High-efficiency evaporation core-shell structure thermal barrier coating powder with micro-explosion effect and preparation method of high-efficiency evaporation core-shell structure thermal barrier coating powder

Abstract

The invention discloses efficient evaporation core-shell structure thermal barrier coating powder with a micro-explosion effect and a preparation method of the efficient evaporation core-shell structure thermal barrier coating powder, and belongs to the technical field of thermal spraying materials, the powder is of a core-shell structure, an inner core of the powder is a hollow polymer microsphere, and a shell of the powder is a nano ceramic particle layer formed by coating nano ceramic particles on the surface of the hollow polymer microsphere; the hollow polymer microspheres comprise one or more of polymethyl methacrylate, polyethylene, polystyrene, polylactic acid, polyacrylic acid, polyvinyl butyral, polyisobutene, polycarbonate and polyethylene glycol terephthalate; the nano ceramic particles comprise one of yttrium oxide stabilized zirconium oxide, rare earth zirconate, multi-element rare earth doped zirconate, rare earth tantalate and oxide. When the core-shell structure powder material disclosed by the invention is heated, the hollow polymer microspheres can be instantly exploded, and the nano ceramic particles are uniformly dispersed into plasma jet, so that efficient and rapid evaporation of the material is realized.

Description

Technical Field

[0001] This invention belongs to the field of thermal spraying materials technology, specifically relating to a high-efficiency evaporation core-shell structure thermal barrier coating powder with micro-explosion effect and its preparation method. Background Technology

[0002] Plasma-physical vapor deposition (PS-PVD) is an advanced surface engineering technology that has been developed in the field of thermal spraying in recent years. It has shown unique advantages, especially in the preparation of thermal barrier coatings (TBCs) required for hot-end components such as aero-engines and gas turbines. It is considered to combine the technical advantages of atmospheric plasma spraying (APS) and electron beam physical vapor deposition (EB-PVD). It can vaporize the spraying material in a low-pressure, high-energy plasma jet and deposit it on the substrate surface in gaseous form to form a coating with a columnar crystal structure. This structure has excellent strain tolerance and thermal shock resistance.

[0003] The characteristics of the sprayed powder are one of the key factors affecting the PS-PVD process and the final coating structure and performance. Currently, PS-PVD mostly uses micron-sized ceramic agglomerates prepared by spray drying. However, such powders are prone to incomplete vaporization in plasma jets, leading to reduced coating deposition efficiency and a loose microstructure, which in turn affects the overall service performance of the coating, including its thermal insulation, corrosion resistance, and erosion resistance. To optimize the vaporization behavior of powders in the PS-PVD process, researchers have focused on powder structure design, such as developing multi-level agglomerate powders. These powders can undergo multiple staged deagglomerations down to the nanoscale after being heated in a plasma jet, which improves vaporization efficiency to some extent, but still cannot completely solve the problem of incomplete vaporization. Summary of the Invention

[0004] In order to overcome the shortcomings of the prior art, the present invention aims to provide a high-efficiency evaporation core-shell thermal barrier coating powder with micro-explosion effect and its preparation method, so as to solve the technical problem that the sprayed powder used in the existing PS-PVD process is prone to insufficient vaporization.

[0005] To achieve the above objectives, the present invention employs the following technical solution: This invention provides a high-efficiency evaporation core-shell structure thermal barrier coating powder with micro-explosion effect. The powder has a core-shell structure, with a hollow polymer microsphere as the core and a nano-ceramic particle layer formed by nano-ceramic particles coating the surface of the hollow polymer microsphere. The hollow polymer microspheres include one or more of polymethyl methacrylate (PMMA), polyethylene (PE), polystyrene (PS), polylactic acid (PLA), polyacrylic acid (PAA), polyvinyl butyral (PVB), polyisobutylene (PIB), polycarbonate (PC), and polyethylene terephthalate (PET). The nano-ceramic particles include one of yttrium oxide-stabilized zirconium oxide (YSZ), rare earth zirconates, multi-element rare earth doped zirconates, rare earth tantalates, and oxides.

[0006] Preferably, the hollow polymer microspheres have a particle size range of 5 μm to 90 μm, and the nano-ceramic particles have a particle size range of 30 nm to 1 μm.

[0007] This invention also provides a method for preparing the above-mentioned high-efficiency evaporation core-shell thermal barrier coating powder with micro-explosion effect, comprising the following steps: 1) The nano-ceramic particles are subjected to surface negative electrochemical treatment to obtain a ceramic slurry with a negatively charged surface; 2) Positively electrify the surface of hollow polymer microspheres; 3) Hollow polymer microspheres with positively charged surfaces and ceramic slurry with negatively charged surfaces are mixed and stirred at low speed to form a core-shell structure precursor slurry; the amount of hollow polymer microspheres used is 1% to 8% of the mass of the nano-ceramic particles; 4) The organic binder solution is added to the core-shell structure precursor slurry and dispersed evenly to form a mixed slurry; 5) The mixed slurry is spray-granulated to coat the surface of hollow polymer microspheres with nano-ceramic particles. After sieving to 5μm-100μm, a core-shell thermal barrier coating powder with a particle size suitable for plasma physical vapor deposition is obtained, wherein the particle size is 5μm-40μm. The spray granulation process conditions include: inlet temperature of 150-200℃ and outlet temperature of 80-120℃.

[0008] Preferably, in step 1), the surface negative electrochemical treatment process includes: mixing nano-ceramic particles, deionized water, and anionic dispersant, stirring evenly, and then ball milling; the weight ratio of the nano-ceramic particles, deionized water, and anionic dispersant is 100:(120~140):(0.5~0.9); the ball milling process uses grinding beads ranging from 5mm to 25mm, the ball milling time is 120~300min, and the ball milling speed is 350~500rpm.

[0009] More preferably, the above-mentioned ball milling process is carried out in a resin ball milling jar.

[0010] Preferably, the anionic dispersant includes one or two of polyacrylic acid (PAA), ammonium polyacrylate (PAA-NH4), ammonium polymethacrylate (PMAA-NH4), and ammonium citrate.

[0011] Preferably, in step 2), the surface positive electrochemical treatment process includes: immersing hollow polymer microspheres in an aqueous solution of cationic surfactant (PDDA) with a concentration of 0.1wt%~1wt%, stirring at low speed, centrifuging to clean and drying.

[0012] Preferably, the cationic surfactant is polydiallyldimethylammonium chloride (PDDA).

[0013] Preferably, the low-speed stirring speed is 100~200 rpm; the centrifugation conditions include: rotation speed of 1000~3000 rpm, time of 3~5 min, and drying environment of drying in an oven at 60℃ for 1~3 h.

[0014] Preferably, in step 4), the organic binder includes one of polyvinyl alcohol (PVA), polyethylene glycol (PEG), and hydroxypropyl methylcellulose (HPMC), with a mass fraction of 1% to 5% of the total mass of the nano-ceramic particles and hollow polymer microspheres. This concentration range provides sufficient bonding force without causing the particles to be too sticky or difficult to dry. The organic binder solution is prepared by dissolving the organic binder in deionized water at a mass percentage concentration of 1% to 5%. The dispersion conditions include: a rotation speed of 2500~4000 rpm and a time of 10~30 min.

[0015] A further preferred embodiment of the spray granulation process includes: pouring the mixed slurry into a spray drying device, atomizing the slurry into fine droplets using the spray drying device; rapidly drying the droplets under hot air conditions (inlet temperature 150~200℃, outlet temperature 80~120℃), evaporating the solvent, and agglomerating the nano-ceramic particles onto the surface of hollow polymer microspheres into spherical particles using an organic binder.

[0016] Preferably, the organic binder solution is prepared by dissolving the organic binder in deionized water at a mass percentage concentration of 1% to 5%.

[0017] Compared with the prior art, the present invention has the following beneficial effects: This invention provides a high-efficiency evaporation core-shell structure thermal barrier coating powder with micro-explosion effect. The powder is a composite structure with hollow polymer microspheres as the core and nano-ceramic particles as the shell. The hollow polymer microspheres act as a carrier and store "micro-explosion" gas in the thermal barrier coating powder. The "micro-explosion" effect, which involves the instantaneous expansion of the gas inside the hollow polymer microspheres at high temperature in the PS-PVD plasma jet and the rapid decomposition of the polymer microspheres, promotes the uniform dispersion of the outer nano-ceramic particles in the PS-PVD jet, thereby achieving efficient and uniform heating and efficient vaporization.

[0018] Hollow polymer microspheres (one or more of polymethyl methacrylate, polyethylene, polystyrene, polylactic acid, polyacrylic acid, polyvinyl butyral, polyisobutylene, polycarbonate and polyethylene terephthalate) are used. They have a low thermal decomposition temperature range and can decompose in high-temperature PS-PVD jets up to thousands of degrees. At the same time, the internal gas expands to produce a "micro-explosion" effect.

[0019] Furthermore, the particle size range of the polymer microspheres is 5µm to 90µm. Too small a particle size may lead to poor flowability and dispersibility, making agglomeration more likely; too large a particle size may affect its heating rate and micro-explosion effect in the plasma jet, thus affecting the dispersion and vaporization of the nano-ceramic particles. The preferred particle size of the nano-ceramic powder is 30nm to 1µm. Nanoscale ceramic powders have higher specific surface area and reactivity, making them easier to achieve rapid and complete heating and vaporization in the plasma jet.

[0020] This invention provides a method for preparing the aforementioned thermal barrier coating powder. By introducing an electrostatic self-assembly strategy, a weakly bonded core-shell structure precursor is pre-constructed before the addition of an organic binder. Specifically, by subjecting the hollow polymer microspheres to positive surface electrochemical treatment and the nano-ceramic particles to negative surface electrochemical treatment, the two spontaneously and uniformly bond during the mixing stage based on Coulomb forces. This reduces non-target structures (such as self-agglomeration of ceramic powder and exposure of polymer microspheres) caused by random agglomeration, improves the formation efficiency and coating uniformity of the target core-shell structure in the subsequent spray granulation process, and enhances the quality consistency and reliability of the powder product. The powder preparation method (spray drying method) is relatively simple, and the parameters are easy to control, which is conducive to achieving stable and large-scale production.

[0021] Furthermore, to achieve the best dispersion effect after micro-explosion, the amount of hollow polymer microspheres used is 1% to 8% of the mass of nano-ceramic particles. This avoids uneven dispersion of nanoparticles after micro-explosion due to insufficient dosage, and low deposition efficiency due to excessive dosage.

[0022] Furthermore, the spray granulation process uses an inlet temperature of 150~200℃ and an outlet temperature of 80~120℃ to quickly dry the slurry and form spherical powders of 5μm~100μm. The powder is then further sieved to obtain a particle size suitable for PS-PVD powder feeding requirements, thus solving the problems of powder feeding blockage and low deposition efficiency caused by uneven powder particle size and poor flowability in the existing technology.

[0023] Furthermore, the weight ratio of nano-ceramic particles, deionized water, and anionic dispersant is 100:(120~140):(0.5~0.9). The ball milling beads are 5~25mm, the ball milling time is 120~300min, and the rotation speed is 350~500rpm. This ensures that the nano-ceramic particles are evenly dispersed, avoids agglomeration, and makes the particle surface uniformly negatively charged. This provides a basis for the subsequent formation of stable electrostatic adsorption with positively charged polymer microspheres, and avoids the incomplete core-shell structure caused by uneven dispersion of ceramic slurry and disordered charge distribution.

[0024] Furthermore, anionic dispersants with good water solubility and compatibility (one or two of polyacrylic acid, ammonium polyacrylate, ammonium polymethacrylate, and ammonium citrate) are used to avoid chemical reactions with nano-ceramic particles and maintain slurry stability.

[0025] Furthermore, by controlling the concentration (0.1wt%~1wt%) of the aqueous solution of cationic surfactant (such as polydiallyldimethylammonium chloride) and low-speed stirring (100~200rpm), the surface of the polymer microspheres is given an appropriate amount and uniform positive charge, which is then electrostatically self-assembled with the negatively charged nano-ceramic particles to form a dense and complete coating shell.

[0026] Furthermore, to remove excess cationic surfactant from the surface of the hollow polymer microspheres and avoid residual impurities affecting the subsequent bonding effect, centrifugation conditions of 1000~3000rpm for 3~5min are used; drying in a 60℃ oven for 1~3h can gently remove moisture, prevent microsphere deformation or breakage, and ensure its intact structure and subsequent micro-explosion performance.

[0027] Furthermore, an organic binder (one of polyvinyl alcohol, polyethylene glycol, and hydroxypropyl methylcellulose) is used at a dosage of 1% to 5%, and the binder is stirred at a speed of 2500 to 4000 rpm for 10 to 30 minutes to fully mix the binder with the precursor slurry, thereby providing a uniform and appropriate amount of binder for the formation of the core-shell structure. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the structure of the high-efficiency evaporation core-shell thermal barrier coating powder with micro-explosion effect of the present invention. Detailed Implementation

[0029] To enable those skilled in the art to understand the features and effects of the present invention, the following descriptions and definitions are only general descriptions of the terms and expressions mentioned in the specification and claims. Unless otherwise specified, all technical and scientific terms used herein have the ordinary meaning understood by those skilled in the art regarding the present invention, and in the event of any conflict, the definitions in this specification shall prevail.

[0030] The theories or mechanisms described and disclosed herein, whether right or wrong, should not in any way limit the scope of the invention, that is, the contents of the invention can be implemented without being limited by any particular theory or mechanism.

[0031] In this document, all features defined by numerical ranges or percentage ranges, such as numerical values, quantities, contents, and concentrations, are for the sake of brevity and convenience only. Accordingly, descriptions of numerical ranges or percentage ranges should be considered as covering and specifically disclosing all possible sub-ranges and individual numerical values ​​(including integers and fractions) within those ranges.

[0032] In this article, unless otherwise specified, “contains,” “includes,” “containing,” “has,” or similar terms cover the meanings of “composed of” and “mainly composed of,” for example, “A contains a” covers the meanings of “A contains a and others” and “A contains only a.”

[0033] For the sake of brevity, not all possible combinations of the technical features in each implementation scheme or embodiment are described herein. Therefore, as long as there is no contradiction in the combination of these technical features, the technical features in each implementation scheme or embodiment can be combined arbitrarily, and all possible combinations should be considered within the scope of this specification.

[0034] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0035] The following examples use instruments and equipment conventional in the art. Experimental methods in the following examples, unless otherwise specified, are generally performed under conventional conditions or as recommended by the manufacturer. All raw materials used in the following examples are conventional commercially available products with specifications conventional in the art. In this specification and the following examples, unless otherwise specified, "%" represents weight percentage, "parts" represents parts by weight, and "ratio" represents weight proportion.

[0036] Unless otherwise specified, all raw materials used in this invention are commercially available conventional products. Unless otherwise specified, all preparation methods described herein are conventional methods in the art.

[0037] The present invention describes the preparation of a high-efficiency evaporation powder with a core-shell thermal barrier coating exhibiting micro-explosion effect. The core of this invention lies in uniformly and stably loading nanoscale ceramic powder onto the surface of polymer microspheres using physical methods, forming a composite powder with a distinct core-shell structure. This composite powder must meet the following basic requirements: (1) a complete core-shell structure and uniform ceramic powder coating; (2) good flowability and dispersibility to meet the powder feeding requirements of PS-PVD; (3) no harmful chemical reactions between the polymer material and the ceramic powder; and (4) the composite powder can exhibit the expected micro-explosion behavior under PS-PVD process conditions.

[0038] Raw material description The hollow polymer microspheres used in this invention are preferably controlled within a particle size range of 5µm to 90µm. Too small a particle size may lead to poor flowability and dispersibility, making agglomeration more likely; too large a particle size may affect its heating rate and micro-explosion effect in the plasma jet, thus affecting the gasification efficiency of the ceramic powder. The polymer material should be selected as one that can rapidly decompose and gasify within the PS-PVD jet. In addition to PMMA, PE, PS, PLA, PAA, PVB, PIB, PC, and PET listed in the claims, other polymer materials with similar thermal behavior may also be considered, but their selection must be based on the premise of achieving effective micro-explosion and not causing adverse reactions with the ceramic material.

[0039] The nano-ceramic powder used in this invention preferably has a particle size of 30 nm to 1 µm. Nanoscale ceramic powders possess higher specific surface area and reactivity, making them easier to heat and vaporize rapidly and fully in plasma jets, which is beneficial for forming a fine-structured, high-performance vapor-deposited coating. The type of ceramic material can be selected according to the application requirements of the final coating.

[0040] Preparation process description The preparation process first requires the preparation of a stable ceramic slurry. A selected organic dispersant is dissolved in a suitable solvent to form a homogeneous organic dispersant solution. Then, the nano-ceramic powder is added to the solution and fully dispersed through mechanical stirring, ball milling, or ultrasonic treatment to form a stable ceramic slurry.

[0041] Then, a stable core-shell structure precursor needs to be prepared. This is achieved by positively electrifying the surface of hollow polymer microspheres (e.g., using PDDA) and simultaneously using an anionic dispersant (e.g., using PAA) to make the surface of the nano-ceramic powder negatively charged, so that the two can spontaneously and uniformly combine during the mixing stage by relying on Coulomb forces. Then, an organic binder is used to make the two uniformly bonded to obtain a mixed slurry.

[0042] The above-mentioned mixed slurry is processed using a spray granulation process: the mixed slurry is poured into a spray drying device and dried simultaneously under controlled temperature conditions (inlet temperature 150~200℃, outlet temperature 80~120℃). This process requires precise control of parameters such as spray rate, atomization pressure, and fluidization state to ensure that the nano-ceramic powder is uniformly coated on the surface of the polymer microspheres, forming a complete core-shell structure.

[0043] The properties of powders can be evaluated and controlled in the following ways: 1. Agglomeration strength and flowability: The angle of repose or flow rate can be measured by a Hall effect flowmeter. If necessary, it can be optimized by adjusting agglomeration process parameters (such as binder content, spray granulation parameters, etc.).

[0044] 2. Microstructure: The morphology, surface structure, and internal distribution of ceramics and polymers of the agglomerated powder were observed using scanning electron microscopy (SEM).

[0045] 3. Microburst characteristics assessment: The behavior of individual aggregates in a simulated PS-PVD heating environment (such as rapid heating to above 1500℃) can be directly observed using a high-temperature hot-stage microscope coupled with a high-speed camera system, and the intensity and dispersion effect of their microbursts can be qualitatively or semi-quantitatively assessed.

[0046] When using the agglomerated composite powder prepared by this invention in the PS-PVD process, it is important to recognize that its physical properties (such as density and heat capacity) and thermal behavior differ from those of traditional ceramic powders. Therefore, PS-PVD process parameters, such as powder feed rate, carrier gas flow rate, plasma gun power (which typically requires higher power to ensure rapid vaporization of the polymer and induce micro-explosions), working pressure, and spraying distance, may need to be appropriately optimized and adjusted based on traditional parameters to match the unique vaporization behavior of the powder, thereby obtaining the best coating deposition effect and microstructure.

[0047] The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited to the detailed methods described above. For those skilled in the art, several improvements and modifications can be made without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

[0048] Example 1 Weigh 1000g of yttrium-stabilized zirconia (YSZ) powder with an average particle size of 80nm, 1200g of deionized water, and 6g of polyacrylic acid (PAA) dispersant (0.6% of the YSZ mass). Mix the powder and pour the mixture into a nylon-lined ball mill jar. Add zirconia grinding beads with a diameter of 10mm, maintaining a ball milling media to powder mass ratio of 3:1. Ball mill at 400rpm for 240min to obtain a uniformly dispersed, highly stable, negatively charged YSZ ceramic slurry.

[0049] 45 g of polymethyl methacrylate (PMMA) hollow microspheres with an average particle size of 50 μm were weighed and immersed in 1500 g of 0.5 wt% polydiallyl dimethyl ammonium chloride (PDDA) aqueous solution. The mixture was stirred at 150 rpm for 30 min. The microspheres were then centrifuged at 2000 rpm for 4 min, the supernatant was discarded, and the microspheres were washed three times with deionized water. The washed PMMA microspheres were then dried in a vacuum oven at 60 °C for 1.5 h to obtain positively charged PMMA microspheres.

[0050] All the positively charged PMMA microspheres were added to the negatively charged YSZ ceramic slurry and stirred at a low speed of 150 rpm for 15 min. The precursor slurry with a weakly bonded core-shell structure was formed by electrostatic adsorption.

[0051] Weigh 31.4g of polyvinyl alcohol (PVA) (3% of the total mass of YSZ and PMMA 1045g), dissolve it in 595g of deionized water (to form a 5wt% solution), heat in an 85℃ water bath and mechanically stir until completely dissolved to obtain a clear and transparent binder solution. Add the PVA binder solution to the core-shell structure precursor slurry and disperse it using a high-speed disperser at 3750rpm for 12min to form a uniform and stable mixed slurry.

[0052] The mixed slurry is fed into a centrifugal spray drying tower for granulation. The feed rate is 20 mL / min, the inlet temperature is set to 185℃, and the outlet temperature is set to 95℃. After sieving to a size of 5 μm to 100 μm, a core-shell thermal barrier coating powder with a particle size of 5 μm to 40 μm is obtained, which is suitable for the particle size required for plasma physical vapor deposition.

[0053] like Figure 1 As shown, the thermal barrier coating powder obtained in this embodiment has good sphericity, high surface roughness, and exhibits a complete and dense core-shell structure. YSZ nanoparticles are uniformly and completely coated on the surface of PMMA microspheres, with a coating integrity of over 95% and an average core-shell thickness of 5 μm. Only a very small amount (<5%) of fine YSZ free aggregates were observed, and no obvious PMMA microsphere exposure was found.

[0054] Example 2 1000g of yttrium-stabilized zirconia (YSZ) powder with an average particle size of 80nm, 1200g of deionized water, and 9g of polyacrylic acid and ammonium polyacrylate dispersant (0.9% of the YSZ mass) were weighed and poured into a nylon-lined ball mill jar. Zirconia grinding beads with a diameter of 5mm were added, with a ball milling media to powder mass ratio of 3:1. The mixture was ball milled at 500rpm for 120min to obtain a uniformly dispersed, highly stable YSZ ceramic slurry with a negatively charged surface. The obtained YSZ ceramic slurry showed no sedimentation after standing for 24h, indicating even better dispersion stability.

[0055] 80 g of hollow microspheres made of polymethyl methacrylate (PMMA), polyethylene (PE), and polystyrene (PS) with an average particle size of 50 μm were weighed and immersed in 1500 g of a 1 wt% aqueous solution of polydiallyl dimethyl ammonium chloride (PDDA). The mixture was stirred at 200 rpm for 10 min. Then, it was centrifuged at 3000 rpm for 3 min, the supernatant was discarded, and the microspheres were washed three times with deionized water. The washed PMMA microspheres were then dried in a vacuum oven at 60 °C for 1 h to obtain positively charged PMMA microspheres.

[0056] All the positively charged hollow polymer microspheres PMMA, PE and PS were added to the negatively charged YSZ ceramic slurry and stirred at a low speed of 200 rpm for 10 min. The precursor slurry with a weakly bonded core-shell structure was formed by electrostatic adsorption.

[0057] Weigh out 54g of polyvinyl alcohol (PVA) and polyethylene glycol (PEG) binder (5% of the total mass of YSZ and hollow polymer microspheres, 1080g), dissolve in 1026g of deionized water (forming a 5wt% solution), heat in an 85℃ water bath and mechanically stir until completely dissolved, obtaining a clear and transparent binder solution. Add the PEG binder solution to the core-shell structure precursor slurry and disperse using a high-speed disperser at 4000rpm for 10min to form a uniform and stable mixed slurry.

[0058] The mixed slurry was fed into a centrifugal spray dryer for granulation at a feed rate of 20 mL / min, with an inlet temperature of 185°C and an outlet temperature of 95°C. After sieving to a particle size of 5 μm–100 μm, a core-shell thermal barrier coating powder with a particle size of 5 μm–40 μm, suitable for plasma physical vapor deposition, was obtained. The final thermal barrier coating powder exhibited sphericity comparable to that of Example 1, but with a smoother and denser shell surface. The YSZ nanoparticles showed high coating integrity, with almost no free aggregates or exposed hollow polymer microspheres observed.

[0059] Example 3 Weigh 1000g of yttrium-stabilized zirconia (YSZ) powder with an average particle size of 80nm, 1200g of deionized water, and 6g of polyacrylic acid (PAA) dispersant (0.6% of the YSZ mass). Mix the powder and pour the mixture into a nylon-lined ball mill jar. Add zirconia grinding balls with a diameter of 15mm, maintaining a grinding media to powder mass ratio of 3:1. Ball mill at 450rpm for 180min to obtain a uniformly dispersed, highly stable, negatively charged YSZ ceramic slurry.

[0060] 45 g of polymethyl methacrylate (PMMA) hollow microspheres with an average particle size of 50 μm were weighed and immersed in 1500 g of 0.2 wt% polydiallyl dimethyl ammonium chloride (PDDA) aqueous solution. The mixture was stirred at 180 rpm for 25 min. The microspheres were then centrifuged at 2500 rpm for 4 min, the supernatant was discarded, and the microspheres were washed three times with deionized water. The washed PMMA microspheres were then dried in a vacuum oven at 60 °C for 2.5 h to obtain positively charged PMMA microspheres.

[0061] All the positively charged PMMA microspheres were added to the negatively charged YSZ ceramic slurry and stirred at a low speed of 180 rpm for 25 min. The precursor slurry with a weakly bonded core-shell structure was formed by electrostatic adsorption.

[0062] Weigh 31.4 g of hydroxypropyl methylcellulose adhesive (3% of the total mass of YSZ and PMMA 1045 g), dissolve it in 1015.3 g of deionized water (forming a 3 wt% solution), heat in an 85°C water bath and mechanically stir until completely dissolved to obtain a clear and transparent adhesive solution. Add the hydroxypropyl methylcellulose adhesive solution to the core-shell structure precursor slurry and disperse it using a high-speed disperser at 3200 rpm for 20 min to form a uniform and stable mixed slurry.

[0063] The mixed slurry was fed into a centrifugal spray dryer for granulation at a feed rate of 20 mL / min, with an inlet temperature of 150°C and an outlet temperature of 80°C. After sieving to a particle size of 5 μm–100 μm, a core-shell thermal barrier coating powder with a particle size of 5 μm–40 μm, suitable for plasma physical vapor deposition, was obtained. The final thermal barrier coating powder exhibited non-uniform morphology. Approximately 70% of the particles formed a core-shell structure similar to that of Example 1, but the shell layer was slightly loose; approximately 25% were large, dense aggregates of YSZ nanoparticles (size 5–15 μm); and approximately 5% of the PMMA microspheres were incompletely coated.

[0064] Example 4 Weigh 1000g of yttrium-stabilized zirconia (YSZ) powder with an average particle size of 80nm, 1200g of deionized water, and 5g of polyacrylic acid (PAA) dispersant (0.5% of the YSZ mass). Mix the powder and pour the mixture into a nylon-lined ball mill jar. Add zirconia grinding balls with a diameter of 25mm, maintaining a ball milling media to powder mass ratio of 3:1. Ball mill at 350rpm for 300min to obtain a uniformly dispersed, highly stable, negatively charged YSZ ceramic slurry.

[0065] 10 g of polymethyl methacrylate (PMMA) hollow microspheres with an average particle size of 50 μm were weighed and immersed in 1500 g of 0.1 wt% polydiallyldimethylammonium chloride (PDDA) aqueous solution, and stirred at 100 rpm for 30 min. Then, the mixture was centrifuged at 1000 rpm for 5 min, the supernatant was discarded, and the microspheres were washed three times with deionized water. The washed PMMA microspheres were then dried in a vacuum oven at 60 °C for 3 h to obtain positively charged PMMA microspheres.

[0066] All the positively charged PMMA microspheres were added to the negatively charged YSZ ceramic slurry and stirred at a low speed of 100 rpm for 30 min. The precursor slurry with a weakly bonded core-shell structure was formed by electrostatic adsorption.

[0067] Weigh 10.1g of polyvinyl alcohol (PVA) (1% of the total mass of YSZ and PMMA 1010g), dissolve it in 1000g of deionized water (to form a 1wt% solution), heat in an 85℃ water bath and mechanically stir until completely dissolved to obtain a clear and transparent binder solution. Add the PVA binder solution to the core-shell structure precursor slurry and disperse it using a high-speed disperser at 2500rpm for 30min to form a uniform and stable mixed slurry.

[0068] The mixed slurry was fed into a centrifugal spray dryer for granulation at a feed rate of 20 mL / min, with an inlet temperature of 200°C and an outlet temperature of 120°C. After sieving to a particle size of 5 μm to 100 μm, a core-shell thermal barrier coating powder with a particle size of 5 μm to 40 μm was obtained, suitable for plasma physical vapor deposition. The average shell thickness of the thermal barrier coating powder obtained in this embodiment is approximately 3 μm (thinner than the 5 μm in Example 1), but defects due to insufficient core and uneven coating are visible in some areas.

[0069] Example 5 1000g of rare earth zirconate GZO (Gd₂Zr₂O₇) powder with an average particle size of 80nm, 1200g of deionized water, and 6g of polymethyl methacrylate dispersant (0.6% of the GZO mass) were weighed and mixed, then poured into a nylon-lined ball mill jar. Zirconia grinding beads with a diameter of 10mm were added, with a ball milling media to powder mass ratio of 3:1. The mixture was ball milled at 400rpm for 240min to obtain a uniformly dispersed, highly stable, negatively charged GZO ceramic slurry.

[0070] 45 g of polylactic acid (PLA) hollow microspheres with an average particle size of 50 μm were weighed and soaked in 1500 g of 0.5 wt% polydiallyldimethylammonium chloride (PDDA) aqueous solution. The mixture was stirred at 150 rpm for 30 min. The microspheres were then centrifuged at 2000 rpm for 4 min, the supernatant was discarded, and the microspheres were washed three times with deionized water. The washed PLA microspheres were then dried in a vacuum oven at 60 °C for 1.5 h to obtain positively charged PLA microspheres.

[0071] All the positively charged PLA microspheres were added to the negatively charged GZO ceramic slurry and stirred at a low speed of 150 rpm for 15 min. The precursor slurry with a weakly bonded core-shell structure was formed by electrostatic adsorption.

[0072] Weigh 31.4g of polyvinyl alcohol (PVA) (3% of the total mass of GZO and PLA 1045g), dissolve it in 595g of deionized water (to form a 5wt% solution), heat in an 85℃ water bath and mechanically stir until completely dissolved to obtain a clear and transparent binder solution. Add the PVA binder solution to the core-shell structure precursor slurry and disperse it using a high-speed disperser at 3750rpm for 12min to form a uniform and stable mixed slurry.

[0073] The mixed slurry is fed into a centrifugal spray drying tower for granulation. The feed rate is 20 mL / min, the inlet temperature is set to 185℃, and the outlet temperature is set to 95℃. After sieving to a size of 5 μm to 100 μm, a core-shell thermal barrier coating powder with a particle size of 5 μm to 40 μm is obtained, which is suitable for the particle size required for plasma physical vapor deposition.

[0074] The thermal barrier coating powder obtained in this embodiment has good sphericity and high surface roughness, exhibiting a complete and dense core-shell structure, with GZO nanoparticles uniformly and completely coated on the surface of PLA microspheres.

[0075] Example 6 Weigh 1000g of yttrium-stabilized zirconia (YSZ) powder with an average particle size of 80nm, 1200g of deionized water, and 6g of polyacrylic acid (PAA) dispersant (0.6% of the YSZ mass). Mix the powder and pour the mixture into a nylon-lined ball mill jar. Add zirconia grinding beads with a diameter of 10mm, maintaining a ball milling media to powder mass ratio of 3:1. Ball mill at 400rpm for 240min to obtain a uniformly dispersed, highly stable, negatively charged YSZ ceramic slurry.

[0076] 45 g of hollow polyvinyl butyral (PVB) microspheres with an average particle size of 50 μm were weighed and soaked in 1500 g of 0.5 wt% polydiallyl dimethyl ammonium chloride (PDDA) aqueous solution. The mixture was stirred at 150 rpm for 30 min. The microspheres were then centrifuged at 2000 rpm for 4 min, the supernatant was discarded, and the microspheres were washed three times with deionized water. The washed PVB microspheres were then dried in a vacuum oven at 60 °C for 1.5 h to obtain positively charged PVB microspheres.

[0077] All the positively charged PVB microspheres were added to the negatively charged YSZ ceramic slurry and stirred at a low speed of 150 rpm for 15 min. The precursor slurry with a weakly bonded core-shell structure was formed by electrostatic adsorption.

[0078] Weigh 31.4g of polyvinyl alcohol (PVA) (3% of the total mass of YSZ and PVB 1045g), dissolve it in 595g of deionized water (to form a 5wt% solution), heat in an 85℃ water bath and mechanically stir until completely dissolved to obtain a clear and transparent binder solution. Add the PVA binder solution to the core-shell structure precursor slurry and disperse it using a high-speed disperser at 3750rpm for 12min to form a uniform and stable mixed slurry.

[0079] The mixed slurry is fed into a centrifugal spray drying tower for granulation. The feed rate is 20 mL / min, the inlet temperature is set to 185℃, and the outlet temperature is set to 95℃. After sieving to a size of 5 μm to 100 μm, a core-shell thermal barrier coating powder with a particle size of 5 μm to 40 μm is obtained, which is suitable for the particle size required for plasma physical vapor deposition.

[0080] The thermal barrier coating powder obtained in this embodiment has good sphericity and high surface roughness, exhibiting a complete and dense core-shell structure, with YSZ nanoparticles uniformly and completely coated on the surface of PVB microspheres.

[0081] Example 7 Weigh out a multi-element rare earth-doped zirconate powder with an average particle size of 30 nm (composed of zirconium oxide and gadolinium oxide co-stabilized zirconium oxide, Y). 0.1 Gd 0.1 Zr 0.81000g of O2, 1200g of deionized water, and 6g of polyacrylic acid (PAA) dispersant (0.6% of the mass of multi-element rare earth doped zirconate) were mixed and poured into a nylon-lined ball mill jar. Zirconia grinding beads with a diameter of 10mm were added, and the mass ratio of grinding media to powder was 3:1. The mixture was ball-milled at 400 rpm for 240 min to obtain a uniformly dispersed, highly stable, negatively charged multi-element rare earth doped zirconate ceramic slurry.

[0082] 45 g of hollow polyvinyl butyral (PVB) microspheres with an average particle size of 5 μm were weighed and soaked in 1500 g of 0.5 wt% polydiallyl dimethyl ammonium chloride (PDDA) aqueous solution. The mixture was stirred at 150 rpm for 30 min. The microspheres were then centrifuged at 2000 rpm for 4 min, the supernatant was discarded, and the microspheres were washed three times with deionized water. The washed PVB microspheres were then dried in a vacuum oven at 60 °C for 1.5 h to obtain positively charged PVB microspheres.

[0083] All the positively charged PVB microspheres were added to the negatively charged multi-element rare earth-doped zirconate ceramic slurry and stirred at a low speed of 150 rpm for 15 min to form a weakly bonded core-shell structure precursor slurry through electrostatic adsorption.

[0084] Weigh 31.4 g of polyvinyl alcohol (PVA) (3% of the total mass of 1045 g of multi-element rare earth doped zirconate and PVB), dissolve it in 595 g of deionized water (to form a 5 wt% solution), heat in an 85°C water bath and mechanically stir until completely dissolved to obtain a clear and transparent binder solution. Add the PVA binder solution to the core-shell structure precursor slurry and disperse it using a high-speed disperser at 3750 rpm for 12 min to form a uniform and stable mixed slurry.

[0085] The mixed slurry is fed into a centrifugal spray drying tower for granulation. The feed rate is 20 mL / min, the inlet temperature is set to 185℃, and the outlet temperature is set to 95℃. After sieving to a size of 5 μm to 100 μm, a core-shell thermal barrier coating powder with a particle size of 5 μm to 40 μm is obtained, which is suitable for the particle size required for plasma physical vapor deposition.

[0086] Example 8 Weigh 1000g of alumina powder with an average particle size of 1μm, 1400g of deionized water, and 6g of polyacrylic acid (PAA) dispersant (0.6% of the alumina mass). Mix the contents and pour the mixture into a nylon-lined ball mill jar. Add 10mm diameter zirconia grinding beads, maintaining a ball milling media to powder mass ratio of 3:1. Ball mill at 400rpm for 240min to obtain a uniformly dispersed, highly stable, negatively charged alumina ceramic slurry.

[0087] 45 g of hollow polyvinyl butyral (PVB) microspheres with an average particle size of 90 μm were weighed and soaked in 1500 g of 0.5 wt% polydiallyl dimethyl ammonium chloride (PDDA) aqueous solution. The mixture was stirred at 150 rpm for 30 min. The microspheres were then centrifuged at 2000 rpm for 4 min, the supernatant was discarded, and the microspheres were washed three times with deionized water. The washed PVB microspheres were then dried in a vacuum oven at 60 °C for 1.5 h to obtain positively charged PVB microspheres.

[0088] All the positively charged PVB microspheres were added to the negatively charged alumina ceramic slurry and stirred at a low speed of 150 rpm for 15 min. The precursor slurry with a weakly bonded core-shell structure was formed by electrostatic adsorption.

[0089] Weigh 31.4g of polyvinyl alcohol (PVA) (3% of the total mass of YSZ and alumina 1045g), dissolve it in 595g of deionized water (to form a 5wt% solution), heat in an 85℃ water bath and mechanically stir until completely dissolved to obtain a clear and transparent binder solution. Add the PVA binder solution to the core-shell structure precursor slurry and disperse it using a high-speed disperser at 3750rpm for 12min to form a uniform and stable mixed slurry.

[0090] The mixed slurry is fed into a centrifugal spray drying tower for granulation. The feed rate is 20 mL / min, the inlet temperature is set to 185℃, and the outlet temperature is set to 95℃. After sieving to a size of 5 μm to 100 μm, a core-shell thermal barrier coating powder with a particle size of 5 μm to 40 μm is obtained, which is suitable for the particle size required for plasma physical vapor deposition.

[0091] Example 9 1000g of rare earth tantalate powder (yttrium tantalate, YTaO4) with an average particle size of 1μm, 1400g of deionized water, and 6g of polyacrylic acid (PAA) dispersant (0.6% of the rare earth tantalate mass) were weighed and poured into a nylon-lined ball mill jar. Zirconia grinding beads with a diameter of 10mm were added, and the mass ratio of grinding media to powder was 3:1. The mixture was ball-milled at 400rpm for 240min to obtain a uniformly dispersed, highly stable, negatively charged rare earth tantalate ceramic slurry.

[0092] 45 g of hollow polyvinyl butyral (PVB) microspheres with an average particle size of 90 μm were weighed and soaked in 1500 g of 0.5 wt% polydiallyl dimethyl ammonium chloride (PDDA) aqueous solution. The mixture was stirred at 150 rpm for 30 min. The microspheres were then centrifuged at 2000 rpm for 4 min, the supernatant was discarded, and the microspheres were washed three times with deionized water. The washed PVB microspheres were then dried in a vacuum oven at 60 °C for 1.5 h to obtain positively charged PVB microspheres.

[0093] All the positively charged PVB microspheres were added to the negatively charged rare earth tantalate ceramic slurry and stirred at a low speed of 150 rpm for 15 min to form a weakly bonded core-shell structure precursor slurry through electrostatic adsorption.

[0094] Weigh 31.4g of polyvinyl alcohol (PVA) (3% of the total mass of rare earth tantalate and PVB 1045g), dissolve it in 595g of deionized water (to form a 5wt% solution), heat in an 85℃ water bath and mechanically stir until completely dissolved to obtain a clear and transparent binder solution. Add the PVA binder solution to the core-shell structure precursor slurry and disperse it using a high-speed disperser at 3750rpm for 12min to form a uniform and stable mixed slurry.

[0095] The mixed slurry is fed into a centrifugal spray drying tower for granulation. The feed rate is 20 mL / min, the inlet temperature is set to 185℃, and the outlet temperature is set to 95℃. After sieving to a size of 5 μm to 100 μm, a core-shell thermal barrier coating powder with a particle size of 5 μm to 40 μm is obtained, which is suitable for the particle size required for plasma physical vapor deposition.

[0096] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A high-efficiency evaporation core-shell structure thermal barrier coating powder with micro-explosion effect, characterized in that, The powder has a core-shell structure, with a core of hollow polymer microspheres and an outer shell of nano-ceramic particles coated on the surface of the hollow polymer microspheres to form a nano-ceramic particle layer. The hollow polymer microspheres include one or more of polymethyl methacrylate, polyethylene, polystyrene, polylactic acid, polyacrylic acid, polyvinyl butyral, polyisobutylene, polycarbonate, and polyethylene terephthalate. The nano-ceramic particles include one of yttrium-stabilized zirconium oxide, rare earth zirconates, multi-element rare earth doped zirconates, rare earth tantalates, and oxides.

2. The high-efficiency evaporation core-shell structure thermal barrier coating powder with micro-explosion effect according to claim 1, characterized in that, The hollow polymer microspheres have a particle size range of 5μm to 90μm, and the nano-ceramic particles have a particle size range of 30nm to 1μm.

3. A method for preparing a high-efficiency evaporation core-shell structure thermal barrier coating powder with micro-explosion effect as described in claim 1 or 2, characterized in that, Includes the following steps: 1) The nano-ceramic particles are subjected to surface negative electrochemical treatment to obtain a ceramic slurry with a negatively charged surface; 2) Positively electrify the surface of hollow polymer microspheres; 3) Hollow polymer microspheres with positively charged surfaces are mixed with ceramic slurry with negatively charged surfaces and stirred at low speed to form a core-shell structure precursor slurry; the amount of hollow polymer microspheres used is 1% to 8% of the mass of nano-ceramic particles in the ceramic slurry; 4) The organic binder solution is added to the core-shell structure precursor slurry and dispersed evenly to form a mixed slurry; 5) The mixed slurry is spray-granulated and sieved to a size of 5μm to 100μm to obtain a core-shell thermal barrier coating powder with a particle size of 5μm to 40μm suitable for plasma physical vapor deposition; the spray granulation process conditions include: inlet temperature of 150 to 200℃ and outlet temperature of 80 to 120℃.

4. The method for preparing a high-efficiency evaporation core-shell structure thermal barrier coating powder with micro-explosion effect according to claim 3, characterized in that, In step 1), the surface negative electrochemical treatment process includes: mixing nano-ceramic particles, deionized water, and anionic dispersant, stirring evenly, and then ball milling; the weight ratio of the nano-ceramic particles, deionized water, and anionic dispersant is 100:(120~140):(0.5~0.9); the ball milling process uses grinding balls ranging from 5mm to 25mm, the ball milling time is 120~300min, and the ball milling speed is 350~500rpm.

5. The method for preparing a high-efficiency evaporation core-shell structure thermal barrier coating powder with micro-explosion effect according to claim 4, characterized in that, The anionic dispersant includes one or two of polyacrylic acid, ammonium polyacrylate, ammonium polymethacrylate, and ammonium citrate.

6. The method for preparing a high-efficiency evaporation core-shell structure thermal barrier coating powder with micro-explosion effect according to claim 3, characterized in that, In step 2), the surface positive electrochemical treatment process includes: immersing hollow polymer microspheres in an aqueous solution of cationic surfactant with a concentration of 0.1wt%~1wt%, stirring at low speed, centrifuging to clean and drying.

7. The method for preparing a high-efficiency evaporation core-shell structure thermal barrier coating powder with micro-explosion effect according to claim 6, characterized in that, The cationic surfactant is polydiallyldimethylammonium chloride.

8. The method for preparing a high-efficiency evaporation core-shell structure thermal barrier coating powder with micro-explosion effect according to claim 6, characterized in that, The low-speed stirring speed is 100~200 rpm; the centrifugation conditions include: rotation speed of 1000~3000 rpm and time of 3~5 min; the drying environment is drying in an oven at 60℃ for 1~3 h.

9. The method for preparing a high-efficiency evaporation core-shell structure thermal barrier coating powder with micro-explosion effect according to claim 3, characterized in that, In step 4), the organic binder in the organic binder solution includes one of polyvinyl alcohol, polyethylene glycol and hydroxypropyl methylcellulose, and its mass fraction is 1% to 5% of the total mass of the nano-ceramic particles and hollow polymer microspheres.

10. The method for preparing a high-efficiency evaporation core-shell structure thermal barrier coating powder with micro-explosion effect according to claim 3, characterized in that, In step 4), the dispersion conditions include: a rotation speed of 2500~4000 rpm and a time of 10~30 min.

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