A high-temperature resistant laser-modified CMAS structure Al2O3-YSZ coating and its preparation method

Abstract

The application provides a high-temperature-resistant laser-modified CMAS-structure-resistant Al2O3-YSZ coating and a preparation method thereof. The coating comprises a metal bonding layer and an Al2O3-YSZ composite ceramic layer prepared on the surface of a high-temperature alloy in sequence. The AYSZ layer is an Al2O3-doped modified YSZ coating obtained by electron beam physical vapor deposition (EB-PVD). The top of the AYSZ layer is treated by a femtosecond laser to form a composite structure comprising a micron-level conical array and nanosynapses. The surface of the top of the ceramic layer is modified by using the ultrafast femtosecond laser processing technology, which can effectively change the surface roughness of the coating under high-temperature conditions, and then has a good alienation and anti-infiltration effect on the immersion of molten CMAS. At the same time, the micro-nano structure modified by the laser is stable, and can still maintain a good effect of alienating the infiltration of molten CMAS under long-time high-temperature conditions.

Description

Technical Field

[0001] This invention relates to the field of thermal barrier coating preparation and high-temperature corrosion protection technology, specifically to a high-temperature resistant laser-modified CMAS structure Al2O3-YSZ coating and its preparation method. Background Technology

[0002] As turbine inlet temperatures in aero-engines continue to rise, molten deposits with a primary chemical composition of CaO-MgO-Al2O3-SiO2 (CMAS) cause a significant decline in the lifespan and service performance of thermal barrier coatings (TBCs) on core hot-end components of the engine, particularly for yttrium-stabilized zirconium oxide (6-8 wt.% YSZ) prepared using the commonly used electron beam physical vapor deposition (EB-PVD) technique. On one hand, YSZ readily reacts chemically with CMAS components, disrupting the original YSZ structure and leading to premature coating peeling. On the other hand, the unique columnar structure of the EB-PVD coating provides channels for the seepage of tiny molten CMAS droplets through the inter-column gaps.

[0003] Currently, there are three main types of protective coatings for CMAS protection: dense, sacrificial, and anti-wetting. Dense coatings are prepared by creating an inert, dense ceramic top layer to prevent the seepage of molten CMAS. Sacrificial coatings are mainly created by modifying ceramics to participate in the CMAS reaction and generate high-melting-point inert compounds to provide CMAS protection. Both of these methods protect the coating from a chemical perspective.

[0004] In recent years, with the development of laser micromachining technology, researchers have discovered that by constructing anti-wetting coatings / structures through laser surface structure optimization methods, the contact area between the coating and molten CMAS can be reduced, thereby achieving physical protection. This method is quick, has a very small heat-affected zone, and also has the advantages of simple operation, wide applicability, high processing accuracy and efficiency, and low cost, showing good application prospects (see Reference 1: Advanced Science, 2023: 2205156.).

[0005] Studies have shown that, compared to YSZ materials, the Al2O3 phase is usually more compact. The introduction of Al2O3 causes a certain amount of amorphous phase to be generated in the YSZ coating. The amorphous phase will recrystallize into the corresponding stable phase and form a nanostructure. Furthermore, due to the incorporation of Al2O3, a certain compressive stress can be generated on the growth of ZrO2 lattice, making it difficult for ZrO2 grains to grow and maintaining its high-temperature stability (see reference 2: Advanced Functional Materials, 2011, 21(21): 4143-4151.). Summary of the Invention

[0006] In view of this, the present invention proposes a thermal barrier coating system comprising a metal bonding layer, an AYSZ ceramic layer, and a surface modification layer sequentially prepared on the surface of a high-temperature alloy. An Al2O3-YSZ composite coating is formed by modifying the YSZ coating with Al2O3, and the surface structure of the coating is modified using a laser method. This system provides synergistic protection against the penetration of molten CMAS while also improving the coating's resistance to high-temperature sintering to a certain extent. The prepared AYSZ ceramic layer exhibits low thermal conductivity, long-term high-temperature stability, and good resistance to high-temperature sintering. The surface modification layer, constructed on the top surface of the AYSZ using femtosecond laser design, features a composite structure with a micron-scale conical array and nanosynapses, effectively preventing the penetration of molten CMAS into the coating.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] A high-temperature resistant laser-modified CMAS structure Al2O3-YSZ coating comprises a metal bonding layer and an Al2O3-YSZ composite ceramic layer (AYSZ layer) sequentially prepared on the surface of a high-temperature alloy.

[0009] The AYSZ layer is an Al2O3-doped modified YSZ coating obtained by electron beam physical vapor deposition (EB-PVD); further, the Al2O3 content in the YSZ layer is 22~28 wt.%, the Y2O3 content is 6~8 wt.%, and the layer thickness is 120~180 μm;

[0010] The top of the AYSZ layer (i.e., the side of the AYSZ layer away from the high-temperature alloy) is treated with a femtosecond laser to form a composite structure comprising a micron-scale conical array and nanosynapses. This composite structure can alter the wetting state of the coating surface, further effectively mitigating and repelling the adhesion and penetration of molten CMAS.

[0011] A method for preparing a high-temperature resistant laser-modified CMAS structured Al2O3-YSZ coating includes the following steps:

[0012] S1. Pretreatment of high-temperature alloys;

[0013] S2. A metal bonding layer is deposited on the surface of the high-temperature alloy after the S1 pretreatment, followed by heat treatment.

[0014] S3. A ceramic layer is prepared on the surface of the metal bonding layer after heat treatment in S2 using the EB-PVD method.

[0015] S4. The surface of the top of the ceramic layer prepared in S3 is modified using femtosecond laser processing technology.

[0016] Optionally, in step S1, the high-temperature alloy is DD6 nickel-based single-crystal high-temperature alloy.

[0017] Optionally, in step S1, the pretreatment includes sequentially sanding the surface of the high-temperature alloy, cleaning with an organic solvent, and sandblasting, wherein the organic solvent is preferably ethanol.

[0018] Optionally, in step S2, the material of the metal bonding layer is selected from one of the following three types: the first type is NiAlHf, whose composition includes 40~60 wt.% Ni, 36~60 wt.% Al and 0.05~2 wt.% Hf; the second type is NiCrAlYSi, whose composition includes 40~62 wt.% Ni, 14~26 wt.% Cr, 15~20 wt.% Al, 0.05~2 wt.% Y and 0.05~2 wt.% Si; the third type is NiPtAl, whose composition includes 40~62 wt.% Ni, 18~20 wt.% Pt and 30~45 wt.% Al.

[0019] Optionally, in step S2, the metal bonding layer is deposited using one of the following three methods: preparing a NiAlHf metal layer using electron beam physical vapor deposition (EB-PVD), preparing a NiCrAlYSi metal layer using multi-arc ion plating, or preparing a NiPtAl metal layer using electroplating and embedding; the total thickness of the metal bonding layer is 30~50μm.

[0020] Optionally, in step S2, the specific steps for preparing the NiAlHf binder layer using electron beam physical vapor deposition are as follows: the pretreated high-temperature alloy substrate is placed on the rotating substrate of the electron beam physical vapor deposition equipment, the target material to be evaporated is placed in a water-cooled copper crucible, and the deposition chamber is evacuated to 10°C. -3 ~10 -2 Pa, the substrate is preheated to 820~920℃, the electron beam voltage is adjusted to 18~21kV, the electron beam current is 1.0A~1.2A, the high-temperature alloy substrate rotation speed is 10~12rpm, and the deposition time is 20~30min, to obtain an adhesive layer with a thickness of 30~50μm.

[0021] Optionally, in step S2, the specific steps for preparing the NiCrAlYSi bonding layer using the multi-arc ion plating method are as follows: The high-temperature alloy substrate is placed on the sample stage of the vacuum chamber, the distance between the high-temperature alloy substrate and the target is set to 250 mm, the sample holder rotation speed is 7 rpm, the vacuum chamber temperature is 480℃, and the vacuum degree inside the furnace chamber during ion bombardment is 3.5 × 10⁻⁶. -3 Pa was used to clean and activate the substrate surface. Coating preparation consisted of two stages: the first stage prepared a NiCrAlYSi underlayer, and the second stage prepared the NiCrAlYSi coating. The reactant gas was N2 at a flow rate of 32 sccm, and the pressure was controlled at 1.5 Pa. The substrate bias voltage was -85 V, the arc current was 110 A, and the deposition time was 60–90 min, resulting in a binder layer with a thickness of 30–50 μm.

[0022] Optionally, in step S2, the specific steps for preparing the NiPtAl metal bonding layer using electroplating and embedding methods are as follows: 30 g / L diammonium nitrite platinum (Pt(NH3)2(NO2)2), 180 g / L ammonium nitrate (NH4NO3), 18 g / L sodium nitrite (NaNO2), and 82 g / L ammonia water (NH3·H2O) are uniformly mixed in a reaction vessel to form a Pt plating solution. The Pt plating solution is then heated to 75°C. The high-temperature alloy is further placed in the Pt plating solution, and the current is set to 0.8~1.0 mA / mm. 2 The electroplating time is 50-70 min to prepare an electroplated Pt layer with a thickness of 4-5 μm. The Pt layer is then aluminized by embedding method with the following process parameters: holding temperature 950-1000℃ and holding time 80-100 min to finally prepare a NiPtAl bonding layer with a thickness of 30-50 μm.

[0023] Optionally, in step S2, the heat treatment parameters include: a heat treatment temperature of 1000~1100℃, a time of 2~3h, and a vacuum degree of 7.5~9.0×10⁻⁶. -5 mbar, cooled to room temperature in a vacuum furnace and then removed.

[0024] Optionally, in step S3, the ceramic layer is prepared as follows: a high-temperature alloy with a metal bonding layer is placed on an electron beam physical vapor deposition (EBPV) rotating substrate, the target to be vaporized is placed in an EBPV crucible, and the vacuum degree of the deposition chamber is 10. -3 The substrate was preheated to 900-950℃, the oxygen flux was set to 100-110 sccm, the voltage was controlled at 19-20 kV, the substrate rotation speed of the high-temperature alloy was kept constant at 15 rpm, and the target rotation speed was 0.8 r / min. Using Al2O3-YSZ target material, with an electron beam current of 0.65-0.75 A and a deposition time of 70-100 min, an AYSZ layer of 120-180 μm could be obtained.

[0025] Optionally, in step S3, the prepared AYSZ ceramic layer has an Al2O3 content of 22~28 wt.%, a Y2O3 content of 6~8 wt.%, and a thickness of 120~180 μm.

[0026] Optionally, in step S4, the process parameters for the femtosecond laser processing are: pulse processing power of 2~6W, pulse frequency of 100~180kHz, pulse width of 100~400fs, wavelength of 1040nm, and scanning speed of 100~800mm / s. This invention mainly limits the laser processing power and pulse frequency. If the processing power is too low, the resulting array structure size will be too small, making it difficult to prevent the melt from penetrating into the coating. If the power is too high, the depth and spacing of the periodic array will be too large, damaging the original AYSZ coating and affecting other performance characteristics. If the pulse frequency is too high, it will affect the energy per unit of processing during laser use, potentially preventing the formation of a complete array structure.

[0027] Optionally, in step S4, the micro / nano structure formed on the surface of the AYSZ ceramic layer by femtosecond laser processing is a composite structure composed of a micron-scale conical array and nano-synapses. The spacing of the micron-scale conical array is 40~60μm, and nano-scale synaptic structures are attached to its surface, which can change the wetting state of the coating surface and effectively alleviate and repel the adhesion and penetration of molten CMAS.

[0028] Compared with the prior art, the present invention has the following advantages:

[0029] 1. The AYSZ ceramic layer was prepared by the EB-PVD method, which has high deposition efficiency, precise control of coating thickness and composition, good bonding between ceramic and metal layers, excellent thermal shock resistance of the entire coating system, and long coating life.

[0030] 2. Al2O3-YSZ (AYSZ) is used as the ceramic top layer. The alumina doping generates a certain compressive stress on the ZrO2 lattice growth, making it difficult for ZrO2 grains to grow and maintaining its high-temperature stability, thereby further improving the anti-sintering performance of the entire coating system. On the other hand, the incorporation of Al2O3 forms an AYSZ coating that is more compact than the YSZ layer. It is also conducive to forming a high-melting-point dense compound with the unblocked molten CMAS, playing the role of a sacrificial coating and playing a certain anti-CMAS characteristic.

[0031] 3. The surface of the top of the ceramic layer is modified using ultrafast femtosecond laser processing technology. This method is simple to operate, has a wide range of applications, high processing accuracy and efficiency, and low cost. It can effectively process composite structures formed by micron-scale conical arrays and nanosynapses, change the surface roughness of the coating under high temperature conditions, and thus play a good role in repelling and anti-wetting of molten CMAS. At the same time, the micro-nano structure modified by laser is stable and can still maintain a good effect of repelling molten CMAS penetration under long-term high temperature conditions. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 This is a schematic diagram of the coating structure of the present invention, wherein (a) is a cross-section of the coating; and (b) is an enlarged microstructure of the top of the ceramic layer after surface modification.

[0034] Figure 2 The image shows the top morphology of the ceramic layer after femtosecond laser modification in Example 1, where (a) is a 2D / 3D contour image; (b) is the surface micromorphology of the conical array; and (c) is the magnified micromorphology of the boxed portion in (b).

[0035] Figure 3 The contact angle between the molten CMAS and the coating system after the sample obtained in Example 1 was etched by CMAS at 1250°C for 120 seconds is shown.

[0036] Figure 4 The contact angle between the molten CMAS and the coating system after the sample obtained in Example 2 was etched by CMAS at 1250°C for 120 seconds is shown. Detailed Implementation

[0037] To make the technical problems, technical solutions and advantages of the present invention clearer, a detailed description will be given below in conjunction with the accompanying drawings and specific embodiments.

[0038] This invention proposes a high-temperature resistant laser-modified CMAS structure Al2O3-YSZ coating, the specific steps of which are as follows:

[0039] Step 1: Pretreatment of high-temperature alloy matrix

[0040] Prepare nickel-based high-temperature alloy test pieces. Use 80#, 400#, 800#, 1200#, 1500#, and 2000# sandpaper to grind the surface of the alloy substrate, and polish it with a high-speed polishing machine. After cleaning the alloy surface with ethanol, perform sandblasting pretreatment to control the surface roughness of the alloy sample to 1μm.

[0041] The second step is to prepare a metal bonding layer on the surface of the high-temperature alloy.

[0042] The metal layer can be prepared by any of the following three methods: a) electron beam physical vapor deposition to prepare NiAlHf metal bond layer; b) multi-arc ion plating to prepare NiCrAlYSi metal bond layer; c) electroplating and embedding method to prepare NiPtAl metal bond layer.

[0043] a) Preparation of NiAlHf metal binder layer by electron beam physical vapor deposition: The pretreated alloy substrate sample is placed on the rotating substrate of the electron beam physical vapor deposition equipment, and then the target material rod to be evaporated is placed in the water-cooled copper crucible. The deposition chamber is evacuated to 10°C. -3 ~10 -2 Pa, the substrate is preheated to 820~920℃, the electron beam voltage is adjusted to 18~21kV, the electron beam current is 1.0A~1.2A, and the sample rotation speed is 10~12rpm. The deposition time of this invention is 20~30min, and an adhesive layer with a thickness of 30~50μm is obtained.

[0044] b) Preparation of NiCrAlYSi metal bonding layer by multi-arc ion plating method: The high-temperature alloy sample was pretreated by grinding and polishing, and then placed on the sample stage of the vacuum chamber. The distance between the sample and the target was set to approximately 250 mm, the sample holder rotation speed was 7 rpm, the vacuum chamber temperature was 480 °C, and the vacuum degree in the furnace chamber during ion bombardment was 3.5 × 10⁻⁶. -3 Pa was used to clean and activate the substrate surface. Coating preparation consisted of two stages: the first stage prepared a NiCrAlYSi underlayer, and the second stage prepared the NiCrAlYSi coating. The reactant gas was N2 with a flow rate of 32 sccm and a controlled pressure of 1.5 Pa. The substrate bias voltage was -85 V, the arc current was 110 A, and the deposition time was approximately 60–90 min, resulting in a metal bonding layer with a thickness of 30–50 μm.

[0045] c) Preparation of NiPtAl metal binder layer by electroplating and embedding method: 30 g / L diammonium nitrite platinum (Pt(NH3)2(NO2)2), 180 g / L ammonium nitrate (NH4NO3), 18 g / L sodium nitrite (NaNO2), and 82 g / L ammonia water (NH3·H2O) were uniformly mixed in a reaction vessel to form a Pt plating solution. The Pt plating solution was heated to 75℃, and further, a high-temperature alloy was placed in the Pt plating solution, with a current of 0.8~1.0 mA / mm.2 The electroplating time is 50-70 min to prepare an electroplated Pt layer with a thickness of 4-5 μm. The Pt layer is then aluminized by an embedding method with the following process parameters: holding temperature 950-1000℃ and holding time 80-100 min, finally preparing a NiPtAl metal bonding layer with a thickness of 30-50 μm.

[0046] After the metal bonding layer is prepared, the alloy is removed and placed in a vacuum furnace. The heat treatment temperature is set to 1000~1100℃, the time to 2~3 hours, and the vacuum degree is set to 7.5~9.0×10⁻⁶. -5 mbar, cooled in the furnace, and removed at room temperature.

[0047] The third step involves preparing an AYSZ ceramic layer on the surface of the metal bonding layer using the EB-PVD method. The steps are as follows: the sample to be evaporated is placed on a rotating substrate for electron beam physical vapor deposition, the target to be evaporated is placed in the electron beam physical deposition crucible, and the vacuum degree of the deposition chamber is 10... -3 The substrate was preheated to 900-950℃, the oxygen flux was set to 100-110 sccm, the voltage was controlled at 19-20 kV, the sample substrate rotation speed was kept constant at 15 rpm, and the target rotation speed was 0.8 r / min. Using a self-made Al2O3-YSZ target, with an electron beam current of 0.65-0.75 A and a deposition time of 70-100 min, an AYSZ layer with a thickness of 120-180 μm could be obtained.

[0048] The fourth step involves using ultrafast femtosecond laser processing technology to modify the surface of the top ceramic layer. The main process parameters for laser processing are: pulse processing power 2~6W, pulse frequency 100~180kHz, pulse width 100~400fs, wavelength 1040nm, and scanning speed 100~800mm / s.

[0049] Figure 1 This is a schematic diagram of the coating structure of the present invention, where (a) is a cross-section of the coating, comprising, from bottom to top, a high-temperature alloy substrate, a metal bonding layer, an AYSZ ceramic layer, and a surface-modified portion located on top of the ceramic layer. The ceramic layer, prepared by the EB-PVD method, has a columnar structure with a micron-scale conical array and nanosynapses on its surface obtained by femtosecond laser processing, such as... Figure 1 As shown in (b).

[0050] Example 1

[0051] A composite thermal barrier coating consisting of a NiAlHf metal binder layer (prepared by EB-PVD), an AYSZ ceramic layer (prepared by EB-PVD), and a laser-modified top ceramic layer was sequentially prepared on the surface of a high-temperature alloy substrate. The specific steps are as follows:

[0052] Step 1, High-temperature alloy polishing treatment: Prepare a second-generation single-crystal high-temperature alloy (DD6) specimen with a size of φ30×2.5mm. Use 80#, 400#, 800#, 1200#, 1500#, and 2000# sandpaper to polish the surface of the alloy substrate, and polish it with a high-speed polishing machine. After cleaning the alloy surface with ethanol, perform sandblasting pretreatment to control the surface roughness of the alloy specimen to 1μm.

[0053] The second step involves preparing a NiAlHf metal bonding layer on the surface of the high-temperature alloy: the pretreated alloy substrate sample is placed on the rotating substrate of an electron beam physical vapor deposition (EBV) apparatus, and then the target material to be evaporated is placed in a water-cooled copper crucible. The deposition chamber is then evacuated to 10°C. -3 Pa, the substrate was preheated to 850℃, the electron beam voltage was adjusted to 19kV, the electron beam current to 1.1A, the sample rotation speed to 12rpm, and the deposition time to 25min, to obtain an adhesive layer with a thickness of 40μm.

[0054] The third step involves depositing an AYSZ coating on the NiAlHf metal binder layer: the sample to be evaporated is placed on an electron beam physical vapor deposition (EBPV) rotating substrate, the target to be evaporated is placed in an EBPV crucible, and the vacuum level of the deposition chamber is 10. -3 The substrate was preheated to 930℃, the oxygen flux was set to 100 sccm, the voltage was controlled at 19 kV, the substrate rotation speed was kept constant at 15 rpm, and the target rotation speed was 0.8 r / min. A self-made Al2O3-YSZ target was used, the electron beam current was 0.68 A, and the deposition time was 70 min, resulting in an AYSZ layer with a thickness of 120 μm.

[0055] The fourth step is to perform laser surface modification on the top of the AYSZ layer: the pulse processing power of the laser equipment is set to 3W, the pulse frequency to 140kHz, the pulse width to 200fs, the wavelength to 1040nm, and the scanning speed to 400mm / s.

[0056] Figure 2 The image shows the top morphology of the ceramic layer after femtosecond laser modification in Example 1. (a) is a 2D / 3D contour image, which shows that the obtained composite structure includes a micron-scale conical array with a spacing of about 40 μm; (b) is the surface micromorphology of the conical array; (c) is the magnified micromorphology of the boxed part in (b), which shows that the nanoscale synapses have spherical and rod-shaped microstructures.

[0057] The thermal barrier coating system prepared in this embodiment exhibits a thermal conductivity of only 0.94 W / (m·K) at 1200℃, and its microstructure remains stable over a long period. After 120 s of CMAS etching at 1250℃, the contact angle between the molten CMAS and the coating system was observed to be >90°, demonstrating characteristics of resisting molten CMAS. Furthermore, after 5 hours of etching, no sintering or growth of the micro-nano structure on the ceramic layer surface occurred, indicating that the coating system has excellent resistance to CMAS. This demonstrates that under long-term high-temperature conditions, the coating system effectively prevents the penetration of molten CMAS.

[0058] Example 2

[0059] A composite thermal barrier coating was sequentially prepared on the surface of a high-temperature alloy substrate, comprising a NiCrAlYSi metal bonding layer (prepared by multi-arc ion plating), an AYSZ ceramic layer (prepared by EB-PVD), and a laser-modified top ceramic layer. The specific steps are as follows:

[0060] Step 1, High-temperature alloy polishing treatment: Prepare a second-generation single-crystal high-temperature alloy (DD6) specimen with a size of φ30×2.5mm. Use 80#, 400#, 800#, 1200#, 1500#, and 2000# sandpaper to polish the surface of the alloy substrate, and polish it with a high-speed polishing machine. After cleaning the alloy surface with ethanol, perform sandblasting pretreatment to control the surface roughness of the alloy specimen to 1μm.

[0061] The second step involves preparing a NiCrAlYSi metal bonding layer on the surface of the high-temperature alloy: The high-temperature alloy sample undergoes grinding and polishing pretreatment, and is then placed on the sample stage in the vacuum chamber. The distance between the sample and the target is approximately 250 mm, the sample holder rotation speed is 7 rpm, the vacuum chamber temperature is 480 °C, and the vacuum degree inside the furnace chamber during ion bombardment is 3.5 × 10⁻⁶. -3 Pa was used to clean and activate the substrate surface. Coating preparation consisted of two stages: the first stage prepared a NiCrAlYSi underlayer, and the second stage prepared the NiCrAlYSi coating. The reactant gas was N2 with a flow rate of 32 sccm and a controlled pressure of 1.5 Pa. The substrate bias voltage was -85 V, the arc current was 110 A, and the deposition time was approximately 70 min, resulting in a 35 μm thick adhesive layer.

[0062] The third step involves depositing an AYSZ coating on the surface of the NiCrAlYSi metal bond layer: The sample to be evaporated is placed on a rotating substrate for electron beam physical vapor deposition, and the target to be evaporated is placed in the electron beam physical deposition crucible. The vacuum level of the deposition chamber is 10. -3The substrate was preheated to 930℃, the oxygen flux was set to 100 sccm, the voltage was controlled at 19 kV, the sample substrate rotation speed was kept constant at 15 rpm, and the target rotation speed was 0.8 r / min. A self-made Al2O3-YSZ target was used, the electron beam current was 0.68 A, the deposition time was 80 min, and an AYSZ layer with a thickness of 100 μm was obtained.

[0063] The fourth step is to perform laser surface modification on the top of the AYSZ layer: the pulse processing power of the laser equipment is set to 5W, the pulse frequency to 160kHz, the pulse width to 400fs, the wavelength to 1040nm, and the scanning speed to 600mm / s.

[0064] The thermal barrier coating system prepared in this embodiment exhibits a thermal conductivity of only 0.99 W / (m·K) at 1200℃. The coating's microstructure remains stable over long periods. After laser modification, the top ceramic layer displays a 50 μm-spaced conical array and nanosynaptic structures. After CMAS etching at 1250℃ for 120 s, the contact angle between the molten CMAS and the coating system is observed to be >90°, demonstrating characteristics of resisting molten CMAS. Furthermore, after 5 hours of etching, no sintering or growth of the micro-nano structure on the ceramic layer surface occurred, indicating excellent CMAS resistance. This demonstrates that under long-term high-temperature conditions, the coating system effectively prevents the penetration of molten CMAS.

[0065] Example 3

[0066] A composite thermal barrier coating was sequentially prepared on the surface of a high-temperature alloy substrate, comprising a NiPtAl metal binder layer (prepared by electroplating and embedding), an AYSZ ceramic layer (prepared by EB-PVD), and a laser-modified top ceramic layer. The specific steps are as follows:

[0067] Step 1, High-temperature alloy polishing treatment: Prepare a second-generation single-crystal high-temperature alloy (DD6) specimen with a size of φ30×2.5mm. Use 80#, 400#, 800#, 1200#, 1500#, and 2000# sandpaper to polish the surface of the alloy substrate, and polish it with a high-speed polishing machine. After cleaning the alloy surface with ethanol, perform sandblasting pretreatment to control the surface roughness of the alloy specimen to 1μm.

[0068] The second step involves preparing a NiPtAl metal bonding layer on the surface of the high-temperature alloy: 30 g / L diammonium nitrite platinum (Pt(NH3)2(NO2)2), 180 g / L ammonium nitrate (NH4NO3), 18 g / L sodium nitrite (NaNO2), and 82 g / L ammonia water (NH3·H2O) are uniformly mixed in a reaction vessel to form a Pt plating solution. The Pt plating solution is then heated to 75°C. Further, the high-temperature alloy is placed in the Pt plating solution, and a current of 0.8~1.0 mA / mm is applied. 2The electroplating time was 60 min, and a 5 μm electroplated Pt layer was obtained. The Pt layer was then aluminized by embedding method with the following process parameters: holding temperature 950℃ and holding time 80 min, and a 45 μm thick NiPtAl bonding layer was finally obtained.

[0069] The third step involves depositing an AYSZ coating on the NiPtAl metal binder surface: the sample to be evaporated is placed on an electron beam physical vapor deposition (EBPV) rotating substrate, the target to be evaporated is placed in an EBPV crucible, and the vacuum level of the deposition chamber is 10. -3 The substrate was preheated to 900℃, the oxygen flux was set to 100 sccm, the voltage was controlled at 19 kV, the sample substrate rotation speed was kept constant at 15 rpm, and the target rotation speed was 0.8 r / min. A self-made Al2O3-YSZ target was used, the electron beam current was 0.68 A, the deposition time was 90 min, and an AYSZ layer with a thickness of 140 μm was obtained.

[0070] The fourth step is to perform laser surface modification on the top of the AYSZ layer: the pulse processing power of the laser equipment is set to 6W, the pulse frequency to 160kHz, the pulse width to 200fs, the wavelength to 1040nm, and the scanning speed to 400mm / s.

[0071] The thermal barrier coating system prepared in this embodiment exhibits a thermal conductivity of only 0.96 W / (m·K) at 1200℃. The coating's microstructure remains stable over long periods. After laser modification, the top ceramic layer displays a 53 μm-spaced conical array and nanosynaptic structures. After CMAS etching at 1250℃ for 120 s, the contact angle between the molten CMAS and the coating system is observed to be >90°, demonstrating characteristics of resisting molten CMAS. Furthermore, after 5 hours of etching, no sintering or growth of the micro-nano structure on the ceramic layer surface occurred, indicating excellent CMAS resistance. This demonstrates that under long-term high-temperature conditions, the coating system effectively prevents the penetration of molten CMAS.

[0072] Comparative Example 1

[0073] In the fourth step, the pulse processing power for laser surface modification is 20W, and the other steps and parameters are the same as in Example 1.

[0074] The laser pulse processing power used in Comparative Example 1 was too high. The coating system prepared therein, after laser modification, had an array structure spacing of 100 μm on the surface of the top ceramic layer, which was too large and affected the coating life and other properties.

[0075] Comparative Example 2

[0076] In the fourth step, the pulse frequency for laser surface modification is 0.5W, and the other steps and parameters are the same as in Example 1.

[0077] The laser pulse processing power used in Comparative Example 2 was too low. The micro-nano structure size of the top ceramic layer in the prepared coating system after laser modification was too small, approximately 20 μm. After 120 s of CMAS etching at 1250 °C, the contact angle between the molten CMAS and the coating system was observed to be <90°, and after 5 h of etching, the ceramic coating was destroyed by CMAS etching.

[0078] Comparative Example 3

[0079] In the fourth step, the pulse frequency for laser surface modification is 400 kHz, and the other steps and parameters are the same as in Example 1.

[0080] The laser pulse frequency used in Comparative Example 3 was too high. The coating system prepared there did not form a clear conical array and nanosynaptic structure in the top ceramic layer after laser modification. After 120 seconds of CMAS etching at 1250℃, the contact angle between the molten CMAS and the coating system was observed to be <90°, and after 5 hours of etching, the ceramic coating was destroyed by CMAS etching.

[0081] Comparative Example 4

[0082] The fourth step was not performed; that is, the preparation was completed by depositing an AYSZ coating only on the surface of the NiAlHf metal binder. The other steps and parameters were the same as in Example 1.

[0083] Comparative Example 4 did not undergo laser surface modification on the top of the AYSZ layer; therefore, similar to Comparative Example 3, the top ceramic layer lacked a conical array and nanosynaptic structure. The high-temperature stability of the ceramic coating decreased, and after 5 hours of etching, the coating was severely damaged by CMAS corrosion.

[0084] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A high-temperature resistant laser-modified Al2O3-YSZ coating with a hydrophobic CMAS structure, characterized in that, This includes a metal bonding layer and an Al2O3-YSZ composite ceramic layer (AYSZ layer) sequentially prepared on the surface of a high-temperature alloy. The AYSZ layer is an Al2O3-doped modified YSZ coating obtained by electron beam physical vapor deposition (EB-PVD); the top of the AYSZ layer is treated with a femtosecond laser to form a composite structure including a micron-scale cone array and nanosynapses.

2. The high-temperature resistant laser-modified sparse CMAS structure Al2O3-YSZ coating according to claim 1, characterized in that, The YSZ layer contains 22-28 wt.% Al2O3, 6-8 wt.% Y2O3, and has a layer thickness of 120-180 μm.

3. The method for preparing the high-temperature resistant laser-modified sparse CMAS structure Al2O3-YSZ coating according to claim 1 or 2, characterized in that, Includes the following steps: S1. Pretreatment of high-temperature alloys; S2. A metal bonding layer is deposited on the surface of the high-temperature alloy after S1 pretreatment, followed by heat treatment. S3. A ceramic layer is prepared on the surface of the metal bonding layer after heat treatment in S2 using the EB-PVD method. S4. The surface of the top of the ceramic layer prepared in S3 is modified using femtosecond laser processing technology.

4. The method for preparing the high-temperature resistant laser-modified sparse CMAS structure Al2O3-YSZ coating according to claim 3, characterized in that, In step S1, the high-temperature alloy is DD6 nickel-based single-crystal high-temperature alloy.

5. The method for preparing the high-temperature resistant laser-modified sparse CMAS structure Al2O3-YSZ coating according to claim 3, characterized in that, In step S1, the pretreatment includes sanding the surface of the high-temperature alloy in sequence, cleaning with organic solvent, and sandblasting, wherein the organic solvent is preferably ethanol.

6. The method for preparing the high-temperature resistant laser-modified sparse CMAS structure Al2O3-YSZ coating according to claim 3, characterized in that, In step S2, the material of the metal bonding layer is selected from one of the following three types: the first type is NiAlHf, whose composition includes 40~60wt.% Ni, 36~60wt.% Al and 0.05~2wt.% Hf; the second type is NiCrAlYSi, whose composition includes 40~62wt.% Ni, 14~26wt.% Cr, 15~20wt.% Al, 0.05~2wt.% Y and 0.05~2wt.% Si; the third type is NiPtAl, whose composition includes 40~62wt.% Ni, 18~20wt.% Pt and 30~45wt.% Al.

7. The method for preparing the high-temperature resistant laser-modified sparse CMAS structure Al2O3-YSZ coating according to claim 3, characterized in that, In step S2, the heat treatment parameters include: a heat treatment temperature of 1000~1100℃, a time of 2~3 hours, and a vacuum degree of 7.5~9.0×10⁻⁶. -5 mbar, cooled to room temperature in a vacuum furnace and then removed.

8. The method for preparing the high-temperature resistant laser-modified sparse CMAS structure Al2O3-YSZ coating according to claim 3, characterized in that, In step S4, the process parameters for the femtosecond laser processing are: pulse processing power of 2~6W, pulse frequency of 100~180kHz, pulse width of 100~400fs, wavelength of 1040nm, and scanning speed of 100~800mm / s.

9. The method for preparing the high-temperature resistant laser-modified sparse CMAS structure Al2O3-YSZ coating according to claim 3, characterized in that, In step S4, the micro-nano structure formed on the surface of the AYSZ ceramic layer by femtosecond laser processing is a composite structure composed of a micron-scale conical array and nanosynapses.

10. The method for preparing the high-temperature resistant laser-modified sparse CMAS structure Al2O3-YSZ coating according to claim 9, characterized in that, The spacing of the micron-scale conical array is 40~60μm.

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