Ytterbium-doped gadolinium tantalate thermal barrier coating ceramic material as well as preparation method and application thereof

Abstract

The invention discloses a ytterbium-doped gadolinium tantalate thermal barrier coating ceramic material and a preparation method and application thereof.The preparation method includes the steps that Yb2O3, Gd2O3 and Ta2O5 powder raw materials are mixed in proportion, absolute ethyl alcohol and ZrO2 ball-milling beads are added for ball milling to be mixed evenly, a sample obtained after the mixture is dried is placed into a crucible and placed in a muffle furnace for heating reaction, and the ytterbium-doped gadolinium tantalate thermal barrier coating ceramic material is obtained; after the reaction is finished, cooling to room temperature along with the furnace, grinding, sieving through a 150-mesh sieve to obtain (Gd1-xYbx) TaO4 powder (0.2 < = x < = 0.5), and carrying out dry pressing to obtain the compact ceramic material. The (Gd1-xYbx) TaO4 has higher hardness and lower elastic modulus than GdTaO4, the CMAS corrosion resistance is also improved, and the (Gd1-xYbx) TaO4 can be used for preparing a thermal barrier coating of an aero-engine.

Description

Technical Field

[0001] The invention belongs to the technical field of thermal barrier coating ceramic materials for aircraft engines, and in particular relates to an ytterbium-doped gadolinium tantalate thermal barrier coating ceramic material and a preparation method and application thereof. Background Art

[0002] When the high-temperature alloy components of aircraft engines operate for a long time under high temperature, high pressure and harsh turbine environment, the thermal barrier coating ceramic materials on their surface must meet a series of strict requirements. First, the material should have a low thermal conductivity to ensure excellent thermal insulation performance, thereby effectively protecting the substrate material from high temperature. Secondly, the coating must have good mechanical properties to enhance its ability to withstand stress and strain, thereby preventing coating failure caused by stress concentration. In addition, the coating should also 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 working conditions.

[0003] Some scholars have proposed that rare earth tantalate ceramic materials exhibit a ferroelastic toughening effect similar to that of zirconia toughened ceramics (YSZ). Preliminary calculation results show that this type of ceramic material has extremely low thermal conductivity, which helps to provide excellent thermal insulation performance, thereby significantly increasing its operating temperature. In addition, tantalate ceramics, like YSZ, have similar ferroelastic phase transition properties. This makes rare earth tantalate ceramic materials show the potential to replace YSZ ceramics and is expected to become an ideal choice for the next generation of thermal barrier coating ceramic materials.

[0004] Gadolinium tantalate, as a kind of rare earth tantalate, has low thermal conductivity and good fracture toughness. In order to make it have better physical properties and resistance to CMAS corrosion, it needs to be ion-doped and modified. Ytterbium, as a homologous element of lanthanide elements, has similar properties to lanthanide elements, but the application of ytterbium and gadolinium tantalate in thermal barrier coatings for aircraft engines has not been reported yet. Summary of the invention

[0005] In view of the shortcomings of the prior art, the present invention aims to provide a ytterbium-doped gadolinium tantalate thermal barrier coating ceramic material and a preparation method and application thereof. The method adopts a solid phase reaction method to prepare (Gd 1-x Yb x )TaO 4 , which has the advantages of simple reaction principle, low synthesis temperature, and small particle size of the obtained powder. The Ytterbium-doped Gadolinium Tantalate Thermal Barrier Coating Ceramic Material prepared by the present invention can not only improve the mechanical and thermophysical properties of the thermal barrier coating material by doping with rare earth elements with small ion radius, but also reduce the chemical affinity between the CMAS medium and the thermal barrier coating material, and can be used to prepare aero-engine thermal barrier coatings to improve the physical properties of tantalate and its ability to resist CMAS corrosion.

[0006] In order to solve the problems of the prior art, the technical solution adopted by the present invention is:

[0007] A method for preparing a gadolinium tantalate thermal barrier coating ceramic material doped with ytterbium, wherein Yb 2 O 3 Powder, Gd 2 O 3 Powder and Ta 2 O 5 After the powders are mixed in proportion, anhydrous ethanol and ZrO 2 The ball milling beads are used to make the mixture uniform, and after drying, the mixture is placed in a muffle furnace for heating reaction, cooled to room temperature with the furnace, and then subjected to grinding, sieving, PVA granulation, dry pressing, debinding, and high-temperature sintering in sequence to obtain (Gd 1-x Yb x )TaO 4 Powder, wherein 0.2≤x≤0.5.

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

[0009] Step 1: Calculate the amount of oxide according to the molar ratio of the elements and weigh Yb 2 O 3 Powder, Gd 2 O 3 Powder and Ta 2 O 5 Powder, and pour the three powders into a ball mill, and then add anhydrous ethanol to fully dissolve the mixed powder;

[0010] Step 2, placing the ball milling jar in a planetary ball mill for ball milling to obtain a uniform mixed solution;

[0011] Step 3, drying the mixed solution and subjecting it to a high-temperature solid phase reaction to obtain a ceramic powder;

[0012] Step 4: Grind, sieve, PVA granulate, dry press, debind, and sinter at high temperature the ceramic powder obtained in step 3 to obtain a ceramic powder having a chemical formula of (Gd 1-x Yb x )TaO 4 Ytterbium-doped gadolinium tantalate thermal barrier coating material.

[0013] As an improvement, in step 1, Yb 2 O 3 Powder, Gd 2 O 3 Powder and Ta 2 O 5 The purity of the powder is ≥99.99%.

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

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

[0016] As an improvement, the mesh size of the sieving in step 4 is 150-300 mesh, the first pressurization of dry pressing is 180-200 MPa, the time is 60-70 s, the second pressurization is 160-170 MPa, the time is 30-35 s, the debinding temperature is 500-550°C, the time is 2-3 h, and the sintering temperature is 1500-1600°C, and the time is 5-6 h.

[0017] The crystal structure of the physical 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 ytterbium-doped gadolinium tantalate thermal barrier coating ceramic material is used in the preparation of thermal barrier coatings on the surfaces of hot end components of aircraft engines.

[0019] Beneficial effects:

[0020] Compared with the prior art, the present invention provides a ytterbium-doped gadolinium tantalate thermal barrier coating ceramic material and its preparation method and application, and obtains a new type of thermal barrier coating material (Gd 1-x Yb x )TaO 4 , compared with GdTaO 4 Compared with SS100, 8K stainless steel has a denser crystal structure and better phase stability, so it has higher hardness, lower elastic modulus and resistance to CMAS corrosion, which will be able to improve the service capability of thermal barrier coatings in harsh turbine working environments and can be used for thermal barrier coatings on the surface of hot end components of engines in the aviation field. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 The (Gd 1-x Yb x )TaO 4 XRD schematic diagram of ceramic materials;

[0022] Figure 2 The (Gd 1-x Yb x )TaO 4 Schematic diagram of the microscopic morphology of 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 corrosion: (A) surface morphology after corrosion for 1 hour; (B) surface morphology after corrosion for 5 hours; (C) surface morphology after corrosion for 10 hours;

[0024] Figure 4 The cross-sectional morphology of Example 2 after CMAS corrosion: (A) surface morphology after corrosion for 1 hour; (B) surface morphology after corrosion for 5 hours; (C) surface morphology after corrosion for 10 hours;

[0025] Figure 5 The cross-sectional morphology of Example 3 after CMAS corrosion: (A) surface morphology after corrosion for 1 hour; (B) surface morphology after corrosion for 5 hours; (C) surface morphology after corrosion for 10 hours;

[0026] Figure 6 The cross-sectional morphology of comparative example 1 after CMAS corrosion: (A) surface morphology after corrosion for 1 hour; (B) surface morphology after corrosion for 5 hours; (C) surface morphology after corrosion for 10 hours;

[0027] Figure 7 For the (Gd prepared in Example 1-3 1-x Yb x )TaO 4 Compared with the GdTaO prepared in Comparative Example 1 4 Comparison chart of hardness and elastic modulus. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments of the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present application.

[0029] A method for preparing a gadolinium tantalate thermal barrier coating ceramic material doped with ytterbium, wherein Yb 2 O 3 Powder, Gd 2 O 3 Powder and Ta 2 O 5 After the powders are mixed in proportion, anhydrous ethanol and ZrO 2 The ball milling beads are used to make the mixture uniform, and after drying, the mixture is placed in a muffle furnace for heating reaction, cooled to room temperature with the furnace, and then subjected to grinding, sieving, PVA granulation, dry pressing, debinding, and high-temperature sintering in sequence to obtain (Gd 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 comprises the following steps:

[0031] Step 1: Calculate the amount of oxide according to the molar ratio of the elements and weigh Yb 2 O 3 Powder, Gd 2 O 3 Powder and Ta 2 O 5 Powder, and pour the three powders into a ball mill, and then add anhydrous ethanol to fully dissolve the mixed powder;

[0032] Step 2, placing the ball milling jar in a planetary ball mill for ball milling to obtain a uniform mixed solution;

[0033] Step 3, drying the mixed solution and subjecting it to a high-temperature solid phase reaction to obtain a ceramic powder;

[0034] Step 4: Grind, sieve, PVA granulate, dry press, debind, and sinter at high temperature the ceramic powder obtained in step 3 to obtain a ceramic powder having a chemical formula of (Gd 1-x Yb x )TaO 4 Ytterbium-doped gadolinium tantalate thermal barrier coating material.

[0035] As an improvement, in step 1, Yb 2 O 3 Powder, Gd 2 O 3 Powder and Ta 2 O 5 The purity of the powder is ≥99.99%.

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

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

[0038] As an improvement, the mesh size of the sieving in step 4 is 150-300 mesh, the first pressurization of dry pressing is 180-200 MPa, the time is 60-70 s, the second pressurization is 160-170 MPa, the time is 30-35 s, the debinding temperature is 500-550°C, the time is 2-3 h, and the sintering temperature is 1500-1600°C, and the time is 5-6 h.

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

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

[0041] Example 1

[0042] (1) Calculate the amount of oxide according to the molar ratio of n(Gd):n(Yb):n(Ta)=0.8:0.2:1, and then weigh the required amount of Yb 2 O 3 Powder, Gd 2 O 3 Powder and Ta 2 O 5 Powder, pour the three powders into the ball mill jar in turn, and then pour in anhydrous ethanol to dissolve the powder;

[0043] (2) placing the ball mill in a planetary ball mill and milling the ball mill to obtain a uniform mixed solution. The ball milling time is 16 h 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°C for 10 hours, and the high-temperature solid-phase reaction temperature is 1600°C for 8 hours.

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

[0046] Among them, the PVA concentration is 5%, the purpose is to enhance the plasticity of ceramic powder and achieve granulation effect. The mesh size of the sieve is 150 mesh, the first pressure of dry pressing is 200Mpa, the time is 60s, the second pressure is 160MPa, the time is 30s, the debinding temperature is 550℃, the time is 2h, and the sintering temperature is 1550℃, the time is 8h.

[0047] Example 2

[0048] (1) Calculate the amount of oxide according to the molar ratio of n(Gd):n(Yb):n(Ta)=0.6:0.4:1, and then weigh the required amount of Yb 2 O 3 Powder, Gd 2 O 3 Powder and Ta 2 O5 Powder, pour the three powders into the ball mill jar in turn, and then pour in anhydrous ethanol to dissolve the powder;

[0049] (2) placing the ball mill jar in a planetary ball mill to obtain a uniform mixed solution. The ball milling time is 12 h 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°C, the time is 12 hours, and the high-temperature solid-phase reaction temperature is 1600°C, and the time is 6 hours.

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

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

[0053] Example 3

[0054] (1) Calculate the amount of oxide according to the molar ratio of n(Gd):n(Yb):n(Ta)=0.5:0.5:1, and then weigh the required amount of Yb 2 O 3 Powder, Gd 2 O 3 Powder and Ta 2 O 5 Powder, pour the three powders into the ball mill jar in turn, and then pour in anhydrous ethanol to dissolve the powder;

[0055] (2) placing the ball mill in a planetary ball mill and milling the mixture to obtain a uniform mixed solution. The milling time is 8 h and the 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°C, the time is 12 hours, and the high-temperature solid-phase reaction temperature is 1600°C, and the time is 7 hours.

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

[0058] The PVA concentration is 5%, the purpose is to enhance the plasticity of ceramic powder and achieve granulation effect. The mesh size of the sieve is 150 mesh, the first pressure of dry pressing is 200Mpa, the time is 60s, the second pressure is 160MPa, the time is 30s, the debinding temperature is 550℃, the time is 2h, and the sintering temperature is 1550℃, the time is 9h.

[0059] Comparative Example 1

[0060] (1) Calculate the amount of oxide based on the molar ratio of n(Gd):n(Ta)=1:1, and then weigh the required amount of Gd 2 O 3 Powder and Ta 2 O 5 Powder, pour the three powders into the ball mill jar in turn, and then pour in anhydrous ethanol to dissolve the powder;

[0061] (2) placing the ball mill in a planetary ball mill to obtain a uniform mixed solution. The ball milling time is 18 h 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°C, the time is 14 hours, and the high-temperature solid-phase reaction temperature is 1600°C, and the time is 10 hours.

[0063] (4) The obtained ceramic powder is ground, sieved, PVA granulated and dry pressed, and then debinded and sintered in a muffle furnace to obtain the desired GdTaO 4 Ceramic blocks.

[0064] Among them, the PVA concentration is 5%, the purpose is to enhance the plasticity of ceramic powder and achieve granulation effect. The mesh size of the sieve is 150 mesh, the first pressure of dry pressing is 200Mpa, the time is 60s, the second pressure is 160MPa, the time is 30s, the debinding temperature is 550℃, the time is 2h, and the sintering temperature is 1580℃, the time is 8h.

[0065] Performance Testing

[0066] Figure 1 The (Gd 1-x Yb x )TaO 4 XRD diagram of ceramic materials. Figure 1 It can be seen that the materials (Gd 1-x Yb x )TaO 4GdTaO 4 Based on Yb doping, GdTaO 4 And from the surface morphology of Examples 1 to 3, it can be seen that the surface of the ceramic material is dense and the porosity is low. Figure 2 shown.

[0067] CMAS corrosion test: The surfaces of the Yb-doped gadolinium tantalate thermal barrier coating ceramic materials prepared in Examples 1-3 and the material prepared in Comparative Example 1 were polished and 30 mg / cm 2 The density of 33CaO-9MgO-7Al 2 O 3 -45SiO 2 (CMAS) powder was coated on the sample surface. Then, they were placed in a muffle furnace heated to 1300°C for 1h, 5h and 10h respectively, and the CAMS corrosion samples were observed by SEM. The results are shown in Figure 3-6 shown.

[0068] from Figure 3-6 From the cross-sectional morphology, it can be seen that in the above four thermal barrier coating materials, the top is a CMAS molten glass layer, the middle is a mutual reaction layer, and the bottom is a ceramic layer that is not corroded. 1-x Yb x )TaO 4 Ceramic and GdTaO of Comparative Example 1 4 The ceramics all have residual CMAS on their surfaces after CMAS corrosion for 1 hour, proving that these four thermal barrier coating materials have a certain ability to resist CMAS corrosion in the early stage of corrosion. As the corrosion time increases, the ability of the doped ceramics to resist corrosion becomes better than that of the undoped ceramics. It can be clearly seen from the comparison between Example 1 and Comparative Example 1 that under the same CMAS corrosion time, the doping of Yb can reduce the thickness of the mutual reaction layer, which means that it has better corrosion resistance. This is mainly because Yb doping causes GdTaO 4 The slight contraction of the lattice (the ionic radius of Yb is smaller than that of Gd) leads to a denser lattice structure. This microscopic adjustment will reduce the wettability of the CMAS melt and reduce the corrosive contact of the melt with the coating. However, it can be seen from the comparison between Example 3 and Comparative Example 1 that the more Yb doping content, the better, and excessive doping cannot effectively improve its own corrosion resistance.

[0069] Depend on Figure 7 It can be seen that (Gd 1-x Yb x )TaO 4 Compared with the GdTaO ceramic of Comparative Example 1 4Ceramics have higher hardness and lower elastic modulus, which is beneficial to enhance the strain tolerance and particle erosion resistance of coating materials.

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

[0071] The present invention and its embodiments are described schematically above, and the description is not restrictive. The drawings show only one embodiment of the present invention, and the actual structure is not limited thereto. Therefore, if a person skilled in the art is inspired by it and designs a structural method and an embodiment similar to the technical solution without creativity without departing from the purpose of the invention, they shall all fall within the protection scope of the present invention.

Claims

1. A method for preparing a ytterbium-doped gadolinium tantalate thermal barrier coating ceramic material, characterized in that: Yb2O3 powder, Gd2O3 powder and Ta2O5 powder were mixed in proportion, anhydrous ethanol and ZrO2 ball milling beads were added to make the mixture uniform, and then placed in a muffle furnace for heating reaction, cooled to room temperature with the furnace, and then subjected to grinding, sieving, PVA granulation, dry pressing, debinding and high temperature sintering to obtain (Gd 1-x Yb x )TaO4 powder, wherein 0.2≤x≤0.

5.

2. The method for preparing a ytterbium-doped gadolinium tantalate thermal barrier coating ceramic material according to claim 1, characterized in that: The specific steps include: Step 1, calculate the amount of oxide according to the molar ratio of the elements, weigh Yb2O3 powder, Gd2O3 powder and Ta2O5 powder respectively, pour the three powders into a ball mill, and then add anhydrous ethanol to fully dissolve the mixed powder; Step 2, placing the ball milling jar in a planetary ball mill for ball milling to obtain a uniform mixed solution; Step 3, drying the mixed solution and subjecting it to a high-temperature solid phase reaction to obtain a ceramic powder; Step 4: Grind, sieve, PVA granulate, dry press, debind, and sinter at high temperature the ceramic powder obtained in step 3 to obtain a ceramic powder having a chemical formula of (Gd 1-x Yb x )TaO4-doped gadolinium tantalate thermal barrier coating material.

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

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

5. The method for preparing a ytterbium-doped gadolinium tantalate thermal barrier coating ceramic material according to claim 2, characterized in that: In step 3, the drying temperature is 70-90° C., the time is 8-15 h, and the temperature of the high-temperature solid phase reaction is 1600-1650° C., and the time is 5-10 h.

6. The method for preparing a ytterbium-doped gadolinium tantalate thermal barrier coating ceramic material according to claim 2, characterized in that: The mesh size of the sieve in step 4 is 150-300 mesh, the first pressurization of dry pressing is 180-200 MPa, the time is 60-70 s, the second pressurization is 160-170 MPa, the time is 30-35 s, the debinding temperature is 500-550°C, the time is 2-3 h, and the sintering temperature is 1500-1600°C, the time is 5-6 h.

7. The ytterbium-doped gadolinium tantalate thermal barrier coating ceramic material prepared by any one of the preparation methods of claims 1 to 6, characterized in that: The crystal structure of the physical phase of the ytterbium-doped gadolinium tantalate thermal barrier coating ceramic material is a monoclinic phase.

8. Use of the ytterbium-doped gadolinium tantalate thermal barrier coating ceramic material according to claim 7 in preparing a thermal barrier coating on the surface of a hot end component of an aero-engine.

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