A biomimetic thermal barrier coating against cmas infiltration and a method of making

Abstract

The present application relates to the technical field of thermal barrier coating surface corrosion and protection, in particular to a kind of anti-CMAS infiltration biomimetic thermal barrier coating and preparation method.The anti-CMAS infiltration biomimetic thermal barrier coating, from substrate, inside to outside, in turn includes: metal bonding layer, inner ceramic layer and micro-nano structure outer ceramic layer;The micro-nano structure outer ceramic layer is NdYbZr2O7.The present application adopts suspension plasma spraying technology to prepare micro-nano structure outer ceramic layer on the surface of inner ceramic layer.The present application selects new NdYbZr2O7 material as outer ceramic layer material, and simultaneously based on suspension plasma spraying technology, from material component optimization and structure control two aspects, realizes the CMAS protection effect of active / passive combination, improves the anti-CMAS infiltration and corrosion performance of coating.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of hot corrosion and protection of thermal barrier coating surfaces, and particularly relates to a biomimetic thermal barrier coating resistant to CMAS infiltration and a preparation method. BACKGROUND

[0002] In recent years, with the continuous development of aerospace technology, the thrust-to-weight ratio of turbine engines is continuously increasing, and the temperature of the turbine inlet is also continuously increasing. The design inlet temperature of the turbine of an aero-engine with a thrust-to-weight ratio of 12-15 has reached 2100-2200K, far exceeding the temperature limit of the single-crystal high-temperature alloy material used in the turbine blades. To solve this problem, a coating with high thermal insulation performance, i.e., a thermal barrier coating, can be deposited on the surface of the high-temperature alloy. During the service of the aero-engine, dust (such as sand, dust, and volcanic ash, mainly composed of CaO-MgO-Al2O3-SiO2, referred to as CMAS) in the atmosphere will inevitably be sucked into the aero-engine, melt and deposit on the surface of the blade under the action of high temperature, block the film cooling holes, corrode and damage the thermal barrier coating, and seriously threaten the safety of aviation.

[0003] In view of the CMAS corrosion problem faced by the thermal barrier coating, domestic and foreign scholars have carried out a large amount of research and put forward effective protection methods, mainly focusing on the following three aspects:

[0004] (1) Physical barrier method: depositing a dense high-temperature stable inert metal layer (such as Pd-Ag layer) on the surface of the thermal barrier coating to achieve physical isolation of the molten CMAS and the thermal barrier coating, thereby blocking the penetration of the molten CMAS into the coating;

[0005] (2) Chemical reaction method: doping TiO2, Al2O3, etc. oxides in yttria-stabilized zirconia (YSZ) material or depositing a new material protection layer (such as Gd2Zr2O7, LaMgAl 11 O 19 , etc.) on the surface, which reacts violently with the molten CMAS to generate a dense high-temperature stable phase, which can not only consume CMAS but also block the continuous penetration of molten CMAS;

[0006] (3) Structure optimization method: using polishing, laser etching, laser cladding, etc. to change the surface microstructure and roughness of the thermal barrier coating, reduce the infiltration tendency of the molten CMAS on the surface, and reduce the contact area between the two, thereby weakening the corrosion and damage of the molten CMAS to the thermal barrier coating.

[0007] The high-temperature infiltration behavior of molten CMAS on the surface of thermal barrier coating is similar to the wetting and spreading process of water droplets on the surface of solid materials at room temperature. Inspired by the principle of bionics, the deposition of thermal barrier coating with micro-nano features becomes the key to alleviate the CMAS corrosion problem, and there are few relevant public reports. The published patent (CN114457307B) combines femtosecond laser and surface carbon spraying technology to construct a micro-nano structure similar to a lotus leaf on the surface of YSZ coating, which realizes complete non-infiltration of molten CMAS in a vacuum environment. However, under atmospheric conditions closer to the real service environment of the engine, the protective effect of the coating is greatly reduced. The published patent (CN106086765B) uses plasma spraying physical vapor deposition (PS-PVD) technology to prepare a micro-nano structure protective layer on the surface of the YSZ coating, which shows good wetting resistance to molten CMAS. However, the protective layer prepared by this technology is a quasi-columnar crystal structure, and the vertical pores between the columns exacerbate the penetration of CMAS. The published patent (CN114752881B) uses solution precursor plasma spraying (SPPS) technology to prepare a micro-nano structure ceramic top layer on the surface of the ceramic base layer to improve the CMAS corrosion resistance. However, this scheme uses pure YSZ and Yb-doped YSZ (YbYSZ) as the top layer material, which is prone to chemical reaction with molten CMAS and thus induces coating failure. SUMMARY

[0008] In order to overcome the deficiencies of the prior art, the present application provides a bionic thermal barrier coating resistant to CMAS infiltration and a preparation method. From the perspective of material selection and preparation process optimization, the present application provides a micro-nano structure bionic thermal barrier coating with excellent comprehensive performance and a preparation method. The micron-scale cluster protrusions and nano-scale particles on the surface of the bionic thermal barrier coating of the present application cooperate with each other to effectively increase the contact angle of molten CMAS, thereby improving the resistance to CMAS infiltration and corrosion.

[0009] To achieve the above-mentioned purpose, the present application provides the following solutions:

[0010] One of the technical solutions of the present application is a bionic thermal barrier coating resistant to CMAS infiltration, which comprises, from the substrate, in order: a metal bonding layer, an inner ceramic layer, and a micro-nano structure outer ceramic layer.

[0011] The micro-nano structure outer ceramic layer is NdYbZr2O7.

[0012] The second technical solution of the present application is a preparation method of the above-mentioned bionic thermal barrier coating resistant to CMAS infiltration, which uses suspension plasma spraying technology to prepare a micro-nano structure outer ceramic layer on the surface of the inner ceramic layer.

[0013] The third technical solution of the present application is the application of the above-mentioned bionic thermal barrier coating resistant to CMAS infiltration in a turbine engine.

[0014] The present application discloses the following technical effects:

[0015] (1) The present application selects a new type of NdYbZr2O7 material as the outer ceramic layer material, and simultaneously based on the suspension plasma spraying technology, realizes the CMAS protection effect of the combination of the main and passive from the aspects of material component optimization and structure regulation, and makes up for the deficiencies of the prior art. On the one hand, the NdYbZr2O7 material has high chemical reactivity, can rapidly react with CMAS at high temperature, and generates dense arranged apatite grains to block the continuous penetration of CMAS to the inside of the coating; on the other hand, the cross-scale micro-nano structure can reduce the infiltration tendency of the molten CMAS at high temperature (1250℃), and reduce the corrosion contact area of the molten CMAS on the surface of the coating.

[0016] (2) The outer ceramic layer prepared by using the suspension plasma spraying technology not only has the micro-nano structure characteristics, but also has a relatively loose structure, the pores and micro-cracks in the coating are small and uniformly distributed, and a large strain tolerance is exhibited. Such structural characteristics can effectively relieve the thermal stress of the coating in the cold and hot cycle process, avoid the premature peeling failure of the coating, and prolong the service life of the coating.

[0017] (3) The anti-CMAS infiltration biomimetic thermal barrier coating prepared according to the present application uses a double ceramic layer structure (an inner ceramic layer and a micro-nano structure outer ceramic layer), which improves the CMAS protection effect while ensuring the overall performance of the thermal barrier coating system. The thermal expansion coefficient of the YSZ material is about 10×10 -6 -11×10 -6 K -1 between 200-1200℃, which is between the metal bonding layer material and the NdYbZr2O7 material, and exists between the metal bonding layer and the micro-nano structure outer ceramic layer as an inner ceramic layer, so that there is a gradient change in the thermal expansion coefficient between the layers, and the risk of cracking or even peeling of the coating due to excessive thermal stress is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments. Obviously, the drawings in the following description only constitute some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained from these drawings without creative labor.

[0019] Figure 1 is a schematic diagram of the anti-CMAS infiltration biomimetic thermal barrier coating structure system of the present application.

[0020] Figure 2These are surface morphology images of the outer ceramic layer of the NdYbZr2O7 micro / nano structure in Embodiment 1 of the present invention; wherein, a is a surface morphology image at low magnification; and b is a surface morphology image at high magnification.

[0021] Figure 3 These are surface morphology images of lotus leaves; where a is the surface morphology image at low magnification and b is the surface morphology image at high magnification. Detailed Implementation

[0022] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0023] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0024] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0025] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be obvious to those skilled in the art. This specification and embodiments are merely exemplary.

[0026] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0027] The first aspect of the present invention provides a biomimetic thermal barrier coating that resists CMAS wetting, which, starting from the substrate and from the inside out, sequentially includes: a metal bonding layer, an inner ceramic layer, and a micro-nano structured outer ceramic layer;

[0028] The outer ceramic layer of the micro / nano structure is NdYbZr2O7.

[0029] NdYbZr2O7 has a low thermal conductivity (1.26 W·m). -1 ·K -1 (1200℃) and high fracture toughness (1.50MPa·m) 1 / 2 With advantages such as excellent thermal protection and thermal shock resistance, NdYbZr2O7 exhibits higher resistance to high-temperature sintering and CMAS corrosion than traditional YSZ materials.

[0030] In some embodiments of the present invention, the metal bonding layer is NiAl or MCrAlY; wherein M is Ni and / or Co.

[0031] In some embodiments of the present invention, the inner ceramic layer is yttrium oxide-stabilized zirconium oxide.

[0032] In some embodiments of the present invention, the thickness of the metal bonding layer is 50-80 μm; the thickness of the inner ceramic layer is 100-180 μm; and the thickness of the outer ceramic layer of the micro / nano structure is 60-100 μm.

[0033] In some embodiments of the present invention, the surface of the outer ceramic layer of the micro-nano structure contains a large number of micro-nano hierarchical structures, that is, the surface of the outer ceramic layer of the micro-nano structure is distributed with a large number of clusters and protrusions with a size of 60-100μm and particles with a size of 200-700nm; more preferably, the size of the clusters and protrusions is controlled at about 70μm.

[0034] A second aspect of the present invention provides a method for preparing the above-mentioned biomimetic thermal barrier coating that resists CMAS wetting, wherein a micro-nano structured outer ceramic layer is prepared on the surface of an inner ceramic layer using a suspension plasma spraying technique.

[0035] In some embodiments of the present invention, the process parameters of the suspension plasma spraying technology are as follows: working voltage is 60-70V, working current is 600-700A, argon flow rate is 70-80L / min, hydrogen flow rate is 20-30L / min, powder feeding rate is 6-10g / min, and spraying distance is 80-140mm.

[0036] In some embodiments of the present invention, the solid content of NdYbZr2O7 nanopowder in the NdYbZr2O7 suspension used to prepare the micro / nano structure outer ceramic layer is 40-60 wt%; the NdYbZr2O7 suspension also contains PEG1000 surfactant; the mass concentration of PEG1000 surfactant is 1-3 wt%; and the solvent of the NdYbZr2O7 suspension is anhydrous ethanol.

[0037] In this invention, the preparation method of NdYbZr2O7 suspension includes the following steps: NdYbZr2O7 nanopowder with a solid content of 40-60wt% and PEG1000 surfactant with 1-3wt% are added to anhydrous ethanol, and then ball-milled and filtered in a planetary ball mill to obtain a slurry with uniform composition, which is NdYbZr2O7 suspension.

[0038] In this invention, the grinding media used in the ball milling process are zirconia balls with diameters of 1 mm, 3 mm, and 5 mm, respectively, in a weight ratio of 3:4:3.

[0039] In some embodiments of the present invention, the preparation of the micro / nano structure outer ceramic layer includes the steps of preparing a metal bonding layer on the substrate surface and preparing the micro / nano structure outer ceramic layer on the surface of the metal bonding layer before the preparation of the micro / nano structure outer ceramic layer.

[0040] In this invention, the base material is a high-temperature alloy; the dimensions can be Φ12.7mm×4mm.

[0041] In some embodiments of the present invention, the process of preparing the metal bonding layer further includes a step of sandblasting the high-temperature alloy substrate and cleaning it with acetone; the sandblasting medium is 120-220 mesh Al2O3 sand particles, and the pressure is 0.2-0.5 MPa.

[0042] In some embodiments of the present invention, the metal bonding layer is prepared by atmospheric plasma spraying, supersonic flame spraying or arc spraying technology;

[0043] When preparing the metal bonding layer, the specific parameters for atmospheric plasma spraying are: working voltage of 55-70V, working current of 600-700A, argon flow rate of 40-60L / min, hydrogen flow rate of 3-8L / min, powder feed rate of 20-30g / min, and spraying distance of 100-130mm; the specific parameters for supersonic flame spraying are: oxygen flow rate of 2000-2200SCFH, carrier gas of 9-13SCFH, kerosene flow rate of 6-7GPH, powder feed rate of 5-8r / min, and spraying distance of 350-400mm; the specific parameters for arc spraying are: working voltage of 30-34V, working current of 210-230A, atomizing air pressure of 0.5-0.8MPa, and spraying distance of 120-180mm.

[0044] In some embodiments of the present invention, the inner ceramic layer is prepared by atmospheric plasma spraying, supersonic flame spraying, or electron beam physical vapor deposition.

[0045] The specific parameters for atmospheric plasma spraying in preparing the inner ceramic layer are as follows: working voltage 70-90V, working current 600-700V, argon flow rate 80-90L / min, hydrogen flow rate 8-15L / min, powder feed rate 20-30g / min, and spraying distance 80-90mm; the specific parameters for supersonic flame spraying are as follows: oxygen flow rate 1800-2100SCFH, carrier gas 10-13SCFH, kerosene flow rate 6-7GPH, powder feed rate 5-8r / min, and spraying distance 300-400mm; the specific parameters for electron beam physical vapor deposition are as follows: vacuum degree 1×10⁻⁶. -2 -5×10 -2 Pa, electron beam voltage of 23-28 kW, oxygen flow rate of 250-350 cm⁻¹ 3 The substrate preheating temperature is 800-900℃, and the rotation speed is 10-30 rpm.

[0046] This invention provides a method for preparing a biomimetic thermal barrier coating resistant to CMAS wetting. The method employs SPS technology to prepare a micro / nano-structured outer ceramic layer, overcoming the limitations of traditional plasma spraying with solid powder feed, and using a suspension of nanopowder as the spraying material. The ceramic layer prepared according to this method contains a large number of micron-scale clusters and nano-scale particles on its surface. This multi-level micro / nano structure can inhibit the wetting and spreading of CMAS at high temperatures, increase the contact angle of molten CMAS, and suppress CMAS adhesion, penetration, and corrosion, thereby improving the coating's resistance to CMAS wetting and corrosion.

[0047] A third aspect of the present invention provides the application of the above-mentioned biomimetic thermal barrier coating that resists CMAS wetting in a turbine engine.

[0048] Unless otherwise specified, all raw materials used in the embodiments of this invention can be obtained through commercial channels.

[0049] The present invention will be further illustrated by specific embodiments below.

[0050] Example 1

[0051] One such Figure 1 The biomimetic thermal barrier coating structure system shown consists of, from bottom to top, a metal bonding layer, an inner YSZ ceramic layer, and an outer NdYbZr2O7 micro / nano structure ceramic layer.

[0052] The metal substrate used in this embodiment is DD6 single crystal high-temperature alloy. Before preparing the metal bonding layer, it is first sandblasted with 150-mesh corundum sand at a pressure of 0.5 MPa, and then cleaned and dried in acetone solution.

[0053] A NiCrAlY metal binder layer was deposited on the surface of a DD6 substrate using atmospheric plasma spraying technology. Prior to spraying, the substrate surface was preheated to 400℃±20℃ using a spray gun. The main process parameters were: operating voltage 60V, operating current 650A, argon flow rate 50L / min, hydrogen flow rate 5L / min, powder feed rate 20g / min, and spraying distance 120mm. The binder layer thickness was controlled at 80μm±10μm.

[0054] A YSZ inner ceramic layer was deposited on the surface of the NiCrAlY binder using atmospheric plasma spraying technology. Prior to spraying, the surface of the metal binder was preheated to 600℃±20℃ using a spray gun. The main process parameters were: operating voltage 80V, operating current 600A, argon flow rate 80L / min, hydrogen flow rate 10L / min, powder feed rate 25g / min, and spraying distance 80mm. The thickness of the inner ceramic layer was controlled at 150μm±10μm.

[0055] The NdYbZr2O7 micro / nano structured outer ceramic layer is deposited on the surface of the inner ceramic layer of YSZ using suspension plasma spraying technology, and the following steps are taken:

[0056] (1) Preparation of suspension: NdYbZr2O7 nanoparticles with an average particle size of 50nm and PEG1000 surfactant were added to anhydrous ethanol, wherein the solid content of NdYbZr2O7 nanoparticles was 40wt% and the content of PEG1000 surfactant was 1wt%. Then, the mixture was ball-milled and filtered in a planetary ball mill. The ball milling media used in the ball milling process were zirconia balls with diameters of 1mm, 3mm and 5mm, respectively, in a weight ratio of 3:4:3. After ball milling for 4 hours, a slurry (suspension) with uniform composition was obtained.

[0057] (2) Spraying: A NdYbZr2O7 micro / nano structure outer ceramic layer was deposited on the surface of the inner ceramic layer of YSZ using suspension plasma spraying technology. Before spraying, the surface of the inner ceramic layer of YSZ was preheated to 700℃±20℃ using a spray gun. The main process parameters used were: working voltage 60V, working current 600A, argon flow rate 80L / min, hydrogen flow rate 20L / min, powder feed rate 7g / min, and spraying distance 120mm. The thickness of the outer ceramic layer was controlled at 80μm±10μm.

[0058] Figure 2 The surface morphology of the NdYbZr2O7 micro / nano structure outer ceramic layer prepared in this embodiment shows that the coating surface consists of clusters of protrusions with a size of approximately 80 μm and a large number of randomly distributed particles with a diameter of approximately 600 nm. Figure 3The surface structure of the lotus leaf shown is similar. YSZ material has advantages such as low thermal conductivity, high fracture toughness, and moderate coefficient of thermal expansion. As an inner ceramic layer between the metal bonding layer and the micro / nano structure outer ceramic layer, it can effectively alleviate the problem of thermal stress concentration caused by the difference in the coefficient of thermal expansion within the coating system, and prevent premature cracking or even peeling failure of the coating during service. In addition, the YSZ inner ceramic layer prepared by atmospheric plasma spraying technology has a typical lamellar structure and low thermal conductivity, which can provide excellent thermal protection.

[0059] CMAS powder was pressed into small cylinders with a diameter and height of 3 mm, and placed on the surfaces of NdYbZr2O7 micro / nanostructure coatings and conventional YSZ coatings, respectively, and held at 1200℃ for 20 min. Compared with the conventional YSZ coating, the CMAS contact angle on the NdYbZr2O7 micro / nanostructure coating surface increased by nearly 30° (approximately 108°), reducing the contact area of ​​CMAS and thus significantly improving the resistance to CMAS wetting and corrosion.

[0060] Example 2

[0061] The metal substrate used in this embodiment is DZ125 directional solidification high-temperature alloy. Before preparing the bonding layer, it is first sandblasted with 220-mesh corundum sand at a pressure of 0.4 MPa, and then cleaned and dried in acetone solution.

[0062] A NiCoCrAlY metal binder layer was deposited on the surface of a DZ125 substrate using supersonic flame spraying technology. Prior to spraying, the substrate was heated to 300℃±20℃. The main process parameters used were: oxygen flow rate of 2000 SCFH, carrier gas of 10 SCFH, kerosene flow rate of 6 GPH, powder feed rate of 6 r / min, and spraying distance of 380 mm. The thickness of the binder layer was controlled at 50 μm±10 μm.

[0063] A YSZ inner ceramic layer was deposited on the surface of a NiCoCrAlY metal binder using supersonic flame spraying technology. Prior to spraying, the binder was heated to 300℃±20℃. The main process parameters used were: oxygen flow rate of 1800 SCFH, carrier gas of 12 SCFH, kerosene flow rate of 7 GPH, powder feed rate of 8 r / min, and spraying distance of 350 mm. The thickness of the inner ceramic layer was controlled at 100 μm±10 μm.

[0064] A NdYbZr2O7 micro / nano structured outer ceramic layer was deposited on the surface of the inner ceramic layer of YSZ using suspension plasma spraying technology. The specific steps were similar to those in Example 1.

[0065] (1) Preparation of suspension: NdYbZr2O7 nanoparticles with an average particle size of 50nm and PEG1000 surfactant were added to anhydrous ethanol, wherein the solid content of NdYbZr2O7 nanoparticles was 50wt% and the content of PEG1000 surfactant was 2wt%. Then, the mixture was ball-milled and filtered in a planetary ball mill. The ball milling media used in the ball milling process were zirconia balls with diameters of 1mm, 3mm and 5mm, respectively, in a weight ratio of 3:4:3. After ball milling for 5h, a slurry with uniform composition was obtained.

[0066] (2) Spraying: A NdYbZr2O7 micro / nano structure outer ceramic layer was deposited on the surface of the inner ceramic layer of YSZ using suspension plasma spraying technology. Before spraying, the surface of the inner ceramic layer of YSZ was preheated to 700℃±20℃ using a spray gun. The main process parameters used were: working voltage 70V, working current 650A, argon flow rate 80L / min, hydrogen flow rate 25L / min, powder feed rate 6g / min, and spraying distance 100mm. The thickness of the outer ceramic layer was controlled at 80μm±10μm.

[0067] The surface of the NdYbZr2O7 micro / nano structure outer ceramic layer prepared in this embodiment consists of clusters of protrusions with a size of approximately 80 μm and a large number of randomly distributed particles with a diameter of approximately 600 nm. Compared with atmospheric plasma spraying, the YSZ inner ceramic layer prepared by supersonic flame spraying is more dense, with a porosity of only about 2%, which can effectively prevent oxygen permeation and molten CMAS penetration, thereby improving the overall performance stability of the coating system.

[0068] Wetting experiments of CMAS on the coating surface were conducted at 1200℃. It was found that the CMAS contact angle on the NdYbZr2O7 micro-nano structure coating surface was about 105°, showing excellent resistance to CMAS wetting and corrosion.

[0069] Example 3

[0070] In this embodiment, the metal substrate used is N5 high-temperature alloy. Before preparing the adhesive layer, it is first sandblasted with 180-mesh corundum sand at a pressure of 0.4 MPa, and then cleaned and dried in acetone solution.

[0071] A NiAl metal binder layer was deposited on the surface of an N5 substrate using arc spraying technology. The main process parameters were: operating voltage of 32V, operating current of 220A, atomizing air pressure of 0.6MPa, and spraying distance of 120mm. The thickness of the binder layer was controlled to be around 100μm.

[0072] A YSZ inner ceramic layer was deposited on the surface of a NiAl metal binder using electron beam physical vapor deposition (EBPV). First, a Φ70mm × 100mm YSZ target was prepared by cold isostatic pressing and high-temperature sintering. Then, the target was placed in a crucible within the EBPV apparatus, and the chamber door was closed. The deposition chamber was then evacuated to 5 × 10⁻⁵ mm. -2 Pa, the substrate was preheated to 800℃±20℃, the electron beam voltage was adjusted to 24kW, and the oxygen flow rate was 280cm. 3 The substrate rotation speed was 30 rpm. The YSZ target was melted using a high-energy electron beam, and the target evaporated and deposited on the NiAl binder surface. After 1 hour of deposition, the thickness of the ceramic layer within the YSZ was approximately 150 μm.

[0073] A NdYbZr2O7 micro / nano structured outer ceramic layer was deposited on the surface of the inner ceramic layer of YSZ using suspension plasma spraying technology. The specific steps were similar to those in Example 1.

[0074] (1) Preparation of suspension: NdYbZr2O7 nanoparticles with an average particle size of 50nm and PEG1000 surfactant were added to anhydrous ethanol, wherein the solid content of NdYbZr2O7 nanoparticles was 60wt% and the content of PEG1000 surfactant was 3wt%. Then, the mixture was ball-milled and filtered in a planetary ball mill. The ball milling media used in the ball milling process were zirconia balls with diameters of 1mm, 3mm and 5mm, respectively, in a weight ratio of 3:4:3. After ball milling for 8 hours, a slurry with uniform composition was obtained.

[0075] (2) Spraying: A NdYbZr2O7 micro / nano structure outer ceramic layer was deposited on the surface of the inner ceramic layer of YSZ using suspension plasma spraying technology. Before spraying, the surface of the inner ceramic layer of YSZ was preheated to 700℃±20℃ using a spray gun. The main process parameters were: working voltage 65V, working current 600A, argon flow rate 70L / min, hydrogen flow rate 25L / min, powder feed rate 8g / min, and spraying distance 120mm. The thickness of the outer ceramic layer was controlled at 80μm±10μm.

[0076] The surface of the prepared NdYbZr2O7 micro / nano structure outer ceramic layer consists of clusters of protrusions approximately 80 μm in size and a large number of randomly distributed particles approximately 600 nm in diameter. In this embodiment, the YSZ inner ceramic layer is prepared by electron beam physical vapor deposition, exhibiting high bonding strength with the binder layer and a typical columnar crystal structure with high strain tolerance, thus improving the thermal shock and corrosion resistance of the coating system.

[0077] High-temperature wetting experiments revealed that the contact angle of CMAS on the surface of the NdYbZr2O7 micro / nano structure coating was significantly larger than that on the surface of the traditional YSZ coating. The CMAS contact angle on the surface of the NdYbZr2O7 micro / nano structure coating was approximately 110°, indicating that the biomimetic micro / nano structure coating prepared in this embodiment has excellent anti-CMAS wetting properties.

[0078] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A biomimetic thermal barrier coating resistant to CMAS wetting, characterized in that, Starting from the substrate, from the inside out, it includes: a metal bonding layer, an inner ceramic layer, and a micro / nano structure outer ceramic layer; The outer ceramic layer of the micro / nano structure is NdYbZr2O7; the surface of the outer ceramic layer of the micro / nano structure is composed of micron-scale clusters and nano-scale particles. The metal bonding layer is NiAl or MCrAlY; where M is Ni and / or Co. The inner ceramic layer is yttrium oxide stabilized zirconium oxide; The thickness of the metal bonding layer is 50-80 μm; the thickness of the inner ceramic layer is 100-180 μm; and the thickness of the outer ceramic layer of the micro / nano structure is 60-100 μm. A micro-nano structured outer ceramic layer was prepared on the surface of the inner ceramic layer using suspension plasma spraying technology; The process parameters of the suspension plasma spraying technology are as follows: working voltage is 60-70V, working current is 600-700A, argon flow rate is 70-80L / min, hydrogen flow rate is 20-30L / min, powder feeding rate is 6-10g / min, and spraying distance is 80-140mm. The solid content of NdYbZr2O7 nanopowder in the NdYbZr2O7 suspension used to prepare the micro-nano structure outer ceramic layer is 40-60 wt%.

2. The biomimetic thermal barrier coating against CMAS wetting according to claim 1, characterized in that, The process includes the steps of preparing a metal bonding layer on the substrate surface and preparing the micro-nano structure outer ceramic layer on the surface of the metal bonding layer before preparing the micro-nano structure outer ceramic layer.

3. The biomimetic thermal barrier coating against CMAS wetting according to claim 2, characterized in that, The metal bonding layer is prepared by atmospheric plasma spraying, supersonic flame spraying or arc spraying technology; the inner ceramic layer is prepared by atmospheric plasma spraying, supersonic flame spraying or electron beam physical vapor deposition technology.

4. The application of the biomimetic thermal barrier coating with anti-CMAS wetting as described in any one of claims 1-3 in a turbine engine.

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