A high-temperature gradient structure thermal barrier coating and a preparation method thereof

Abstract

The application discloses a high-temperature gradient structure thermal barrier coating and a preparation method thereof, and belongs to the technical field of thermal barrier coatings.The high-temperature gradient structure thermal barrier coating comprises, from bottom to top, a substrate, a bonding layer, an 8YSZ layer and a rare earth zirconate layer.The bonding layer is made of NiCrAlY alloy; the 8YSZ layer is ZrO2 stabilized by 8% mass fraction of Y2O3; and the chemical composition of the rare earth zirconate layer is LaYbZrCeO7.The application introduces the rare earth doping and double-layer structure design idea into the structure of the thermal barrier coating, so that low thermal conductivity, high thermal expansion coefficient and excellent thermal cycle life can be obtained, and the application has a wide application prospect in the field of thermal barrier coating materials.

Description

Technical Field

[0001] This invention relates to the field of thermal barrier coating technology, specifically to a high-temperature gradient structure thermal barrier coating and its preparation method. Background Technology

[0002] Thermal barrier coatings are crucial protective materials for turbine blade substrates in aero-engines and are closely related to the future development of the aerospace industry. The high-temperature phase transformation characteristics of traditional yttrium partially stabilized zirconia (YSZ) TBCs limit their application to below 1200℃. In recent years, Ln₂Zr₂O₇ (Ln = La, Gd, Sm, Yb, etc.) ceramic materials, possessing high-temperature phase stability, low thermal conductivity, high melting point, and chemical inertness, have attracted significant attention from experts both domestically and internationally. Ln₂Zr₂O₇, in particular, has a thermal conductivity of only 1.089 W / (m·K) at 1000℃, far lower than YSZ (3.293 W / (m·K)). However, the thermophysical properties of Ln₂Zr₂O₇ can no longer meet the aerospace industry's requirements for low thermal conductivity and high coefficient of thermal expansion. Research has confirmed that rare-earth doping causes lattice distortion, exacerbating phonon scattering and further reducing the thermal conductivity of ceramic materials. Simultaneously, rare-earth doping can also weaken the A₂B₂O₇ crystal structure. 3+ and B 4+ This increases the strength of ionic bonds between sites, thereby improving the coefficient of thermal expansion of ceramic materials.

[0003] The working environment of ceramic materials used in thermal barrier coatings is extremely harsh, requiring comprehensive consideration of various needs. They must meet the requirements for heat insulation and cooling while also exhibiting good compatibility with other components of the thermal barrier coating system. Therefore, ceramic materials used in thermal barrier coatings must possess: low thermal conductivity, high coefficient of thermal expansion, and good thermal cycling life.

[0004] Leveraging the high thermal expansion coefficient of traditional YSZ, it is combined with rare-earth-doped La2Zr2O7 ceramics to form a bilayer ceramic layer, effectively compensating for the thermal mismatch between the rare-earth-doped La2Zr2O7 ceramic and the binder layer (MCrAlY, M = Ni or Ni + Cr). Therefore, the design concept of rare-earth element doping and bilayer ceramic structure is of great significance for developing novel high-temperature gradient thermal barrier coatings with good thermophysical properties and excellent thermal cycling life.

[0005] A search revealed Chinese patent document CN111471998A, which discloses a Yb-modified anti-CMAS composite thermal barrier coating and its preparation method. The Yb-modified anti-CMAS composite thermal barrier coating is characterized by comprising: an adhesive layer, a first thermal insulation layer, and an anti-CMAS corrosion layer sequentially stacked on the surface of a substrate; wherein the anti-CMAS corrosion layer has a dense layered structure, is made of Yb-modified rare-earth zirconate, and possesses a fluorite structure; the first thermal insulation layer has a columnar structure, is made of Yb-modified rare-earth zirconate, and possesses a fluorite structure. The material of the anti-CMAS corrosion layer is (Ln... 1 1-x1 Yb x1 )2Zr2O7, where 0.2≤x1≤0.5, Ln 1 It is any one of La, Ce, Nd, Sm, and Gd; the material of the first heat insulation layer is (Ln 1 1-x2 Yb x2 )2Zr2O7, where 0 <x2≤0.5,Ln 1 The material is any one of La, Ce, Nd, Sm, and Gd; where x1 > x2. The main advantage of this invention lies in using the same elemental composition for both the anti-CMAS corrosion layer and the first thermal insulation layer, which can alleviate the thermal mismatch stress between the two layers and improve their bonding strength.

[0006] Chinese patent document CN110923611A discloses a composite thermal barrier coating, which includes an adhesive layer and a ceramic coating, wherein the ceramic coating is distributed on the adhesive layer, and the ceramic coating includes R. x Ce y Zr 1-x-y O 2-0.5x (0 < x ≤ 0.06, 0.1 ≤ y ≤ 0.16, R = La, Nd, Sm, Eu, Gd, Dy, Er, Yb, Y or Sc) and perlite vitrified microspheres. The R... x Ce y Zr 1-x- y O 2-0.5x 85-95 parts of perlite vitrified microspheres, 5-15 parts of perlite vitrified microspheres. This invention mainly involves the combination of perlite vitrified microspheres and R... x Ce y Zr 1-x-y O 2-0.5x By using a reasonable ratio, the crystal structure of the coating can achieve high-temperature phase stability, and the thermal conductivity of the thermal barrier coating can be between 0.41 W / (m·K) and 1.1 W / (m·K), thus achieving low thermal conductivity of the coating, which is also adjustable and controllable.

[0007] Chinese patent document CN111850454A discloses a thermal barrier coating resistant to CMAS erosion. The thermal barrier coating consists of an adhesive layer, a ceramic layer, and an apatite phase barrier layer from bottom to top. The adhesive layer is made of CoCrAlYTaSi material; the ceramic layer is a rare earth zirconate material with the chemical formula RE2Zr2O7, where RE represents any one or two different elements selected from Yb, La, Ce, and Gd, and the molar ratio of RE elements to the total elements is less than 20%; the thickness of the adhesive layer is 50-150 μm, the thickness of the ceramic layer is 100-300 μm, and the thickness of the apatite phase barrier layer is 5-10 μm. The main advantage of this invention is the formation of a dense apatite phase barrier layer on the surface. This layer has a high melting point, high density, good phase stability, and strong bonding force. It can not only fill the unavoidable pores and cracks on the surface of the ceramic layer during spraying but also seal the CMAS diffusion channels inside the ceramic layer, effectively improving the thermal barrier coating's resistance to CMAS erosion.

[0008] Chinese patent document CN109706418A discloses a double-ceramic-layer structure 8YSZ thermal barrier coating and its preparation method. The thermal barrier coating comprises, from bottom to top, an adhesive layer, an 8YSZ transition layer, and an 8YSZ top layer. The adhesive layer has a thickness of 50–150 μm, the transition layer has a thickness of 20–60 μm, and the top layer has a thickness of 200–400 μm. The adhesive layer is an MCrAlY metal adhesive layer with a surface roughness Ra of 4–6 μm, Rz of 25–45 μm, RSm of 140–180 μm, and Rsk of 0.05–0.25. This invention mainly focuses on preparing plasma-sprayed nano-double-ceramic-layer structure thermal barrier coatings with a nanostructured transition layer and a nanostructured top layer, as well as plasma-sprayed double-ceramic-layer structure thermal barrier coatings with a layered transition layer and a nanostructured top layer. Compared to single-ceramic-layer structure thermal barrier coatings, this invention improves the bonding strength, thermal shock resistance, and thermal cycling life of the thermal barrier coating.

[0009] Although various layered structures have been disclosed in the prior art regarding thermal barrier coatings, the inventive concepts, layered structures and chemical compositions of these inventions differ, and the technical problems they aim to solve and the effects they seek to achieve are also different.

[0010] Therefore, developing a thermal expansion coating with low thermal conductivity, high coefficient of thermal expansion, and good thermal cycle life still requires creative effort, even under different inventive concepts. Summary of the Invention

[0011] In view of this, in order to solve the above-mentioned technical problems, the purpose of this invention is to propose a high-temperature gradient structure thermal barrier coating and its preparation method, which has low thermal conductivity, high coefficient of thermal expansion and good thermal cycling life.

[0012] The technical solution adopted is as follows:

[0013] The present invention discloses a high-temperature gradient structure thermal barrier coating, which comprises, from bottom to top, a substrate, an adhesive layer, an 8YSZ layer, and a rare earth zirconate layer, wherein the adhesive layer is a NiCrAlY alloy; the 8YSZ layer is ZrO2 stabilized with Y2O3 containing 8% by mass; and the rare earth zirconate layer has the chemical composition LaYbZrCeO7.

[0014] Furthermore, the bonding layer is a NiCrAlY alloy with the following mass percentage composition: Ni 65%-70%, Cr 23%-28%, Al 3%-7%, and Y 0.5%-1%. For example, its mass percentage composition is Ni 69%, Cr 24.90%, Al 5.5%, and Y 0.60%.

[0015] Furthermore, the rare earth zirconate layer has the chemical composition LaYbZrCeO7, exhibiting a single fluorite phase structure, with a molar percentage of LaO... 1.5 25%, YbO 1.5 25%, ZrO225%, CeO225%.

[0016] Furthermore, the matrix is ​​a nickel-based alloy matrix.

[0017] Furthermore, the rare earth zirconate layer has a thickness of 96-100 μm, the 8YSZ layer has a thickness of 163-166 μm, and the adhesive layer has a thickness of 33-35 μm. For example, the rare earth zirconate layer has a thickness of 98 μm, the 8YSZ layer has a thickness of 165 μm, and the adhesive layer has a thickness of 34 μm.

[0018] A method for preparing the high-temperature gradient structure thermal barrier coating described above according to the present invention includes the following steps:

[0019] S1. Powder preparation: La2O3, Yb2O3, ZrO2 and CeO2 were weighed and mixed in ethanol according to the molar percentage, mechanically ball-milled, dried and then the resulting mixture was sintered in solid phase to obtain LaYbZrCeO7 fine powder.

[0020] S2. Powder processing: LaYbZrCeO7 fine powder is mixed with polyvinyl alcohol and deionized water to prepare a slurry, and then thoroughly mixed using a magnetic stirrer;

[0021] S3. Spray granulation: The resulting slurry is shaped into spherical micron-sized particles for plasma spraying;

[0022] S4. Surface treatment of the substrate: The substrate is immersed in NaOH solution for degreasing, ultrasonically cleaned with ethanol, dried, and then sandblasted.

[0023] S5. Thermal spray adhesive layer: An adhesive layer is prepared by spraying onto the substrate using plasma spraying technology;

[0024] S6. Thermal spraying of 8YSZ layer: The 8YSZ layer is prepared by spraying it onto the adhesive layer using plasma spraying technology;

[0025] S7. Thermal spraying of rare earth zirconate layer: A rare earth zirconate layer is prepared by spraying it onto the adhesive layer using plasma spraying technology.

[0026] Furthermore, in S1, the solid-state sintering temperature is 1600℃, and the holding time is 20-24 hours.

[0027] Furthermore, in S2, the mass ratio of LaYbZrCeO7 fine powder is 60%-65%; the mass ratio of polyvinyl alcohol is 2%-5%, and the remainder is deionized water.

[0028] Furthermore, in S3, spray granulation is performed using a spray granulator, with the input and output air temperatures set to 300℃ and 100℃, respectively, and the creeping speed and atomization pressure set to 35r / min and 0.2MPa, respectively.

[0029] Furthermore, in S5, S6, and S7, the thickness of the rare earth zirconate layer sprayed is 96-100 μm, the thickness of the 8YSZ layer sprayed is 163-166 μm, and the thickness of the adhesive layer sprayed is 33-35 μm.

[0030] The beneficial effects of this invention are as follows:

[0031] The high-temperature gradient structure thermal barrier coating of this invention is a double-layer ceramic layer structure, wherein the double-layer ceramic layer consists of a top layer of rare earth zirconate and a bottom layer of 8YSZ. The rare earth zirconate material is LaYbZrCeO7, which possesses thermophysical properties of low thermal conductivity and high coefficient of thermal expansion. This coating structure exhibits excellent thermal cycling life and is expected to be applied in the field of thermal barrier coatings.

[0032] For example, at temperatures of 1100-1200℃, the LaYbZrCeO7 material in this thermal barrier coating exhibits excellent thermophysical properties, namely low thermal conductivity and high coefficient of thermal expansion, which in turn gives the thermal barrier coating excellent thermophysical properties, namely low thermal conductivity and high coefficient of thermal expansion.

[0033] At a temperature of 1100°C, this thermal barrier coating exhibits excellent thermal cycling life.

[0034] Meanwhile, the method of the present invention also has the advantages of simple and efficient preparation process, low cost, strong controllability, and easy large-scale implementation.

[0035] In summary, this invention introduces rare earth doping and a bilayer structure design into the thermal barrier coating structure, which can achieve low thermal conductivity, high coefficient of thermal expansion and excellent thermal cycling life, and has broad application prospects in the field of thermal barrier coating materials. Attached Figure Description

[0036] Figure 1 Thermal conductivity diagrams for La2Zr2O7 and LaYbZrCeO7 ceramics.

[0037] Figure 2 The thermal expansion coefficient diagrams for La2Zr2O7 and LaYbZrCeO7 ceramics are shown.

[0038] Figure 3 The cross-sectional morphology diagrams of the thermal barrier coatings are shown: (a) La2Zr2O7 / YSZ, (b) LaYbZrCeO7 / YSZ;

[0039] Figure 4 Thermal cycling lifetime diagrams for La2Zr2O7 / 8YSZ and LaYbZrCeO7 / 8YSZ thermal barrier coatings. Detailed Implementation

[0040] The present invention will be described in detail below through specific embodiments. However, the uses and purposes of these exemplary embodiments are only for illustrating the present invention and do not constitute any limitation on the actual protection scope of the present invention, nor are they intended to limit the protection scope of the present invention to these embodiments.

[0041] It should be noted that the 8YSZ layer is ZrO2 stabilized with 8% Y2O3 by mass; that is, ZrO2-8%Y2O3, and the Y2O3 mass fraction in 8YSZ is 8%.

[0042] Polyvinyl alcohol is abbreviated as PVA.

[0043] Example 1

[0044] This embodiment provides a method for preparing a rare earth zirconate material, comprising the following steps:

[0045] S1. Using La2O3, Yb2O3, ZrO2, and CeO2 as raw materials, the molar percentage ratio is: LaO 1.5 25%, YbO 1.5 25% ZrO2 and 25% CeO2 were weighed, mixed and dissolved in ethanol, mechanically ball-milled, and dried. The resulting mixture was then sintered at 1600℃ for 20 hours without pressure to obtain LaYbZrCeO7 fine powder.

[0046] S2. LaYbZrCeO7 fine powder was mixed with PVA and deionized water, with the mass ratio of LaYbZrCeO7 fine powder being 60% and the mass ratio of PVA being 2%, with the remainder being deionized water, to prepare a slurry, which was then thoroughly mixed using a magnetic stirrer.

[0047] S3. Use a spray granulator to perform spray granulation. Set the input and output air temperatures to 300℃ and 100℃, respectively. Set the creep speed and atomization pressure to 35r / min and 0.2MPa, respectively. Shape the resulting slurry into spherical micron-sized particles for plasma spraying.

[0048] S4. LaYbZrCeO7 ceramic sample blocks were prepared on the surface of graphite blocks using plasma spraying technology.

[0049] Comparative Example 1

[0050] Referring to Example 1, the difference is that in this comparative example, La2O3 and ZrO2 are used as raw materials in step S1, and are weighed and mixed in ethanol at a molar ratio of 1:2. The other steps are the same as in Example 1, and finally a La2Zr2O7 ceramic sample block is obtained.

[0051] Performance testing

[0052] Thermal conductivity (sample size: Φ10mm×1mm) and coefficient of thermal expansion (sample size: 25mm×4mm×4mm) experiments were conducted on the La2Zr2O7 and LaYbZrCeO7 ceramic samples prepared in Comparative Example 1 and Example 1 to better present the thermophysical properties of LaYbZrCeO7 material.

[0053] Test Results

[0054] Figure 1 Thermal conductivity diagrams for La2Zr2O7 and LaYbZrCeO7 ceramics.

[0055] like Figure 1 As shown, at 1100℃, the thermal conductivity of LaYbZrCeO7 and La2Zr2O7 ceramics are 1.326 W / (m·K) and 2.077 W / (m·K), respectively; at 1200℃, the thermal conductivity of LaYbZrCeO7 and La2Zr2O7 ceramics are 1.311 W / (m·K) and 2.122 W / (m·K), respectively. This demonstrates the good thermal insulation ability of LaYbZrCeO7 ceramics.

[0056] Figure 2 The thermal expansion coefficient diagrams for La2Zr2O7 and LaYbZrCeO7 ceramics are shown.

[0057] like Figure 2As shown, at 1100℃, the coefficients of thermal expansion of LaYbZrCeO7 and La2Zr2O7 ceramics are 10.431 × 10⁻⁶ and 10⁻⁶, respectively. -6 / K and 8.853×10 -6 At 1200℃, the coefficients of thermal expansion of LaYbZrCeO7 and La2Zr2O7 ceramics are 10.554 × 10⁻⁶ K and 1200℃, respectively. -6 / K and 8.888×10 -6 / K. This indicates that LaYbZrCeO7 ceramics have a high coefficient of thermal expansion.

[0058] Example 2

[0059] The method for preparing a high-temperature gradient structure thermal barrier coating according to this embodiment includes the following steps:

[0060] Repeat steps S1-S3 in Example 1;

[0061] S4. Surface treatment of the substrate: The nickel-based superalloy (GH4169, size 30mm×10mm×3mm) substrate is immersed in NaOH solution for degreasing treatment, ultrasonically cleaned with ethanol for 15 minutes, dried, and then sandblasted with 24-mesh brown corundum.

[0062] S5. Thermal spray adhesive layer: An adhesive layer with a thickness of 34 μm is prepared by spraying on the substrate using plasma spraying technology; the adhesive layer is a NiCrAlY alloy with a mass percentage of Ni 69%, Cr 24.90%, Al 5.5%, and Y 0.60%.

[0063] S6. Thermal spraying of 8YSZ layer: An 8YSZ layer with a thickness of 165μm is prepared by spraying on the adhesive layer using plasma spraying technology;

[0064] S7. Thermal spraying of rare earth zirconate layer: A rare earth zirconate layer with a thickness of 98 μm is prepared by spraying it onto the adhesive layer using plasma spraying technology.

[0065] The resulting thermal barrier coating is denoted as LaYbZrCeO7 / 8YSZ.

[0066] Comparative Example 2

[0067] The preparation method of a high-temperature gradient structure thermal barrier coating in this comparative example includes the following steps:

[0068] S1. Using La2O3 and ZrO2 as raw materials, weigh them in a molar ratio of 1:2, mix and dissolve them in ethanol, mechanically ball mill them, dry them, and then sinter the resulting mixture at 1600℃ for 20h without pressure to obtain La2Zr2O7 fine powder.

[0069] S2.La2Zr2O7 fine powder was mixed with PVA and deionized water, with the mass ratio of La2Zr2O7 fine powder being 60% and the mass ratio of PVA being 2%, and the remainder being deionized water, to prepare a slurry, which was then thoroughly mixed using a magnetic stirrer.

[0070] S3. Use a spray granulator to perform spray granulation. Set the input and output air temperatures to 300℃ and 100℃, respectively. Set the creep speed and atomization pressure to 35r / min and 0.2MPa, respectively. Shape the resulting slurry into spherical micron-sized particles for plasma spraying.

[0071] S4. Surface treatment of the substrate: The nickel-based superalloy (GH4169, size 30mm×10mm×3mm) substrate is immersed in NaOH solution for degreasing treatment, ultrasonically cleaned with ethanol for 15 minutes, dried, and then sandblasted with 24-mesh brown corundum.

[0072] S5. Thermal spray adhesive layer: An adhesive layer with a thickness of 33μm is prepared by spraying it onto the substrate using plasma spraying technology;

[0073] S6. Thermal spraying of 8YSZ layer: An 8YSZ layer with a thickness of 150μm is prepared by spraying it onto the adhesive layer using plasma spraying technology;

[0074] S7. Thermal spraying of rare earth zirconate layer: A rare earth zirconate layer with a thickness of 86 μm is prepared by spraying it onto the adhesive layer using plasma spraying technology.

[0075] The resulting thermal barrier coating is denoted as La2Zr2O7 / 8YSZ.

[0076] Performance testing

[0077] After preparing the La2Zr2O7 / 8YSZ thermal barrier coating and the LaYbZrCeO7 / 8YSZ thermal barrier coating in Comparative Example 2 and Example 2, thermal cycling life performance tests were conducted to compare them with the La2Zr2O7 / YSZ thermal barrier coating, in order to better demonstrate the thermal cycling life of the LaYbZrCeO7 / 8YSZ thermal barrier coating.

[0078] Test Results

[0079] Figure 3 Cross-sectional morphology of La2Zr2O7 / 8YSZ and LaYbZrCeO7 / 8YSZ thermal barrier coatings.

[0080] like Figure 3As shown, the thicknesses of the La2Zr2O7, 8YSZ, and NiCrAlY layers in the La2Zr2O7 / 8YSZ thermal barrier coating are 86, 150, and 33 μm, respectively; the thicknesses of the LaYbZrCeO7, 8YSZ, and NiCrAlY layers in the LaYbZrCeO7 / 8YSZ thermal barrier coating are approximately 98, 165, and 34 μm, respectively.

[0081] Figure 4 Thermal cycling lifetime diagrams for La2Zr2O7 / 8YSZ and LaYbZrCeO7 / 8YSZ thermal barrier coatings (1100℃, 5 min holding, 5 min air cooling).

[0082] like Figure 4 As shown, when the area of ​​the top ceramic layer detachment exceeds 10%, the thermal cycle life of the LaYbZrCeO7 / 8YSZ thermal barrier coating is 249 cycles, while that of the La2Zr2O7 / 8YSZ thermal barrier coating is 180 cycles. The LaYbZrCeO7 / 8YSZ thermal barrier coating (249 cycles) is nearly 38.3% higher than that of the La2Zr2O7 / 8YSZ thermal barrier coating (180 cycles). Therefore, at a temperature of 1100℃, the LaYbZrCeO7 / 8YSZ thermal barrier coating exhibits excellent thermal cycle life.

[0083] The detailed descriptions listed above are merely specific illustrations of feasible embodiments of the present invention and are not intended to limit the scope of protection of the present invention. All equivalent embodiments or modifications made without departing from the spirit of the present invention should be included within the scope of protection of the present invention.

Claims

1. A high-temperature gradient structure thermal barrier coating, characterized in that, From bottom to top, it consists of a substrate, a binder layer, an 8YSZ layer, and a rare earth zirconate layer. The binder layer is a NiCrAlY alloy; the 8YSZ layer is ZrO2 stabilized with 8% Y2O3 by mass; the rare earth zirconate layer has the chemical composition LaYbZrCeO7; and exhibits a single fluorite phase structure with a molar percentage of LaO... 1.5 25%, YbO 1.5 25%, ZrO2 25%, CeO2 25%; the thickness of the rare earth zirconate layer is 96-100 μm, the thickness of the 8YSZ layer is 163-166 μm, and the thickness of the adhesive layer is 33-35 μm; The method for preparing the high-temperature gradient structure thermal barrier coating includes the following steps: S1. Powder preparation: La2O3, Yb2O3, ZrO2 and CeO2 were weighed and mixed in ethanol according to the molar percentage, mechanically ball-milled, dried and then the resulting mixture was sintered in a solid state to obtain LaYbZrCeO7 fine powder; the solid state sintering temperature was 1600℃ and the holding time was 20-24 hours. S2. Powder processing: LaYbZrCeO7 fine powder is mixed with polyvinyl alcohol and deionized water to prepare a slurry, and then thoroughly mixed using a magnetic stirrer; S3. Spray granulation: The obtained slurry is shaped into spherical micron-sized particles for plasma spraying; spray granulation is performed using a spray granulator, with the input and output air temperatures set to 300°C and 100°C respectively, and the creeping speed and atomization pressure set to 35 r / min and 0.2 MPa respectively. S4. Surface treatment of the substrate: The substrate is immersed in NaOH solution for degreasing, ultrasonically cleaned with ethanol, dried, and then sandblasted. S5. Thermal spray adhesive layer: An adhesive layer is prepared by spraying onto the substrate using plasma spraying technology; S6. Thermal spraying of 8YSZ layer: An 8YSZ layer is prepared by spraying it onto the adhesive layer using plasma spraying technology; S7. Thermal spraying of rare earth zirconate layer: A rare earth zirconate layer is prepared by spraying it onto the adhesive layer using plasma spraying technology.

2. The high-temperature gradient structure thermal barrier coating according to claim 1, characterized in that, The bonding layer is a NiCrAlY alloy with a mass percentage of Ni 65%-70%, Cr 23%-28%, Al 3%-7%, and Y 0.5%-1%.

3. The high-temperature gradient structure thermal barrier coating according to claim 1, characterized in that, The matrix is ​​a nickel-based alloy matrix.

4. A method for preparing a high-temperature gradient structure thermal barrier coating according to any one of claims 1-3, characterized in that, Includes the following steps: S1. Powder preparation: La2O3, Yb2O3, ZrO2 and CeO2 are used as raw materials. They are weighed and mixed in ethanol according to the molar percentage. After mechanical ball milling and drying, the resulting mixture is sintered in solid phase to obtain LaYbZrCeO7 fine powder. S2. Powder processing: LaYbZrCeO7 fine powder is mixed with polyvinyl alcohol and deionized water to prepare a slurry, and then thoroughly mixed using a magnetic stirrer; S3. Spray granulation: The resulting slurry is shaped into spherical micron-sized particles for plasma spraying; S4. Surface treatment of the substrate: The substrate is immersed in NaOH solution for degreasing, ultrasonically cleaned with ethanol, dried, and then sandblasted. S5. Thermal spray adhesive layer: An adhesive layer is prepared by spraying onto the substrate using plasma spraying technology; S6. Thermal spraying of 8YSZ layer: An 8YSZ layer is prepared by spraying it onto the adhesive layer using plasma spraying technology; S7. Thermal spraying of rare earth zirconate layer: A rare earth zirconate layer is prepared by spraying it onto the adhesive layer using plasma spraying technology.

5. The method for preparing a high-temperature gradient structure thermal barrier coating according to claim 4, characterized in that, In S2, the mass ratio of LaYbZrCeO7 fine powder is 60%-65%; the mass ratio of polyvinyl alcohol is 2%-5%, and the remainder is deionized water.

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