High-temperature-resistant thermal barrier coating for aero-engine and preparation method thereof

Abstract

The invention discloses a high-temperature-resistant thermal barrier coating for an aero-engine and a preparation method of the high-temperature-resistant thermal barrier coating, the high-temperature-resistant thermal barrier coating is prepared from a high-temperature-resistant thermal barrier material, the chemical composition of the high-temperature-resistant thermal barrier material is (ZrO2) xAyBzCn, A is any one or more of oxides of Y, Mg, Ca, Sn, Be, V, Mn, Co, Ni and Nb; b is any one or more of oxides of La, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu; c is any one or more of boron nitride, silicon nitride, boron carbide, silicon carbide, tantalum carbide and tungsten carbide; x is equal to 80-100 wt%, y is equal to 0-20 wt%, z is equal to 0-20 wt%, n is equal to 0-20 wt%, and x + y + z + n is equal to 100 wt%. According to the invention, various oxides, carbides and nitrides are doped in a ZrO2 matrix, so that the thermal stability and mechanical properties of the coating are improved, the thermal conductivity is reduced and the like, the high-temperature resistance of the coating is remarkably improved, and the problems that the thermal barrier coating is easy to fall off and poor in long-time service performance are solved.

Description

Technical Field

[0001] This invention belongs to the technical field of high-temperature thermal barrier coating materials, specifically relating to a high-temperature thermal barrier coating for aero-engines and its preparation method. Background Technology

[0002] The ignition system is an essential component in aero-engines for achieving ignition functionality. It typically includes ignition cables, ignition nozzles, and ignition devices. The ignition device is often installed near the combustion chamber of the aero-engine, where the hot-end components are exposed to high temperatures. Therefore, a thermal barrier coating needs to be deposited on the surface of these hot-end components. This thermal barrier coating provides both insulation and protection, primarily used to isolate the heated components from the high-temperature environment, thus protecting them.

[0003] Currently, thermal barrier coatings typically utilize ceramic materials with high temperature resistance, high coefficient of thermal expansion, and low thermal conductivity. For example, ZrO2 coatings containing 6wt%–8wt% Y₂O₃ (6wt%–8wt% YSZ, yttrium-stabilized zirconium oxide) offer advantages such as high melting point, low thermal conductivity, and high melting point. However, YSZ coatings are prone to the tetragonal-to-monoclinic phase transition. The volume changes during this phase transition induce stress, easily leading to coating detachment and failure. Furthermore, with the improvement in aero-engine performance, their internal operating temperatures are continuously increasing, and traditional YSZ coatings will no longer meet the requirements for long-term high-temperature service. Therefore, there is an urgent need to develop a new type of thermal barrier coating to meet these higher operational demands. Summary of the Invention

[0004] The purpose of this invention is to provide a high-temperature resistant thermal barrier coating for aero-engines and its preparation method, thereby solving the above-mentioned problems.

[0005] This invention is mainly achieved through the following technical solutions:

[0006] A high-temperature thermal barrier coating for aero-engines is prepared using a high-temperature thermal barrier material, wherein the chemical composition of the high-temperature thermal barrier material is as follows:

[0007] (ZrO2) x A y B z C n ,

[0008] Wherein: A is any one or more oxides of Y, Mg, Ca, Sn, Be, V, Mn, Co, Ni, and Nb;

[0009] B is any one or more of the oxides of La, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu;

[0010] C can be any one or more of boron nitride, silicon nitride, boron carbide, silicon carbide, tantalum carbide, and tungsten carbide;

[0011] Using ZrO2 as the matrix material, x = 80-100wt%, y = 0-20wt%, z = 0-20wt%, n = 0-20wt%, where x, y, z, and n represent the mass percentage of the corresponding substances in the total mass of the high-temperature thermal barrier material, and x+y+z+n = 100wt%.

[0012] To better realize the present invention, the chemical composition of the high-temperature resistant thermal barrier material is further defined as (ZrO2). 95 (Y2O3)4(La2O3)1.

[0013] To better realize the present invention, the chemical composition of the high-temperature resistant thermal barrier material is further defined as (ZrO2). 90 (Y2O3)4(Gd2O3)4(SiC)2.

[0014] To better realize the present invention, the chemical composition of the high-temperature resistant thermal barrier material is further defined as (ZrO2). 85 (Y2O3)5(MgO)3(Dy2O3)4(BN)3.

[0015] To better realize the present invention, the chemical composition of the high-temperature resistant thermal barrier material is further defined as (ZrO2). 87 (Y₂O₃)₅(IrO₂)₄(Pr₆O) 11 )2(SiN)2.

[0016] This invention is mainly achieved through the following technical solutions:

[0017] A method for preparing a high-temperature thermal barrier coating for aero-engines includes the following steps:

[0018] Step S1: Using ZrO2 as the matrix material, ZrO2 and any one or more of oxide A, oxide B, and compound C are loaded into a ball mill and ball-milled. After the powder is mixed evenly, it is dried to obtain the powder to be sintered.

[0019] Step S2: The powder to be sintered is hot-pressed to obtain a ZrO2-doped sintered material;

[0020] Step S3: Crush the ZrO2-doped sintered material and put it into a ball mill for ball milling. Then, dry the ball-milled powder to obtain a high-temperature thermal barrier resistant material.

[0021] Step S4: Apply the high-temperature thermal barrier material to the substrate containing the metal bonding layer using a thermal spraying method to obtain a high-temperature thermal barrier coating.

[0022] To better realize the present invention, in step S2, the hot pressing sintering temperature is 1400-2000℃, the pressure is 5-20MPa, and the sintering time is 2-6h.

[0023] To better realize the present invention, in step S3, the particle size of the high-temperature thermal barrier material is 10-150 μm.

[0024] To better realize the present invention, further, in step S4, the thermal spraying distance is 50-200mm, the nozzle moving speed is 100-1000mm / min, the powder feeding speed is 10-50g / min, the working current is 400-800A, the working voltage is 40-100V, and the argon flow rate is 10-50L / min.

[0025] To better realize the present invention, in step S4, the coating thickness of the high-temperature thermal barrier coating is 50-2000 μm.

[0026] The beneficial effects of this invention are as follows:

[0027] To address the problems of easy peeling and poor long-term service performance of current thermal barrier coatings, this invention employs high-temperature resistant thermal barrier materials to prepare high-temperature resistant thermal barrier coatings. The preferred high-temperature resistant thermal barrier material is a YSZ thermal barrier coating doped with 6wt%–8wt% of metal oxides, carbides, and nitrides, which effectively improves the thermal stability of the coating. This invention, by doping various types of oxides, carbides, and nitrides into the ZrO2-based thermal barrier coating, benefits the coating's thermal stability, mechanical properties, and reduces thermal conductivity, significantly improving the coating's high-temperature resistance.

[0028] This invention increases the complexity of the crystal structure by doping a ZrO2 matrix with rare earth oxides, inducing low-frequency optical phonons, enhancing phonon scattering, and thus reducing the thermal conductivity of the coating. The ZrO2 matrix is ​​doped with main group and transition group elements, and the ZrO2 matrix is ​​partially replaced by metal cations. +4 The ions form a substitutional solid solution, which hinders the transformation of the tetragonal phase to the monoclinic phase, keeping the thermal barrier coating in a metastable state.

[0029] This invention involves doping a ZrO2 matrix with carbides and nitrides, which introduces a mismatch between the ionic radius and the lattice ionic radius within the thermal barrier coating, thereby reducing the ion diffusion coefficient and improving sintering resistance. Simultaneously, the chemical stability, high temperature resistance, and good mechanical properties of carbides and nitrides will improve the high-temperature performance of the ZrO2-based thermal barrier coating. Attached Figure Description

[0030] Figure 1This is a scanning electron microscope image of the high-temperature thermal barrier coating prepared in Example 1;

[0031] Figure 2 This is a scanning electron microscope image of the high-temperature thermal barrier coating prepared in Example 2. Detailed Implementation

[0032] Example 1:

[0033] A high-temperature resistant thermal barrier coating for aero-engines is prepared using a high-temperature resistant thermal barrier material, the chemical composition of which is (ZrO2). 95 (Y₂O₃)₄(La₂O₃)₁. The specific preparation method includes the following steps:

[0034] 1) Weigh each component according to the weight ratio of ZrO2∶Y2O3∶La2O3=95∶4∶1 and mix them.

[0035] 2) Place the above 200g mixture in a ball mill jar for ball milling. The ball milling medium is anhydrous ethanol. The ball milling balls are made of alumina ceramic with a diameter of 2mm and a ball-to-material ratio of 5. The ball mill speed is 180r / min, with a 10min pause every 2 hours to prevent the powder from overheating. The total ball milling time is 10 hours. After ball milling, dry the powder to obtain the powder to be sintered for later use.

[0036] 3) The powder to be sintered is hot-pressed to obtain a ZrO2-doped sintered material, wherein the sintering temperature is 1600℃, the pressure is 10MPa, and the sintering time is 4h.

[0037] 4) After crushing the ZrO2-doped sintered material into small pieces, put it into a ball mill for ball milling with the same parameters as above, and then dry the ball-milled powder for later use.

[0038] 5) A thermal barrier coating was prepared on a substrate containing a metal binder layer by thermal spraying. The thermal spraying distance was 50 mm, the nozzle moving speed was 150 mm / min, the powder feeding speed was 12 g / min, the working current was 450 A, the working voltage was 100 V, and the argon flow rate was 20 L / min.

[0039] like Figure 1 As shown, the prepared high-temperature resistant thermal barrier coating is dense. The thermal conductivity of this coating is 0.60 W / mK, which is lower than that of general thermal barrier coatings (about 2 W / mK). Due to the addition of rare earth oxides, the thermal conductivity of the ZrO2-based thermal barrier coating is reduced, resulting in good temperature resistance and less phase change during service.

[0040] Example 2:

[0041] A high-temperature resistant thermal barrier coating for aero-engines is prepared using a high-temperature resistant thermal barrier material, the chemical composition of which is (ZrO2). 90 (Y₂O₃)₄(Gd₂O₃)₄(SiC)₂. The specific preparation method includes the following steps:

[0042] 1) Weigh and mix each component according to the weight ratio of ZrO2∶Y2O3∶Gd2O3∶SiC=90∶4∶4∶2.

[0043] 2) Place the above 200g mixture in a ball mill jar for ball milling. The ball milling medium is anhydrous ethanol. The ball milling balls are made of alumina ceramic with a diameter of 2mm and a ball-to-material ratio of 4. The ball mill speed is 200r / min, with a 10min pause every 2 hours to prevent the powder from overheating. The total ball milling time is 15 hours. After ball milling, dry the powder to obtain the powder to be sintered for later use.

[0044] 3) The powder to be sintered is hot-pressed to obtain a ZrO2-doped sintered material. The sintering temperature is 1700℃, the pressure is 15MPa, and the sintering time is 3h.

[0045] 4) After crushing the ZrO2-doped sintered material into small pieces, put it into a ball mill for ball milling with the same parameters as above, and then dry the ball-milled powder for later use.

[0046] 5) A thermal barrier coating was prepared on a substrate containing a metal bonding layer by thermal spraying. The thermal spraying distance was 40 mm, the nozzle moving speed was 200 mm / min, the powder feeding speed was 15 g / min, the working current was 400 A, the working voltage was 50 V, and the argon flow rate was 20 L / min.

[0047] like Figure 2 As shown, the prepared high-temperature thermal barrier coating is more dense, and the thermal conductivity of the coating is 0.73 W / mK. Due to the addition of rare earth oxides and carbides, the ZrO2-based thermal barrier coating has low thermal conductivity, high thermal stability and good mechanical properties. The phase content of the thermal barrier coating changes less during high-temperature service and has good temperature resistance.

[0048] Example 3:

[0049] A high-temperature resistant thermal barrier coating for aero-engines is prepared using a high-temperature resistant thermal barrier material, the chemical composition of which is (ZrO2). 85 (Y₂O₃)₅(MgO)₃(Dy₂O₃)₄(BN)₃. The specific preparation method includes the following steps:

[0050] 1) Weigh and mix each component according to the weight ratio of ZrO2∶Y2O3∶MgO∶Dy2O3∶BN=85∶5∶3∶4∶3.

[0051] 2) Place the above 200g mixture in a ball mill jar for ball milling. The ball milling medium is anhydrous ethanol. The ball milling balls are made of alumina ceramic with a diameter of 2mm and a ball-to-material ratio of 3. The ball mill speed is 150r / min, with a 15min pause every 1.5h to prevent the powder from overheating. The total ball milling time is 20h. After ball milling, dry the powder to obtain the powder to be sintered for later use.

[0052] 3) The powder to be sintered is hot-pressed to obtain a ZrO2-doped sintered material. The sintering temperature is 1750℃, the pressure is 16.5MPa, and the sintering time is 4h.

[0053] 4) After crushing the ZrO2-doped sintered material into small pieces, put it into a ball mill for ball milling with the same parameters as above, and then dry the ball-milled powder for later use.

[0054] 5) A thermal barrier coating was prepared on a substrate containing a metal bonding layer by thermal spraying. The thermal spraying distance was 40 mm, the nozzle moving speed was 100 mm / min, the powder feeding speed was 20 g / min, the working current was 400 A, the working voltage was 50 V, and the argon flow rate was 15 L / min.

[0055] The thermal conductivity of the coating is 0.78 W / mK. Due to the addition of rare earth oxides and nitrides, the ZrO2-based thermal barrier coating has low thermal conductivity, high thermal stability and good mechanical properties. In addition, MgO effectively improves the coating adhesion and reduces defects. The phase content of the thermal barrier coating changes little during high-temperature service and has good temperature resistance.

[0056] Example 4:

[0057] A high-temperature resistant thermal barrier coating for aero-engines is prepared using a high-temperature resistant thermal barrier material, the chemical composition of which is (ZrO2). 87 (Y₂O₃)₅(IrO₂)₄(Pr₆O) 11 )2(SiN)2. The specific preparation method includes the following steps:

[0058] 1) According to ZrO2∶Y2O3∶IrO2∶Pr6O 11 Weigh out the components and mix them in a weight ratio of 87:5:4:2:2 for SiN.

[0059] 2) Place the above 200g mixture in a ball mill jar for ball milling. The ball milling medium is anhydrous ethanol. The ball milling balls are made of alumina ceramic with a diameter of 2mm and a ball-to-material ratio of 4. The ball mill speed is 100r / min, with a 10min pause every 1.5h to prevent the powder from overheating. The total ball milling time is 13.5h. After ball milling, dry the powder to obtain the powder to be sintered for later use.

[0060] 3) The powder to be sintered is hot-pressed to obtain a ZrO2-doped sintered material, wherein the sintering temperature is 1750℃, the pressure is 15.5MPa, and the sintering time is 3.5h.

[0061] 4) After crushing the ZrO2-doped sintered material into small pieces, put it into a ball mill for ball milling with the same parameters as above, and then dry the ball-milled powder for later use.

[0062] 5) A thermal barrier coating was prepared on a substrate containing a metal bonding layer by thermal spraying. The thermal spraying distance was 30 mm, the nozzle moving speed was 100 mm / min, the powder feeding speed was 15 g / min, the working current was 400 A, the working voltage was 50 V, and the argon flow rate was 15 L / min.

[0063] The thermal conductivity of the coating is 1.12 W / mK. Due to the addition of rare earth oxides and nitrides, the ZrO2-based thermal barrier coating has low thermal conductivity, high thermal stability and good mechanical properties. Furthermore, the high temperature stability of IrO2 is beneficial to improving the high temperature performance of the coating. The phase content of this thermal barrier coating changes little during high-temperature service and has good temperature resistance.

[0064] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications or equivalent changes made to the above embodiments based on the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A high-temperature thermal barrier coating for aero engines, characterized in that, A high-temperature resistant thermal barrier coating is prepared using a high-temperature resistant thermal barrier material, the chemical composition of which is as follows: (ZrO2) x A y B z C n , Wherein: A is any one or more oxides of Y, Mg, Ca, Sn, Be, V, Mn, Co, Ni, and Nb; B is any one or more of the oxides of La, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu; C can be any one or more of boron nitride, silicon nitride, boron carbide, silicon carbide, tantalum carbide, and tungsten carbide; x = 80–100 wt%, y = 0–20 wt%, z = 0–20 wt%, n = 0–20 wt%, where x, y, z, and n represent the mass percentage of the corresponding substances in the total mass of the high-temperature thermal barrier material, and x + y + z + n = 100 wt%.

2. The high-temperature thermal barrier coating for aero-engines according to claim 1, characterized in that, The chemical composition of the high-temperature resistant thermal barrier material is (ZrO2). 95 (Y2O3)4(La2O3)1.

3. The high-temperature thermal barrier coating for aero-engines according to claim 1, characterized in that, The chemical composition of the high-temperature resistant thermal barrier material is (ZrO2). 90 (Y2O3)4(Gd2O3)4(SiC)2.

4. The high-temperature thermal barrier coating for aero-engines according to claim 1, characterized in that, The chemical composition of the high-temperature resistant thermal barrier material is (ZrO2). 85 (Y2O3)5(MgO)3(Dy2O3)4(BN)3.

5. The high-temperature thermal barrier coating for aero-engines according to claim 1, characterized in that, The chemical composition of the high-temperature resistant thermal barrier material is (ZrO2). 87 (Y₂O₃)₅(IrO₂)₄(Pr₆O) 11 )2(SiN)2.

6. A method for preparing a high-temperature resistant thermal barrier coating for aero-engines, characterized in that, Includes the following steps: Step S1: Using ZrO2 as the matrix material, ZrO2 and any one or more of oxide A, oxide B, and compound C are loaded into a ball mill and ball-milled. After the powder is mixed evenly, it is dried to obtain the powder to be sintered. Step S2: The powder to be sintered is hot-pressed to obtain a ZrO2-doped sintered material; Step S3: Crush the ZrO2-doped sintered material and put it into a ball mill for ball milling. Then, dry the ball-milled powder to obtain a high-temperature thermal barrier resistant material. Step S4: Apply the high-temperature thermal barrier material to the substrate containing the metal bonding layer using a thermal spraying method to obtain a high-temperature thermal barrier coating.

7. The method for preparing a high-temperature resistant thermal barrier coating for an aero-engine according to claim 6, characterized in that, In step S2, the hot pressing sintering temperature is 1400-2000℃, the pressure is 5-20MPa, and the sintering time is 2-6h.

8. The method for preparing a high-temperature thermal barrier coating for an aero-engine according to claim 6, characterized in that, In step S3, the particle size of the high-temperature thermal barrier material is 10-150 μm.

9. The method for preparing a high-temperature thermal barrier coating for an aero-engine according to claim 6, characterized in that, In step S4, the thermal spraying distance is 50-200mm, the nozzle moving speed is 100-1000mm / min, the powder feeding speed is 10-50g / min, the working current is 400-800A, the working voltage is 40-100V, and the argon flow rate is 10-50L / min.

10. A method for preparing a high-temperature resistant thermal barrier coating for an aero-engine according to claim 6 or 9, characterized in that, In step S4, the coating thickness of the high-temperature thermal barrier coating is 50–2000 μm.

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