A composite thermal barrier coating and its preparation method and application

Abstract

The application provides a composite structure thermal barrier coating and a preparation method and application thereof, and relates to the field of coating technology.The composite structure thermal barrier coating provided by the application comprises a metal bonding layer, a columnar crystal structure ceramic layer, a ceramic transition layer and a layered structure ceramic layer which are stacked in sequence.In the application, the columnar crystal structure ceramic layer has low thermal conductivity, excellent thermal cycle performance and heat insulation performance;at the same time, the columnar crystal structure ceramic layer has small interlayer stress under high temperature difference, so that the composite structure thermal barrier coating is not easy to fall off and has excellent thermal shock resistance.The existence of the ceramic transition layer makes the composite structure thermal barrier coating have good layer interface continuity.The layered structure ceramic layer (surface layer) has a layered structure, and has better erosion resistance than the columnar structure, so that the existence of the layered structure ceramic layer further increases the erosion resistance of the composite structure thermal barrier coating.

Description

Technical Field

[0001] This invention relates to the field of coating technology, specifically to a composite thermal barrier coating, its preparation method, and its application. Background Technology

[0002] With the technological advancements in gas turbine engines, the extreme conditions that engine blades must withstand during operation, such as complex stresses, high temperatures, and gas thermal corrosion, are gradually increasing, making them highly susceptible to surface burn-out, spalling, and cracking. Therefore, improving the blades' resistance to high-temperature oxidation and thermal corrosion is of great significance. Preparing thermal barrier coatings (TBCs) on the surface of gas turbine engine blades can significantly improve the overall performance of aero-engines and ground-based gas turbines, extending their service life, and is one of the key aspects of developing high-performance aero-engines and gas turbines. Existing thermal barrier coatings typically consist of an MCrAlY layer, a Pt / Al metal bonding layer, and a YSZ ceramic layer. However, these thermal barrier coatings suffer from incompatibility issues regarding thermal cycling performance and thermal insulation properties. Summary of the Invention

[0003] In view of this, the purpose of the present invention is to provide a composite structure thermal barrier coating, its preparation method and application. The composite structure thermal barrier coating provided by the present invention has both excellent thermal cycling performance and thermal insulation performance.

[0004] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0005] The present invention provides a composite thermal barrier coating comprising a metal bonding layer, a columnar crystalline ceramic layer, a ceramic transition layer and a layered ceramic layer stacked sequentially.

[0006] Preferably, the metal bonding layer includes an MCrAlY coating, a Pt / Al coating, or a NiCoCrAlYHf coating; the thickness of the metal bonding layer is 20–120 μm.

[0007] Preferably, the columnar crystal structure ceramic layer includes a YSZ coating; the thickness of the columnar crystal structure ceramic layer is 30–130 μm.

[0008] Preferably, the ceramic transition layer includes a YSZ coating; the thickness of the ceramic transition layer is 5–25 μm.

[0009] Preferably, the layered ceramic layer includes a YSZ coating or a GYbZ coating; the thickness of the layered ceramic layer is 30–130 μm.

[0010] This invention provides a method for preparing the composite thermal barrier coating described in the above technical solution, comprising the following steps:

[0011] Using metal bonding layer raw materials, multi-arc ion plating is performed on the substrate surface to form a metal bonding layer on the substrate surface;

[0012] The metal bonding layer is surface activated and then placed in a PS-PVD device. Using columnar crystal structure ceramic layer raw material powder, a first plasma physical vapor deposition is performed on the surface of the metal bonding layer to form a columnar crystal structure ceramic layer. The vacuum degree of the chamber for the first plasma physical vapor deposition is 100-300 Pa, and the spray gun power is 50-70 kW.

[0013] Using ceramic transition layer raw material powder, a second plasma physical vapor deposition is performed on the surface of the columnar crystal structure ceramic layer to form a ceramic transition layer; the vacuum degree of the chamber for the second plasma physical vapor deposition is 3000-10000 Pa, and the spray gun power is 30-60 kW.

[0014] Using layered ceramic layer raw material powder, a third plasma physical vapor deposition is performed on the surface of the ceramic transition layer to form a layered ceramic layer, forming a composite thermal barrier coating on the substrate surface; the vacuum degree of the chamber for the third plasma physical vapor deposition is 10-10000 Pa, and the spray gun power is 30-60 kW.

[0015] Preferably, the substrate undergoes surface treatment before use, the surface treatment including sequentially performing a first cleaning, a first drying, surface activation, a second cleaning, and a second drying; the surface activation includes sandblasting or polishing; the substrate includes a high-temperature alloy.

[0016] Preferably, the surface activation includes sandblasting or polishing.

[0017] The surface activation process also includes sequential cleaning and drying.

[0018] Preferably, the operating parameters for the first, second, and third plasma physical vapor depositions include: argon flow rate of 20–40 L / min, helium flow rate of 50–80 L / min, oxygen flow rate of 1–5 L / min, spraying distance of 800–1500 mm, powder carrier gas flow rate of 5–20 L / min, and powder feed rate of 4–20 g / min.

[0019] This invention provides the application of the composite thermal barrier coating described in the above technical solution or the composite thermal barrier coating prepared by the above technical solution in aero engines or gas turbines.

[0020] This invention provides a composite thermal barrier coating comprising a metal bonding layer, a columnar crystalline ceramic layer, a ceramic transition layer, and a layered ceramic layer stacked sequentially. In this invention, the columnar crystalline ceramic layer possesses low thermal conductivity while exhibiting excellent thermal cycling and insulation properties. Furthermore, the columnar crystalline ceramic layer exhibits low interlayer stress under high temperature differences, making the composite thermal barrier coating less prone to detachment and providing excellent thermal shock resistance. The presence of the ceramic transition layer ensures good interfacial continuity in the composite thermal barrier coating. The layered ceramic layer (top layer) has a layered structure, which offers better erosion resistance compared to a columnar structure; therefore, the presence of the layered ceramic layer further enhances the erosion resistance of the composite thermal barrier coating.

[0021] Plasma spraying (APS) and electron beam physical vapor deposition (EB-PVD) are relatively mature processes for preparing thermal barrier coatings for aero-engine blades. APS produces a layered ceramic layer with low thermal conductivity but relatively high porosity and poor thermal cycling performance. EB-PVD produces a columnar ceramic layer with strong adhesion and good thermal cycling performance, but relatively high thermal conductivity. This invention utilizes plasma physical vapor deposition (PS-PVD) with good coating wrap-around properties, ensuring the substrate (e.g., the blade) is completely immersed in the plasma beam, resulting in excellent coating uniformity. For multi-unit turbine guide vanes with complex structures and multiple blind spots, especially since turbine guide vanes are typically multi-unit blades with complex structures and multiple blind spots, the PS-PVD used in this invention has strong wrap-around properties, enabling non-line-of-sight deposition, avoiding complex blade movements during spraying, and producing a composite thermal barrier coating with excellent thickness uniformity. This invention utilizes PS-PVD to prepare a columnar-like ceramic layer, combining the advantages of APS and EB-PVD. It exhibits both high thermal cycling performance and low thermal conductivity, along with excellent thermal cycling and insulation properties. The ceramic transition layer can be prepared simply by increasing the vacuum level of PS-PVD, eliminating the need for other intermediate processes and improving coating interface continuity. The preparation process is simple. PS-PVD has a short vacuum time, eliminating the need for the high vacuum conditions required for EB-PVD. Furthermore, to prepare the same thickness of ceramic coating, PS-PVD requires only 1 / 10 the time of EB-PVD, resulting in high deposition efficiency and high production efficiency for composite thermal barrier coatings. Moreover, by preparing a layered ceramic layer under low vacuum using PS-PVD, this invention results in a layered ceramic layer with less oxidation, fewer defects, lower porosity, and excellent resistance to interlayer spalling (CMAS) and erosion. Attached Figure Description

[0022] Figure 1This is a schematic diagram of a substrate-composite thermal barrier coating, where 1 is the substrate, 2 is the composite thermal barrier coating, 21 is the metal bonding layer, 22 is the columnar crystalline ceramic layer, 23 is the ceramic transition layer, and 24 is the layered ceramic layer.

[0023] Figure 2 This is a flowchart illustrating the preparation process of the composite thermal barrier coating.

[0024] Figure 3 This is a cross-sectional SEM image of the YSZ-type columnar crystal structure ceramic layer prepared in Example 1;

[0025] Figure 4 The image shows a cross-sectional SEM image of the YSZ layered ceramic layer prepared in Example 1.

[0026] Figure 5 The image shows a cross-sectional SEM image of the composite thermal barrier coating prepared in Example 1.

[0027] Figure 6 This is a cross-sectional SEM image of the YSZ layered ceramic layer prepared in Example 3;

[0028] Figure 7 Here is a cross-sectional SEM image of a typical columnar ceramic layer prepared by EB-PVD in Comparative Example 1.

[0029] Figure 8 A cross-sectional SEM image of the APS nanostructured coating prepared in Comparative Example 2;

[0030] Figure 9 The image shows the morphology of the composite thermal barrier coating prepared in Example 1 after 60 water quenchings at 1100℃.

[0031] Figure 10 The figure shows the thermal shock test results of the composite thermal barrier coating prepared in Comparative Example 2.

[0032] Figure 11 The image shows the thermal shock test results of the composite thermal barrier coating prepared in Example 1.

[0033] Figure 12 The thermal conductivity curve of the composite thermal barrier coating prepared in Example 1 is shown. Detailed Implementation

[0034] The present invention provides a composite thermal barrier coating comprising a metal bonding layer, a columnar crystalline ceramic layer, a ceramic transition layer and a layered ceramic layer stacked sequentially.

[0035] In this invention, a schematic diagram of the composite thermal barrier coating containing a substrate is shown below. Figure 1As shown, 1 is the substrate, 2 is the composite thermal barrier coating, 21 is the metal bonding layer, 22 is the columnar crystal structure ceramic layer, 23 is the ceramic transition layer, and 24 is the layered structure ceramic layer.

[0036] In this invention, the metal bonding layer preferably includes an MCrAlY coating, a Pt / Al coating, or a NiCoCrAlYHf coating; the thickness of the metal bonding layer is preferably 20–120 μm, more preferably 50–100 μm.

[0037] In this invention, the columnar crystal structure ceramic layer preferably includes a YSZ coating; the thickness of the columnar crystal structure ceramic layer is preferably 30-130 μm, more preferably 50-100 μm; and the porosity of the columnar crystal structure ceramic layer is preferably 12-20%, more preferably 15%.

[0038] In this invention, the ceramic transition layer preferably includes a YSZ coating; the thickness of the ceramic transition layer is preferably 5-25 μm, more preferably 10-20 μm.

[0039] In this invention, the layered ceramic layer preferably includes a YSZ coating or a GYbZ coating; the thickness of the layered ceramic layer is preferably 30-130 μm, more preferably 50-100 μm.

[0040] This invention provides a method for preparing the composite thermal barrier coating described in the above technical solution, comprising the following steps:

[0041] Using metal bonding layer raw materials, multi-arc ion plating is performed on the substrate surface to form a metal bonding layer on the substrate surface;

[0042] The metal bonding layer is surface activated and then placed in a PS-PVD device. Using columnar crystal structure ceramic layer raw material powder, a first plasma physical vapor deposition is performed on the surface of the metal bonding layer to form a columnar crystal structure ceramic layer. The vacuum degree of the chamber for the first plasma physical vapor deposition is 100-300 Pa, and the spray gun power is 50-70 kW.

[0043] Using ceramic transition layer raw material powder, a second plasma physical vapor deposition is performed on the surface of the columnar crystal structure ceramic layer to form a ceramic transition layer; the vacuum degree of the chamber for the second plasma physical vapor deposition is 3000-10000 Pa, and the spray gun power is 30-60 kW.

[0044] Using layered ceramic layer raw material powder, a third plasma physical vapor deposition is performed on the surface of the ceramic transition layer to form a layered ceramic layer, forming a composite thermal barrier coating on the substrate surface; the vacuum degree of the chamber for the third plasma physical vapor deposition is 10-10000 Pa, and the spray gun power is 30-60 kW.

[0045] Unless otherwise specified, all raw materials used in this invention are commercially available products.

[0046] Figure 2 This is a flowchart illustrating the preparation process of the composite thermal barrier coating. The following section combines... Figure 2 The preparation method of the composite thermal barrier coating is described in detail.

[0047] This invention uses metal bonding layer raw materials to perform multi-arc ion plating on the substrate surface to form a metal bonding layer on the substrate surface.

[0048] In this invention, the matrix preferably comprises a high-temperature alloy. This invention does not have any special limitation on the high-temperature alloy, and any high-temperature alloy well known to those skilled in the art can be used. In a specific embodiment of this invention, the high-temperature alloy is preferably a high-temperature alloy for aero-engine blades or gas turbine blades.

[0049] In this invention, the substrate is preferably subjected to surface treatment before use. The surface treatment preferably includes sequentially performing a first cleaning, a first drying, surface activation, a second cleaning, and a second drying. In this invention, the first cleaning preferably includes sequentially performing ultrasonic cleaning and water rinsing. The ultrasonic cleaning agent preferably includes water or ethanol. The first cleaning time is preferably 5-15 minutes, more preferably 10 minutes. The purpose of the first cleaning is to remove impurities such as grease from the substrate surface. In this invention, the first drying method is preferably air drying. In this invention, the surface activation preferably includes sandblasting or polishing. In this invention, the sandblasting is preferably wet sandblasting. The sandblasting conditions include: the abrasive particles are preferably white corundum, and the particle size of the white corundum is preferably 100-200 mesh; the compressed air pressure is preferably 0.2-0.4 MPa, more preferably 0.3 MPa; the sandblasting angle is preferably 45-75°, more preferably 50-60°; the sandblasting distance is preferably 200-500 mm, more preferably 300-400 mm; and the sandblasting time is preferably 2-5 minutes, more preferably 3-5 minutes. In this invention, the polishing treatment is preferably magnetic polishing. The polishing conditions include: the polishing medium is preferably a stainless steel grinding needle, the diameter of which is preferably 0.6–1.2 mm, more preferably 0.8–1 mm; the frequency is preferably 50–70 Hz, more preferably 60 Hz; and the polishing time is preferably 5–15 min, more preferably 10 min. In this invention, the purpose of surface activation is to reduce surface roughness and improve surface stress, thereby improving the coating's erosion resistance and adhesion. In this invention, the second cleaning is preferably ultrasonic cleaning, the cleaning agent for which the ultrasonic cleaning preferably includes water or ethanol, and the second cleaning time is preferably 5–15 min, more preferably 10 min. In this invention, the temperature of the second drying is preferably 80–120 °C, more preferably 90–110 °C, and the second drying time is preferably 5–10 min, more preferably 7–8 min; the second drying is preferably carried out in a forced-air drying oven.

[0050] In this invention, when the metal bonding layer is an MCrAlY coating, the raw material of the metal bonding layer (i.e., the raw material of the MCrAlY coating) is preferably an MCrAlY target, and the grade of the MCrAlY target is preferably HY3 or HY5. In this invention, when the metal bonding layer is a Pt / Al coating, the raw material of the metal bonding layer (i.e., the raw material of the Pt / Al coating) is preferably a platinum solution and an aluminum-iron block, and the Pt / Al coating is preferably prepared according to the preparation method of the Pt-modified aluminum compound coating disclosed in the literature "Zhang Lei, Wu Yong, Xia Siyao, et al. Preparation of Pt-modified aluminum compound coating by CVD method and its hot corrosion behavior study [J]. Materials Protection, 2020, 53(3):7". In this invention, when the metal bonding layer is a NiCoCrAlYHf coating, the raw material of the metal bonding layer (i.e., the raw material of the NiCoCrAlYHf coating) is preferably a NiCoCrAlYHf target.

[0051] In this invention, the operating parameters of the multi-arc ion plating include: an arc current preferably of 120–180 A, more preferably 150–180 A; a heating temperature preferably of 300–400 °C, more preferably 330–350 °C; a bias voltage preferably of 20–40 V, more preferably 30 V; and an argon flow rate preferably of 100–300 sccm, more preferably 200 sccm. This invention does not have a specific limitation on the time of the multi-arc ion plating, as long as a metal bonding layer with a thickness of 20–120 μm is obtained.

[0052] After obtaining the metal bonding layer, the present invention performs surface activation on the metal bonding layer, and then places it in a PS-PVD device, using columnar crystal structure ceramic layer raw material powder, to perform a first plasma physical vapor deposition on the surface of the metal bonding layer to form a columnar crystal structure ceramic layer.

[0053] In this invention, the columnar crystal structure ceramic layer raw material powder preferably includes YSZ powder, and the grade of the YSZ powder is preferably Metco 6700.

[0054] In this invention, the surface activation preferably includes sandblasting or polishing; the sand particles used for sandblasting are preferably white corundum, and the particle size of the white corundum is preferably 150-300 mesh, more preferably 200-250 mesh; the other conditions for sandblasting and polishing are the same as those for sandblasting and polishing in the aforementioned surface treatment process of the substrate, and will not be repeated here.

[0055] After the surface activation is completed, the present invention preferably further includes cleaning and drying the obtained surface-activated metal adhesive layer in sequence; the cleaning and drying conditions are the same as the second cleaning and second drying conditions in the aforementioned surface treatment process of the substrate, and will not be repeated here.

[0056] In this invention, the operating parameters of the first plasma physical vapor deposition include: the PS-PVD equipment is evacuated to 10–100 Pa before the spray gun is applied; the center of the sample (to be deposited) and the center of the plasma beam are preferably at the same height; the spraying time is preferably 5–30 min, more preferably 10–25 min, and even more preferably 15–20 min; the chamber vacuum degree is 100–300 Pa, preferably 150–250 Pa, and even more preferably 200 Pa; the spray gun power is 50–70 kW, preferably 55–65 kW, and even more preferably 60 kW; the argon flow rate is preferably 20–40 L / min, more preferably 25–35 L / min, and even more preferably 30 L / min; the helium flow rate is preferably… The flow rate is preferably 50–80 L / min, more preferably 55–75 L / min, and even more preferably 60–70 L / min; the oxygen flow rate is preferably 1–5 L / min, more preferably 2–4 L / min, and even more preferably 3 L / min; the spraying distance is preferably 800–1500 mm, more preferably 900–1400 mm, and even more preferably 1000–1200 mm; the powder carrier gas flow rate is preferably 5–20 L / min, more preferably 8–18 L / min, and even more preferably 10–15 L / min, wherein the powder carrier gas is preferably argon; the powder feeding rate is preferably 4–20 g / min, more preferably 5–20 g / min, and even more preferably 10–20 g / min. In this invention, during the first plasma physical vapor deposition process, the surface-activated metal binder layer does not move out of the beam region.

[0057] After obtaining the columnar crystal structure ceramic layer, the present invention uses ceramic transition layer raw material powder to perform a second plasma physical vapor deposition on the surface of the columnar crystal structure ceramic layer to form a ceramic transition layer.

[0058] In this invention, the operating parameters of the second plasma physical vapor deposition include: a chamber vacuum of 3000–10000 Pa, preferably 4000–8000 Pa, more preferably 5000–6000 Pa, wherein the chamber vacuum is preferably continuously increased from the vacuum of the first plasma physical vapor deposition, and the rate of continuous increase of the vacuum is preferably 5–100 Pa / s, more preferably 10–20 Pa / s; a spray gun power of 30–60 kW, preferably 35–55 kW, more preferably 40–50 kW; wherein the spray gun power is preferably continuously decreased from the spray gun power of the first plasma physical vapor deposition, and the continuous decrease of the spray gun power is preferably reduced by 5 kW every 3–60 s (more preferably 20 s); this invention does not have a special limitation on the spraying time, as long as a ceramic transition layer with a thickness of 5–25 μm can be obtained; other operating parameters of the second plasma physical vapor deposition are the same as those of the first plasma physical vapor deposition, and will not be repeated here.

[0059] After obtaining the ceramic transition layer, the present invention uses layered ceramic layer raw material powder to perform a third plasma physical vapor deposition on the surface of the ceramic transition layer to form a layered ceramic layer, thereby forming a composite thermal barrier coating on the substrate surface.

[0060] In this invention, the layered ceramic layer raw material powder preferably includes YSZ powder or GYbZ powder, the grade of YSZ powder is preferably Metco 6700, and the grade of GYbZ powder is preferably JL-17NP.

[0061] In this invention, the operating parameters of the third plasma physical vapor deposition include: a spraying time preferably of 5 to 20 minutes, more preferably of 10 to 15 minutes; a chamber vacuum of 10 to 10,000 Pa, preferably of 50 to 5,000 Pa, more preferably of 100 to 3,000 Pa; and a power of 30 to 60 kW, preferably of 35 to 55 kW, more preferably of 40 to 50 kW. Other operating parameters of the third plasma physical vapor deposition are the same as those of the first plasma physical vapor deposition, and will not be repeated here.

[0062] This invention provides the application of the composite thermal barrier coating described in the above technical solution or the composite thermal barrier coating prepared by the above technical solution in aero engines or gas turbines.

[0063] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0064] The YSZ powder used in the following examples is of the brand name Metco 6700, and the GYbZ powder is of the brand name JL-17NP.

[0065] Example 1

[0066] Step 1, Surface treatment: The blade is ultrasonically cleaned in anhydrous ethanol for 10 minutes, then rinsed with water and dried. The surface is wet-blasted for 2 minutes using white corundum with a particle size of 150 mesh under the conditions of compressed air at 0.3 MPa, blasting angle of 45° and blasting distance of 300 mm. After ultrasonic cleaning with pure water for 10 minutes, it is dried in an 80°C forced-air drying oven for 10 minutes to obtain the surface treatment.

[0067] Step 2, Preparation of the metal bonding layer: The surface-treated blade sample is placed in a multi-arc ion plating device for multi-arc ion plating to obtain a NiCrAlYSi metal bonding layer with a thickness of 60-90 μm.

[0068] Step 3, Surface activation: Using white corundum with a particle size of 150 mesh, the surface of the NiCrAlYSi metal bonding layer was wet-blasted for 2 minutes under the conditions of compressed air of 0.3 MPa, blasting angle of 45° and blasting distance of 300 mm. The surface-activated sample was ultrasonically cleaned with pure water for 10 minutes and then placed in a forced-air drying oven at 80°C for 10 minutes to dry.

[0069] Step 4, Preparation of the columnar-like ceramic layer: Using YSZ powder as raw material, the sample obtained in Step 3 was placed in a PS-PVD device, and the vacuum was evacuated to 20 Pa before ignition. After ignition, the first plasma physical vapor deposition was started to obtain a YSZ columnar-like ceramic layer with a thickness of 80 μm. The working parameters of the first plasma physical vapor deposition were as follows: the center of the sample and the center of the plasma beam were at the same height, the spraying time was 8 min, the chamber vacuum degree was 200 Pa, the argon flow rate was 30 L / min, the helium flow rate was 60 L / min, the oxygen flow rate was 1 L / min, the spray gun power was 60 kW, the spraying distance was 1200 mm, the powder carrier gas flow rate was 10 L / min, and the powder feed rate was 10 g / min.

[0070] Step 5, Preparation of the ceramic transition layer: After the YSZ-type columnar crystal structure ceramic layer is sprayed, the chamber vacuum is continuously increased to 5000 Pa for approximately 2 minutes while keeping other parameters constant. The spray gun power is decreased by 5 kW every 20 seconds until the spraying power reaches 35 kW. During this continuous parameter variation, a second plasma physical vapor deposition is performed to obtain a ceramic transition layer with a thickness of 10 μm. The other operating parameters for the second plasma physical vapor deposition are the same as those for the first plasma physical vapor deposition.

[0071] Step 6, Preparation of the layered ceramic layer: Using YSZ powder as raw material, a third plasma physical vapor deposition (PVD) is performed on the surface of the ceramic transition layer of the sample obtained in Step 5 to obtain a YSZ layered ceramic layer with a thickness of 80 μm. After spraying, the sample is removed by breaking the cavity, resulting in a composite thermal barrier coating containing the substrate. The operating parameters for the third plasma physical vapor deposition are as follows: the center of the sample and the center of the plasma beam are at the same height; the spraying time is 8 min; the chamber vacuum is 6000 Pa; the argon flow rate is 35 L / min; the helium flow rate is 10 L / min; the oxygen flow rate is 5 L / min; the spray gun power is 35 kW; the spraying distance is 800 mm; the powder carrier gas flow rate is 10 L / min; and the powder feed rate is 10 g / min.

[0072] Figure 3 This is a cross-sectional SEM image of the YSZ-type columnar crystal structure ceramic layer prepared in Example 1. Figure 3 It can be seen that the columnar crystal structure ceramic layer prepared by the present invention has a certain amount of micro and nano particles in the columnar crystal gaps and inside the columnar crystals, indicating that the coating is a quasi-columnar structure coating, and the porosity of the columnar crystal structure ceramic layer is 14%.

[0073] Figure 4 This is a cross-sectional SEM image of the YSZ layered ceramic layer prepared in Example 1. Figure 4 It can be seen that the coating structure is similar to the layered structure obtained by APS spraying, and has strong heat insulation performance.

[0074] Figure 5 This is a cross-sectional SEM image of the composite thermal barrier coating prepared in Example 1. Figure 5 It can be seen that the composite thermal barrier coating has good interlayer continuity and no obvious defects between the columnar crystal structure and the layered structure.

[0075] Example 2

[0076] Changing the powder feeding parameters of the layered ceramic layer

[0077] The composite thermal barrier coating was prepared according to the method of Example 1, the only difference from Example 1 being that the powder carrier gas flow rate in step 5 was 5 L / min and the powder feeding amount was 20 g / min.

[0078] In step 6, the working parameters for the third plasma physical vapor deposition are as follows: the center of the sample and the center of the plasma beam are at the same height, the spraying time is 8 min, the chamber vacuum degree is 200 Pa, the argon flow rate is 35 L / min, the helium flow rate is 10 L / min, the oxygen flow rate is 5 L / min, the spray gun power is 35 kW, the spraying distance is 1200 mm, the powder carrier gas is 5 L / min, and the powder feed rate is 20 g / min.

[0079] Example 3

[0080] Change the spraying position of the layered ceramic layer

[0081] The composite thermal barrier coating was prepared according to the method of Example 1, with the only difference from Example 1 being:

[0082] In step 5, the center of the blade is offset from the center of the plasma beam by 50–70 mm.

[0083] The operating parameters for the third plasma physical vapor deposition in step 6 are the same as those for the first plasma physical vapor deposition in Example 1.

[0084] Figure 6This is a cross-sectional SEM image of the YSZ layered ceramic layer prepared in Example 3, compared with... Figure 4 The comparison shows that the spraying position affects the structure of the layered ceramic layer.

[0085] Example 4

[0086] The composite thermal barrier coating was prepared according to the method of Example 1, with the only difference being that the metal binder was a NiCoCrAlYHf metal binder. Compared with the NiCrAlYSi metal binder, the NiCoCrAlYHf metal binder exhibits better oxidation resistance.

[0087] Example 5

[0088] The composite thermal barrier coating was prepared according to the method of Example 1, with the only difference being that the metal binder was a PtAl (platinum-aluminized) metal binder. Compared with the NiCrAlYSi metal binder, the PtAl metal binder exhibits better oxidation resistance.

[0089] Example 6

[0090] The composite thermal barrier coating was prepared according to the method of Example 1, with the only difference being that GYbZ powder was used as the raw material in step 6 to obtain a GYbZ layered ceramic layer. Compared with YSZ powder, GYbZ powder has a finer particle size, resulting in a denser GYbZ layered ceramic layer.

[0091] Comparative Example 1

[0092] The composite thermal barrier coating was prepared according to the method of Example 1, with the only difference being that steps 4-6 used electron beam physical vapor deposition (EB-PVD) equipment to prepare columnar ceramic layers, ceramic transition layers, and layered ceramic layers. The operating parameters of EB-PVD were as follows: the vacuum level in the equipment chamber was below 3E. -2 After Pa, the target material is baked using an electron beam until the vacuum level drops below 3E again. -2 Pa. Oxygen is introduced into the equipment at a pressure of 100 sccm until the vacuum level reaches 1.2E. -1 The blades were preheated using an electron beam at 100℃ for 30 minutes. The columnar ceramic layer was evaporated using a YSZ target with an electron beam current of 0.9 A and a target feed rate of 0.6 mm / min. The transition layer was evaporated using a YSZ target with an electron beam current of 1.5-2 A and a target feed rate of 1.1 mm / min. The layered ceramic layer was evaporated using a YSZ target with an electron beam current of 2-3 A and a target feed rate of 1.4 mm / min.

[0093] Comparative Example 2

[0094] The composite thermal barrier coating was prepared according to the method of Example 1, with the only difference being that steps 4-6 used plasma spraying (APS) equipment. APS was used to prepare a nanostructured coating with a thickness of 0.1-2 mm. The APS operating parameters were as follows: columnar ceramic layer: spraying current 900 A, argon: 45 L / min, hydrogen: 6 L / min, powder feed rate 25 g / min, spraying distance 80 mm; transition layer: spraying current 750 A, argon: 40 L / min, hydrogen: 6 L / min, powder feed rate 35 g / min, spraying distance 100 mm; layered ceramic layer: spraying current 600 A, argon: 40 L / min, hydrogen: 6 L / min, powder feed rate 40 g / min, spraying distance 120 mm.

[0095] Figure 7 This is a cross-sectional SEM image of a typical columnar ceramic layer prepared by EB-PVD in Comparative Example 1. Figure 8 This is a cross-sectional SEM image of the APS nanostructured coating prepared in Comparative Example 2. Figure 3 and Figures 7-8 It can be seen that, with Figure 7 The typical columnar structure coating of EB-PVD shown is as follows: Figure 8 The comparison of APS nanostructure coatings shown shows that the columnar crystal structure ceramic layer prepared by PS-PVD process combines the advantages of columnar and layered ceramic layers. Columnar crystals can achieve good stress release, and a large number of pores can provide good thermal insulation effect for the coating.

[0096] Test Example 1

[0097] 1. Water quenching experiment

[0098] The composite thermal barrier coating sample prepared in Example 1 was water-quenched 60 times at 1100℃, with each water quenching holding time being 5 min. The surface morphology of the composite thermal barrier coating is as follows: Figure 9 As shown, by Figure 9 It can be seen that after 60 water quenchings at 1100℃, the peeling rate of the composite thermal barrier coating is <5%, indicating that the composite thermal barrier coating prepared by the present invention has good thermal stress resistance.

[0099] 2. Thermal shock

[0100] The thermal shock performance was tested according to the Q / AVIC06016.1 standard. The specific steps are as follows: The composite thermal barrier coating samples prepared in Example 1 and Comparative Example 2 were subjected to heat preservation and air cooling (considered as one cycle) for 12,000 cycles. The heat preservation temperature was 1100℃, the heat preservation time was 5 min, and the air cooling time was 5 min.

[0101] Figure 10The thermal shock test results of the composite thermal barrier coating prepared in Comparative Example 2 are presented by... Figure 10 It is known that the thermal shock life of ordinary APS thermal barrier coatings is generally 4,000 to 7,000 cycles, while the thermal shock life of the modified prefabricated vertical crack structure thermal barrier coating prepared by APS can reach nearly 10,000 cycles. The coating of the sample remained intact after 9,490 thermal shocks.

[0102] Figure 11 The thermal shock test results of the composite thermal barrier coating prepared in Example 1 are provided by... Figure 11 It can be seen that the multi-arc ion-plated NiCrAlYSi+ composite thermal barrier coating prepared by the present invention remains intact after 10,000 thermal shocks, and the peeling area of ​​the coating is still less than 5% of the total coating area after 12,000 thermal shocks, indicating that the composite thermal barrier coating prepared by the present invention has good thermal cycling performance.

[0103] 3. Thermal conductivity

[0104] The thermal conductivity was tested according to the Q-AVIC 06019 standard. The specific steps are as follows: The thermal diffusivity of the composite thermal barrier coatings prepared in Examples 1-6 and Comparative Examples 1-2 was tested at different test temperatures using a laser thermal conductivity meter. The test results are shown in Table 1.

[0105] Table 1 Thermal diffusivity α (mm) of composite structure coating 2 / s)

[0106]

[0107]

[0108] The thermal conductivity of the composite thermal barrier coating is calculated using equation (1) based on the coating density ρ, thermal diffusivity α, and specific heat capacity Cp:

[0109] λ=ρ·α·Cp Equation (1);

[0110] The density of the composite thermal barrier coating prepared in Example 1, as determined by the Archimedes method, was 4.97 g / cm³. 3 .

[0111] The thermal conductivity curve of the composite thermal barrier coating prepared in Example 1 is shown below. Figure 12 As shown, by Figure 12 It can be seen that when the temperature exceeds 600℃, the thermal conductivity of the composite thermal barrier coating is ≤1.0W / (m·K), indicating that the composite thermal barrier coating prepared by the present invention has excellent thermal insulation performance.

[0112] In summary, the composite thermal barrier coating prepared by this invention has both excellent thermal cycling performance and thermal insulation performance.

[0113] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A composite thermal barrier coating, characterized in that, It comprises a metal bonding layer, a columnar crystal structure ceramic layer, a ceramic transition layer, and a layered ceramic layer stacked sequentially; the porosity of the columnar crystal structure ceramic layer is 12-20%; the thickness of the ceramic transition layer is 5-25 μm; The method for preparing the composite thermal barrier coating includes the following steps: Using metal bonding layer raw materials, multi-arc ion plating is performed on the substrate surface to form a metal bonding layer on the substrate surface; The metal bonding layer is surface activated and then placed in a PS-PVD device. Using columnar crystal structure ceramic layer raw material powder, a first plasma physical vapor deposition is performed on the surface of the metal bonding layer to form a columnar crystal structure ceramic layer. The vacuum degree of the first plasma physical vapor deposition chamber is 100~300Pa, and the spray gun power is 50~70kW. Using ceramic transition layer raw material powder, a second plasma physical vapor deposition is performed on the surface of the columnar crystal structure ceramic layer to form a ceramic transition layer; the vacuum degree of the chamber for the second plasma physical vapor deposition is 3000~10000Pa, and the spray gun power is 30~60kW. Using layered ceramic layer raw material powder, a third plasma physical vapor deposition is performed on the surface of the ceramic transition layer to form a layered ceramic layer, forming a composite thermal barrier coating on the substrate surface; the vacuum degree of the chamber for the third plasma physical vapor deposition is 10~10000Pa, and the spray gun power is 30~60kW.

2. The composite thermal barrier coating according to claim 1, characterized in that, The metal bonding layer includes an MCrAlY coating, a Pt / Al coating, or a NiCoCrAlYHf coating; the thickness of the metal bonding layer is 20~120μm.

3. The composite thermal barrier coating according to claim 1, characterized in that, The columnar crystal structure ceramic layer includes a YSZ coating; the thickness of the columnar crystal structure ceramic layer is 30~130μm.

4. The composite thermal barrier coating according to claim 1, characterized in that, The ceramic transition layer includes a YSZ coating.

5. The composite thermal barrier coating according to claim 1, characterized in that, The layered ceramic layer includes a YSZ coating or a GYbZ coating; the thickness of the layered ceramic layer is 30~130μm.

6. The method for preparing the composite thermal barrier coating according to any one of claims 1 to 5, characterized in that, Includes the following steps: Using metal bonding layer raw materials, multi-arc ion plating is performed on the substrate surface to form a metal bonding layer on the substrate surface; The metal bonding layer is surface activated and then placed in a PS-PVD device. Using columnar crystal structure ceramic layer raw material powder, a first plasma physical vapor deposition is performed on the surface of the metal bonding layer to form a columnar crystal structure ceramic layer. The vacuum degree of the first plasma physical vapor deposition chamber is 100~300Pa, and the spray gun power is 50~70kW. Using ceramic transition layer raw material powder, a second plasma physical vapor deposition is performed on the surface of the columnar crystal structure ceramic layer to form a ceramic transition layer; the vacuum degree of the chamber for the second plasma physical vapor deposition is 3000~10000Pa, and the spray gun power is 30~60kW. Using layered ceramic layer raw material powder, a third plasma physical vapor deposition is performed on the surface of the ceramic transition layer to form a layered ceramic layer, forming a composite thermal barrier coating on the substrate surface; the vacuum degree of the chamber for the third plasma physical vapor deposition is 10~10000Pa, and the spray gun power is 30~60kW.

7. The preparation method according to claim 6, characterized in that, The substrate undergoes surface treatment before use, which includes sequentially performing a first cleaning, a first drying, surface activation, a second cleaning, and a second drying; the surface activation includes sandblasting or polishing; the substrate comprises a high-temperature alloy.

8. The preparation method according to claim 6, characterized in that, The surface activation includes sandblasting or polishing. The surface activation process also includes sequential cleaning and drying.

9. The preparation method according to claim 6, characterized in that, The operating parameters for the first, second, and third plasma physical vapor depositions include: argon flow rate of 20-40 L / min, helium flow rate of 50-80 L / min, oxygen flow rate of 1-5 L / min, spraying distance of 800-1500 mm, powder carrier gas flow rate of 5-20 L / min, and powder feed rate of 4-20 g / min.

10. The application of the composite thermal barrier coating according to any one of claims 1 to 5 or the composite thermal barrier coating prepared by the preparation method according to any one of claims 6 to 9 in an aero-engine or gas turbine.

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