Scandium-doped gadolinium tantalate thermal barrier coating ceramic material, and preparation method and application thereof

Abstract

This invention provides a method for preparing a scandium-doped gadolinium tantalate thermal barrier coating ceramic material and its application. The chemical formula of the thermal barrier coating ceramic material of this invention is (Gd... 1‑x Sc x TaO4, where n(Gd):n(Sc):n(Ta) = 1 - x:x:1, and the value of x ranges from 0.2 to 0.4; the thermal barrier coating ceramic material is synthesized from Gd2O3 powder, Sc2O3 powder, and Ta2O5 powder by a high-temperature solid-state reaction method, and the purity of Gd2O3 powder, Sc2O3 powder, and Ta2O5 powder is ≥99.9%. This invention uses scandium-doped gadolinium tantalate. Scandium, as a member of the lanthanide group, has properties similar to those of the lanthanides. Furthermore, Sc... 3+ With Gd 3+ Significant differences exist in both ionic radius and ionic mass, which can effectively induce lattice distortion and reduce thermal conductivity.

Description

Technical Field

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

[0002] Thermal barrier coating technology has become the most widely used high-temperature protection method for the surface of high-temperature alloy components. However, as aero-engines develop towards higher thrust-to-weight ratios and lower fuel consumption, the temperature at the turbine inlet is constantly increasing. Currently, the commonly used thermal barrier material is yttrium-stabilized zirconia (6%-8% YSZ). However, at temperatures above 1200℃, YSZ materials are prone to phase transformation, leading to volume expansion and causing coating material detachment and failure, which greatly limits the operating temperature range of yttrium-stabilized zirconia materials.

[0003] Among numerous potential thermal barrier coating materials, rare earth tantalates (RETaO4) have attracted widespread research and attention due to their excellent high-temperature phase stability, low thermal conductivity, and high melting point. The low thermal conductivity is beneficial for providing superior thermal insulation, thereby increasing the operating temperature. Therefore, rare earth tantalate ceramic materials are expected to replace YSZ ceramics as the next generation of thermal barrier coating ceramic materials.

[0004] Gadolinium tantalate, as a rare earth tantalate, requires ion doping modification to achieve lower thermal conductivity and better physical properties. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a scandium-doped gadolinium tantalate thermal barrier coating ceramic material, its preparation method, and its application. This invention uses a solid-state reaction method to prepare (Gd... 1-x Sc x TaO4 has the advantages of simple reaction principle, low synthesis temperature, and the resulting powder has low thermal conductivity and small particle size.

[0006] To achieve the above technical objectives, the technical solution adopted in the embodiments of the present invention is as follows:

[0007] In a first aspect, embodiments of the present invention provide a scandium-doped gadolinium tantalate thermal barrier coating ceramic material, wherein the chemical formula of the thermal barrier coating ceramic material is (Gd... 1-x Sc x TaO4, where n(Gd):n(Sc):n(Ta) = 1 - x:x:1, and the value of x ranges from 0.2 to 0.4.

[0008] Furthermore, the thermal barrier coating ceramic material is synthesized from Gd2O3 powder, Sc2O3 powder and Ta2O5 powder by a high-temperature solid-state reaction method, and the purity of the Gd2O3 powder, Sc2O3 powder and Ta2O5 powder is ≥99.9%.

[0009] In a second aspect, embodiments of the present invention provide a method for preparing the scandium-doped gadolinium tantalate thermal barrier coating ceramic material as described in the first aspect, comprising the following steps:

[0010] (1) Calculate the amount of the corresponding oxide according to the molar ratio of the metal elements in the thermal barrier coating ceramic material, weigh the corresponding amount of Gd2O3 powder, Sc2O3 powder and Ta2O5 powder, and pour these three powders into the ball mill jar in sequence, and then add anhydrous ethanol to the ball mill jar.

[0011] (2) Place the ball mill jar into a planetary ball mill and ball mill to obtain a uniform mixed slurry;

[0012] (3) The mixed slurry is dried and subjected to a high-temperature solid-phase reaction to obtain ceramic powder;

[0013] (4) The powder obtained in step (3) is ground, sieved, PVA granulated, dry-pressed, debinded, and sintered at high temperature to obtain a product with the chemical formula (Gd). 1-x Sc x Scandium-doped gadolinium tantalate thermal barrier coating ceramic material of TaO4.

[0014] Furthermore, in step (2), the ball milling speed is 350-450 rpm and the time is 12-24 h.

[0015] Furthermore, in step (3), the drying temperature is 70-90℃ and the time is 10-20h, and the high-temperature solid-phase reaction temperature is 1500-1600℃ and the time is 6-10h.

[0016] Furthermore, in step (4), the sieve mesh size is 150-300 mesh, the first pressure of dry pressing is 180-200 MPa for 60-70 s, the second pressure is 160-170 MPa for 30-35 s, the glue discharge temperature is 500-550℃ for 2-3 h, and the sintering temperature is 1450-1500℃ for 5-6 h.

[0017] Thirdly, embodiments of the present invention provide the ceramic material described in the first aspect for preparing a thermal barrier coating on the surface of aero-engine hot-end components.

[0018] The beneficial effects of the technical solution provided by the embodiments of the present invention are as follows:

[0019] This invention employs scandium-doped gadolinium tantalate. Scandium, as a member of the lanthanide group, possesses properties similar to those of the lanthanides. Furthermore, Sc... 3+ With Gd 3+ Significant differences exist in both ionic radius and ionic mass, which can effectively induce lattice distortion and reduce thermal conductivity.

[0020] This invention provides a scandium-doped gadolinium tantalate thermal barrier coating ceramic material obtained through dry pressing and high-temperature sintering. This material exhibits a thermal conductivity of <1.95 W / (m·K) at 900℃, effectively reducing heat transfer. The material's preparation process is reliable, its performance is stable, and it is suitable for large-scale mass production, showing great promise for application in the thermal insulation and protection of hot-end components in gas turbines, aero engines, and other similar applications. Attached Figure Description

[0021] Figure 1 This is a flowchart illustrating the preparation process of the scandium-doped gadolinium tantalate thermal barrier coating ceramic material of this invention.

[0022] Figure 2 (Gd) prepared in Example 1 of this invention 0.8 Sc 0.2 XRD pattern of TaO4.

[0023] Figure 3 (Gd) prepared in Example 1 of this invention 0.8 Sc 0.2 )Morphological diagram of TaO4.

[0024] Figure 4 (Gd) prepared in Examples 1-2 of this invention 1-x Sc x Comparison of thermal conductivity between TaO4 and GdTaO4 prepared in Comparative Example 1. Detailed Implementation

[0025] A scandium-doped gadolinium tantalate thermal barrier coating ceramic material, wherein the chemical formula of the thermal barrier coating ceramic material is (Gd 1-x Sc x TaO4, where n(Gd):n(Sc):n(Ta) = 1 - x:x:1, and the value of x ranges from 0.2 to 0.4.

[0026] like Figure 1 As shown, the present invention provides a method for preparing a scandium-doped gadolinium tantalate thermal barrier coating ceramic material. The thermal barrier coating ceramic material is synthesized from Gd2O3 powder, Sc2O3 powder and Ta2O5 powder by a high-temperature solid-state reaction method, and a dense ceramic block is obtained by dry pressing and high-temperature sintering. The purity of Gd2O3 powder, Sc2O3 powder and Ta2O5 powder is ≥99.9%.

[0027] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0028] Example 1

[0029] like Figure 1 As shown, a method for preparing a scandium-doped gadolinium tantalate thermal barrier coating ceramic material includes the following steps:

[0030] (1) Calculate the amount of oxides according to the molar ratio of n(Gd):n(Sc):n(Ta)=0.8:0.2:1, then weigh the required amount of Sc2O3 powder, Gd2O3 powder and Ta2O5 powder, pour these three powders into the ball mill jar in sequence, and then pour anhydrous ethanol into the ball mill jar.

[0031] (2) Place the ball milling jar into a planetary ball mill and ball mill to obtain a uniform mixed slurry. The ball milling time is 12 hours and the ball milling speed is 400 rpm.

[0032] (3) The mixed slurry was dried at 80°C for 10 hours. The dried mixture was then placed in a muffle furnace for a high-temperature solid-phase reaction to obtain the desired ceramic powder. The high-temperature solid-phase reaction temperature was 1600°C and the time was 8 hours.

[0033] (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 desired (Gd) 0.8 Sc 0.2 TaO4 ceramic blocks.

[0034] The PVA concentration is 5%, and it is mixed with the ceramic powder at 8% of the ceramic powder mass to enhance the plasticity of the ceramic powder and achieve granulation. The sieve mesh size is 150 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 1500℃ for 5 hours.

[0035] Example 2

[0036] like Figure 1 As shown, a method for preparing a scandium-doped gadolinium tantalate thermal barrier coating ceramic material includes the following steps:

[0037] (1) Calculate the amount of oxides according to the molar ratio of n(Gd):n(Sc):n(Ta)=0.6:0.4:1, then weigh the required amount of Sc2O3 powder, Gd2O3 powder and Ta2O5 powder, pour these three powders into the ball mill jar in sequence, and then pour anhydrous ethanol into the ball mill jar.

[0038] (2) Place the ball milling jar into a planetary ball mill and ball mill to obtain a uniform mixed slurry. The ball milling time is 12 hours and the ball milling speed is 400 rpm.

[0039] (3) The mixed slurry was dried at 80°C for 10 hours. The dried mixture was then placed in a muffle furnace for a high-temperature solid-phase reaction to obtain the desired ceramic powder. The high-temperature solid-phase reaction temperature was 1600°C and the time was 8 hours.

[0040] (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 desired (Gd) 0.6 Sc 0.4 TaO4 ceramic blocks.

[0041] The PVA concentration is 5%, and it is mixed with the ceramic powder at 8% of the ceramic powder mass to enhance the plasticity of the ceramic powder and achieve granulation. The sieve mesh size is 150 mesh. The first pressing pressure is 200 MPa for 60 s, the second pressing pressure is 160 MPa for 30 s, the debinding temperature is 550℃ for 2 h, and the sintering temperature is 1500℃ for 5 h.

[0042] Comparative Example 1

[0043] A method for preparing a gadolinium tantalate thermal barrier coated ceramic material includes the following steps:

[0044] (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 anhydrous ethanol into the ball mill jar.

[0045] (2) Place the ball milling jar into a planetary ball mill and ball mill to obtain a uniform mixed slurry. The ball milling time is 12 hours and the ball milling speed is 400 rpm.

[0046] (3) The mixed slurry is dried and then 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.

[0047] (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.

[0048] The PVA concentration is 5%, and it is mixed with the ceramic powder at 8% of the ceramic powder mass to enhance the plasticity of the ceramic powder and achieve granulation. The sieve mesh size is 150 mesh. The first pressing pressure is 200 MPa for 60 s, the second pressing pressure is 160 MPa for 30 s, the debinding temperature is 550℃ for 2 h, and the sintering temperature is 1500℃ for 5 h.

[0049] Performance testing

[0050] Figure 2 The (Gd) prepared in Example 1 of this invention 0.8 Sc 0.2 XRD pattern of TaO4 ceramic material. (From...) Figure 2 It can be seen that the material (Gd) synthesized by solid-state reaction method in Example 1 is... 0.8 Sc 0.2 TaO4 is based on GdTaO4, and Sc doping does not alter the structure of GdTaO4. Furthermore, as can be seen from the surface morphology of Example 1, the ceramic material has a dense surface and low porosity. Figure 3 As shown.

[0051] Depend on Figure 4 It can be seen that the thermal conductivity of the material in Example 1 is 1.42-3.5 W / (m·K), the thermal conductivity of the material in Example 2 is 1.34-3.3 W / (m·K), and the thermal conductivity of the comparative example 1GdTaO4 is 1.53-4.1 W / (m·K), indicating that the Sc-doped material has lower thermal conductivity.

[0052] Finally, it should be noted that the above specific embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to examples, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method of producing a scandium-doped gadolinium tantalate thermal barrier coating ceramic material, characterized in that, Includes the following steps: (1) Calculate the amount of the corresponding oxide according to the molar ratio of the metal elements in the thermal barrier coating ceramic material, weigh the corresponding amount of Gd2O3 powder, Sc2O3 powder and Ta2O5 powder, and pour these three powders into the ball mill jar in sequence, and then add anhydrous ethanol to the ball mill jar. (2) Place the ball mill jar into a planetary ball mill and ball mill to obtain a uniform mixed slurry; (3) The mixed slurry is dried and subjected to a high-temperature solid-phase reaction to obtain ceramic powder; (4) The powder obtained in step (3) is ground, sieved, PVA granulated, dry-pressed, debinded, and sintered at high temperature to obtain a product with the chemical formula (Gd). 1-x Sc x A scandium-doped gadolinium tantalate thermal barrier coating ceramic material of TaO4, wherein n(Gd):n(Sc):n(Ta) = 1-x:x:1, and the value of x ranges from 0.2 to 0.4; In step (3), the high-temperature solid-phase reaction temperature is 1500-1600℃ and the time is 6-10h; In step (4), the first pressure applied during dry pressing is 180-200 MPa for 60-70 s, the second pressure applied is 160-170 MPa for 30-35 s, the temperature for debinding is 500-550 ℃ for 2-3 h, and the high-temperature sintering temperature is 1450-1500 ℃ for 5-6 h.

2. The method of claim 1, wherein the scandium-doped gadolinium tantalate thermal barrier coating ceramic material is prepared by the steps of: The purity of the Gd2O3 powder, Sc2O3 powder and Ta2O5 powder is ≥99.9%.

3. The method for preparing scandium-doped gadolinium tantalate thermal barrier coating ceramic material according to claim 1, characterized in that, In step (2), the ball milling speed is 350-450 rpm and the time is 12-24 h.

4. The method for preparing scandium-doped gadolinium tantalate thermal barrier coating ceramic material according to claim 1, characterized in that, In step (3), the drying temperature is 70-90℃ and the time is 10-20h.

5. The method of claim 1, wherein the scandium-doped gadolinium tantalate thermal barrier coating ceramic material is prepared by the steps of: In step (4), the sieve mesh size is 150-300 mesh.

6. A scandium-doped gadolinium tantalate thermal barrier coating ceramic material, characterized in that, The scandium-doped gadolinium tantalate thermal barrier coating ceramic material prepared by any one of claims 1-5 has a thermal conductivity of <1.95 W / (m•K) at 900℃.

7. The scandium-doped gadolinium tantalate thermal barrier coating ceramic material of claim 6 is used to prepare a thermal barrier coating on the surface of aero-engine hot-end components.

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