A multi-element rare earth modified zirconia double-layer thermal barrier coating and a preparation method thereof

Abstract

This invention discloses a multi-element rare-earth modified zirconia double-layer thermal barrier coating. The coating, from the inside out, consists of a NiCoCrAlYHf metal binder layer, a YSZ ceramic underlayer, and a SYYSZ ceramic surface layer. The ceramic underlayer and the ceramic surface layer constitute a double-layer ceramic functional layer, forming the multi-element rare-earth modified zirconia double-layer thermal barrier coating. Furthermore, this invention provides a method for preparing this coating, which is prepared sequentially using electron beam physical vapor deposition. This invention significantly improves the phase stability of zirconia, reduces thermal conductivity, and weakens its reactivity with CMAS by synergistically modifying the ceramic surface layer with Sc and Yb. The coating exhibits excellent thermal insulation, anti-sintering, resistance to high-temperature phase transformation, and resistance to CMAS corrosion. The interface bonding is strong, meeting the ultra-high temperature and long-life service requirements of next-generation aero-engines.

Description

Technical Field

[0001] This invention belongs to the field of thermal barrier coating technology, specifically relating to a multi-element rare earth modified zirconium oxide double-layer thermal barrier coating and its preparation method. Background Technology

[0002] Thermal barrier coatings, as a core thermal protection technology for hot-end components of aero-engines and gas turbines, provide effective thermal protection for high-temperature alloy substrates by depositing high-temperature resistant and highly heat-insulating ceramic coatings on the surface of the substrate. This fundamentally breaks through the service temperature limit of high-temperature alloys and is a key support for improving the thrust-to-weight ratio, thermal efficiency, and service life of engines. It has vital strategic significance in the field of high-end equipment manufacturing.

[0003] Traditional thermal barrier coatings using 8wt.% yttria-stabilized zirconia (YSZ) layers have long been widely used as the mainstream coating material due to their low thermal conductivity, high coefficient of thermal expansion, and good compatibility with metal bonding layers. However, at temperatures above 1200℃, they are prone to a tetragonal-to-monoclinic phase transformation, accompanied by a volume expansion of approximately 3% to 5%, leading to coating failures such as cracking and peeling. Furthermore, at high temperatures above 1200℃, their grains grow rapidly, and the sintering shrinkage effect is significant. On the other hand, engine hot-end components are subjected to harsh environments of high-temperature exhaust gas erosion and molten calcium magnesium aluminum silicate (CMAS) corrosion. When the YSZ layer is exposed to molten CMAS corrosion, it easily reacts with CMAS to form a low-melting-point phase, resulting in a loose coating structure and peeling, significantly shortening the service life of the thermal barrier coating. This makes it unable to meet the ultra-high temperature, long life, and CMAS resistance requirements of next-generation aero-engines.

[0004] The invention patent CN119433407A proposes a double-layer thermal barrier coating technology that uses atmospheric plasma spraying to prepare the double-layer thermal barrier coating. Traditional YSZ serves as the bottom layer, acting as a transition to the metal layer, while the doping of elements such as Yb in the LaYbZrCeO7 surface layer provides protection against CMAS corrosion. In this patent, the interface between the sprayed YSZ layer and the sprayed LaYbZrCeO7 layer is mainly mechanically interlocked with localized metallurgical bonding. In contrast, the double-layer thermal barrier coating prepared by electron beam physical vapor deposition (EB-PVD) exhibits a continuous columnar crystal morphology, demonstrating significantly superior static bonding strength at room temperature and interfacial bonding stability under high-temperature thermal cycling compared to traditional APS coatings. On the other hand, current research commonly uses materials with significantly different compositional systems from YSZ as the surface coating in double-layer thermal barrier coatings, which can easily lead to potential problems with poor interfacial compatibility.

[0005] Therefore, developing novel thermal barrier coating materials with high phase stability, low thermal conductivity, and resistance to CMAS, and constructing interface-compatible double-layer thermal barrier coatings by adapting to the advanced EB-PVD coating preparation process, has become an urgent technical challenge in the field of thermal barrier coating technology, and is also a core research direction for breaking through the bottleneck of ultra-high temperature service of engines. Summary of the Invention

[0006] The technical problem to be solved by this invention is to address the shortcomings of the prior art by providing a multi-element rare earth modified zirconia double-layer thermal barrier coating. This coating uses a YSZ layer as the ceramic underlayer and a Sc-Yb co-modified YSZ layer as the ceramic surface layer to form a multi-element rare earth modified zirconia double-layer thermal barrier coating. This solves the problems of high-temperature phase transformation, severe sintering, CMAS corrosion failure, and poor interfacial bonding of traditional YSZ layers, achieving a synergistic improvement in high phase stability, low thermal conductivity, excellent CMAS resistance, and good interfacial bonding.

[0007] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a multi-element rare earth modified zirconia double-layer thermal barrier coating, characterized in that the coating consists of a metal bonding layer, a ceramic underlayer, and a ceramic surface layer from the inside out; the metal bonding layer is a NiCoCrAlYHf layer, the ceramic underlayer is a YSZ layer, the YSZ layer is composed of the following mass percentage components: 7%~8% Y2O3, with the balance being ZrO2; the ceramic surface layer is a Sc-Yb co-modified YSZ layer, i.e., a SYYSZ layer; the SYYSZ layer is composed of the following mass percentage components: 3.9%~4.1% Sc2O3, 11.2%~11.4% Yb2O3, 7%~8% Y2O3, with the balance being ZrO2; the ceramic underlayer and the ceramic surface layer constitute a double-layer ceramic functional layer, forming a multi-element rare earth modified zirconia double-layer thermal barrier coating.

[0008] In this invention, YSZ is used as the ceramic underlayer, which has a slightly higher coefficient of thermal expansion than the SYYSZ layer, resulting in better compatibility with the metal bonding layer. This effectively reduces thermal mismatch stress and serves as a functionally graded transition layer to improve the interfacial compatibility of the bilayer ceramic structure. The SYYSZ layer is used as the ceramic surface layer, where Sc and Yb co-doping improves the stability of the tetragonal zirconium phase. Sc2O3 helps stabilize the defective fluorite structure and reduces the driving force for high-temperature sintering, while Yb2O3 introduces larger lattice distortion and reduces phonon propagation ability, thereby reducing thermal conductivity. During high-temperature CMAS corrosion, Yb can preferentially react with Si, Ca, and other components in CMAS to form a high-viscosity rare-earth silicate phase, thus hindering further penetration of CMAS and preventing coating peeling caused by the release of large stress during the reaction between YSZ and CMAS, thereby improving the resistance to CMAS corrosion. In addition, the bilayer ceramic structure uses a YSZ / SYYSZ system with similar compositions, avoiding the interfacial mismatch problem caused by excessive differences in material systems in traditional bilayer thermal barrier coatings, which is conducive to the formation of a continuous columnar crystal structure.

[0009] In this invention, the SYYSZ layer is composed of the following mass percentages: 3.9%~4.1% Sc2O3, 11.2%~11.4% Yb2O3, 7%~8% Y2O3, with the balance being ZrO2. Based on this, the molar percentages of the three trivalent doped oxides Sc2O3:Yb2O3:Y2O3 are calculated to be 1:1:1.15, with a total doping content of 12.0 mol%~13.4 mol%. Using this SYYSZ layer composition can significantly reduce the thermal conductivity of traditional YSZ materials, with the thermal conductivity of SYYSZ at 1200℃ being 1.73 W / (m²). The thermal conductivity of YSZ is 2.34 W / (m²). K), which simultaneously improves the material's phase stability and resistance to CMAS corrosion.

[0010] The aforementioned multi-element rare-earth modified zirconia double-layer thermal barrier coating is characterized in that the metal bonding layer, ceramic substrate, and ceramic surface layer are all prepared by electron beam physical vapor deposition. The metal bonding layer uses a NiCoCrAlYHf target, which is composed of the following mass percentages: 10%~15% Co, 18%~23% Cr, 8%~12% Al, 0.1%~0.5% Y, 0.2%~0.5% Hf, with the balance being Ni. The ceramic substrate uses a YSZ target, which is composed of the following mass percentages: 7%~8% Y₂O₃, with the balance being ZrO₂. The ceramic surface layer uses a SYYSZ target, which is composed of the following mass percentages: 3.9%~4.1% Sc₂O₃, 11.2%~11.4 ... Yb2O3, 7%~8% Y2O3, balance ZrO2.

[0011] The above-mentioned multi-element rare earth modified zirconia double-layer thermal barrier coating is characterized in that the thickness of the metal bonding layer is 40μm~70μm; the thickness of the ceramic substrate is 50μm~100μm; the thickness of the ceramic surface layer is 50μm~100μm; the columnar crystals of the ceramic substrate and the ceramic surface layer are continuously transitioned without obvious interface; the tilt angle of the columnar crystals of the ceramic surface layer is 3°~8°; and the difference in tilt angle between the columnar crystals of the ceramic substrate and the ceramic surface layer is not greater than 5°. This invention balances oxidation protection and thermal stress buffering capabilities by controlling the thickness of the metal bonding layer, preventing insufficient Al reserves due to excessive thickness and the introduction of residual stress due to excessive thickness. Controlling the thickness of the ceramic substrate ensures a smooth transition of thermal expansion between the ceramic layer and the metal bonding layer. Controlling the thickness of the ceramic surface layer fully utilizes the low thermal conductivity, high phase stability, and CMAS corrosion resistance of the SYYSZ layer. It prevents both insufficient thickness (limited functional enhancement) and excessive thickness (excessive thermal stress accumulation). Controlling the tilt angle of the columnar crystals on the ceramic surface improves the strain tolerance between the columnar crystals. Simultaneously controlling the difference in tilt angle between the columnar crystals in the ceramic substrate and surface layers, as well as the continuous transition of the columnar crystals without obvious interfaces, promotes continuous growth of the columnar crystals and reduces the risk of interface defects and crack initiation.

[0012] The aforementioned multi-element rare-earth modified zirconia bilayer thermal barrier coating is characterized in that the substrate for coating deposition is a high-temperature alloy, wherein the high-temperature alloy includes nickel-based single-crystal high-temperature alloys DD5, DD6, or IC21. This invention is applicable to the preparation of multi-element rare-earth modified zirconia bilayer thermal barrier coatings on the surfaces of various high-temperature alloys.

[0013] In addition, the present invention also provides a method for preparing a multi-element rare earth modified zirconia bilayer thermal barrier coating, characterized in that the method uses electron beam physical vapor deposition to sequentially prepare a metal binder layer, a ceramic underlayer, and a ceramic surface layer, specifically including the following steps: Step 1: Pre-treat the high-temperature alloy; Step 2: On the surface of the high-temperature alloy that was pretreated in Step 1, a metal bonding layer is prepared by electron beam physical vapor deposition, and then heat-treated in a vacuum heat treatment furnace; Step 3: On the surface of the metal bonding layer after heat treatment in Step 2, a ceramic underlayer is prepared by electron beam physical vapor deposition; Step 4: On the ceramic substrate prepared in Step 3, an electron beam physical vapor deposition is used to prepare a ceramic surface layer, resulting in a multi-element rare earth modified zirconia double thermal barrier coating.

[0014] The above method is characterized in that the pretreatment in step one includes sequential polishing with 240#, 400#, and 800# diamond abrasive paper and ultrasonic degreasing and cleaning. This invention completely removes wire cutting marks and surface impurities from the substrate surface through pretreatment, improving the bonding strength of subsequent coatings and ensuring the quality of the multi-element rare earth modified zirconia double-layer thermal barrier coating.

[0015] The above method is characterized in that the parameters for electron beam physical vapor deposition in step two are: vacuuming to 1.1 × 10⁻⁶. -2 Pa ~ 5.3 × 10 -2 Pa and hold for 10-15 minutes, then turn on the preheating electron gun, preheat the workpiece to 780-850°C and hold for 10-15 minutes, then turn on the evaporation electron gun and adjust the beam current to 0.65A-0.98A, depositing for 40-80 minutes; the parameters of the heat treatment are: at a vacuum degree less than 1×10 -3 Under the condition of Pa, vacuum annealing is carried out at 1000℃~1100℃ for 1h~2h. This invention ensures the quality of the metal binder layer by controlling the parameters of electron beam physical vapor deposition.

[0016] The above method is characterized in that the parameters for electron beam physical vapor deposition in step three are: vacuuming to 1.1 × 10⁻⁶. -2 Pa ~ 5.3 × 10 -2 The temperature is maintained at 900°C to 1000°C for 10-15 minutes, then the preheating electron gun is turned on to preheat the workpiece to 900°C to 1000°C and maintained for 10-15 minutes. Oxygen is then introduced at a flow rate of 50-100 sccm for pre-oxidation for 20-30 minutes. Subsequently, the evaporation electron gun is turned on and the beam current is adjusted to 0.58A-0.85A for deposition for 60-80 minutes. This invention ensures the quality of the ceramic substrate by controlling the parameters of electron beam physical vapor deposition.

[0017] The above method is characterized by the following parameters for electron beam physical vapor deposition in step four: After step three is completed, the workpiece is not removed from the furnace. Simultaneously, the evaporation electron gun current corresponding to the YSZ target is adjusted to 0A and the evaporation electron gun current corresponding to the SYYSZ target is adjusted to 0.58A~0.85A. The workpiece is then pushed to slowly and uniformly move from above the YSZ target to above the SYYSZ target. At the same time, the preheating electron gun position is adjusted to above the SYYSZ target to maintain the workpiece temperature at 900℃~1000℃ for continuous evaporation and deposition for 60min~80min. In this invention, after step three is completed, there is no need to break the vacuum; only the sample position needs to be adjusted to continuously perform step four, reducing the operation process, lowering production costs, and ensuring the quality of the ceramic surface layer by controlling the parameters of electron beam physical vapor deposition.

[0018] Compared with the prior art, the present invention has the following advantages: 1. This invention uses a SYYSZ layer as a ceramic surface layer. Through the synergistic effect of Sc and Yb, the tetragonal phase of zirconia is effectively stabilized, and the phase transformation at high temperature is suppressed. At the same time, the reactivity of the SYYSZ layer with molten CMAS is significantly reduced, avoiding the coating peeling caused by the release of large stress during the reaction between the YSZ layer and CMAS, and greatly improving the coating's resistance to CMAS corrosion.

[0019] 2. The present invention designs a double-layer ceramic structure with SYYSZ layer and YSZ layer. The composition of the bottom ceramic layer and the surface layer are similar, with excellent interfacial compatibility. There is no visible interface between the two coating layers. It is a continuously growing columnar crystal with high strain tolerance and low sintering rate. It can still maintain a stable heat insulation effect after long-term heat exposure.

[0020] 3. In this invention, the ceramic bottom layer serves as a transition layer between the surface layer and the metal bonding layer. Due to the introduction of oxygen vacancies by Sc and Yb oxide doping, the ceramic surface layer has lower thermal conductivity and better phase stability than the traditional YSZ layer. This solves the problems of high-temperature phase transformation, severe sintering, CMAS corrosion failure, and poor interface bonding of the double coating layer in the traditional YSZ layer, and achieves a synergistic improvement in high phase stability, low thermal conductivity, excellent anti-CMAS performance and good interface bonding.

[0021] 4. This invention uses a one-step electron beam physical vapor deposition process to prepare the coating. The vacuum degree, substrate temperature and electron beam power of the deposition process are precisely controlled in stages. The vacuum environment inside the furnace is maintained in each step to avoid introducing impurities into the coating interface. This results in a uniform columnar crystal structure in the coating, with tight and defect-free bonding between the layers. It also takes into account the heat insulation, anti-sintering and anti-CMAS properties of the coating.

[0022] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the structure of the multi-element rare earth modified zirconium oxide double-layer thermal barrier coating of the present invention.

[0024] Figure 2 This is a SEM image of the cross-section of the multi-element rare earth modified zirconium oxide double-layer thermal barrier coating prepared in Example 1 of the present invention.

[0025] Figure 3 The image shows the Yb element energy spectrum distribution of the cross section of the multi-element rare earth modified zirconium oxide double thermal barrier coating prepared in Example 1 of this invention.

[0026] Figure 4The image shows the Sc element energy spectrum distribution of the cross section of the multi-element rare earth modified zirconium oxide double thermal barrier coating prepared in Example 1 of this invention.

[0027] Figure 5 The image shows the XRD pattern of the multi-element rare earth modified zirconia double-layer thermal barrier coating prepared in Example 1 of this invention after aging at 1400℃ for 100h.

[0028] Figure 6 The image shows a high-angle slow-scan XRD pattern of the thermal barrier coating prepared in Comparative Example 1 of this invention after aging at 1400℃ for 100 hours.

[0029] Figure 7 The image shows a comparison of the surface morphology of the multi-element rare earth modified zirconium oxide double-layer thermal barrier coating prepared in Example 1 of the present invention and the thermal barrier coating prepared in Comparative Example 1 after CMAS etching at 1250℃ for 4 hours.

[0030] Explanation of reference numerals in the attached figures: 1-High temperature alloy; 2-Metallic bonding layer; 3-Ceramic base layer; 4-Ceramic surface layer. Detailed Implementation

[0031] Figure 1 This is a schematic diagram of the structure of the multi-element rare earth modified zirconium oxide double-layer thermal barrier coating of the present invention. Figure 1 As can be seen from the figure, the present invention uses high-temperature alloy 1 as the substrate, and sequentially prepares a metal bonding layer 2, a ceramic bottom layer 3 and a ceramic surface layer 4 on its surface.

[0032] Example 1 This embodiment includes the following steps: Step 1: Polish the nickel-based single-crystal high-temperature alloy DD5 sequentially with 240#, 400# and 800# diamond abrasive paper, and then perform ultrasonic degreasing and cleaning to obtain the pretreated high-temperature alloy. Step 2: Load the pretreated high-temperature alloy obtained in Step 1 into the furnace and install it on the workpiece rack. Set the rotation speed of the workpiece rack to 15 r / min and evacuate to 2.5 × 10⁻⁶. -2 After Pa stabilization for 12 min, the pretreated high-temperature alloy was preheated to 820°C using a preheating electron gun and held for 12 min. Then, the evaporation electron gun was activated and the beam current adjusted to 0.8 A, and deposition was carried out for 50 min to deposit a NiCoCrAlYHf metallic binder layer on the surface of the pretreated high-temperature alloy. After deposition, the alloy was placed in a vacuum heat treatment furnace at a vacuum level less than 1 × 10⁻⁶. -3 Under the condition of Pa, vacuum annealing at 1100℃ for 2h yields a pretreated high-temperature alloy with a metal bonding layer; the NiCoCrAlYHf target material is composed of the following components by mass percentage: 12% Co, 20% Cr, 10% Al, 0.3% Y, 0.3% Hf, with the balance being Ni. Step 3: Load the pretreated high-temperature alloy with a metallic bonding layer obtained in Step 2 into the furnace and install it on the workpiece rack. Set the rotation speed of the workpiece rack to 15 r / min and evacuate to 2.8 × 10⁻⁶. -2 After Pa, the temperature was stabilized for 12 minutes. Then, the preheating electron gun was turned on to preheat the pretreated high-temperature alloy with the metal binder layer to 950°C and held for 12 minutes. Next, oxygen was introduced at a flow rate of 80 sccm to pre-oxidize the metal binder layer for 25 minutes. Then, the evaporation electron gun was turned on and the beam current was adjusted to 0.7A for 65 minutes to deposit a YSZ ceramic underlayer on the surface of the pretreated high-temperature alloy with the metal binder layer, thus obtaining a pretreated high-temperature alloy with a ceramic underlayer. The YSZ target material is composed of the following composition by mass percentage: 7.8% Y2O3, with the balance being ZrO2. Step 4: After completing Step 3, maintain the vacuum state inside the furnace, and do not remove the workpiece from the furnace. Simultaneously, adjust the evaporation electron gun current corresponding to the YSZ target to 0A and the evaporation electron gun current corresponding to the SYYSZ target to 0.7A. Start the workpiece pushing to slowly and uniformly move the workpiece from above the YSZ target to above the SYYSZ target. At the same time, adjust the position of the preheating electron gun to above the SYYSZ target to maintain the workpiece temperature at 980℃ and perform continuous evaporation for 70 minutes to obtain a multi-element rare earth modified zirconia double-layer thermal barrier coating. The SYYSZ target is composed of the following components by mass percentage: 4.1% Sc2O3, 11.2% Yb2O3, 7.9% Y2O3, with the balance being ZrO2.

[0033] Upon testing, the metal binder layer of the multi-element rare earth modified zirconia double-layer thermal barrier coating prepared in this embodiment is composed of the following mass percentages: 11.8% Co, 19.6% Cr, 9.7% Al, 0.28% Y, 0.29% Hf, with the balance being Ni; the ceramic substrate is composed of the following mass percentages: 7.7% Y₂O₃, with the balance being ZrO₂; the ceramic surface layer is composed of the following mass percentages: 4.0% Sc₂O₃, 11.2% Yb₂O₃, 7.8% Y₂O₃, with the balance being ZrO₂; the thickness of the metal binder layer is 50 μm; the thickness of the ceramic substrate is 70 μm; and the thickness of the ceramic surface layer is 75 μm.

[0034] Figure 2 This is a SEM image of the cross-section of the multi-element rare-earth modified zirconium oxide bilayer thermal barrier coating prepared in this embodiment. Figure 2As can be seen from the above, the ceramic bottom layer (YSZ layer) and the ceramic surface layer (SYYSZ layer) in the multi-element rare earth modified zirconia double thermal barrier coating prepared in this embodiment are both typical columnar crystal structures. The columnar crystals of the ceramic bottom layer and the ceramic surface layer are continuously transitioned without obvious interfaces. The interlayer bonding is dense and defect-free. The tilt angle of the columnar crystals in the SYYSZ layer (the angle between the columnar crystals and the normal / vertical direction of the substrate) is 3°~7°, and the difference in tilt angle between the columnar crystals of the ceramic bottom layer and the ceramic surface layer is no greater than 5°.

[0035] Figure 3 and Figure 4 The images show the energy dispersive spectral distributions of Yb and Sc elements in the cross-section of the multi-element rare-earth modified zirconia double-layer thermal barrier coating prepared in Example 1 of this invention. Figure 3 and Figure 4 The upper part of the white dotted line represents the ceramic surface layer, and the lower part represents the ceramic base layer. Figure 3 and Figure 4 As can be seen from the above, the composition of the doping elements Sc and Yb at the interface between the ceramic bottom layer and the ceramic surface layer in the multi-element rare earth modified zirconia bilayer thermal barrier coating prepared in this embodiment is significantly different. The two elements are concentrated in the ceramic surface layer, which is consistent with the designed coating composition.

[0036] Comparative Example 1 This comparative example includes the following steps: Step 1: Polish the nickel-based single-crystal high-temperature alloy DD5 sequentially with 240#, 400# and 800# diamond abrasive paper, and then perform ultrasonic degreasing and cleaning to obtain the pretreated high-temperature alloy. Step 2: Load the pretreated high-temperature alloy obtained in Step 1 into the furnace and install it on the workpiece rack. Set the rotation speed of the workpiece rack to 15 r / min and evacuate to 2.5 × 10⁻⁶. -2 After Pa stabilization for 12 min, the pretreated high-temperature alloy was preheated to 820°C using a preheating electron gun and held for 12 min. Then, the evaporation electron gun was activated and the beam current adjusted to 0.8 A, and deposition was carried out for 50 min to deposit a NiCoCrAlYHf metallic binder layer on the surface of the pretreated high-temperature alloy. After deposition, the alloy was placed in a vacuum heat treatment furnace at a vacuum level less than 1 × 10⁻⁶. -3 Under the condition of Pa, vacuum annealing at 1100℃ for 2h yields a pretreated high-temperature alloy with a metal bonding layer; the NiCoCrAlYHf target material is composed of the following components by mass percentage: 12% Co, 20% Cr, 10% Al, 0.3% Y, 0.3% Hf, with the balance being Ni. Step 3: Load the pretreated high-temperature alloy with a metallic bonding layer obtained in Step 2 into the furnace and install it on the workpiece rack. Set the rotation speed of the workpiece rack to 15 r / min and evacuate to 2.8 × 10⁻⁶. -2After Pa, the temperature was stabilized for 12 minutes. Then, the preheating electron gun was turned on to preheat the pretreated high-temperature alloy with the metal binder layer to 950°C and held for 12 minutes. Next, oxygen was introduced at a flow rate of 80 sccm to pre-oxidize the metal binder layer for 25 minutes. Then, the evaporation electron gun was turned on and the beam current was adjusted to 0.7A. Deposition was carried out for 135 minutes to deposit a YSZ ceramic underlayer on the surface of the pretreated high-temperature alloy with the metal binder layer, thus obtaining a thermal barrier coating. The YSZ target material is composed of the following composition by mass percentage: 7.8% Y2O3, with the balance being ZrO2.

[0037] Upon testing, the thermal barrier coating prepared in this comparative example was found to contain the following components by mass percentage: 11.6% Co, 19.8% Cr, 9.8% Al, 0.25% Y, 0.27% Hf, with the balance being Ni; the ceramic substrate was found to contain the following components by mass percentage: 7.7% Y₂O₃, with the balance being ZrO₂; the thickness of the metal adhesive layer was 50 μm; and the thickness of the ceramic substrate was 145 μm.

[0038] The multi-element rare earth modified zirconia bilayer thermal barrier coating prepared in Example 1 and the thermal barrier coating prepared in Comparative Example 1 were placed in a muffle furnace and aged at 1400℃ for 100 h in an atmospheric environment. XRD tests were then performed, and the test results are shown below. Figure 5 and Figure 6 As shown, from Figure 5 As can be seen from the XRD pattern, no characteristic diffraction peaks of monoclinic ZrO2 (m-ZrO2) were detected in the multi-element rare earth modified zirconia bilayer thermal barrier coating prepared in Example 1; only stable tetragonal ZrO2 (t / t'-ZrO2) was present, exhibiting excellent high-temperature phase stability. Figure 6 As can be seen from the data, the thermal barrier coating of Comparative Example 1 exhibits m-ZrO2 characteristic diffraction peaks in low-angle XRD, indicating a significant high-temperature phase transition.

[0039] The surface of the multi-element rare earth modified zirconia bilayer thermal barrier coating prepared in Example 1 and the thermal barrier coating prepared in Comparative Example 1 were uniformly coated with CMAS powder (CaO-MgO-Al2O3-SiO2, K powder) at a coating amount of 20 mg / cm², and then placed in an atmospheric environment at 1250℃ for 4 h. The test results are as follows. Figure 7 As shown, Figure 7 The upper image shows the image before corrosion, and the lower image shows the image after corrosion. SYYSZ represents Example 1, and YSZ represents Comparative Example 1. Figure 7 As can be seen from the above, the surface of the multi-element rare earth modified zirconia double-layer thermal barrier coating prepared in Example 1 is intact without peeling or obvious corrosion pits, and has excellent resistance to CMAS corrosion. The thermal barrier coating of Comparative Example 1 shows large-area peeling, severe melting corrosion and cracks, and has obviously failed.

[0040] Example 2 This embodiment includes the following steps: Step 1: Polish the nickel-based single crystal high-temperature alloy DD6 sequentially with 240#, 400# and 800# diamond sandpaper, and then perform ultrasonic degreasing and cleaning to obtain the pretreated high-temperature alloy. Step 2: Load the pretreated high-temperature alloy obtained in Step 1 into the furnace and install it on the workpiece rack. Set the rotation speed of the workpiece rack to 12 r / min and evacuate to 5.3 × 10⁻⁶. -2 After Pa, the temperature was stabilized for 15 min. Then, the preheating electron gun was turned on to preheat the pretreated high-temperature alloy to 850°C and held for 10 min. Subsequently, the evaporation electron gun was turned on and the beam current was adjusted to 0.65 A. Deposition was carried out for 40 min to deposit a NiCoCrAlYHf metal binder layer on the surface of the pretreated high-temperature alloy. After deposition, the alloy was placed in a vacuum heat treatment furnace at a vacuum degree of less than 1×10⁻⁶. -3 Under the condition of Pa, vacuum annealing at 1000℃ for 1h yields a pretreated high-temperature alloy with a metal bonding layer; the NiCoCrAlYHf target material is composed of the following components by mass percentage: 15% Co, 18% Cr, 12% Al, 0.1% Y, 0.5% Hf, with the balance being Ni. Step 3: Load the pretreated high-temperature alloy with a metallic bonding layer obtained in Step 2 into the furnace and install it on the workpiece rack. Set the rotation speed of the workpiece rack to 12 r / min and evacuate to 5.3 × 10⁻⁶. -2 After Pa, the temperature was stabilized for 15 min. Then, the preheating electron gun was turned on to preheat the pretreated high-temperature alloy with the metal binder layer to 900°C and held for 15 min. Next, oxygen was introduced at a flow rate of 50 sccm to pre-oxidize the metal binder layer for 30 min. Then, the evaporation electron gun was turned on and the beam current was adjusted to 0.58 A for 60 min to deposit a YSZ ceramic underlayer on the surface of the pretreated high-temperature alloy with the metal binder layer, thus obtaining a pretreated high-temperature alloy with a ceramic underlayer. The YSZ target material is composed of the following composition by mass percentage: 7.5% Y2O3, with the balance being ZrO2. Step 4: After completing Step 3, maintain the vacuum state inside the furnace, prevent the workpiece from leaving the furnace, maintain the workpiece rack rotation speed at 12 r / min, and simultaneously adjust the evaporation electron gun current corresponding to the YSZ target to 0A and the evaporation electron gun current corresponding to the SYYSZ target to 0.58A. Start the workpiece push to slowly and uniformly move the workpiece from above the YSZ target to above the SYYSZ target. At the same time, adjust the position of the preheating electron gun to above the SYYSZ target to maintain the workpiece temperature at 900℃ and perform continuous evaporation for 60 min to obtain a multi-element rare earth modified zirconia double-layer thermal barrier coating. The SYYSZ target is composed of the following components by mass percentage: 3.9% Sc2O3, 11.3% Yb2O3, 8% Y2O3, with the balance being ZrO2.

[0041] Testing revealed that the metal binder layer of the multi-element rare-earth modified zirconia bilayer thermal barrier coating prepared in this embodiment consists of the following mass percentages: 14.9% Co, 17.8% Cr, 11.7% Al, 0.1% Y, 0.49% Hf, with the balance being Ni; the ceramic substrate consists of the following mass percentages: 7.3% Y₂O₃, with the balance being ZrO₂; and the ceramic surface layer consists of the following mass percentages: 3.9% Sc₂O₃, 11.3% Yb₂O₃, 8%... Y2O3, with the balance being ZrO2, has a metal bonding layer thickness of 40 μm; the ceramic substrate has a thickness of 50 μm; the ceramic surface layer has a thickness of 50 μm; both the ceramic substrate and the ceramic surface layer have typical columnar crystal structures, with continuous transitions between the columnar crystals of the ceramic substrate and the ceramic surface layer without obvious interfaces, and dense, defect-free interlayer bonding; the tilt angle of the columnar crystals of the ceramic surface layer is 3°~8°, and the difference in tilt angle between the columnar crystals of the ceramic substrate and the ceramic surface layer is no greater than 5°.

[0042] Example 3 This embodiment includes the following steps: Step 1: Polish the nickel-based single-crystal high-temperature alloy IC21 sequentially with 240#, 400# and 800# diamond sandpaper, and then perform ultrasonic degreasing and cleaning to obtain the pretreated high-temperature alloy. Step 2: Load the pretreated high-temperature alloy obtained in Step 1 into the furnace and install it on the workpiece rack. Set the rotation speed of the workpiece rack to 10 r / min and evacuate to 1.1 × 10⁻⁶. -2 After Pa, the temperature was stabilized for 10 min. Then, the preheating electron gun was turned on to preheat the pretreated high-temperature alloy to 780°C and held for 15 min. Subsequently, the evaporation electron gun was turned on and the beam current was adjusted to 0.98 A. Deposition was carried out for 80 min to deposit a NiCoCrAlYHf metal binder layer on the surface of the pretreated high-temperature alloy. After deposition, the alloy was placed in a vacuum heat treatment furnace at a vacuum degree of less than 1×10⁻⁶. -3Under the condition of Pa, vacuum annealing at 1050℃ for 1.5h yields a pretreated high-temperature alloy with a metal bonding layer; the NiCoCrAlYHf target material is composed of the following components by mass percentage: 10% Co, 23% Cr, 8% Al, 0.5% Y, 0.2% Hf, with the balance being Ni. Step 3: Load the pretreated high-temperature alloy with a metallic bonding layer obtained in Step 2 into the furnace and install it on the workpiece holder. Set the rotation speed of the workpiece holder to 10 r / min and evacuate to 1.1 × 10⁻⁶. -2 After Pa, the temperature was stabilized for 10 min. Then, the preheating electron gun was turned on to preheat the pretreated high-temperature alloy with the metal binder layer to 1000℃ and held for 10 min. Next, oxygen was introduced at a flow rate of 100 sccm to pre-oxidize the metal binder layer for 20 min. Then, the evaporation electron gun was turned on and the beam current was adjusted to 0.85 A for 80 min to deposit a YSZ ceramic underlayer on the surface of the pretreated high-temperature alloy with the metal binder layer, thus obtaining a pretreated high-temperature alloy with a ceramic underlayer. The YSZ target material is composed of the following composition by mass percentage: 7.9% Y2O3, with the balance being ZrO2. Step 4: After completing Step 3, maintain the vacuum state inside the furnace, do not remove the workpiece from the furnace, maintain the workpiece rack rotation speed at 10 r / min, and simultaneously adjust the evaporation electron gun beam current corresponding to the YSZ target to 0A and the evaporation electron gun beam current corresponding to the SYYSZ target to 0.85A. Start the workpiece push to slowly and uniformly move the workpiece from above the YSZ target to above the SYYSZ target. At the same time, adjust the position of the preheating electron gun to above the SYYSZ target to maintain the workpiece temperature at 1000℃ and perform continuous evaporation for 80 min to obtain a multi-element rare earth modified zirconia double-layer thermal barrier coating. The SYYSZ target is composed of the following components by mass percentage: 4.1% Sc2O3, 11.4% Yb2O3, 7% Y2O3, with the balance being ZrO2.

[0043] Testing revealed that the metal binder layer of the multi-element rare-earth modified zirconia bilayer thermal barrier coating prepared in this embodiment consists of the following mass percentages: 10% Co, 22.8% Cr, 7.9% Al, 0.5% Y, 0.2% Hf, with the balance being Ni; the ceramic substrate consists of the following mass percentages: 7.9% Y₂O₃, with the balance being ZrO₂; and the ceramic surface layer consists of the following mass percentages: 4.1% Sc₂O₃, 11.4% Yb₂O₃, 7%... Y2O3, with the balance being ZrO2, has a metal bonding layer thickness of 70 μm; the ceramic substrate has a thickness of 100 μm; the ceramic surface layer has a thickness of 100 μm; both the ceramic substrate and the ceramic surface layer have typical columnar crystal structures, with continuous transitions between the columnar crystals of the ceramic substrate and the ceramic surface layer without obvious interfaces, and dense interlayer bonding without defects. The tilt angle of the columnar crystals of the ceramic surface layer is 3°~8°, and the difference in tilt angle between the columnar crystals of the ceramic substrate and the ceramic surface layer is no greater than 5°.

[0044] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any way. Any simple modifications, alterations, and equivalent changes made to the above embodiments based on the inventive essence shall still fall within the protection scope of the present invention.

Claims

1. A multi-element rare earth modified zirconium oxide double-layer thermal barrier coating, characterized in that, The coating consists of a metal bonding layer, a ceramic underlayer, and a ceramic surface layer from the inside out. The metal bonding layer is a NiCoCrAlYHf layer, the ceramic underlayer is a YSZ layer, and the YSZ layer is composed of the following mass percentages: 7%~8% Y2O3, with the balance being ZrO2. The ceramic surface layer is a Sc-Yb co-modified YSZ layer, i.e., a SYYSZ layer. The SYYSZ layer is composed of the following mass percentages: 3.9%~4.1% Sc2O3, 11.2%~11.4% Yb2O3, 7%~8% Y2O3, with the balance being ZrO2. The ceramic underlayer and the ceramic surface layer constitute a double-layer ceramic functional layer, forming a multi-element rare earth modified zirconia double-layer thermal barrier coating.

2. The multi-element rare earth modified zirconium oxide double-layer thermal barrier coating according to claim 1, characterized in that, The metal bonding layer, ceramic underlayer, and ceramic surface layer are all prepared by electron beam physical vapor deposition. The metal bonding layer uses a NiCoCrAlYHf target, which is composed of the following mass percentages: 10%~15% Co, 18%~23% Cr, 8%~12% Al, 0.1%~0.5% Y, 0.2%~0.5% Hf, with the balance being Ni. The ceramic underlayer uses a YSZ target, which is composed of the following mass percentages: 7%~8% Y2O3, with the balance being ZrO2. The ceramic surface layer uses a SYYSZ target, which is composed of the following mass percentages: 3.9%~4.1% Sc2O3, 11.2%~11.4% Yb2O3, 7%~8% Y2O3, with the balance being ZrO2.

3. The multi-element rare earth modified zirconium oxide double-layer thermal barrier coating according to claim 1, characterized in that, The thickness of the metal bonding layer is 40μm~70μm; the thickness of the ceramic substrate is 50μm~100μm; the thickness of the ceramic surface layer is 50μm~100μm; the columnar crystals of the ceramic substrate and the ceramic surface layer are continuously transitioned without obvious interface; the tilt angle of the columnar crystals of the ceramic surface layer is 3°~8°; and the difference in tilt angle between the columnar crystals of the ceramic substrate and the ceramic surface layer is not greater than 5°.

4. The multi-element rare earth modified zirconium oxide double-layer thermal barrier coating according to claim 1, characterized in that, The substrate for coating deposition is a high-temperature alloy, including nickel-based single-crystal high-temperature alloys DD5, DD6, or IC21.

5. A method for preparing a multi-element rare earth modified zirconium oxide bilayer thermal barrier coating as described in any one of claims 1 to 4, characterized in that, This method employs electron beam physical vapor deposition to sequentially prepare a metal bonding layer, a ceramic underlayer, and a ceramic surface layer, specifically including the following steps: Step 1: Pre-treat the high-temperature alloy; Step 2: On the surface of the high-temperature alloy that was pretreated in Step 1, a metal bonding layer is prepared by electron beam physical vapor deposition, and then heat-treated in a vacuum heat treatment furnace; Step 3: On the surface of the metal bonding layer after heat treatment in Step 2, a ceramic underlayer is prepared by electron beam physical vapor deposition; Step 4: On the ceramic substrate prepared in Step 3, an electron beam physical vapor deposition is used to prepare a ceramic surface layer, resulting in a multi-element rare earth modified zirconia double thermal barrier coating.

6. The method according to claim 5, characterized in that, The pretreatment described in step one includes sequential polishing with 240#, 400# and 800# diamond sandpaper and ultrasonic degreasing and cleaning.

7. The method according to claim 5, characterized in that, The parameters for electron beam physical vapor deposition in step two are: vacuum level to 1.1 × 10⁻⁶. -2 Pa ~ 5.3 × 10 -2 Pa and hold for 10-15 minutes, then turn on the preheating electron gun, preheat the workpiece to 780-850°C and hold for 10-15 minutes, then turn on the evaporation electron gun and adjust the beam current to 0.65A-0.98A, depositing for 40-80 minutes; the parameters of the heat treatment are: at a vacuum degree less than 1×10 -3 Under the condition of Pa, vacuum anneal at 1000℃~1100℃ for 1h~2h.

8. The method according to claim 5, characterized in that, The parameters for electron beam physical vapor deposition in step three are: vacuum level to 1.1 × 10⁻⁶. -2 Pa ~ 5.3 × 10 -2 Pa and hold for 10-15 minutes, then turn on the preheating electron gun, preheat the workpiece to 900-1000°C and hold for 10-15 minutes, then introduce oxygen at a flow rate of 50-100 sccm for pre-oxidation for 20-30 minutes, then turn on the evaporation electron gun and adjust the beam current to 0.58-0.85 A for deposition for 60-80 minutes.

9. The method according to claim 5, characterized in that, The parameters for electron beam physical vapor deposition in step four are as follows: After step three is completed, the workpiece is not removed from the furnace. At the same time, the evaporation electron gun current corresponding to the YSZ target is adjusted to 0A and the evaporation electron gun current corresponding to the SYYSZ target is adjusted to 0.58A~0.85A. The workpiece is pushed to move the workpiece slowly and uniformly from above the YSZ target to above the SYYSZ target. At the same time, the position of the preheating electron gun is adjusted to above the SYYSZ target to keep the workpiece temperature at 900℃~1000℃ for continuous evaporation and deposition for 60min~80min.

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