transition buffer layer, delaying the concentrated evaporation of the primary particles; the tertiary structure particles act as a skeleton to slow down the overall evaporation rate, ensuring a long-term, stable and uniform evaporation process, realizing continuous and discrete evaporation, and also ensuring the flowability of the powder during powder feeding. At the same time, the large size of the tertiary structure particles can effectively resist sand and dust impact. The tertiary structure particles formed by the agglomeration of primary and secondary structure particles can ensure that the meso-entropy ceramic powder continuously and discretely evaporates in each region of the spraying jet, avoiding concentrated evaporation at a certain position, which causes local temperature to be too low.

[0030] Further, 1% to 2% of anhydrous ethanol by mass percentage is added in the ball milling process to further improve the mixing uniformity and control the particle morphology, which can improve the material density and erosion resistance.

[0031] Further, low-temperature drying at 40-60℃ avoids the agglomeration of nano-powder, ensuring the uniformity of the composition.

[0032] Further, argon protection prevents the high-temperature oxidation or volatilization loss of rare earth oxides, ensuring the long-term phase stability of the material in a high-temperature environment.

[0033] Further, high-temperature solid-phase reaction at 1400-1600℃ for 6-8h precisely controls the formation of pyrochlore phase, avoiding the generation of impurities.

[0034] Further, the gasification temperature of 200-250℃ is the forming window of the viscous flow state of phenolic resin. Below 200℃, the resin is not fully softened, and the particles are not firmly bonded; above 250℃, the resin is excessively carbonized, losing the bonding ability. Within this temperature range, the resin partially decomposes to form mesoporous structures, reserving channels for the evaporation of primary particles. The inlet temperature of 150-180℃ allows the gradient evaporation of water, preserving the integrity of the particles. An outlet temperature of 80-90℃ allows the resin to semi-cure and set, and the particles to flow freely. An outlet temperature of <80℃ causes the particles to stick together, and an outlet temperature of >90℃ causes the particles to glass transition, leading to pore collapse.

[0035] Further, the gasification temperature of 150-200℃ is the activation window of the modified epoxy resin and the hydrolysis-condensation reaction temperature of the silane coupling agent, which helps to generate active sites resistant to sand and dust corrosion. A temperature of <150℃ results in incomplete reaction, and a temperature of >200℃ causes the epoxy resin to open and self-polymerize. An inlet temperature of 150-180℃ allows the solvent to be completely removed, and an outlet temperature of 65-80℃ maintains the elasticity of the particles. A temperature of <65℃ causes the particles to stick to the wall, and a temperature of >80℃ increases the cross-linking degree of the epoxy resin, causing the particles to become brittle.

[0036] The present invention also provides applications for the aforementioned medium-entropy ceramic powder material in thermal barrier coatings. The multi-stage particles evaporate sequentially and discretely during thermal spraying, reducing droplet splashing, forming a dense, crack-free coating, and improving coating uniformity. Rare earth elements such as Gd and Yb effectively react with molten sand dust to form high-melting-point products, preventing corrosion penetration. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 (Y 1 / 3 Gd 1 / 3 Yb 1 / 3 ) XRD pattern of 2Zr2O7 ceramic powder;

[0038] Figure 2 (Y) obtained after sintering Example 1 of the present invention 1 / 3 Gd 1 / 3 Yb 1 / 3 ) Scanning photo of the 2Zr2O7 ceramic surface;

[0039] Figure 3 (a) is Example 1 of the present invention (Y 1 / 3 Gd 1 / 3 Yb 1 / 3 ) High-magnification scanning photo of 2Zr2O7 primary structure particles;

[0040] Figure 3 (b) and Figure 3 (c) are respectively the multi-level structure (Y 1 / 3 Gd 1 / 3 Yb 1 / 3 ) High-magnification scanning photos of the cross section and surface of 2Zr2O7 powder;

[0041] Figure 4 For Example 1 (Y 1 / 3 Gd 1 / 3 Yb 1 / 3 ) High-magnification scanning photos and EDS surface scanning results of the cross section of 2Zr2O7 after sand and dust corrosion at 1300℃ for 20h;

[0042] Figure 5 For Example 1 (Y 1 / 3 Gd 1 / 3 Yb 1 / 3 ) EDS spectrum results of 2Zr2O7 corrosion cross section;

[0043] Figure 6 Example 2) (La 1 / 4 Y 1 / 4 Gd 1 / 4 Yb 1 / 4 ) XRD pattern of 2Zr2O7 ceramic powder;

[0044] Figure 7 For Example 2 (La 1 / 4 Y 1 / 4 Gd 1 / 4 Yb 1 / 4 Cross-section high-magnification scanning photograph and EDS area scanning result of 700℃ sand dust corrosion for 20h of (La

[0045] Figure 8 Schematic diagram for preparation of multi-stage structure powder of the present application;

[0046] Wherein, 1-primary structure particle, 2-secondary agglomerated particle, 3-tertiary agglomerated particle. DETAILED DESCRIPTION

[0047] To enable persons skilled in the art to understand the features and effects of the present application, the following only describes and defines the terms and phrases mentioned in the specification and claims. Unless otherwise specified, all technical and scientific words used herein are the usual meanings understood by those skilled in the art for the present application, and in case of conflict, the definition in the specification shall prevail.

[0048] Theories or mechanisms described and disclosed herein, whether correct or not, should not be considered limiting the scope of the present application, i.e., the present application can be practiced without relying on any particular theory or mechanism.

[0049] Herein, all features defined in the form of numerical ranges or percentage ranges such as numerical values, quantities, contents and concentrations are only for the sake of brevity and convenience. Accordingly, the description of numerical ranges or percentage ranges should be considered to have encompassed and specifically disclosed all possible sub-ranges and individual numerical values within the range (including integers and fractions).

[0050] Herein, unless otherwise specified, “comprise”, “include”, “contain”, “have” or similar words encompass the meaning of “consist of” and “consist essentially of”, for example, “A comprises a” encompasses the meaning of “A comprises a and other” and “A only comprises a”.

[0051] Herein, for the sake of brevity, all possible combinations of the technical features in each embodiment or example are not described. Therefore, as long as the combinations of the technical features do not contradict each other, the technical features in each embodiment or example can be combined arbitrarily, and all possible combinations should be considered as the scope disclosed in the specification.

[0052] In order to overcome the problems in the prior art, the application provides a multi-level structure continuous discrete evaporation medium-entropy ceramic powder material and a preparation method thereof.

[0053] The application provides a multi-level structure continuous discrete evaporation medium-entropy ceramic powder material. x Yb y Gd z La r )2Zr2O7, wherein values of at least two of x, y, z and r are greater than 0, and x+y+z+r=1; the medium-entropy ceramic powder material has a pyrochlore structure crystal.

[0054] The application further provides a preparation method of the multi-level structure continuous discrete evaporation medium-entropy ceramic powder material.

[0055] 1) The raw materials are weighed according to the stoichiometric ratio of the corresponding elements in the chemical formula of the medium-entropy ceramic powder material, the raw materials include ZrO2 powder and at least two of Y2O3, Yb2O3, Gd2O3 and La2O3, and ultrasonic-assisted ball milling is used to form mixed raw materials, so as to enhance the mixing uniformity and reduce the agglomeration phenomenon; the ball milling time is 12-20 hours, so as to ensure sufficient dispersion of the nanoparticles; 1%-2% of anhydrous ethanol is added in the ball milling process;

[0056] 2) The mixed raw materials are dried at low temperature to retain the nano characteristics of the materials, so as to obtain mixed powder; the low-temperature drying temperature is 40-60 DEG C;

[0057] 3) The mixed powder is subjected to high-temperature solid-phase reaction, the reaction temperature is 1400-1600 DEG C, and the reaction time is 6-8 hours, so as to obtain the powder material; inert atmosphere is used in the reaction process to control the oxidation state of the material and optimize the phase structure, and the flow rate of the inert atmosphere is 200-500 mL / min;

[0058] 4) The powder material is cooled, crushed and sieved, so as to obtain the required primary structure particles with a particle size of 0.2-1 mu m;

[0059] 5) The primary structure particles are bonded into 1 mu m-5 mu m secondary structure agglomerated particles by using a superfine agglomeration granulation method through phenolic resin; the addition amount of the phenolic resin is 8%-12% of the mass of the dry resin powder relative to the mass of the primary structure particles to be bonded, the gasification temperature is 200-250 DEG C; the inlet air temperature is 150-180 DEG C, and the outlet air temperature is 80-90 DEG C;

[0060] 6) The primary structure particles and the secondary structure agglomerated particles are bonded into 5-25 μm tertiary structure agglomerated particles by a spray granulation method through modified epoxy resin, the mass fraction of the primary structure particles in the tertiary structure agglomerated particles is 10%-30%, the added amount of the epoxy resin is 12%-18% of the total mass of the primary structure particles and the secondary structure agglomerated particles to be bonded, the gasification temperature is 150-200 ℃, the inlet air temperature is 150-180 ℃, and the outlet air temperature is 65-80 ℃.

[0061] The preparation method is prepared from nanoscale Y2O3, Yb2O3, Gd2O3, La2O3 and ZrO2 as main raw materials through accurate proportioning, ball milling mixing and high-temperature solid phase reaction. The primary structure particles of the powder are 0.2 μm-1 μm nanoceramic particles of pyrochlore structure multi-main element rare earth zirconate, the secondary structure is 1 μm-5 μm agglomerated particles formed by agglomeration of the primary structure, and the tertiary structure is 5 μm-25 μm agglomerated particles formed by agglomeration of the primary structure and the secondary structure. The powder structure of the application can ensure that the powder is uniformly and continuously evaporated in each region of the spraying jet, avoids local temperature too low caused by concentrated evaporation at a position, and the meso-entropy ceramic bulk prepared through dry pressing and high-temperature sintering process, such as (Y 1 / 3Gd 1 / 3 Yb 1 / 3 )2Zr2O7 and (La 1 / 4 Y 1 / 4 Gd 1 / 4 Yb 1 / 4 )2Zr2O7 bulk material also shows excellent resistance to molten sand dust erosion.

[0062] The application will be further described in conjunction with specific examples. It should be understood that these examples are only used to illustrate the application and not used to limit the scope of the application. In addition, it should be understood that those skilled in the art can make various modifications or changes to the application after reading the content of the application, and these equivalent forms also fall within the scope defined by the appended claims of the application.

[0063] The following examples use the conventional apparatus in the art. The experimental method in the following examples is not specified, which is usually according to the conventional condition, or according to the condition suggested by the manufacturer. The following examples use various raw materials, unless otherwise specified, which are conventional commercially available products, and the specifications are conventional specifications in the art. In the specification of the application and the following examples, unless otherwise specified, “%” means weight percent, “parts” means weight parts, and the ratio means weight ratio.

[0064] Example 1

[0065] A preparation method of a multi-level structure continuously dispersed evaporation medium-entropy ceramic powder material, comprising the following steps:

[0066] 1) Nanoscale Y2O3, Yb2O3, Gd2O3 and ZrO2 powders are weighed according to a molar ratio of 1:1:1:3, and an ultrasonic-assisted ball milling is used to form a mixed raw material, so as to enhance the mixing uniformity and reduce the agglomeration phenomenon; the ball milling time is 12 hours, so as to ensure the sufficient dispersion of the nanoparticles; 1% of anhydrous ethanol is added in the ball milling process;

[0067] 2) The mixed raw material is subjected to low-temperature drying to retain the nanometer characteristics of the material, so as to obtain a mixed powder; the low-temperature drying temperature is 40℃;

[0068] 3) The mixed powder is subjected to a high-temperature solid-phase reaction, the reaction temperature is 1400℃, and the reaction time is 6 hours, so as to obtain a powder material; argon gas is used in the reaction process to control the oxidation state of the material and optimize the phase structure, and the flow rate of the argon gas is 200 mL / min;

[0069] 4) The powder material is subjected to cooling, crushing and sieving processes, so as to obtain first-level structure particles with a particle size of 0.2-1 μm;

[0070] 5) The first-level structure particles are bonded into 1 μm-5 μm second-level structure agglomerated particles by using a superfine agglomeration granulation method through phenolic resin; the addition amount of the phenolic resin is 8% of the mass of the dry powder of the resin relative to the mass of the first-level structure particles to be bonded, the gasification temperature is 200℃, the air inlet temperature is 150℃, and the air outlet temperature is 80℃;

[0071] 6) The first-level structure particles and the second-level structure agglomerated particles are bonded into 5-25 μm third-level structure agglomerated particles by using a spray granulation method through modified epoxy resin, and the medium-entropy ceramic powder material is prepared through dry pressing and high-temperature sintering processes; the chemical formula of the medium-entropy ceramic powder material is (Y 1 / 3 Gd 1 / 3 Yb 1 / 3 )2Zr2O7, in the third-level structure agglomerated particles, the mass fraction of the first-level structure particles is 20%; the addition amount of the epoxy resin is 12% of the mass of the dry powder of the epoxy resin relative to the total mass of the first-level structure particles and the second-level structure agglomerated particles to be bonded, the gasification temperature is 150℃, the air inlet temperature is 150℃, and the air outlet temperature is 65℃.

[0072] The XRD pattern of the medium-entropy ceramic powder prepared in the embodiment is shown in Figure 1 , the scanning photos of the first-level structure particles are shown in Figure 3 (a) and Figure 3 (b) and 3(c) are the surface and cross-section scanning photos of the third-level structure particle powder.

[0073] The prepared (Y1 / 3 Gd 1 / 3 Yb 1 / 3 The primary structure particles in the 2Zr2O7 medium entropy ceramic powder material are prepared into ceramic blocks through a high temperature sintering process using hot isostatic pressing. The sintering temperature is set at 1550°C, the holding time is 20 hours, the pressure is 150MPa, and argon protection is used to ensure the high temperature stability and density of the material. The surface of the obtained ceramic block is ground and polished. Figure 2 It can be seen that (Y 1 / 3 Gd 1 / 3 Yb 1 / 3 )2Zr2O7 ceramic block material has a dense microstructure with an average grain size of 1.128 microns. Sand dust powder is mixed with an appropriate amount of anhydrous ethanol in a volume ratio of 1:2 and deposited on the surface of the polished ceramic block. After drying, the block is placed in a high-temperature furnace for a molten sand dust corrosion test. The high-temperature furnace is heated at a heating rate of 10℃ / min below 1000℃ and at a heating rate of 5℃ / min at 1000℃. After constant temperature maintenance, the cooling rate above 1000℃ is 5℃ / min, and then the power is turned off and the furnace is cooled. Figure 4 as well as Figure 5 The results show that after 20 hours of molten sand and dust corrosion at 1300°C, the corrosion depth is only 4 microns, demonstrating excellent resistance to molten sand and dust erosion. During the molten sand and dust corrosion process, a dense (Y-Yb-Gd)Si2O7 silicate protective layer forms on the sample surface, effectively preventing further penetration of sand and dust, significantly improving the material's resistance to sand and dust erosion.

[0074] Example 2

[0075] A method for preparing a medium-entropy ceramic powder material with a multi-level structure and continuous discrete evaporation, comprising the following steps:

[0076] 1) Nanoparticles of Y2O3, Yb2O3, Gd2O3, La2O3, and ZrO2 were weighed in a molar ratio of 1:1:1:1:4 and subjected to ultrasonic-assisted ball milling to form a mixed raw material to enhance mixing uniformity and reduce agglomeration. The ball milling time was 15 hours to ensure sufficient dispersion of the nanoparticles. 1.5% by weight of anhydrous ethanol was added during the ball milling process.

[0077] 2) The mixed raw materials are dried at low temperature to retain the nano-properties of the materials to obtain a mixed powder; the low temperature drying temperature is 50°C;

[0078] 3) subjecting the mixed powder to a high-temperature solid-phase reaction at 1500° C. for 7 hours to obtain a powder material. An inert atmosphere was used during the reaction to control the oxidation state of the material and optimize the phase structure. The inert atmosphere flow rate was 300 mL / min.

[0079] 4) Cooling, crushing and sieving the powder material to obtain the required primary structure particles with a particle size of 0.2 to 1 μm;

[0080] 5) The primary structure particles are bonded into 1 μm-5 μm secondary structure agglomerated particles using an ultrafine agglomeration granulation method with phenolic resin; the amount of phenolic resin added is 10% of the mass of the resin dry powder based on the mass of the primary structure particles to be bonded; the gasification temperature is 225°C; the air inlet temperature is 165°C, and the air outlet temperature is 85°C;

[0081] 6) The primary structure particles and the secondary structure agglomerated particles are bonded into 5-25 μm tertiary structure agglomerated particles by using a spray particle method through modified epoxy resin, and then dry pressed and high temperature sintered to obtain (La 1 / 4 Y 1 / 4 Gd 1 / 4 Yb 1 / 4 )2Zr2O7 medium entropy ceramic powder material; the mass fraction of the primary structure particles in the tertiary structure agglomerated particles is 30%; the amount of epoxy resin added is that the mass of the epoxy resin dry powder accounts for 15% of the total mass of the primary structure particles and the secondary structure agglomerated particles to be bonded, the gasification temperature is 170°C; the air inlet temperature is 160°C, and the air outlet temperature is 70°C.

[0082] The (La 1 / 4 Y 1 / 4 Gd 1 / 4 Yb 1 / 4 )2Zr2O7 medium entropy ceramic powder XRD pattern Figure 6 As shown;

[0083] The obtained (La 1 / 4 Y 1 / 4 Gd 1 / 4 Yb 1 / 4 )2Zr2O7 medium entropy ceramic powder's primary structure particles are prepared into ceramic blocks by hot isostatic pressing. The sintering temperature is set to 1550°C, the holding time is 20 hours, the pressure is 150MPa, and argon protection is used to ensure the high-temperature stability and density of the material. The surface of the obtained ceramic block is ground and polished, and the sand dust powder is mixed with an appropriate amount of anhydrous ethanol in a volume ratio of 1:2, and deposited on the polished surface of the ceramic block. After drying, the block is placed in a high-temperature furnace for a molten sand dust corrosion experiment. The high-temperature furnace is heated at a heating rate of 10°C / min below 1000°C and at a heating rate of 5°C / min at 1200°C. After constant temperature insulation, the cooling rate above 1000°C is 5°C / min, and then the power is turned off and the furnace is cooled. By Figure 7It can be seen that after the molten sand dust corrosion for 20 hours at 1300℃, the corrosion depth is only 5 microns, which shows excellent resistance to molten sand dust corrosion. During the molten sand dust corrosion process, a dense (Y-Yb-Gd) Si2O7 silicate protective layer can be formed on the surface of the sample, effectively blocking the further penetration of the sand dust and significantly improving the sand dust corrosion resistance of the material.

[0084] Example 3

[0085] A preparation method of a multi-level structure continuous dispersion evaporation medium-entropy ceramic powder material, comprising the following steps:

[0086] 1) Nanoscale Y2O3, Yb2O3, Gd2O3, La2O3 and ZrO2 powders are weighed according to a molar ratio of 1:1:1:1:4, and an ultrasonic-assisted ball milling is used to form a mixed raw material, so as to enhance the mixing uniformity and reduce the agglomeration phenomenon; the ball milling time is 20 hours to ensure the sufficient dispersion of the nanoparticles; 2% of anhydrous ethanol is added during the ball milling treatment;

[0087] 2) Low-temperature drying is used for the mixed raw material to retain the nanometer characteristics of the material, so as to obtain a mixed powder; the low-temperature drying temperature is 60℃;

[0088] 3) The mixed powder is subjected to high-temperature solid-phase reaction, the reaction temperature is 1600℃, and the reaction time is 8 hours, so as to obtain a powder material; an inert atmosphere is used during the reaction process to control the oxidation state of the material and optimize the phase structure, and the flow rate of the inert atmosphere is 500 mL / min;

[0089] 4) The powder material is subjected to cooling, crushing and sieving treatment, so as to obtain first-level structure particles with a particle size of 0.2-1 μm;

[0090] 5) The first-level structure particles are bonded into 1 μm-5 μm second-level structure agglomerated particles by using a superfine agglomeration granulation method through phenolic resin; the addition amount of the phenolic resin is 12% of the mass of the dry powder of the resin to the mass of the first-level structure particles to be bonded, and the gasification temperature is 250℃; the inlet air temperature is 180℃, and the outlet air temperature is 90℃;

[0091] 6) The first-level structure particles and the second-level structure agglomerated particles are bonded into 5-25 μm third-level structure agglomerated particles by using a spray granulation method through modified epoxy resin, and the medium-entropy ceramic powder material is prepared through dry pressing and high-temperature sintering processes; in the third-level structure agglomerated particles, the mass fraction of the first-level structure particles is 10%; the addition amount of the epoxy resin is 18% of the mass of the dry powder of the epoxy resin to the total mass of the first-level structure particles and the second-level structure agglomerated particles to be bonded, and the gasification temperature is 200℃; the inlet air temperature is 180℃, and the outlet air temperature is 80℃.

[0092] Figure 8The structure and preparation flowchart of the multi-stage structure powder of the present application, wherein 1 is the primary particle with a particle size of 0.2-1 μm, 2 is the secondary agglomerated particle with a particle size of 1-5 μm, and 3 is the tertiary agglomerated particle with a particle size of 5-25 μm.

[0093] The above is only to illustrate the technical idea of the present application, and cannot limit the protection scope of the present application. Any modification made according to the technical idea of the present application on the basis of the technical scheme falls within the protection scope of the present application.

Claims

1. A medium entropy ceramic powder material with a multi-level structure and continuous discrete evaporation, characterized in that: The chemical formula of the medium entropy ceramic powder material is: (Y x Yb y Gd z La r )2Zr2O7, wherein at least two of x, y, z and r have values ​​greater than 0, and x+y+z+r=1; the medium-entropy ceramic powder material has a pyrochlore structure crystal.

2. A method for preparing a medium-entropy ceramic powder material with a multi-level structure and continuous discrete evaporation according to claim 1, characterized in that: The following steps are involved: 1) weighing raw materials according to the stoichiometric ratio of the corresponding elements in the chemical formula of the medium-entropy ceramic powder material, and mixing them by ball milling to form a mixed raw material; the raw materials include ZrO2 powder and at least two of Y2O3, Yb2O3, Gd2O3 and La2O3; 2) drying the mixed raw materials at low temperature to obtain a mixed powder; 3) subjecting the mixed powder to a high-temperature solid-phase reaction under an inert atmosphere to obtain a powder material; 4) Cooling, crushing and sieving the powder material to obtain primary structure particles; 5) bonding the primary structure particles into secondary structure agglomerated particles with phenolic resin, wherein the amount of phenolic resin added is 8% to 12% of the mass of the primary structure particles to be bonded by the mass of the phenolic resin dry powder; 6) The primary structure particles and the secondary structure agglomerated particles are bonded into tertiary structure agglomerated particles by modified epoxy resin to obtain a medium-entropy ceramic powder material; the amount of epoxy resin added is that the mass of the epoxy resin dry powder accounts for 12% to 18% of the total mass of the primary structure particles and the secondary structure agglomerated particles to be bonded; and the mass fraction of the primary structure particles in the tertiary structure agglomerated particles is 10% to 30%.

3. The method for preparing a medium-entropy ceramic powder material with a multi-level structure and continuous discrete evaporation according to claim 2, characterized in that: In step 4), the particle size of the primary structure particles is 0.2 μm-1 μm; in step 5), the particle size of the secondary structure agglomerated particles is 1 μm-5 μm; in step 6), the particle size of the tertiary structure agglomerated particles is 5 μm-25 μm.

4. The method for preparing a medium-entropy ceramic powder material with a multi-level structure and continuous discrete evaporation according to claim 3, characterized in that: In step 1), 1% to 2% by mass of anhydrous ethanol is added during the ball milling process.

5. The method for preparing a medium-entropy ceramic powder material with a multi-level structure and continuous discrete evaporation according to claim 3, characterized in that: In step 2), the low-temperature drying temperature is 40-60°C.

6. The method for preparing a medium-entropy ceramic powder material with a multi-level structure and continuous discrete evaporation according to claim 3, characterized in that: In step 3), the inert atmosphere is argon, and the argon flow rate is 200 to 500 mL / min.

7. The method for preparing a medium-entropy ceramic powder material with a multi-level structure and continuous discrete evaporation according to claim 3, characterized in that: In step 3), the conditions for the high-temperature solid-phase reaction include: a reaction temperature of 1400-1600° C. and a reaction time of 6-8 hours.

8. The method for preparing a medium-entropy ceramic powder material with a multi-level structure and continuous discrete evaporation according to claim 3, characterized in that: In step 5), the gasification temperature is 200-250°C; the air inlet temperature is 150-180°C, and the air outlet temperature is 80-90°C.

9. The method for preparing a medium-entropy ceramic powder material with a multi-level structure and continuous discrete evaporation according to claim 3, characterized in that: In step 6), the gasification temperature is 150-200°C; the air inlet temperature is 150-180°C, and the air outlet temperature is 65-80°C.

10. Application of the medium-entropy ceramic powder material with a multi-level structure and continuous discrete evaporation according to claim 1 in the field of thermal barrier coating materials.

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