A method for preparing an ultra-high temperature EB-PVD thermal barrier coating

Abstract

This invention discloses a method for preparing an ultra-high temperature EB-PVD thermal barrier coating. The method involves first obtaining target material powder by spray granulation of five rare earth oxides (nano-Sm₂O₃, nano-Eu₂O₃, nano-Tb₂O₃, nano-Dy₂O₃, nano-Lu₂O₃, and nano-ZrO₂) with zirconium oxide. After sieving, spherical powders with different particle size ratios are obtained. A target green body is then fabricated using cold isostatic pressing, followed by sintering. Finally, a high-entropy zirconate ceramic coating is deposited on the surface of the sample coated with a binder layer using EB-PVD technology. The coating prepared by this invention exhibits good high-temperature phase stability, a thermal expansion coefficient more compatible with the substrate material, and extremely low high-temperature thermal conductivity. In particular, it demonstrates excellent stability in phase, structure, and composition under high-temperature service conditions of 1700℃, and can replace currently used single-system EB-PVD materials, improving the high-temperature stability of existing thermal barrier coatings.

Description

Technical Field

[0001] This invention belongs to the field of high-temperature thermal protective coatings and relates to a method for preparing an ultra-high temperature EB-PVD thermal barrier coating (TBC). Background Technology

[0002] Thermal barrier coatings (TBCs), a commonly used thermal protection technology, provide thermal insulation to metal substrates, protecting them from the effects of high-temperature gases. TBCs are primarily deposited onto the surface of alloy substrates (mainly high-temperature alloys) using methods such as atmospheric plasma spraying (APS) and electron beam physical vapor deposition (EB-PVD). Different deposition methods result in TBCs with different structures, thus affecting their performance. To increase the compatibility between the substrate and the ceramic surface layer and reduce thermal expansion during use, a metal binder layer is usually added. Materials used to form TBCs include binder materials such as NiCoCrAlY, NiCrAlY, and NiAl, and surface layer materials such as yttrium-stabilized zirconia (YSZ), alumina, and other advanced ceramic raw materials. Coating preparation can be categorized into gaseous processes, solution processes, molten or semi-molten processes, and solid processes, depending on the material state. Gaseous processes mainly correspond to physical vapor deposition (PVD) and chemical vapor deposition (CVD). In recent years, EB-PVD technology has been widely used in defense and civilian fields due to its numerous advantages, including high evaporation and deposition rates, dense coatings, easy and precise control of chemical composition, ability to obtain columnar crystal structures, no pollution, high thermal efficiency, and strong adhesion between the substrate and the film. The EB-PVD method requires a temperature below 10°C to prepare the coating. -3The vacuum coating process of EB-PVD involves first rapidly heating the raw materials to a vaporized state using a high-energy-density electron beam. Then, the vaporized material, under the influence of a deflecting magnetic field, continuously deposits and grows into columnar crystals on a pre-treated substrate surface. EB-PVD coatings exhibit high bonding strength with the substrate, can withstand high external tensile or bending stresses, and have excellent thermal shock resistance, significantly extending the coating's lifespan to approximately seven times that of APS coatings. EB-PVD thermal barrier coatings are primarily used on rotating components of turbine engines, such as turbine blades and shafts. Due to the dense structure of EB-PVD coatings, their thermal conductivity is significantly higher than that of plasma coatings. This high thermal conductivity is highly detrimental to thermal barrier coatings, negatively impacting their insulation capabilities and hindering further applications. The most widely used ceramic coating material in the EB-PVD field is 6–8 wt% yttrium-stabilized zirconia (YSZ). YSZ coatings are typically prepared using a combination of EB-PVD and APS. In particular, the introduction of columnar structures through EB-PVD can improve strain compliance, enabling long-term operation below 1150℃. However, YSZ coatings suffer from severe sintering and phase transformation, leading to total thermal barrier (TBC) failure (>1200℃). Moreover, coatings prepared by EB-PVD have poor thermal insulation performance due to their inherent columnar crystal structure. To overcome the shortcomings of EB-PVD in preparing thermal barrier coatings, the search for novel ceramic materials with lower thermal conductivity to replace YSZ is currently one of the hot research topics in the field of thermal barrier coatings.

[0003] For the reasons mentioned above, there is a need to develop new ceramic materials with low thermal conductivity and high thermal stability. Rare earth oxide-stabilized ZrO2, pyrochlore materials, perovskite oxides, and aluminates have been extensively studied as potential successors to YSZ. Among these, pyrochlore materials have been studied most extensively. In particular, A2B2O7 ceramic materials possess the advantages of a high melting point (>2000℃) and a low thermal conductivity (1.56 W / (m·K) at 1000℃).

[0004] Multi-component high-entropy ceramic design is considered a solution to the material selection problem at higher temperatures for thermal barrier coatings. High-entropy ceramics have been reported to possess outstanding comprehensive properties, compensating for the shortcomings of single-component thermal barrier coatings (TBCs). Research shows that multi-component high-entropy design endows high-entropy ceramics with high-entropy effects, lattice distortion effects, cocktail effects, and hysteresis diffusion effects, resulting in relatively higher phase stability, lower thermal conductivity, adjustable performance, and better high-temperature mechanical properties. Current research indicates that A₂B₂O₇ (where A represents a rare earth element) is the most promising new ceramic material for thermal barrier coatings, but reports on the preparation and performance of thermal barrier coatings using this system are scarce.

[0005] Current research focuses primarily on the ceramic materials themselves, with no reports yet on their application in high-entropy EB-PVD targets and coatings. This is because controlling the composition of coating materials becomes difficult when the EB-PVD coating material has complex components, hindering the application of high-entropy ceramic materials in EB-PVD coatings. Furthermore, the preparation of high-entropy ceramic targets requires solid-state synthesis followed by target sintering to ensure density. The difficulty in ensuring uniformity of various rare-earth oxides and the complexity of the process further limit the development of high-entropy EB-PVD coatings. Summary of the Invention

[0006] To address the problems of existing EB-PVD thermal barrier coatings, such as inferior thermal barrier performance compared to APS-based thermal barrier coatings of the same grade, susceptibility to phase transitions, and high high-temperature thermal conductivity leading to coating service failure, this invention provides a method for preparing ultra-high temperature EB-PVD thermal barrier coatings. This invention provides a high-entropy EB-PVD target material through multi-element high-entropy design of traditional zirconates, and prepares the coating using the EB-PVD method. The prepared coating exhibits better high-temperature phase stability, a thermal expansion coefficient more compatible with the substrate material, and extremely low high-temperature thermal conductivity. It can replace the currently used single-system EB-PVD material, improve the high-temperature stability of rare-earth zirconate thermal barrier coatings, and extend their service life.

[0007] The objective of this invention is achieved through the following technical solution:

[0008] A method for preparing an ultra-high temperature EB-PVD thermal barrier coating includes the following steps:

[0009] Step 1: Add zirconia grinding balls and an appropriate amount of deionized water to a vertical ball mill. Then add a certain mass of dispersant to the deionized water. After the dispersant is completely dissolved, proceed according to (Sm... 0.2 Eu 0.2 Tb 0.2 Dy 0.2 Lu 0.2 The mixture of Zr2O7 (SETDL) in the indicated proportions was ball-milled with nano-Sm2O3 powder, nano-Eu2O3 powder, nano-Tb2O3 powder, nano-Dy2O3 powder, nano-Lu2O3 powder, and nano-ZrO2 powder for a period of time. After adding a certain amount of binder, the mixture was ball-milled again for a period of time to obtain a uniform slurry.

[0010] The particle size of the nano-Sm2O3 powder is 5-90 nm;

[0011] The particle size of the nano-Eu2O3 powder is 5-90 nm;

[0012] The particle size of the nano-Tb2O3 powder is 5-90 nm;

[0013] The particle size of the nano-Dy2O3 powder is 5-90 nm.

[0014] The particle size of the nano-Lu2O3 powder is 5-90 nm.

[0015] The particle size of the nano-ZrO2 powder is 5–90 nm;

[0016] The nano Sm2O3 powder, nano Eu2O3 powder, nano Tb2O3 powder, nano Dy2O3 powder, nano Lu2O3 powder, and nano ZrO2 powder raw materials are of 4N purity.

[0017] The amount of deionized water used is 0.5 to 3 times the total mass of the nanoparticles;

[0018] The dispersant is sodium tripolyphosphate (Na5P3O4). 10 The dispersant consists of one or more of the following: sodium hexametaphosphate ((NaPO3)6), sodium pyrophosphate (Na4P2O7), ammonium citrate (C6H5O7(NH4)3), sodium citrate (C6H5Na3O7), polyvinyl alcohol (PVA), and polyethylene glycol (PEG). The amount of dispersant used is 0.03 to 6% of the total mass of the nanoparticles.

[0019] The diameter of the zirconia grinding balls is 2-10 mm, the amount of zirconia grinding balls used is 1-5 times the total mass of the nanopowder, the total grinding time is 6-24 h, and the rotation speed is 300-1000 rpm.

[0020] The binder is one of the following: gum arabic (Acacia), polyvinyl alcohol (PVA), carboxymethyl cellulose (CMC), ethyl silicate (TEOS), etc., and the amount of binder used is 0.1-10% of the total mass of the nanoparticles;

[0021] Step 2: The slurry obtained in Step 1 is spray-granulated to obtain micron-sized nanostructured spherical rare earth oxide powder, wherein:

[0022] The parameters for the spray granulation are as follows: the inlet air temperature is set to 200-250℃, the outlet air temperature is set to 100-130℃, the peristaltic pump speed is set to 30-45r / min, and the needle speed is set to 10-15t / min.

[0023] Step 3: The rare earth oxide powder obtained in Step 2 is sieved according to particle size. The spherical powders of different particle sizes are then proportioned and pressed using a cold isostatic pressing method to obtain target green bodies with different porosities.

[0024] The sieving specifications are 50-150 mesh, 150-300 mesh, and 300-400 mesh, with a mass ratio of 2-6:1-3:1-5, and are used according to the particle size distribution and different porosity requirements of the granulated powder;

[0025] During the pressing process, the pressure is controlled at 150-250 MPa, and the holding time is controlled at 120-300 s.

[0026] The cold isostatic pressing method can use forming methods such as wet bag cold isostatic pressing, dry bag cold isostatic pressing, and press pre-pressing. Preferably, the cold isostatic pressing method is wet bag cold isostatic pressing.

[0027] Step 4: Sinter the target green material to obtain SETDL high-entropy zirconate EB-PVD target material, wherein:

[0028] The sintering mechanism is as follows: First, the temperature is increased to 350℃ (removal temperature) at a rate of 1-10℃ / min and held for 300-420 min. Then, the temperature is increased to 1100℃ at a rate of 1-10℃ / min and held for 180-250 min. Subsequently, the temperature is increased to 1400℃ (synthesis temperature) at a rate of 1-10℃ / min and held for 480-600 min. Finally, the temperature is reduced to room temperature.

[0029] The discharge temperature is related to the type of dispersant and adhesive used in granulation, and the synthesis temperature is related to different high-entropy systems.

[0030] Step 5: After grinding and polishing the surface of the high-temperature alloy substrate to achieve a smooth surface, sandblasting is performed to create a certain roughness. Then, ultrasonic cleaning is carried out using acetone and ethanol respectively. After drying, an alloy bonding layer (MCrAlX) is prepared on the surface using thermal spraying technology, wherein:

[0031] The high-temperature alloy matrix can be one of nickel-based, cobalt-based, iron-based, or other high-temperature alloys;

[0032] The thermal spraying technology can be one of atmospheric plasma spraying (APS), low-pressure plasma spraying (LPPS), or high-velocity oxygen flame spraying (HVOF).

[0033] The alloy bonding layer can be NiCrAlY, CoCrAlY, NiCoCrAlY, etc.;

[0034] Step Six: High-entropy zirconate EB-PVD target material is deposited onto the surface of the MCrAlY alloy binder layer obtained in Step Five using vapor deposition, forming a SETDL high-entropy zirconate ceramic coating. This yields an ultra-high temperature EB-PVD thermal barrier coating system with low thermal conductivity and a good match with the thermal expansion coefficient of the substrate, consisting of a single ceramic layer.

[0035] The parameters for preparing the SETDL high-entropy zirconate ceramic coating are as follows: the substrate temperature is heated from room temperature to 600–850°C; the distance between the substrate and the evaporation target (target-substrate distance) and the angle between the substrate plane normal and the incident vapor particles (incident angle) can be adjusted according to actual needs, with a maximum target-substrate distance of 500 mm and an incident angle set at 45°; during coating preparation, the electron accelerating voltage is 20–25 kV, and the vacuum degree is below 1 × 10⁻⁶ kV. -2 Pa achieves control of the deposition rate by controlling the electron beam current and adjusting the size of the evaporation target molten pool. The deposition rate can reach up to 1-10 μm / min, and the deposition coating thickness is 100-500 μm.

[0036] The vapor deposition method can be a surface protection preparation process such as electron beam physical vapor deposition (EB-PVD) or physical vapor deposition (PVD).

[0037] Compared with the prior art, the present invention has the following advantages:

[0038] 1. This invention utilizes nanoparticle regranulation technology and cold isostatic pressing technology to prepare SETDL high-entropy zirconate into a target material suitable for electron beam physical vapor deposition, providing a method for implementing this high-performance high-entropy material on thermal spray coatings.

[0039] 2. This invention utilizes particle size classification and distribution technology to press rare earth oxide spherical powder into green embryos. To ensure that the overall volume shrinkage rate of the target material is minimized and that it meets the requirements of a certain porosity, the solid-phase synthesis sintering route is combined with the target material sintering route. This allows for strict control of porosity and volume shrinkage, solving problems such as unstable dimensions of the target material after sintering and the need for subsequent turning processing. This simplifies the target material preparation process and reduces production costs.

[0040] 3. The SETDL target material prepared by this invention has high purity, excellent mechanical properties, and a smooth coating surface structure. It can be used to replace traditional EB-PVD coating materials as high-performance thermal barrier coating materials for aero-engines and gas turbines.

[0041] 4. This invention is the first to utilize EB-PVD technology to prepare a SETDL high-entropy zirconate thermal barrier coating, overcoming the problem of phase structure decomposition and rare earth element segregation in vapor-deposited high-entropy coatings under the influence of saturated vapor pressure. The high-entropy EB-PVD thermal barrier coating has a columnar crystal structure with several pores between the columnar crystals. Under high-temperature service conditions of 1700℃, the high-entropy EB-PVD thermal barrier coating exhibits excellent stability in phase, structure, and composition, retaining the pyrochlore phase with no element segregation or precipitation. This invention possesses advantages such as high energy, wide applicability of materials, ease of operation, high deposition efficiency, and ease of industrialization.

[0042] 5. This invention solves the problem of poor thermal barrier effect caused by the EB-PVD coating structure. The prepared coating has low thermal conductivity at high temperature, stable phase structure, and good thermal expansion coefficient matching with the matrix alloy. It can replace the existing dual ceramic coating system as a thermal barrier coating and has broad application prospects. Attached Figure Description

[0043] Figure 1 This is a process flow diagram for the preparation of SETDL high-entropy zirconate EB-PVD target material and ultra-high temperature EB-PVD thermal barrier coating;

[0044] Figure 2 This is a macroscopic structural diagram of the target material after sintering in Example 1;

[0045] Figure 3 This is a cross-sectional structural diagram of the target material in Example 1;

[0046] Figure 4 This is the surface morphology and energy spectrum of the molten pool after the target material evaporates in Example 1;

[0047] Figure 5 These are XRD comparison images of the target molten pool, coating, and original target material in Example 1;

[0048] Figure 6 This is a cross-sectional view of the coating prepared by EB-PVD in Example 1;

[0049] Figure 7 Surface image of the coating prepared by EB-PVD in Example 1. Detailed Implementation

[0050] The technical solution of the present invention will be further described below with reference to the embodiments, but it is not limited thereto. Any modifications or equivalent substitutions to the technical solution of the present invention without departing from the spirit and scope of the technical solution of the present invention should be covered within the protection scope of the present invention.

[0051] Example 1:

[0052] This embodiment provides a method for preparing an ultra-high temperature EB-PVD thermal barrier coating. The method involves first obtaining target material raw material powder by spray granulation of five rare earth oxides (nano Sm2O3 powder, nano Eu2O3 powder, nano Tb2O3 powder, nano Dy2O3 powder, nano Lu2O3 powder, and nano ZrO2 powder) with zirconium oxide. After sieving, spherical powders with different particle size ratios are obtained. A target green body is then fabricated using cold isostatic pressing, followed by sintering. Finally, a high-entropy zirconate ceramic coating is deposited on the surface of the sample coated with a binder layer using electron beam physical vapor deposition (EB-PVD). Specifically, this is achieved through the following steps:

[0053] Step 1: According to (Sm)0.2 Eu 0.2 Tb 0.2 Dy 0.2 Lu 0.2 According to the proportions shown in 2Zr2O7, nano-Sm2O3 powder, nano-Eu2O3 powder, nano-Tb2O3 powder, nano-Dy2O3 powder, nano-Lu2O3 powder, and nano-ZrO2 powder were weighed, wherein: the particle size of the nano-Sm2O3 powder is 20nm; the particle size of the nano-Eu2O3 powder is 20nm; the particle size of the nano-Tb2O3 powder is 20nm; the particle size of the nano-Dy2O3 powder is 20nm; the particle size of the nano-Lu2O3 powder is 20nm; and the particle size of the nano-ZrO2 powder is 20nm.

[0054] Step 2: Add deionized water to a vertical ball mill jar, then add ammonium citrate dispersant, nano-Sm2O3 powder, nano-Eu2O3 powder, nano-Tb2O3 powder, nano-Dy2O3 powder, nano-Lu2O3 powder, nano-ZrO2 powder, and zirconia grinding balls. Ball mill for 12 hours to obtain a uniform slurry. The amount of deionized water is twice the total mass of the nano-powder, the amount of ammonium citrate is 0.5% of the total mass of the nano-powder, the diameter of the zirconia grinding balls is 3 mm and 5 mm, the mass ratio is 6:4, and the mass of the zirconia grinding balls is 2.5 times the total mass of the nano-powder.

[0055] Step 3: Add the binder gum arabic to the uniform slurry obtained in Step 2 and ball mill for 0.5 hours to obtain a uniform slurry. The amount of gum arabic is 1.0% of the total mass of the nanoparticles.

[0056] Step 4: Add the slurry obtained in Step 3 to the mixer and spray granulate to obtain agglomerated powder. The mixer parameters are 15 rpm, and the spray granulation parameters are: inlet air temperature of 245℃, outlet air temperature of 120℃, needle frequency of 10 times per minute, and peristaltic pump speed of 40 rpm.

[0057] Step 5: The agglomerated powder obtained after spray granulation in Step 4 is sieved using 400 mesh, 200 mesh, and 100 mesh sieves. The resulting powders of these three specifications are mixed in a mass ratio of 2:2:6 and then subjected to wet bag cold isostatic pressing at 200 MPa for 120 seconds. This reduces the need for pre-pressing and molding in the early stages, resulting in a target green with a diameter of 80 mm and a height of 110 mm. The particle size distribution can be adjusted appropriately according to different process requirements.

[0058] Step 6: Sinter the target green material using a box sintering furnace. Increase the temperature to 350℃ (removal temperature) at 5℃ / min and hold for 300 min. Then increase the temperature to 1100℃ at 5℃ / min and hold for 180 min. Finally, increase the temperature to 1400℃ (synthesis temperature) at 5℃ / min and hold for 480 min before slowly cooling to room temperature to obtain SETDL high-entropy zirconate target material.

[0059] Step 7: After polishing the surface of the GH4169 nickel-based superalloy with 40-200 mesh silicon carbide sandpaper, the substrate surface is then sandblasted with 60-mesh brown corundum to achieve a certain surface roughness. Next, it is ultrasonically cleaned with anhydrous ethanol and acetone for 30 minutes each. After drying, a NiCrAlY alloy bonding layer is prepared on the surface using supersonic flame spraying technology. The bonding layer preparation parameters are: spraying distance 240 mm, powder feed rate 30 g / min, carrier gas flow rate 5 NLPM, shielding gas flow rate 360 ​​NLPM, fuel gas flow rate 180 NLPM, oxygen flow rate 240 NLPM, and the bonding layer thickness is 100 μm.

[0060] Step 8: Deposit the high-entropy target material sintered in Step 6 onto the surface of the adhesive layer prepared in Step 7 using EB-PVD to obtain the SETDL EB-PVD ceramic coating. The preparation parameters for the EB-PVD coating are: substrate temperature 650℃, target-substrate distance 250mm, incident angle set at 45°, electron accelerating voltage 20kV, and vacuum degree below 1×10⁻⁶. －2 Pa, the thickness of the deposited coating is 200 μm.

[0061] In this embodiment, the macroscopic structure diagram of the target material after sintering is as follows: Figure 2 As shown, by Figure 2 It can be seen that the macroscopic dimensions meet the requirements and the surface quality is good; the cross-sectional structure diagram of the target material is as follows. Figure 3 As shown, by Figure 3 It can be seen that the pores are uniformly distributed, the pore size is uniformly distributed, and there are no obvious internal defects; the surface morphology and energy dispersive spectroscopy of the molten pool after target evaporation are shown in the figure. Figure 4 As shown, by Figure 4 It can be seen that the molten pool melted well after electron beam melting, the molten droplets were uniform with no obvious cracks, and the element distribution was uniform; the XRD comparison images of the target molten pool, coating, and original target are shown below. Figure 5 As shown, by Figure 5 It can be seen that the phase structure remains unchanged before and after deposition, indicating a stable phase structure; the coating cross-sectional diagram is shown below. Figure 6 As shown, by Figure 6 It can be seen that the coating exhibits a standard columnar crystal structure, with good overall quality and no obvious defects; the coating surface image is shown below. Figure 7 As shown, by Figure 7It can be seen that the surface quality is smooth and dense with low roughness; the density and volume shrinkage rate of the target material are shown in Table 1.

[0062] Table 1

[0063]

[0064] Example 2:

[0065] This embodiment provides a method for preparing an ultra-high temperature EB-PVD thermal barrier coating, which is achieved through the following steps:

[0066] Step 1: According to (Sm) 0.2 Eu 0.2 Tb 0.2 Dy 0.2 Lu 0.2 According to the proportions shown in 2Zr2O7, nano-Sm2O3 powder, nano-Eu2O3 powder, nano-Tb2O3 powder, nano-Dy2O3 powder, nano-Lu2O3 powder, and nano-ZrO2 powder were weighed, wherein: the particle size of the nano-Sm2O3 powder is 20nm; the particle size of the nano-Eu2O3 powder is 20nm; the particle size of the nano-Tb2O3 powder is 20nm; the particle size of the nano-Dy2O3 powder is 20nm; the particle size of the nano-Lu2O3 powder is 20nm; and the particle size of the nano-ZrO2 powder is 20nm.

[0067] Step 2: Add deionized water to a vertical ball mill jar, then add ammonium citrate dispersant, nano-Sm2O3 powder, nano-Eu2O3 powder, nano-Tb2O3 powder, nano-Dy2O3 powder, nano-Lu2O3 powder, nano-ZrO2 powder, and zirconia grinding balls. Ball mill for 10 hours to obtain a uniform slurry. The amount of deionized water is twice the total mass of the nano-powder, the amount of ammonium citrate is 0.5% of the total mass of the nano-powder, the diameter of the zirconia grinding balls is 3 mm and 5 mm, and the mass of the zirconia grinding balls is 2.5 times the total mass of the nano-powder.

[0068] Step 3: Add the binder gum arabic to the uniform slurry obtained in Step 2 and ball mill for 0.5 hours to obtain a uniform slurry. The amount of gum arabic is 1.0% of the total mass of the nanoparticles.

[0069] Step 4: Add the slurry obtained in Step 3 to the mixer and spray granulate to obtain agglomerated powder. The mixer parameters are 20 rpm, and the spray granulation parameters are: inlet air temperature of 220℃, outlet air temperature of 100℃, needle frequency of 15 times per minute, and peristaltic pump speed of 35 rpm.

[0070] Step 5: The agglomerated powder obtained after spray granulation in Step 4 is sieved using 400 mesh, 200 mesh, and 50 mesh sieves. The resulting powders of these three specifications are mixed in a mass ratio of 3:3:4 and then subjected to wet bag cold isostatic pressing at 200 MPa for 150 seconds. This reduces the need for pre-pressing and molding in the early stages, resulting in a target green with a diameter of 80 mm and a height of 110 mm. The particle size distribution can be adjusted appropriately according to different process requirements.

[0071] Step 6: Sinter the target green material using a box sintering furnace. The temperature is increased to 350℃ (binding temperature) at 5℃ / min and held for 300 min. Then, the temperature is increased to 1100℃ at 5℃ / min and held for 250 min. Finally, the temperature is increased to 1400℃ (synthesis temperature) at 5℃ / min and held for 600 min. After that, the temperature is decreased to 800℃ at 2℃ and held for 200 min. Then, the temperature is slowly decreased to room temperature to obtain SETDL high-entropy zirconate target material. The density and volume shrinkage rate of the target material are shown in Table 2.

[0072] Step 7: After polishing the surface of the GH4169 nickel-based superalloy with 40-200 mesh silicon carbide sandpaper, the substrate surface is then sandblasted with 60-mesh brown corundum to achieve a certain surface roughness. Next, it is ultrasonically cleaned with anhydrous ethanol and acetone for 30 minutes each. After drying, a PtAl alloy bonding layer is prepared on the surface using supersonic flame spraying technology. The bonding layer preparation parameters are: spraying distance 240 mm, powder feed rate 25 g / min, carrier gas flow rate 8 NLPM, shielding gas flow rate 360 ​​NLPM, fuel gas flow rate 180 NLPM, oxygen flow rate 240 NLPM, and the bonding layer thickness is 150 μm.

[0073] Step 8: Deposit the high-entropy target material sintered in Step 6 onto the surface of the adhesive layer prepared in Step 7 using EB-PVD to obtain the SETDL EB-PVD ceramic coating. The preparation parameters for the EB-PVD coating are: substrate temperature 600℃, target-substrate distance 280mm, incident angle set to 45°, electron accelerating voltage 25kV, and vacuum degree below 1×10⁻⁶. -2 Pa, the thickness of the deposited coating is 200 μm.

Claims

1. A method of making an ultra-high temperature EB-PVD thermal barrier coating, characterized in that The method comprises the following steps: Step one, in the vertical ball mill is added zirconium oxide ball and appropriate amount of deionized water, then to the deionized water is added dispersant, after the dispersant is completely dissolved according to (Sm 0.2 Eu 0.2 Tb 0.2 Dy 0.2 Lu 0.2 )2Zr2O7 shows the ratio, the addition of nano Sm2O3 powder, nano Eu2O3 powder, nano Tb2O3 powder, nano Dy2O3 powder, nano Lu2O3 powder and nano ZrO2 powder ball mill for a period of time, after adding binder continue to ball mill for a period of time, get uniform slurry, wherein: the amount of deionized water is 0.5~3 times of the total mass of nano powder, the amount of dispersant is 0.03~6% of the total mass of nano powder, the amount of binder is 0.1~10% of the total mass of nano powder; Step two, the slurry obtained in step one is spray granulated to obtain micron-sized nano-structured spherical rare earth oxide powder; Step three, the nano-structured spherical rare earth oxide powder obtained in step two is sieved according to particle size, the sieved spherical powder of different particle sizes is proportioned, and then cold isostatic pressing is performed to obtain target material green bodies with different porosities, wherein the sieving specifications are 50-150 mesh, 150-300 mesh and 300-400 mesh, and the mass ratio is 2-6:1-3:1-5; Step four, the target material green body is sintered to obtain a high-entropy zirconate EB-PVD target material, and the sintering mechanism is as follows: first, increase to 350℃ at a rate of 1-10℃ / min and keep for 300-420min, then increase to 1100℃ at a rate of 1-10℃ / min and keep for 180-250min, then increase to 1400℃ at a rate of 1-10℃ / min and keep for 480-600min, and finally, reduce the temperature to room temperature; Step five, after surface grinding and polishing of the high-temperature alloy substrate are finished, sand blasting treatment is performed, then the high-temperature alloy substrate is ultrasonically cleaned with acetone and ethanol respectively, and after drying, an alloy bonding layer is prepared on the surface of the high-temperature alloy substrate by using thermal spraying technology; Step six, the high-entropy zirconate EB-PVD target material is deposited on the surface of the alloy bonding layer obtained in step five by using a vapor deposition method to form a high-entropy zirconate ceramic coating.

2. The method of producing ultra-high-temperature EB-PVD thermal barrier coatings according to claim 1, characterized in that The particle sizes of the nano-Sm2O3 powder, the nano-Eu2O3 powder, the nano-Tb2O3 powder, the nano-Dy2O3 powder, the nano-Lu2O3 powder and the nano-ZrO2 powder are all 5-90nm; the dispersant is one or more of sodium tripolyphosphate, sodium hexametaphosphate, sodium pyrophosphate, ammonium citrate, sodium citrate, polyvinyl alcohol and polyethylene glycol; the binder is one of gum arabic, polyvinyl alcohol, carboxymethyl cellulose and ethyl silicate; the diameter of the zirconia grinding ball is 2-10mm, the amount of the zirconia grinding ball is 1-5 times the total mass of the nano-powder, the total ball milling time is 6-24h, and the rotation speed is 300-1000r / min.

3. The method of producing ultra-high-temperature EB-PVD thermal barrier coatings according to claim 1, characterized in that The parameters of the spray granulation are as follows: the inlet air temperature is set to 200-250℃, the outlet air temperature is set to 100-130℃, the peristaltic pump rate is set to 30-45r / min, and the needle passing rate is set to 10-15t / min.

4. The method of producing ultra-high-temperature EB-PVD thermal barrier coatings according to claim 1, characterized in that The pressure of the pressing is controlled to be 150-250Mpa, and the pressure holding time is controlled to be 120-300s.

5. The method of producing ultra-high-temperature EB-PVD thermal barrier coatings according to claim 1, characterized in that The cold isostatic pressing method uses wet bag cold isostatic pressing or dry bag cold isostatic pressing.

6. The method of producing an ultra-high-temperature EB-PVD thermal barrier coating according to claim 1, characterized in that The high-temperature alloy substrate is one of nickel-based, cobalt-based and iron-based high-temperature alloys.

7. The method of producing an ultra-high-temperature EB-PVD thermal barrier coating according to claim 1, characterized in that The thermal spraying technology is one of atmospheric plasma spraying, low-pressure plasma spraying and high-velocity oxygen fuel spraying.

8. The method of producing an ultra-high-temperature EB-PVD thermal barrier coating according to claim 1, characterized in that The alloy bonding layer is one of NiCrAlY, CoCrAlY and NiCoCrAlY.

9. The method of producing an ultra-high-temperature EB-PVD thermal barrier coating according to claim 1, characterized in that The parameters in the preparation process of the high-entropy zirconate ceramic coating are as follows: the substrate temperature is heated from room temperature to 600-850 DEG C, the acceleration voltage of electrons is 20-25 kV, the vacuum degree is lower than 1*10 -2 Pa, the deposition rate is 1-10 mu m / min, and the deposition coating thickness is 100-500 mu m.

10. The method of producing an ultra-high-temperature EB-PVD thermal barrier coating according to claim 1, characterized in that The vapor deposition method is physical vapor deposition.

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