A Ytterbium-Doped Gadolinate Thermal Barrier Coated Ceramic Material, Its Preparation Method and Application

Abstract

This invention discloses a gadolinium tantalate thermal barrier coating ceramic material doped with ytterbium, its preparation method, and its application. First, Yb₂O₃, Gd₂O₃, and Ta₂O₅ powders are mixed in a specific ratio. Then, anhydrous ethanol and ZrO₂ ball milling beads are added, and the mixture is ball-milled until homogeneous. The dried sample is placed in a crucible and heated in a muffle furnace for reaction. After the reaction, the mixture is cooled to room temperature with the furnace. The resulting product is then ground and passed through a 150-mesh sieve to obtain (Gd₂O₃)-doped gadolinium tantalate thermal barrier coating ceramic material. 1‑x Yb x TaO4 powder, wherein 0.2 ≤ x ≤ 0.5, was used to obtain a dense ceramic material by dry pressing. (Gd 1‑ x Yb x TaO4 has higher hardness and lower elastic modulus than GdTaO4, and its resistance to CMAS corrosion is also improved, making it suitable for preparing thermal barrier coatings for aero-engines.

Description

Technical Field

[0001] This invention belongs to the technical field of thermal barrier coating ceramic materials for aero-engines, specifically relating to a gadolinium tantalate thermal barrier coating ceramic material doped with ytterbium, its preparation method, and its application. Background Technology

[0002] During long-term operation in the high-temperature, high-pressure, and harsh turbine environments of high-temperature alloy components in aero-engines, the thermal barrier coating ceramic materials on their surfaces must meet a series of stringent requirements. First, the material should possess low thermal conductivity to ensure excellent thermal insulation performance, thereby effectively protecting the substrate material from high temperatures. Second, the coating must have good mechanical properties to enhance its ability to withstand stress and strain, thus preventing coating failure caused by stress concentration. Furthermore, the coating should exhibit excellent resistance to CMAS corrosion to significantly extend the service life of the thermal barrier coating and ensure its reliability and durability under extreme operating conditions.

[0003] Some scholars have proposed that rare-earth tantalate ceramics exhibit a similar ferroelastic toughening effect to zirconia-toughened ceramics (YSZ). Preliminary calculations show that these ceramics have extremely low thermal conductivity, a characteristic that contributes to excellent thermal insulation performance, thereby significantly increasing their operating temperature. Furthermore, tantalate ceramics, like YSZ, possess similar ferroelastic phase transition characteristics. This makes rare-earth tantalate ceramics a potential alternative to YSZ ceramics, and they are expected to become an ideal choice for next-generation thermal barrier coating ceramics.

[0004] Gadolinium tantalate, a rare-earth tantalate, possesses low thermal conductivity and good fracture toughness. To enhance its physical properties and resistance to CMAS corrosion, ion doping modification is necessary. Ytterbium, a member of the lanthanides, exhibits similar properties, but its application in thermal barrier coatings for aero-engines has not yet been reported. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a gadolinium tantalate thermal barrier coating ceramic material doped with ytterbium, its preparation method, and its application. This method employs a solid-state reaction method to prepare (Gd... 1-x Yb x TaO4 has advantages such as simple reaction principle, low synthesis temperature, and small particle size of the obtained powder. The gadolinium tantalate thermal barrier coating ceramic material doped with ytterbium prepared in this invention can not only improve the mechanical and thermophysical properties of thermal barrier coating materials by using rare earth elements with small ionic radii, but also reduce the chemical affinity between CMAS media and thermal barrier coating materials. It can be used to prepare thermal barrier coatings for aero-engines to improve the physical properties and CMAS corrosion resistance of tantalates.

[0006] To address the problems in the existing technology, the technical solution adopted by this invention is as follows:

[0007] A method for preparing a ytterbium-doped gadolinium tantalate thermal barrier coating ceramic material involves mixing Yb₂O₃ powder, Gd₂O₃ powder, and Ta₂O₅ powder in a specific ratio, then adding anhydrous ethanol and ZrO₂ ball milling beads for ball milling to ensure uniform mixing. After drying, the mixture is placed in a muffle furnace for heating and reaction, and then cooled to room temperature with the furnace. The mixture is then subjected to a series of processes including grinding, sieving, PVA granulation, dry pressing, debinding, and high-temperature sintering to obtain (Gd₂O₃)-doped gadolinium tantalate thermal barrier coating ceramic material. 1-x Yb x TaO4 powder, wherein 0.2≤x≤0.5.

[0008] The preparation method of the above-mentioned ytterbium-doped gadolinium tantalate thermal barrier coating ceramic material includes the following steps:

[0009] Step 1: Calculate the amount of oxides to be used based on the molar ratio of the elements. Weigh out Yb2O3 powder, Gd2O3 powder and Ta2O5 powder respectively, pour these three powders into a ball mill jar, and add anhydrous ethanol to make the mixed powder fully dissolved.

[0010] Step 2: Place the ball mill jar into a planetary ball mill and ball mill to obtain a homogeneous mixed solution;

[0011] Step 3: The mixed solution is dried and subjected to a high-temperature solid-state reaction to obtain ceramic powder;

[0012] Step 4: The ceramic powder obtained in Step 3 is ground, sieved, granulated with PVA, dry-pressed, debinded, and sintered at high temperature to obtain a product with the chemical formula (Gd). 1-x Yb x Ytterbium-doped gadolinium tantalate thermal barrier coating material of TaO4.

[0013] As an improvement, the purity of the Yb2O3 powder, Gd2O3 powder and Ta2O5 powder mentioned in step 1 is all ≥99.99%.

[0014] As an improvement, the ball milling speed in step 2 is 300-500 r / min, and the time is 12-24 h.

[0015] As an improvement, the drying temperature in step 3 is 70-90℃ and the time is 8-15h, and the temperature of the high-temperature solid-phase reaction is 1600-1650℃ and the time is 5-10h.

[0016] As an improvement, in step 4, the sieve mesh size is 150-300 mesh, the first pressure for dry pressing is 180-200 MPa for 60-70 s, the second pressure is 160-170 MPa for 30-35 s, the discharge temperature is 500-550℃ for 2-3 h, and the sintering temperature is 1500-1600℃ for 5-6 h.

[0017] The crystal structure of the phase of the ytterbium-doped gadolinium tantalate thermal barrier coating ceramic material prepared by the above preparation method is a monoclinic phase.

[0018] The above-mentioned gadolinium tantalate thermal barrier coating ceramic material doped with ytterbium is used in the preparation of thermal barrier coatings on the surface of hot-end components of aero-engines.

[0019] Beneficial effects:

[0020] Compared with existing technologies, this invention provides a gadolinium tantalate thermal barrier coating ceramic material doped with ytterbium, its preparation method, and its application. A novel thermal barrier coating material (Gd) is obtained through dry pressing and high-temperature sintering. 1-x Yb x TaO4 has a denser crystal structure and better phase stability than GdTaO4, resulting in higher hardness, lower elastic modulus, and resistance to CMAS corrosion. This will enhance the service capability of thermal barrier coatings in harsh turbine operating environments and can be used for thermal barrier coatings on the surface of hot-end components of aerospace engines. Attached Figure Description

[0021] Figure 1 The (Gd) prepared in Examples 1-3 and Comparative Example 1 of this invention 1-x Yb x XRD pattern of TaO4 ceramic material;

[0022] Figure 2 The (Gd) prepared in Examples 1-3 and Comparative Example 1 1-x Yb x Microscopic morphology diagrams of TaO4 ceramic materials: (A) Example 1; (B) Example 2; (C) Example 3; (D) Comparative Example 1;

[0023] Figure 3 The cross-sectional morphology of Example 1 after CMAS etching is as follows: (A) Surface morphology after 1 hour of etching; (B) Surface morphology after 5 hours of etching; (C) Surface morphology after 10 hours of etching.

[0024] Figure 4 The cross-sectional morphology of Example 2 after CMAS etching is as follows: (A) Surface morphology after 1 hour of etching; (B) Surface morphology after 5 hours of etching; (C) Surface morphology after 10 hours of etching.

[0025] Figure 5 The cross-sectional morphology of Example 3 after CMAS etching is as follows: (A) Surface morphology after 1 hour of etching; (B) Surface morphology after 5 hours of etching; (C) Surface morphology after 10 hours of etching.

[0026] Figure 6 The cross-sectional morphology of Comparative Example 1 after CMAS etching is as follows: (A) Surface morphology after 1 hour of etching; (B) Surface morphology after 5 hours of etching; (C) Surface morphology after 10 hours of etching.

[0027] Figure 7 (Gd) prepared in Examples 1-3 1-x Yb x Comparison of hardness and elastic modulus between TaO4 and GdTaO4 prepared in Comparative Example 1. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this application.

[0029] A method for preparing a ytterbium-doped gadolinium tantalate thermal barrier coating ceramic material involves mixing Yb₂O₃ powder, Gd₂O₃ powder, and Ta₂O₅ powder in a specific ratio, then adding anhydrous ethanol and ZrO₂ ball milling beads for ball milling to ensure uniform mixing. After drying, the mixture is placed in a muffle furnace for heating and reaction, and then cooled to room temperature with the furnace. The mixture is then subjected to a series of processes including grinding, sieving, PVA granulation, dry pressing, debinding, and high-temperature sintering to obtain (Gd₂O₃)-doped gadolinium tantalate thermal barrier coating ceramic material. 1-x Yb x TaO4 powder, wherein the value of x ranges from 0.2 to 0.5.

[0030] The preparation method of the above-mentioned ytterbium-doped gadolinium tantalate thermal barrier coating ceramic material includes the following steps:

[0031] Step 1: Calculate the amount of oxides to be used based on the molar ratio of the elements. Weigh out Yb2O3 powder, Gd2O3 powder and Ta2O5 powder respectively, pour these three powders into a ball mill jar, and add anhydrous ethanol to make the mixed powder fully dissolved.

[0032] Step 2: Place the ball mill jar into a planetary ball mill and ball mill to obtain a homogeneous mixed solution;

[0033] Step 3: The mixed solution is dried and subjected to a high-temperature solid-state reaction to obtain ceramic powder;

[0034] Step 4: The ceramic powder obtained in Step 3 is ground, sieved, granulated with PVA, dry-pressed, debinded, and sintered at high temperature to obtain a product with the chemical formula (Gd). 1-x Yb x Ytterbium-doped gadolinium tantalate thermal barrier coating material of TaO4.

[0035] As an improvement, the purity of the Yb2O3 powder, Gd2O3 powder and Ta2O5 powder mentioned in step 1 is all ≥99.99%.

[0036] As an improvement, the ball milling speed in step 2 is 300-500 r / min, and the time is 12-24 h.

[0037] As an improvement, the drying temperature in step 3 is 70-90℃ and the time is 8-15h, and the temperature of the high-temperature solid-phase reaction is 1600-1650℃ and the time is 5-10h.

[0038] As an improvement, in step 4, the sieve mesh size is 150-300 mesh, the first pressure for dry pressing is 180-200 MPa for 60-70 s, the second pressure is 160-170 MPa for 30-35 s, the discharge temperature is 500-550℃ for 2-3 h, and the sintering temperature is 1500-1600℃ for 5-6 h.

[0039] The gadolinium tantalate thermal barrier coating ceramic material doped with ytterbium prepared by the above method has better phase stability during corrosion, and the thermal barrier coating has CMAS corrosion resistance.

[0040] The above-mentioned gadolinium tantalate thermal barrier coating ceramic material doped with ytterbium is used in the preparation of thermal barrier coatings on the surface of hot-end components of aero-engines.

[0041] Example 1

[0042] (1) Calculate the amount of oxides based on the molar ratio of n(Gd):n(Yb):n(Ta) = 0.8:0.2:1. Then weigh the required amount of Yb2O3 powder, Gd2O3 powder and Ta2O5 powder, pour these three powders into the ball mill jar in sequence, and then pour in anhydrous ethanol to dissolve the powder.

[0043] (2) Place the ball milling jar into a planetary ball mill and ball mill to obtain a uniform mixed solution. The ball milling time is 16 hours and the ball milling speed is 400 r / min.

[0044] (3) The mixture is dried and placed in a muffle furnace for high-temperature solid-phase reaction to obtain the desired ceramic powder. The drying temperature is 80℃ and the time is 10h. The high-temperature solid-phase reaction temperature is 1600℃ and the time is 8h.

[0045] (4) The obtained ceramic powder is ground, sieved, granulated with PVA, and dry-pressed. Then, it is debinded and sintered in a muffle furnace to obtain the desired (Gd) 0.8 Yb 0.2 TaO4 ceramic blocks.

[0046] The PVA concentration is 5% to enhance the plasticity of the ceramic powder and achieve granulation. The sieve mesh size is 150 mesh. The first pressing is 200 MPa for 60 seconds, the second pressing is 160 MPa for 30 seconds, the debinding temperature is 550℃ for 2 hours, and the sintering temperature is 1550℃ for 8 hours.

[0047] Example 2

[0048] (1) Calculate the amount of oxides based on the molar ratio of n(Gd):n(Yb):n(Ta) = 0.6:0.4:1. Then weigh the required amount of Yb2O3 powder, Gd2O3 powder and Ta2O5 powder, pour these three powders into the ball mill jar in sequence, and then pour in anhydrous ethanol to dissolve the powder.

[0049] (2) Place the ball milling jar into a planetary ball mill and ball mill to obtain a uniform mixed solution. The ball milling time is 12 hours and the ball milling speed is 450 r / min.

[0050] (3) The mixture is dried and placed in a muffle furnace for high-temperature solid-phase reaction to obtain the desired ceramic powder; the drying temperature is 78℃ and the time is 12h, the high-temperature solid-phase reaction temperature is 1600℃ and the time is 6h.

[0051] (4) The obtained ceramic powder is ground, sieved, granulated with PVA, and dry-pressed. Then, it is debinded and sintered in a muffle furnace to obtain the desired (Gd) 0.6 Yb 0.4 TaO4 ceramic blocks.

[0052] The PVA concentration is 5% to enhance the plasticity of the ceramic powder and achieve a granulation effect. The sieve mesh size is 200 mesh. The first pressing pressure is 200 MPa for 60 seconds, the second pressing pressure is 160 MPa for 30 seconds, the debinding temperature is 550℃ for 2 hours, and the sintering temperature is 1580℃ for 8 hours.

[0053] Example 3

[0054] (1) Calculate the amount of oxides based on the molar ratio of n(Gd):n(Yb):n(Ta) = 0.5:0.5:1. Then weigh the required amount of Yb2O3 powder, Gd2O3 powder and Ta2O5 powder, pour these three powders into the ball mill jar in sequence, and then pour in anhydrous ethanol to dissolve the powder.

[0055] (2) Place the ball milling jar into a planetary ball mill and ball mill to obtain a uniform mixed solution. The ball milling time is 8 hours and the ball milling speed is 500 rpm.

[0056] (3) The mixture is dried and placed in a muffle furnace for high-temperature solid-phase reaction to obtain the desired ceramic powder; the drying temperature is 80℃ and the time is 12h, the high-temperature solid-phase reaction temperature is 1600℃ and the time is 7h.

[0057] (4) The obtained ceramic powder is ground, sieved, granulated with PVA, and dry-pressed. Then, it is debinded and sintered in a muffle furnace to obtain the desired (Gd) 0.5 Yb 0.5 TaO4 ceramic blocks.

[0058] The PVA concentration is 5% to enhance the plasticity of the ceramic powder and achieve granulation. The sieve mesh size is 150 mesh. The first pressing is 200 MPa for 60 seconds, the second pressing is 160 MPa for 30 seconds, the debinding temperature is 550℃ for 2 hours, and the sintering temperature is 1550℃ for 9 hours.

[0059] Comparative Example 1

[0060] (1) Calculate the amount of oxides based on the molar ratio of n(Gd):n(Ta) = 1:1, then weigh the required amount of Gd2O3 powder and Ta2O5 powder, pour these three powders into the ball mill jar in sequence, and then pour in anhydrous ethanol to dissolve the powder.

[0061] (2) Place the ball milling jar into a planetary ball mill and ball mill to obtain a uniform mixed solution. The ball milling time is 18 hours and the ball milling speed is 400 rpm.

[0062] (3) The mixture is dried and placed in a muffle furnace for high-temperature solid-phase reaction to obtain the desired ceramic powder; the drying temperature is 75℃ and the time is 14h, the high-temperature solid-phase reaction temperature is 1600℃ and the time is 10h.

[0063] (4) The obtained ceramic powder is ground, sieved, granulated by PVA and dry pressed, and then debinded and sintered in a muffle furnace to obtain the required GdTaO4 ceramic block.

[0064] The PVA concentration is 5% to enhance the plasticity of the ceramic powder and achieve granulation. The sieve mesh size is 150 mesh. The first pressing is 200 MPa for 60 seconds, the second pressing is 160 MPa for 30 seconds, the debinding temperature is 550℃ for 2 hours, and the sintering temperature is 1580℃ for 8 hours.

[0065] Performance testing

[0066] Figure 1 The (Gd) prepared in Examples 1-3 and Comparative Example 1 of this invention 1-x Yb x XRD pattern of TaO4 ceramic material. (From...) Figure 1 It can be seen that the materials (Gd) synthesized by solid-state reaction method in Examples 1-3 are... 1-x Yb x TaO4 is based on GdTaO4, and Yb doping does not alter the structure of GdTaO4. Furthermore, the surface morphology of Examples 1-3 shows that the ceramic material has a dense surface and low porosity. Figure 2 As shown.

[0067] CMAS corrosion test: The surfaces of the ytterbium-doped gadolinium tantalate thermal barrier coated ceramic materials prepared in Examples 1-3 and the material prepared in Comparative Example 1 were polished and subjected to a corrosion test at 30 mg / cm³. 2 A uniformly dense 33CaO-9MgO-7Al2O3-45SiO2 (CMAS) powder was coated onto the sample surface. The samples were then placed in a muffle furnace heated to 1300℃ and heated for 1 h, 5 h, and 10 h, respectively. The corrosion of the samples by CAMS was observed using SEM. The results are as follows: Figure 3-6 As shown.

[0068] from Figure 3-6 The cross-sectional morphology shows that, among the four thermal barrier coating materials mentioned above, the top layer is a CMAS fused glass layer, the middle layer is an interreactive layer, and the bottom layer is an uncorroded ceramic layer. Examples 1-3 (Gd...) 1-x Yb xBoth TaO4 ceramics and GdTaO4 ceramics of Comparative Example 1 showed residual CMAS on their surfaces after 1 hour of CMAS corrosion, demonstrating that all four thermal barrier coating materials possessed a certain degree of resistance to CMAS corrosion in the early stages of corrosion. As the corrosion time increased, the doped ceramics showed better corrosion resistance than the undoped ones. A comparison between Example 1 and Comparative Example 1 clearly shows that, under the same CMAS corrosion time, Yb doping reduces the thickness of the interreaction layer, indicating better corrosion resistance. This is mainly because Yb doping causes a slight contraction of the GdTaO4 lattice (Yb has a smaller ionic radius than Gd), resulting in a denser lattice structure. This micro-adjustment reduces the wettability of the CMAS melt, decreasing the erosive contact between the melt and the coating. However, a comparison between Example 3 and Comparative Example 1 shows that more Yb doping is not necessarily better; excessive doping does not effectively improve its corrosion resistance.

[0069] Depend on Figure 7 It can be seen that (Gd) in Examples 1-3 1-x Yb x Compared to the GdTaO4 ceramic in Comparative Example 1, TaO4 ceramic exhibits higher hardness and lower elastic modulus. This is beneficial for enhancing the strain tolerance and resistance to particle erosion of the coating material.

[0070] In summary, the ytterbium-doped gadolinium tantalate thermal barrier coating material of the present invention has superior physical properties and CMAS corrosion resistance compared to the gadolinium tantalate thermal barrier coating material, and is expected to be applied in the field of thermal barrier coatings for next-generation high thrust-to-weight ratio aero-engines.

[0071] The present invention and its embodiments have been described above illustratively. This description is not restrictive, and the figures shown are only one embodiment of the present invention; the actual structure is not limited thereto. Therefore, if those skilled in the art are inspired by this description and design similar structures and embodiments without departing from the spirit of the present invention, such designs should fall within the protection scope of the present invention.

Claims

1. A method for preparing a gadolinium tantalate thermal barrier coating ceramic material doped with ytterbium, characterized in that, Yb₂O₃ powder, Gd₂O₃ powder, and Ta₂O₅ powder were mixed in a certain proportion, and then anhydrous ethanol and ZrO₂ ball milling beads were added for ball milling to ensure uniform mixing. After drying, the mixture was placed in a muffle furnace for heating and reaction, and cooled to room temperature with the furnace. The mixture was then subjected to grinding, sieving, PVA granulation, dry pressing, debinding, and high-temperature sintering to obtain (Gd₂O₃) powder. 1-x Yb x The ytterbium-doped gadolinium tantalate thermal barrier coating material of TaO4, wherein 0.2 ≤ x ≤ 0.5, specifically includes the following steps: Step 1: Calculate the amount of oxides to be used based on the molar ratio of the elements. Weigh out Yb2O3 powder, Gd2O3 powder and Ta2O5 powder respectively, pour these three powders into a ball mill jar, and add anhydrous ethanol to make the mixed powder fully dissolved. Step 2: Place the ball mill jar into a planetary ball mill and ball mill to obtain a homogeneous mixed solution; Step 3: The mixed solution is dried at 70~90℃ for 8~15h and subjected to high-temperature solid-state reaction at 1600~1650℃ for 5~10h to obtain ceramic powder; Step 4: The ceramic powder obtained in Step 3 is ground, sieved, granulated with PVA, dry-pressed, debinded, and sintered at high temperature to obtain the product with the chemical formula (Gd). 1-x Yb x The ytterbium-doped gadolinium tantalate thermal barrier coating material of TaO4 is prepared by sieving with a mesh size of 150-300 mesh, dry pressing with a first pressure of 180-200 MPa for 60-70 s, a second pressure of 160-170 MPa for 30-35 s, a debinding temperature of 500-550℃ for 2-3 h, and a sintering temperature of 1500-1600℃ for 5-6 h.

2. The method for preparing a gadolinium tantalate thermal barrier coating ceramic material doped with ytterbium according to claim 1, characterized in that, The purity of the Yb2O3 powder, Gd2O3 powder and Ta2O5 powder mentioned in step 1 is ≥99.99%.

3. The method for preparing a gadolinium tantalate thermal barrier coating ceramic material doped with ytterbium according to claim 1, characterized in that, In step 2, the ball milling speed is 300~500 r / min, and the time is 12~24 h.

4. A gadolinium tantalate thermal barrier coating ceramic material doped with ytterbium prepared by any one of the preparation methods in claims 1-3, characterized in that, The crystal structure of the phase of the ytterbium-doped gadolinium tantalate thermal barrier coating ceramic material is a monoclinic phase.

5. The application of the gadolinium tantalate thermal barrier coating ceramic material doped with ytterbium as described in claim 4 in the preparation of thermal barrier coatings on the surface of hot-end components of aero-engines.

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