Abradable seal coating and method of making, turbine outer ring, and applications

Abstract

The application relates to an abradable seal coating and a preparation method, a turbine outer ring and application thereof. The abradable seal coating is arranged on a metal base material; the metal base material is a high-temperature alloy base material; the abradable seal coating comprises a metal bonding layer and a composite ceramic layer; the metal bonding layer is arranged on the metal base material, and the composite ceramic layer is arranged on one side of the metal bonding layer away from the metal base material; the composite ceramic layer comprises at least two sub-layers; along the direction perpendicular to the metal bonding layer and away from the metal base material, the proportion of columnar crystals in the sub-layers and the thickness of the sub-layers gradually decrease, and the proportion of particles gradually increases. During service, the abradability of the coating decreases with the abrasion of the surface layer to realize effective dynamic sealing, surface damage of components in contact with the coating is avoided, the coating is not easy to peel off from the base material, and the coating has good thermal shock resistance. The preparation method has low overall process complexity, and can obtain the seal coating with good abradability and thermal shock resistance.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of high-performance coating, in particular to an abradable seal coating, a preparation method thereof, a turbine outer ring and application. BACKGROUND

[0002] The abradable seal coating applied to the turbine outer ring of an aero-engine can improve the dynamic seal between the rotating part and the fixed part, reduce oil consumption and improve the overall efficiency of the engine. During the service of the engine, the abradable seal coating serves as a sacrificial layer and is abraded and scraped by the blade tip when the blade rotates. In order to avoid damage to the blade tip, the coating is required to have excellent abradability. At the same time, the seal coating needs to face the scouring of high-speed airflow, and the design thickness of the seal coating is generally large, which is prone to cause the problem of delamination of the coating. Therefore, it is urgent to develop an abradable seal coating with good abradability, tight bonding with the substrate and controllable cost. SUMMARY

[0003] Based on this, the purpose of the present application includes providing an abradable seal coating comprising a metal bonding layer and a composite ceramic layer, wherein the ceramic columnar crystals and particles in the composite ceramic layer have a distribution gradient in the direction perpendicular to the metal bonding layer, and the abradable seal coating can have good abradability, bonding degree with the metal substrate and thermal shock resistance at a lower cost. An abradable seal coating, a preparation method thereof, a turbine outer ring and application are also provided.

[0004] In a first aspect of the present application, an abradable seal coating is provided, which is arranged on a metal substrate; the metal substrate is a high-temperature alloy substrate;

[0005] The abradable seal coating comprises a metal bonding layer and a composite ceramic layer; the metal bonding layer is arranged on the metal substrate, and the composite ceramic layer is arranged on the side of the metal bonding layer away from the metal substrate;

[0006] The composite ceramic layer comprises columnar crystals and particles filled in the gaps between the columnar crystals; the composition of the columnar crystals and the particles each independently comprises one or more of gadolinium zirconate, ytterbium oxide doped gadolinium zirconate;

[0007] The direction from the surface of the composite ceramic layer close to the metal bonding layer to the surface of the composite ceramic layer away from the metal bonding layer is referred to as the first direction;

[0008] The composite ceramic layer comprises a plurality of sub-layers, which are distinguished by the discontinuous regions between the columnar crystal grains in the first direction; the sub-layers comprise the range from the bottom of the columnar crystal in the layer to the bottom of the columnar crystal in the next layer along the first direction; along the first direction, the volume percentage gradient of the columnar crystals in each sub-layer decreases, and the volume percentage gradient of the particles in each sub-layer increases.

[0009] In some embodiments, the abradable seal coating comprises at least i sub-layers, i≥2;

[0010] Each sub-layer of the composite ceramic layer comprises columnar crystals and particles filling in the interstices of the columnar crystals; the compositions of the columnar crystals and the particles each independently comprise one or more of gadolinium zirconate, ytterbium oxide doped gadolinium zirconate;

[0011] A higher volume fraction of particles is distributed between the adjacent two sub-layers as a boundary between the adjacent sub-layers;

[0012] The sub-layers are numbered from small to large along the first direction, and the volume percentages of the columnar crystals in the i-th sub-layer and the i+1-th sub-layer are denoted as A i and A i+1 , respectively; the volume percentages of the particles in the i-th sub-layer and the i+1-th sub-layer are denoted as B i and B i+1 , respectively; the volume percentages of the pores (porosities) in the i-th sub-layer and the i+1-th sub-layer are denoted as C i and C i+1 , respectively; and the thicknesses of the i-th sub-layer and the i+1-th sub-layer are denoted as D i and D i+1 , respectively. i >A i+1 , B i <B i+1 , C i <C i+1 , and D i >D i+1 ; the thickness of the sub-layer refers to the shortest distance from the bottom of the columnar crystals of the layer to the bottom of the columnar crystals of the next layer along the direction perpendicular to the bonding layer.

[0013] In some embodiments, the abradable seal coating comprises at least a first sub-layer and a second sub-layer along the first direction;

[0014] The volume percentage of the columnar crystals in the first sub-layer is 70% to 95%, the volume percentage of the particles in the first sub-layer is 5% to 30%, and the thickness of the first sub-layer is 8 μm to 120 μm;

[0015] The volume percentage of the columnar crystals in the second sub-layer is 60% to 85%, the volume percentage of the particles in the second sub-layer is 10% to 40%, and the thickness of the second sub-layer is 8 μm to 120 μm.

[0016] In some embodiments, the abradable seal coating satisfies one or more of the following characteristics:

[0017] The metal bond layer comprises one of MCrAlY, NiAl and NiPtAl, M in MCrAlY is selected from at least one of Ni and Co;

[0018] The metal bond layer has a thickness of 30 μm to 100 μm.

[0019] In some embodiments, the abradable seal coating satisfies one or more of the following characteristics:

[0020] The composite ceramic layer has a thickness of 70 μm to 300 μm;

[0021] Each sub-layer of the composite ceramic layer has a thickness of 8 μm to 120 μm;

[0022] The columnar crystals in each sub-layer of the composite ceramic layer have a width of 10 μm to 40 μm;

[0023] The columnar crystals in each sub-layer of the composite ceramic layer have a length of 8 μm to 120 μm;

[0024] The particles in each sub-layer of the composite ceramic layer have an average particle size of 0.5 μm to 10 μm.

[0025] In a second aspect, the present application provides a method for preparing an abradable seal coating, comprising the following steps:

[0026] Pre-treatment of the superalloy substrate: pre-treating the superalloy substrate, the pre-treatment comprising polishing, polishing, ultrasonic cleaning and drying treatment of the superalloy substrate;

[0027] Preparation of the metal bond layer: depositing a metal bond layer on one side of the superalloy substrate and performing vacuum heat treatment to obtain the metal bond layer;

[0028] Preparation of the composite ceramic layer: depositing a composite ceramic layer on the side of the metal bond layer away from the superalloy substrate to obtain the composite ceramic layer; the composite ceramic layer comprises at least two sub-layers, each sub-layer of the composite ceramic layer comprises columnar crystals and particles filling the gaps between the columnar crystals; the columnar crystals and the particles in each sub-layer are gradiently distributed along the first direction in the composite ceramic layer; the columnar crystals and the particles independently comprise one or more of yttria-stabilized zirconia, gadolinium zirconate and ytterbium oxide-doped gadolinium zirconate.

[0029] In some embodiments, the method for preparing an abradable seal coating satisfies one or more of the following characteristics:

[0030] The method for depositing the metallic bond layer on one side of the high-temperature alloy substrate is selected from one or more of multi-arc ion plating, electron beam physical vapor deposition, and electroplating-aluminizing;

[0031] The method for depositing the composite ceramic layer on the side of the metallic bond layer away from the high-temperature alloy substrate is selected from plasma physical vapor deposition.

[0032] In some embodiments, in the method for preparation, when the composite ceramic layer is deposited on the side of the metallic bond layer away from the high-temperature alloy substrate by plasma physical vapor deposition, one or more of the following features is met:

[0033] The material used for depositing the composite ceramic layer comprises a ceramic material powder, the average particle size D50 of the ceramic material powder is 10 μm to 100 μm, and the composition of the ceramic material comprises one or more of yttria-stabilized zirconia, gadolinium zirconate, and ytterbium oxide-doped gadolinium zirconate;

[0034] The vacuum degree is set to 1 mbar to 5 mbar;

[0035] The preheating temperature of the sample is set to 600°C to 800°C;

[0036] The atmosphere is an inert gas, and the inert gas is selected from at least one of argon and helium;

[0037] When helium is used as the plasma gas, the flow rate of the helium is 40 L / min to 80 L / min;

[0038] When argon is used as the plasma gas, the flow rate of the argon is 20 L / min to 40 L / min;

[0039] The powder feeding carrier gas is argon, and the powder feeding rate is set to 4 g / min to 14 g / min;

[0040] The distance between the spray gun and the deposition surface is set to 800 mm to 1600 mm;

[0041] The current is set to 1200 A to 2200 A;

[0042] The power is set to 45 kW to 65 kW.

[0043] In a third aspect, the application provides a turbine outer ring, wherein a surface of the turbine outer ring is provided with the abradable seal coating according to the first aspect or prepared by the method according to the second aspect.

[0044] In a fourth aspect, the application provides a use of the abradable seal coating of the first aspect or the abradable seal coating prepared by the method of the second aspect in manufacturing an aero-engine component.

[0045] The abradable seal coating provided in the application is arranged on a high-temperature alloy substrate in sequence with a metal bonding layer and a composite ceramic layer. By setting the proportion of columnar crystals and particles in each sublayer along the first direction in the composite ceramic layer as a gradient distribution along the first direction, the proportion of columnar crystals is higher in the ceramic layer sublayer close to the metal bonding layer, and the mechanical strength is higher. The proportion of particles is higher and the porosity is more in the ceramic layer sublayer close to the surface of the coating, and the layer structure is looser. The binding force between the sublayers close to the surface of the coating is weaker, and the hardness is lower. On the one hand, the abradability of the coating decreases during the service process of the coating to realize effective dynamic sealing of the substrate, thereby avoiding surface damage of the component in contact with the coating. On the other hand, the proportion of columnar crystals is higher in the sublayer in contact with the substrate, and the mechanical properties are excellent, and then the composite ceramic layer and the metal bonding layer are closely combined. The gradient distribution of columnar crystals and particles in the sublayer in the composite ceramic layer is also beneficial to improve the interlayer peeling caused by the sharp change of internal stress when subjected to thermal shock.

[0046] In the preparation method provided in the application, the metal bonding layer and the composite ceramic layer are sequentially deposited on the surface of the high-temperature alloy substrate, and the composite ceramic layer includes at least two sublayers and the columnar crystals and particles in each sublayer along the direction perpendicular to the metal bonding layer are gradiently distributed. The process can deposit a ceramic layer with complex layers in one spraying process without repeatedly turning on and off the equipment, the overall process has lower complexity, and an abradable seal coating with good abradability and thermal shock resistance can be obtained.

[0047] The turbine outer ring provided in the third aspect of the application adopts the abradable seal coating with good abradability and thermal shock resistance and closely combined with the turbine outer ring. The turbine outer ring can withstand high-speed airflow scouring without peeling of the coating, and can also reduce the degree of damage to the blade tip in contact with the turbine outer ring.

[0048] The abradable seal coating provided in the fourth aspect of the application is applied in the process of manufacturing an aero-engine component, and an abradable seal coating closely combined with a metal component can be obtained. Moreover, the coating can effectively protect the components of the aero-engine and avoid wear caused by high-speed airflow scouring or contact with other metal components. BRIEF DESCRIPTION OF DRAWINGS

[0049] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0050] Figure 1 This is a schematic diagram of the structure of a high-temperature gradient wearable sealing coating according to an embodiment of this application; wherein, 1 is a high-temperature alloy substrate, 2 is a metal bonding layer, and 3 is a composite ceramic layer; 31, 32, 33 and 34 are the first sublayer, second sublayer, third sublayer and fourth sublayer of the composite ceramic layer 3, respectively; 35 is columnar crystals, and 36 is particles filling the gaps between columnar crystals.

[0051] Figure 2 ,in Figure 2 (a) is a deposition current-time graph showing the preparation process of the wearable sealing coating in Example 1. Figure 2 (b) is an electron backscatter photograph of the micro-section of the sealing coating prepared in Example 1.

[0052] Figure 3 ,in Figure 3 (a) is a graph showing the spraying distance-time relationship during the preparation of the abrasive sealing coating in Example 2. Figure 3 (b) is an electron backscatter photograph of the micro-section of the sealing coating prepared in Example 2.

[0053] Figure 4 ,in Figure 4 (a) is a graph showing the powder feed rate versus time during the preparation of the abrasive sealing coating in Example 3. Figure 4 (b) is an electron backscatter photograph of the micro-section of the sealing coating prepared in Example 3.

[0054] Figure 5 ,in Figure 5 (a) is a current-time graph showing the sealing coating preparation process in Comparative Example 1. Figure 5 (b) is an electron backscatter photograph of the micro-section of the sealing coating prepared in Example 1.

[0055] Figure 6 ,in Figure 6 (a) is the current-time relationship graph of the sealing coating preparation process in Comparative Example 2. Figure 6 (b) is an electron backscatter photograph of the micro-section of the sealing coating prepared in Example 2. Detailed Implementation

[0056] For the purpose of promoting an understanding of the application, the application will now be described in greater detail with reference to the preferred embodiments. It is to be understood that the application can assume various alternative forms of embodiment, and it is therefore not limited to the embodiments set forth herein. Rather, the embodiments are provided as a full and enabling disclosure of the application, and are presented to give those of ordinary skill in the art enough information to make and use the same.

[0057] The embodiments of the present application will be described in detail with reference to the drawings. The embodiments are implemented on the premise of the technical solutions of the present application, and detailed implementation modes and specific operation processes are given, but the protection scope of the present application is not limited to the following embodiments.

[0058] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description of the application herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0059] The term

[0060] Unless otherwise defined or contradictory, the terms or phrases used herein have the following meanings:

[0061] In the present application, "a plurality of", "a plurality of", etc. are used to describe the purpose, and the difference in content is not understood as limiting the scope of protection of the present application.

[0062] In the present application, "further", "particularly" and the like are used for the purpose of description, indicating the difference in content, but should not be understood as limiting the scope of protection of the present application.

[0063] In the present application, the technical features described in an open manner include the closed technical solutions consisting of the listed features, and also include the open technical solutions containing the listed features.

[0064] In the present application, the numerical interval (i.e. the numerical range) is involved, and if not otherwise specified, the distribution of the selected values in the numerical interval is considered to be continuous, and includes the two numerical endpoints (i.e. the minimum value and the maximum value) of the numerical interval, and every value between the two numerical endpoints. If not otherwise specified, when the numerical interval refers only to the integers in the numerical interval, the two endpoint integers of the numerical range and every integer between the two endpoints are equivalent to directly listing every integer. When multiple numerical ranges are provided to describe a feature or characteristic, these numerical ranges can be combined. In other words, unless otherwise indicated, the numerical range disclosed herein should be understood to include any and all sub-ranges included therein. The "numerical value" in the numerical interval can be any quantitative value, such as a number, a percentage, a ratio, etc. The "numerical interval" is allowed to be broadly included in the numerical interval type, such as percentage interval, ratio interval, ratio interval, etc.

[0065] In the present application, the term "room temperature" generally refers to 4℃-35℃, preferably 20℃±5℃. In some embodiments of the present application, room temperature refers to 20℃-30℃.

[0066] In the present application, unless otherwise specified, the temperature parameter allows both constant temperature treatment and variation within a certain temperature range. It should be understood that the constant temperature treatment allows the temperature to fluctuate within the accuracy range controlled by the instrument. Fluctuation within a range such as ±5℃, ±4℃, ±3℃, ±2℃, ±1℃ is allowed.

[0067] The abradable seal coating refers to a coating that is sprayed on the inner surface of the turbine outer ring using thermal spraying technology, is resistant to high temperature and oxidation, is soft and porous in quality, and can form an abradable seal wear pair with the blade tip.

[0068] Abradability refers to the property of the coating to form an abradable seal wear pair with the turbine blade or compressor blade tip. The abradability of the coating can generally be judged by the hardness or friction and wear test of the coating.

[0069] Thermal shock resistance refers to an important indicator for evaluating the breaking resistance of a material when it is subjected to rapid temperature changes. The thermal shock resistance of the coating can generally be judged by the thermal shock test life.

[0070] The abradable seal coating applied to the turbine outer ring of an aero-engine can improve the dynamic seal between the rotating parts and the fixed parts, reduce oil consumption, and improve the overall efficiency of the engine. During the service of the engine, the abradable seal coating acts as a sacrificial layer and is abraded and scraped by the blade tip when the blade rotates. To avoid damage to the blade tip, the coating is required to have excellent abradability. At the same time, the seal coating needs to face high-speed airflow erosion, and its design thickness is generally large, which is prone to cause delamination and peeling of the coating. Therefore, it is urgent to develop an abradable seal coating with good abradability, tight bonding with the substrate, and controllable cost.

[0071] In the conventional technology, a complex thick coating is generally required to reduce the separation between the ceramic layer and the bonding layer during thermal cycling, such as setting a sealing layer outside the ceramic layer, or using two or more ceramic layers with different compositions and morphologies, so as to achieve close combination with the metal substrate while providing the required abradable performance. Specifically, to improve the abradable performance and thermal shock resistance of the ceramic-based sealing coating, some studies use an inner-outer double-powder feeding structure plasma spraying technology to prepare an abradable sealing coating, the bottom layer of which is a metal layer, and the surface layer is a high-temperature sealing coating with a gradually changing organization composed of alternating ceramic layers and metal layers. The coating system has good thermal expansion coefficient matching, and the bonding strength between the coating and the substrate is excellent. However, due to the hardness of the surface ceramic layer, the abradable performance of the coating is poor, and the high-temperature service performance of the coating as a whole needs to be considered. Some studies use high-temperature abradable sealing coatings with multi-level or gradient pores, which adjust the content and distribution of micro-nano multi-level pores by adjusting the content of filler feeding and porous ceramic feeding, and at the same time improve the abradable performance and thermal shock resistance of the coating; the process of preparing a gradient structure coating by multiple spraying is complex and requires high requirements for the composition and proportion of the filler.

[0072] The present application provides a high-temperature gradient abradable sealing coating comprising a metal bonding layer and a composite ceramic layer, wherein the composite ceramic layer has a distribution gradient of ceramic columnar crystals and particles in the direction perpendicular to the metal bonding layer, which can achieve better abradable performance, bonding degree with the metal substrate and thermal shock resistance at a lower cost; a preparation method of the abradable sealing coating, a turbine outer ring and an application are also provided.

[0073] In a first aspect of the present application, an abradable sealing coating is provided, which is arranged on a metal substrate; the metal substrate is a high-temperature alloy substrate;

[0074] The abradable sealing coating comprises a metal bonding layer and a composite ceramic layer; the metal bonding layer is arranged on the metal substrate, and the composite ceramic layer is arranged on the metal bonding layer away from the metal substrate;

[0075] The composite ceramic layer comprises columnar crystals and particles filled in the gaps of the columnar crystals; the components of the columnar crystals and the particles are independently one or more of yttria-stabilized zirconia, gadolinium zirconate and ytterbium oxide-doped gadolinium zirconate;

[0076] The direction from the surface of the composite ceramic layer close to the metal bonding layer to the surface of the composite ceramic layer away from the metal bonding layer is defined as the first direction;

[0077] The composite ceramic layer comprises several sub-layers, which are distinguished by discontinuous regions between columnar crystal grains in a direction perpendicular to the surface of the bonding layer, and each sub-layer comprises a range from the bottom of a columnar crystal in the layer to the bottom of a columnar crystal in the next layer in the first direction; in each sub-layer, the volume percentage of columnar crystals decreases in the first direction, and the volume percentage of particles increases in the first direction.

[0078] In the present application, the abradable seal coating is arranged on the high-temperature alloy substrate in sequence with a metal bonding layer and a composite ceramic layer. By setting the proportion of columnar crystals and particles in each sub-layer in the composite ceramic layer in the first direction to be distributed in a gradient along the first direction, the proportion of columnar crystals in the sub-layer of the ceramic layer close to the metal bonding layer is high, and the mechanical strength is high. The proportion of particles in the sub-layer of the ceramic layer away from the metal bonding layer is high, and there are more pores and the layer structure is looser. The binding force between the sub-layers close to the surface of the coating is weak, and the hardness is low. On the one hand, the abradability of the coating decreases during the service process of the coating to realize effective dynamic sealing, thereby avoiding surface damage of the components in contact with the coating. On the other hand, the proportion of columnar crystals in the sub-layer of the coating in contact with the substrate is high, and the mechanical properties are excellent, thereby the composite ceramic layer and the metal bonding layer are closely combined, and the gradient distribution of the columnar crystals and the particles in the sub-layers in the composite ceramic layer is also beneficial to improve the layer separation caused by the sharp change of internal stress when subjected to thermal shock impact.

[0079] In the present application, unless otherwise specified, the high-temperature alloy refers to a kind of metal material taking iron, nickel, and cobalt as the base, which can work at high temperature above 600℃ and under certain stress for a long time. It has high high-temperature strength, good oxidation resistance and corrosion resistance, good fatigue performance, fracture toughness, and other comprehensive properties.

[0080] It can be understood that the columnar crystal in the present application refers to a micro entity with a certain radial length and a certain width perpendicular to the radial direction. The columnar crystal can be characterized by imaging under a certain accelerating voltage and magnification by conventional material characterization methods such as field emission scanning electron microscopy. Reference can also be made to the schematic diagram provided in Figure 1 The schematic diagram provided in the present application is a schematic diagram of the abradable seal coating of an embodiment of the present application, which comprises a high-temperature alloy substrate (1), a metal bonding layer (2) arranged on the high-temperature alloy substrate (1), and a composite ceramic layer (3) arranged on the metal bonding layer away from the high-temperature alloy substrate; the composite ceramic layer comprises four sub-layers, namely a first sub-layer 31, a second sub-layer 32, a third sub-layer 33, and a fourth sub-layer 34. The thickness of each sub-layer decreases in turn in a direction perpendicular to the bonding layer. Each sub-layer is composed of columnar crystals (35), and the gaps between the columnar crystals are filled with particles (36).

[0081] It is understood that the components of the columnar crystals and the particles of the composite ceramic layer can be selected from one or more of yttria-stabilized zirconia, gadolinium zirconate (Gd2Zr2O7), ytterbia-doped gadolinium zirconate (ytterbia-doped gadolinium zirconate has a mass percentage of 5% to 8% of ytterbia oxide, preferably ytterbia-doped gadolinium zirconate has a mass percentage of 6.4% of ytterbia oxide, and the chemical formula of the ytterbia-doped gadolinium zirconate is (Gd 0.9 Yb 0.1 )2Zr2O7), and those skilled in the art can replace other ceramic materials without any creative effort, and therefore other ceramic thermal barrier coatings prepared by other ceramic materials having the sublayer characteristics of the composite structure are also within the protection scope of the present patent.

[0082] In some embodiments, the abradable seal coating has a composite ceramic layer including at least i sublayers, i ≥ 2.

[0083] In some embodiments, the abradable seal coating has a composite ceramic layer including at least i sublayers, i ≥ 2.

[0084] The columnar crystals refer to rod-shaped grains with consistent orientation periodically grown, characterized by having feather-like dendrites; the particles refer to spherical and near-spherical particles distributed in the interstices of the columnar crystals; each sublayer of the composite ceramic layer further includes pores between the columnar crystals and the particles filling the interstices of the columnar crystals, and pores between the particles in the sublayer.

[0085] In some embodiments, the abradable seal coating has a composite ceramic layer including at least i sublayers, i ≥ 2.

[0086] In some embodiments, the abradable seal coating has a composite ceramic layer including at least i sublayers, i ≥ 2. i and A i+1 , the volume percentage of the particles in the i-th sublayer and the i+1-th sublayer is denoted as B i and B i+1 , the volume percentage (porosity) of the pores in the i-th sublayer and the i+1-th sublayer is denoted as C i and C i+1 , the thickness of the i-th sublayer and the i+1-th sublayer is denoted as D i and D i+1 , and A i >A i+1 , Bi one or more conditions in <B i+1 one or more conditions in <C i one or more conditions in <D i+1 one or more conditions in >D i one or more conditions in >D i+1 The sub-layer thickness refers to the shortest distance from the bottom of the columnar crystal of the layer to the bottom of the columnar crystal of the next layer in the direction perpendicular to the bonding layer.

[0087] In some embodiments, the abradable seal coating comprises at least a first sub-layer and a second sub-layer along the first direction.

[0088] In some embodiments, the volume percentage of the columnar crystals in the first sub-layer is 70% to 95%, further can be 80% to 85%, and can be selected from any one of the following volume percentages or a range formed by any two of the following volume percentages: 70%, 75%, 80%, 80.77%, 81%, 82%, 82.47%, 82.82%, 85%, 90%, 95%, etc.

[0089] In some embodiments, the volume percentage of the particles in the first sub-layer is 5% to 30%, further can be 6% to 11%, and can be selected from any one of the following volume percentages or a range formed by any two of the following volume percentages: 5%, 6%, 6.22%, 7%, 7.95%, 8%, 9%, 10%, 10.98%, 11%, 15%, 20%, 25%, 30%, etc.

[0090] In some embodiments, the volume percentage of the particles in the first sub-layer is 5% to 30%, further can be 6% to 11%, and can be selected from any one of the following volume percentages or a range formed by any two of the following volume percentages: 5%, 6%, 6.22%, 7%, 7.95%, 8%, 9%, 10%, 10.98%, 11%, 15%, 20%, 25%, 30%, etc.

[0091] In some embodiments, the thickness of the first sub-layer is 8 μm to 120 μm, further can be 70 μm to 90 μm, and can be selected from any one of the following thicknesses or a range formed by any two of the following thicknesses: 8 μm, 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 75 μm, 76 μm, 77 μm, 78 μm, 79 μm, 79.36 μm, 80 μm, 81 μm, 82 μm, 82.78 μm, 83 μm, 84 μm, 85 μm, 86 μm, 86.91 μm, 87 μm, 88 μm, 89 μm, 90 μm, 100 μm, 110 μm, 120 μm, etc.

[0092] In some embodiments, in the abradable seal coating, the volume percentage of the columnar crystals in the second sub-layer is 60-85%, further can be 66-71%, and can be selected from any one of the following volume percentages or an interval formed by any two of the following volume percentages: 60%, 65%, 66%, 67%, 67.95%, 68%, 68.02%, 69%, 70%, 70.44%, 71%, 75%, 80%, 80.77%, 81%, 82%, 82.47%, 82.82%, 83%, 84%, 85%, etc.

[0093] In some embodiments, in the abradable seal coating, the volume percentage of the particles in the second sub-layer is 10-40%, further can be 15-20%, and can be selected from any one of the following volume percentages or an interval formed by any two of the following volume percentages: 10%, 11%, 15%, 15.23%, 16%, 17%, 18%, 18.57%, 19%, 19.31%, 20%, 25%, 30%, 35%, 40%, etc.

[0094] In some embodiments, in the abradable seal coating, the porosity (volume percentage) of the second sub-layer is 12-15%, further can be 12.5-14.5%, and can be selected from any one of the following volume percentages or an interval formed by any two of the following volume percentages: 12%, 12.67%, 13%, 13.48%, 13.5%, 14%, 14.33%, 14.5%, 15%, etc.

[0095] In some embodiments, in the abradable seal coating, the thickness of the second sub-layer is 8-120 μm, further can be 50-70 μm, and can be selected from any one of the following thicknesses or an interval formed by any two of the following thicknesses: 8 μm, 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 61 μm, 62 μm, 63 μm, 64 μm, 65 μm, 66 μm, 66.84 μm, 67 μm, 68 μm, 69 μm, 69.88 μm, 70 μm, 75 μm, 76 μm, 77 μm, 78 μm, 79 μm, 80 μm, 81 μm, 82 μm, 83 μm, 84 μm, 85 μm, 86 μm, 87 μm, 88 μm, 89 μm, 90 μm, 100 μm, 110 μm, 120 μm, etc.

[0096] In some embodiments, in the abradable seal coating, along the first direction, the composite ceramic layer comprises at least a first sub-layer, a second sub-layer, and a third sub-layer.

[0097] In some embodiments, in the abradable seal coating, the volume percentage of the columnar crystals in the third sub-layer is 50% to 75%, further can be 60% to 65%, and can be selected from any one of the following volume percentages or a range formed by any two of the following volume percentages: 50%, 55%, 60%, 61%, 62%, 62.39%, 62.41%, 63%, 64%, 64.56%, 65%, 70%, 75%, etc.

[0098] In some embodiments, in the abradable seal coating, the volume percentage of the particles in the third sub-layer is 15% to 50%, further can be 17% to 22%, and can be selected from any one of the following volume percentages or a range formed by any two of the following volume percentages: 15%, 17%, 17.7%, 18%, 19%, 19.23%, 20%, 21%, 21.11%, 22%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, etc.

[0099] In some embodiments, in the abradable seal coating, the porosity (volume percentage) of the third sub-layer is 14% to 20%, further can be 16.5% to 18.5%, and can be selected from any one of the following volume percentages or a range formed by any two of the following volume percentages: 14%, 15%, 16%, 16.5%, 17%, 17.5%, 17.74%, 18%, 18.36%, 18.5%, 19%, 20%, etc.

[0100] In some embodiments, in the abradable seal coating, the thickness of the third sub-layer is 8 μm to 120 μm, further can be 45 μm to 60 μm, and can be selected from any one of the following thicknesses or a range formed by any two of the following thicknesses: 8 μm, 10 μm, 20 μm, 30 μm, 40 μm, 48.06 μm, 49 μm, 50 μm, 51 μm, 52 μm, 52.8 μm, 53 μm, 54 μm, 55 μm, 56 μm, 56.9 μm, 57 μm, 58 μm, 59 μm, 60 μm, 70 μm, 75 μm, 76 μm, 77 μm, 78 μm, 79 μm, 80 μm, 81 μm, 82 μm, 83 μm, 84 μm, 85 μm, 86 μm, 87 μm, 88 μm, 89 μm, 90 μm, 100 μm, 110 μm, 120 μm, etc.

[0101] In some embodiments, the abradable seal coating has a difference between the volume percentage of the columnar grains in the two adjacent sub-layers of 2-20%. The difference can be selected from any one of the following volume percentages or a range defined by any two of the following volume percentages: 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, 10%, 10.5%, 11%, 11.5%, 12%, 12.5%, 13%, 13.5%, 14%, 14.5%, 15%, 16%, 16.5%, 17%, 17.5%, 18%, 18.5%, 19%, 19.5%, 20%, etc.

[0102] In some embodiments, the abradable seal coating has a difference between the volume percentage of the columnar grains in the first sub-layer and the second sub-layer in the first direction of 5-20%, further can be 12-14.5%, and can be selected from any one of the following volume percentages or a range defined by any two of the following volume percentages: 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 12.5%, 13%, 13.5%, 14%, 14.5%, 15%, 16%, 17%, 18%, 19%, 20%, etc.

[0103] In some embodiments, the abradable seal coating has a difference between the volume percentage of the columnar grains in the second sub-layer and the third sub-layer in the first direction of 2-10%, further can be 5-6%, and can be selected from any one of the following volume percentages or a range defined by any two of the following volume percentages: 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, 10%, etc.

[0104] In some embodiments, the abradable seal coating has a difference between the volume percentage of the particles in the two adjacent sub-layers of 0.5-20%. The difference can be selected from any one of the following volume percentages or a range defined by any two of the following volume percentages: 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, 10%, 10.5%, 11%, 11.5%, 12%, 12.5%, 13%, 13.5%, 14%, 14.5%, 15%, 16%, 16.5%, 17%, 17.5%, 18%, 18.5%, 19%, 19.5%, 20%, etc.

[0105] In some embodiments, the abradable seal coating has a difference between the volume percentage of the particles in the first sublayer and the second sublayer in the first direction of 5-15%, further can be 7-11.5%, and can be selected from any one of the following volume percentages or a range defined by any two of the following volume percentages: 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, 10%, 10.5%, 11%, 11.5%, 12%, 12.5%, 13%, 13.5%, 14%, 14.5%, 15%, etc.

[0106] In some embodiments, the abradable seal coating has a difference between the volume percentage of the particles in the second sublayer and the third sublayer in the first direction of 0.5-5%, further can be 0.5-2%, and can be selected from any one of the following volume percentages or a range defined by any two of the following volume percentages: 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, etc.

[0107] In some embodiments, the abradable seal coating has a difference between the porosity (volume percentage) in the two adjacent sublayers of 1-6%, and can be selected from any one of the following volume percentages or a range defined by any two of the following volume percentages: 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, etc.

[0108] In some embodiments, the abradable seal coating has a difference between the porosity (volume percentage) in the first sublayer and the second sublayer in the first direction of 3-6%, and can be selected from any one of the following volume percentages or a range defined by any two of the following volume percentages: 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, etc.

[0109] In some embodiments, the abradable seal coating has a difference between the porosity (volume percentage) in the second sublayer and the third sublayer in the first direction of 2-5%, and can be selected from any one of the following volume percentages or a range defined by any two of the following volume percentages: 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, etc.

[0110] In some embodiments, the thickness difference between the two adjacent sub-layers in the abradable seal coating is 5 μm to 40 μm. The thickness difference can also be selected from any one of the following or an interval formed by any two of the following: 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm, 17 μm, 18 μm, 19 μm, 20 μm, 21 μm, 22 μm, 23 μm, 24 μm, 25 μm, 26 μm, 27 μm, 28 μm, 29 μm, 30 μm, 31 μm, 32 μm, 33 μm, 34 μm, 35 μm, 36 μm, 37 μm, 38 μm, 39 μm, 40 μm, etc.

[0111] In some embodiments, the thickness difference between the first sub-layer and the second sub-layer in the abradable seal coating is 10 μm to 40 μm along the first direction. The thickness difference can also be selected from any one of the following or an interval formed by any two of the following: 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm, 17 μm, 18 μm, 19 μm, 20 μm, 21 μm, 22 μm, 23 μm, 24 μm, 25 μm, 26 μm, 27 μm, 28 μm, 29 μm, 30 μm, 31 μm, 32 μm, 33 μm, 34 μm, 35 μm, 36 μm, 37 μm, 38 μm, 39 μm, 40 μm, etc.

[0112] In some embodiments, the thickness difference between the second sub-layer and the third sub-layer in the abradable seal coating is 5 μm to 30 μm along the first direction. The thickness difference can also be selected from any one of the following or an interval formed by any two of the following: 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm, 17 μm, 18 μm, 19 μm, 20 μm, 21 μm, 22 μm, 23 μm, 24 μm, 25 μm, 26 μm, 27 μm, 28 μm, 29 μm, 30 μm, etc.

[0113] In the present application, YSZ refers to yttria-doped zirconia, i.e., yttria-stabilized zirconia (Y2O3-stabilized ZrO2), unless otherwise specified. The doping amount of yttria is 6 wt.% to 8 wt.%, which can be adjusted according to the use requirements. GZO refers to gadolinium zirconate, i.e., Gd2Zr2O7; GYbZ refers to ytterbium-doped gadolinium zirconate, preferably ytterbium-doped gadolinium zirconate of the chemical formula (Gd 0.9 Yb 0.1 )2Zr2O7.

[0114] In some embodiments, the metal bond layer in the abradable seal coating comprises one of MCrAlY, NiAl and NiPtAl, wherein M in MCrAlY is selected from at least one of Ni and Co.

[0115] In some embodiments, the metal bond layer in the abradable seal coating has a thickness of 30 μm to 100 μm, and can be selected from any one of the following thicknesses or a range defined by any two of the following thicknesses: 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, etc.

[0116] In some embodiments, the composite ceramic layer in the abradable seal coating has a thickness of 70 μm to 300 μm, and can be selected from any one of the following thicknesses or a range defined by any two of the following thicknesses: 70 μm, 80 μm, 90 μm, 100 μm, 150 μm, 200 μm, 250 μm, 300 μm, etc.

[0117] In some embodiments, each sub-layer of the composite ceramic layer in the abradable seal coating has a thickness of 8 μm to 120 μm, and can be selected from any one of the following thicknesses or a range defined by any two of the following thicknesses: 8 μm, 9 μm, 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 110 μm, 120 μm, etc.

[0118] In some embodiments, the columnar crystals in each sub-layer of the composite ceramic layer in the abradable seal coating have a width of 10 μm to 40 μm, and can be selected from any one of the following widths or a range defined by any two of the following widths: 10 μm, 20 μm, 30 μm, 40 μm, etc.

[0119] In some embodiments, the columnar crystals in each sub-layer of the composite ceramic layer in the abradable seal coating have a length of 8 μm to 120 μm, and can be selected from any one of the following lengths or a range defined by any two of the following lengths: 8 μm, 9 μm, 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 110 μm, 120 μm, etc.

[0120] In some embodiments, the average particle size of the particles in each of the sub-layers of the composite ceramic layer in the abradable seal coating is 0.5 μm to 10 μm, and can be selected from any one of the following average particle sizes or an interval formed by any two of the following average particle sizes: 0.5 μm, 1 μm, 1.5 μm, 2 μm, 2.5 μm, 3 μm, 3.5 μm, 4 μm, 4.5 μm, 5 μm, 5.5 μm, 6 μm, 6.5 μm, 7 μm, 7.5 μm, 8 μm, 8.5 μm, 9 μm, 9.5 μm, 10 μm, etc.

[0121] In the present application, the width of the columnar crystal refers to the maximum radial length of each columnar crystal, and the length of the columnar crystal refers to the longest distance from the bottom to the top of each columnar crystal, unless otherwise specified.

[0122] In a second aspect of the present application, a method for preparing an abradable seal coating is provided, which can be used to prepare the abradable seal coating of the first aspect.

[0123] In some embodiments, the method for preparing an abradable seal coating comprises the following steps:

[0124] providing a high-temperature alloy substrate and performing pretreatment;

[0125] preparing a metal bonding layer on one side of the high-temperature alloy substrate and performing heat treatment;

[0126] preparing a composite ceramic layer on the surface of the metal bonding layer away from the high-temperature alloy substrate, and adjusting the parameters of the deposition process so that the coating comprises a plurality of sub-layers composed of columnar crystals and particles.

[0127] In some embodiments, the method for preparing an abradable seal coating comprises the following steps:

[0128] S100: Pretreatment of the high-temperature alloy substrate: the high-temperature alloy substrate is pretreated, and the pretreatment comprises grinding, polishing, ultrasonic cleaning, and drying treatment of the high-temperature alloy substrate;

[0129] S200: Preparation of the metal bonding layer: depositing a metal bonding layer on one side of the high-temperature alloy substrate and performing vacuum heat treatment to obtain the metal bonding layer;

[0130] S300: Preparation of the composite ceramic layer: depositing a composite ceramic layer on the side of the metallic bonding layer away from the superalloy substrate to obtain a composite ceramic layer; the composite ceramic layer comprises at least 2 sub-layers, each sub-layer of the composite ceramic layer comprises columnar crystals and particles filling the interstices of the columnar crystals; the columnar crystals and the particles in each sub-layer are gradiently distributed along the first direction; the composition of the columnar crystals and the particles independently comprises one or more of yttria-stabilized zirconia, gadolinia, ytterbia-doped gadolinia.

[0131] In the preparation method provided in the present application, a metallic bonding layer and a composite ceramic layer are sequentially deposited on the surface of a superalloy substrate, wherein the composite ceramic layer comprises at least 2 sub-layers, and the columnar crystals and the particles in each sub-layer along the first direction are gradiently distributed. In this process, the ceramic layer with complex layers can be deposited in one spraying process, without repeatedly turning on and off the equipment, so that the complexity of the overall process is low, and a sealing coating with good abradable performance and thermal shock resistance can be obtained.

[0132] In some embodiments, in the preparation method, the method for depositing the metallic bonding layer on one side of the superalloy substrate is selected from one or more of multi-arc ion plating, electron beam physical vapor deposition, and electroplating-aluminizing.

[0133] It can be understood that multi-arc ion plating, electron beam physical vapor deposition, and electroplating-aluminizing are known preparation methods, which will not be described herein.

[0134] In some embodiments, in the preparation method, after depositing the metallic bonding layer on one side of the superalloy substrate, the metallic bonding layer is subjected to vacuum heat treatment.

[0135] In some embodiments, in the preparation method, the temperature for depositing the metallic bonding layer on one side of the superalloy substrate and performing vacuum heat treatment is 900-1050°C, and can be selected from any one of the following temperatures or an interval formed by any two of the following temperatures: 900°C, 950°C, 1000°C, 1050°C, etc. It can be understood that the temperature for depositing the metallic bonding layer on one side of the superalloy substrate and performing vacuum heat treatment.

[0136] In some embodiments, in the S200 step of the preparation method, the time for depositing the metallic bonding layer on one side of the superalloy substrate and performing vacuum heat treatment is 2-6h, and can be selected from any one of the following times or an interval formed by any two of the following times: 2h, 3h, 4h, 5h, 6h, etc. It can be understood that the time for depositing the metallic bonding layer on one side of the superalloy substrate and performing vacuum heat treatment.

[0137] In some embodiments, in the method of preparing, after depositing the metal bond layer, the vacuum degree of vacuum heat treatment performed on the side of the high-temperature alloy substrate where the metal bond layer is deposited is (2x10 -5 )mbar to (7x10 -5 )mbar, and can be selected from any one of the following vacuum degrees or a range formed by any two of the following vacuum degrees: (2x10 -5 )mbar, (3x10 -5 )mbar, (4x10 -5 )mbar, (5x10 -5 )mbar, (6x10 -5 )mbar, (7x10 -5 )mbar, etc. It can be understood that the vacuum degree of vacuum heat treatment performed on the metal bond layer after depositing the metal bond layer on the side of the high-temperature alloy substrate.

[0138] In some embodiments, in the method of preparing, the method of depositing the composite ceramic layer on the side of the metal bond layer away from the high-temperature alloy substrate is selected from plasma physical vapor deposition.

[0139] In the present application, a method of adjusting parameters in the process of plasma physical vapor deposition is also provided, and a composite ceramic layer with more suitable composition, thickness and performance for use as a seal coating can be further obtained. By adjusting process parameters including powder feeding rate, distance between sample and spray gun, and spray gun current, etc., a gradient abradable seal coating comprising multiple sub-layers with more excellent performance can be prepared.

[0140] In some embodiments, in the method of preparing, when the composite ceramic layer is deposited on the side of the metal bond layer away from the high-temperature alloy substrate by plasma physical vapor deposition, the material used for depositing the composite ceramic layer comprises ceramic material powder, and the average particle size D50 of the ceramic material powder is 10 μm to 100 μm, and can be selected from any one of the following average particle sizes or a range formed by any two of the following average particle sizes: 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, etc.

[0141] In some embodiments, in the preparation method, when the composite ceramic layer is deposited on the side of the metal bonding layer away from the high-temperature alloy substrate by the plasma physical vapor deposition method, the material used for depositing the composite ceramic layer comprises yttria-stabilized zirconia (YSZ) with a mass percentage of yttria of 6% to 8%, further 7% to 8%, and further selected from any one of the following mass percentages or an interval formed by any two of the following mass percentages: 6%, 6.5%, 7%, 7.1%, 7.2%, 7.3%, 7.4%, 7.5%, 7.6%, 7.7%, 7.8%, 7.9%, 8%, etc.

[0142] In some embodiments, in the preparation method, when the composite ceramic layer is deposited on the side of the metal bonding layer away from the high-temperature alloy substrate by the plasma physical vapor deposition method, the material used for depositing the composite ceramic layer comprises yttria-stabilized zirconia (YSZ) with a mass percentage of yttria of 6% to 8%, further 7% to 8%, and further selected from any one of the following mass percentages or an interval formed by any two of the following mass percentages: 6%, 6.5%, 7%, 7.1%, 7.2%, 7.3%, 7.4%, 7.5%, 7.6%, 7.7%, 7.8%, 7.9%, 8%, etc. 0.9 Yb 0.1 )2Zr2O7), and further selected from any one of the following mass percentages or an interval formed by any two of the following mass percentages: 5%, 5.5%, 6%, 6.1%, 6.2%, 6.3%, 6.4%, 6.5%, 6.6%, 6.7%, 6.8%, 6.9%, 7%, 7.5%, 8%, etc.

[0143] In some embodiments, in the preparation method, when the composite ceramic layer is deposited on the side of the metal bonding layer away from the high-temperature alloy substrate by the plasma physical vapor deposition method, the vacuum degree is set to 1 mbar to 5 mbar, and further selected from any one of the following vacuum degrees or an interval formed by any two of the following vacuum degrees: 1 mbar, 1.5 mbar, 2 mbar, 2.5 mbar, 3 mbar, 3.5 mbar, 4 mbar, 4.5 mbar, 5 mbar, etc.

[0144] In some embodiments, in the preparation method, when the composite ceramic layer is deposited on the side of the metal bonding layer away from the high-temperature alloy substrate by the plasma physical vapor deposition method, the preheating temperature of the sample is set to 600°C to 800°C, and further selected from any one of the following temperatures or an interval formed by any two of the following temperatures: 600°C, 650°C, 700°C, 750°C, 800°C, etc.

[0145] In some embodiments, in the preparation method, when the composite ceramic layer is deposited on the side of the metallic bonding layer away from the high-temperature alloy substrate by the plasma physical vapor deposition method, the atmosphere is an inert gas selected from at least one of argon and helium.

[0146] In some embodiments, in the preparation method, when the composite ceramic layer is deposited on the side of the metallic bonding layer away from the high-temperature alloy substrate by the plasma physical vapor deposition method, when helium is used as the plasma gas, the flow rate of the helium is 40 L / min to 80 L / min, and can be selected from any one of the following rates or an interval formed by any two of the following rates: 40 L / min, 45 L / min, 50 L / min, 55 L / min, 60 L / min, 65 L / min, 70 L / min, 75 L / min, 80 L / min, and the like.

[0147] In some embodiments, in the preparation method, when the composite ceramic layer is deposited on the side of the metallic bonding layer away from the high-temperature alloy substrate by the plasma physical vapor deposition method, when argon is used as the plasma gas, the flow rate of the argon is 20 L / min to 40 L / min, and can be selected from any one of the following rates or an interval formed by any two of the following rates: 20 L / min, 25 L / min, 30 L / min, 35 L / min, 40 L / min, and the like.

[0148] In some embodiments, in the preparation method, when the composite ceramic layer is deposited on the side of the metallic bonding layer away from the high-temperature alloy substrate by the plasma physical vapor deposition method, when argon is used as the powder feeding carrier gas, the powder feeding rate is set to 4 g / min to 14 g / min, and can be selected from any one of the following rates or an interval formed by any two of the following rates: 4 g / min, 4.5 g / min, 5 g / min, 5.5 g / min, 6 g / min, 6.5 g / min, 7 g / min, 7.5 g / min, 8 g / min, 8.5 g / min, 9 g / min, 9.5 g / min, 10 g / min, 10.5 g / min, 11 g / min, 11.5 g / min, 12 g / min, 12.5 g / min, 13 g / min, 13.5 g / min, 14 g / min, and the like. A suitable powder feeding rate is conducive to obtaining a proper ratio of the gas phase, the liquid phase, and the solid phase in the plasma jet, so as to control the coating structure. If the powder feeding rate is too high, the content of the gas phase can be insufficient, and the content of the columnar crystals in the coating can be too low. If the powder feeding rate is too low, the content of the gas phase can be too high, and the content of the particles in the coating can be too low. Understandably, the powder feeding rate refers to the mass of the powder injected into the plasma jet per minute.

[0149] In some embodiments, in the preparation method, when the composite ceramic layer is deposited on the side of the metallic bonding layer away from the high-temperature alloy substrate by plasma physical vapor deposition, the spraying distance is set to 800 mm to 1600 mm, and can be selected from any one of the following distances or an interval formed by any two of the following distances: 800 mm, 900 mm, 1000 mm, 1100 mm, 1200 mm, 1300 mm, 1400 mm, 1500 mm, 1600 mm, etc. A suitable spraying distance is conducive to obtaining a proper ratio of gas phase, liquid phase and solid phase in the plasma jet, thereby controlling the coating structure. If the distance is too high, the gas phase and the liquid phase in the plasma jet can be re-solidified, the content of the gas phase is insufficient, and the content of the columnar crystal in the coating is too low. If the distance is too low, the content of the gas phase in the plasma jet is too high, and the content of the particles in the coating is too low. It can be understood that the spraying distance refers to the shortest horizontal distance between the outlet of the spray gun and the surface of the sample.

[0150] In some embodiments, in the preparation method, when the composite ceramic layer is deposited on the side of the metallic bonding layer away from the high-temperature alloy substrate by plasma physical vapor deposition, the current is set to 1200 A to 2200 A, and can be selected from any one of the following currents or an interval formed by any two of the following currents: 1200 A, 1300 A, 1400 A, 1500 A, 1600 A, 1700 A, 1800 A, 1900 A, 2000 A, 2100 A, 2200 A, etc. A suitable spray gun current is conducive to obtaining a proper ratio of gas phase, liquid phase and solid phase in the plasma jet, thereby controlling the coating structure. If the current is too low, the powder gasification is insufficient, and the content of the columnar crystal in the coating is too low. If the current is too high, the content of the gas phase is too high, and the content of the particles in the coating is too low.

[0151] In some embodiments, in the preparation method, when the composite ceramic layer is deposited on the side of the metallic bonding layer away from the high-temperature alloy substrate by plasma physical vapor deposition, the power is set to 45 kW to 65 kW, and can be selected from any one of the following powers or an interval formed by any two of the following powers: 45 kW, 50 kW, 55 kW, 60 kW, 65 kW, etc. It can be understood that the power of the plasma jet is determined by the set spray gun current and spray gun voltage, and the power range is a reference value.

[0152] In some embodiments, each sublayer of the composite ceramic layer of the prepared abradable seal coating is composed of columnar crystals and particles, and the length of the columnar crystals decreases layer by layer in the direction perpendicular to the surface of the metal bonding layer, that is, the thickness of the sublayer gradually decreases, while the proportion of particles and pores gradually increases. The columnar crystal structure at the bottom of the seal coating has excellent mechanical properties, which can ensure good thermal shock resistance of the whole coating. The increase of particles and pores on the surface of the coating reduces the hardness of the coating, and the presence of more particles between the top sublayers of the coating causes the bonding force between the top sublayers to be weaker, which can effectively improve the abradability of the coating.

[0153] In the preparation method provided in the present application, a metal bonding layer and a composite ceramic layer are sequentially deposited on the surface of a high-temperature alloy substrate, wherein the composite ceramic layer includes at least two sublayers and the columnar crystals and particles in each sublayer in the first direction are gradiently distributed. The process can deposit a ceramic layer with complex layers in one spraying process without repeatedly turning on and off the equipment, has lower complexity, and can obtain a seal coating with good abradability and thermal shock resistance.

[0154] In a third aspect of the present application, a turbine outer ring is provided, and the surface of the turbine outer ring is provided with the abradable seal coating of the first aspect or the abradable seal coating prepared by the preparation method of the second aspect.

[0155] The turbine outer ring provided in the third aspect of the present application adopts the abradable seal coating which has good abradability and thermal shock resistance and is closely combined with the turbine outer ring. The turbine outer ring can withstand high-speed airflow erosion without peeling of the coating, and can also reduce the degree of tip damage caused by contact with the turbine outer ring.

[0156] In a fourth aspect of the present application, the abradable seal coating of the first aspect or the abradable seal coating prepared by the preparation method of the second aspect is applied in the manufacture of an aero-engine component.

[0157] The abradable seal coating provided in the fourth aspect of the present application is applied in the manufacture of an aero-engine component, and can obtain an abradable seal coating which is closely combined with a metal component, and the coating can also effectively protect the component of the aero-engine to avoid abrasion caused by high-speed airflow erosion or contact with other metal components.

[0158] In order to more easily understand and implement the present application, the following also provides more specific and detailed examples and comparative examples as references.

[0159] The concept, specific examples and resulting technical effects of the present application will be further described below with reference to the accompanying drawings, so as to fully understand the present application. The purpose of providing these descriptions is only to help explain the present application, and should not be used to limit the scope of the claims of the present application.

[0160] The following are specific embodiments, which describe the disclosure of this application in more detail. These embodiments are merely illustrative, as various modifications and variations within the scope of the disclosure of this application will be apparent to those skilled in the art. Unless otherwise stated, all parts, percentages, and ratios reported in the following embodiments are based on weight, and all reagents used in the embodiments are commercially available or synthesized by conventional methods and can be used directly without further processing. The instruments used in the embodiments are also commercially available. Unless otherwise specified, the raw materials used in the following experiments are all commercially available.

[0161] Example 1

[0162] S1: Select size 20×20×2mm 3 Using GH4169 high-temperature alloy as the substrate, the high-temperature alloy substrate was pretreated by grinding the surface of the high-temperature alloy substrate sequentially with 240#, 400# and 800# SiC sandpaper. The surface roughness Ra of the substrate after grinding was about 1μm. The substrate after grinding was then ultrasonically cleaned in acetone, anhydrous ethanol and deionized water sequentially for 10min to 15min each time. The cleaned substrate was then dried.

[0163] S2: A NiPtAl metal bonding layer was prepared on the surface of the pretreated high-temperature alloy substrate using an electroplating-aluminizing method. The specific preparation method is as follows: (1) Prepare an electroplating solution with dinitrosodiammonium platinum (Pt(NH3)2(NO2)2) as the main salt, heat the electroplating solution to 90°C and keep it at that temperature. The high-temperature alloy substrate was clamped in the cathode of a DC power supply and placed in the electroplating solution. The current density was set to 1ASD (ASD: A / dm). 2 (1) Electroplating time was 40 minutes, and the thickness of the Pt layer was about 5 μm. (2) The high-temperature alloy sample with Pt layer was vacuum heat-treated at 1050℃ for 3 h. The vacuum degree of the heat treatment was 2.1×10-5 mbar. The sample was taken out after cooling to room temperature with the furnace. The heat-treated sample was aluminized by vapor phase aluminizing method. The vapor phase aluminizing temperature was 1070℃ and the aluminizing was held for 3 h. Finally, a NiPtAl metal bonding layer was obtained on the surface of the high-temperature alloy substrate.

[0164] S3: Put the high-temperature alloy sample with the NiPtAl metal bonding layer into the clamp, fix the clamp to the sample table of the plasma physical vapor deposition device and set the deposition control program; fill the YSZ (7%~8% yttrium oxide in zirconium oxide stabilized by yttrium oxide) powder into the powder feeder; close the device chamber and vacuumize, when the vacuum degree reaches below 0.1 mbar, fill in argon to 130 mbar; point the gun to arc, when the arc is stable, vacuumize to below 2 mbar, start the control program, move the sample table to the position 1000 mm away from the spray gun, and adjust the spray gun to face the sample; set the helium flow rate to 60 L / min, the argon flow rate to 35 L / min, and preheat the sample to 800℃ by using the plasma jet; heat the temperature in the powder feeder chamber to 60℃, open the powder feeding gas path, and adjust the powder feeding rate to 6 g / min; (i) gradually increase the spray gun current to 1900 A, and spray for 10 min; (ii) reduce the spray gun current to 1400 A, and spray for 3 min; (iii) increase the spray gun current to 1900 A, and spray for 8 min; (iv) reduce the spray gun current to 1400 A, and spray for 3 min; (v) increase the spray gun current to 1900 A, and spray for 6 min; close the powder feeding gas path, gradually reduce the spray gun current and the plasma gas flow rate, fill in argon to 60 mbar, then extinguish the gun, extinguish the arc, and cool for 10 min~20 min, then close the vacuum pump, and take out the sample after the chamber is balanced with the atmospheric pressure. The process can also refer to (a) of Figure 2 Figure 2 (b) is a micro cross-section electron backscatter photo of the seal coating prepared in Example 1. Figure 2 Figure 2 (b) is a micro cross-section electron backscatter photo of the seal coating prepared in Example 1.

[0165] Figure 2 (b) is a micro cross-section electron backscatter photo of the seal coating prepared in Example 1. Figure 2 Figure 2 (b) is a micro cross-section electron backscatter photo of the seal coating prepared in Example 1.

[0166] Example 2

[0167] S1: Select the high-temperature alloy sample with the NiPtAl metal bonding layer, the size of which is 20×20×2 mm 3K3 superalloy as a substrate, the superalloy substrate was pretreated, and the surface of the superalloy substrate was polished in turn using 240#, 400# and 800# SiC sandpaper, the surface roughness Ra of the polished substrate was about 1 μm, and the polished substrate was ultrasonically cleaned in acetone, anhydrous ethanol and deionized water in turn, the cleaning time was 10 min to 15 min, and the cleaned substrate was dried.

[0168] S2: A NiCrAlY metal bonding layer was prepared on the surface of the pretreated superalloy substrate by a multi-arc ion plating method; first, the target material was sputter cleaned, the cleaning bias was -450 V, the cleaning current was 110 A, and the cleaning time was 5 min; during the deposition process, the bias was -30 V, the current was 180 A, the duty cycle was 60%, and the deposition time was 40 min; the superalloy substrate with the deposited metal bonding layer was subjected to vacuum heat treatment, the heat treatment temperature was 1050 °C, the heat treatment time was 3 h, the vacuum degree was 2.1 x 10-5 mbar, and the treated sample was taken out after being cooled to room temperature in the furnace; the surface of the sample was polished appropriately to reduce the roughness of the bonding layer, and the roughness Ra of the polished bonding layer was less than 1 μm.

[0169] S3: The superalloy sample with the NiCrAlY metal bonding layer was placed in a clamp, the clamp was fixed to a sample table of a plasma physical vapor deposition device and a deposition control program was set; YSZ powder was loaded in a powder feeder; the device chamber was closed, the device was checked for sealing and vacuumized, argon was filled to 130 mbar when the vacuum degree reached below 0.1 mbar; the gun was ignited, the vacuum was extracted to below 2 mbar after the arc was stabilized, the control program was started, and the spray gun was adjusted to face the sample directly; the spray gun current was gradually increased to 1900 A, the helium flow rate was set to 60 L / min, the argon flow rate was set to 35 L / min, and the sample was preheated to 800 °C by using a plasma jet; the temperature in the powder feeder chamber was heated to 60 °C, the powder feeding gas path was opened, and the powder feeding rate was adjusted to 6 g / min; (i) the sample table was moved to a position 1000 mm away from the spray gun, and the spraying time was 10 min; (ii) the sample table was moved to a position 1400 mm away from the spray gun, and the spraying time was 3 min; (iii) the sample table was moved to a position 1000 mm away from the spray gun, and the spraying time was 8 min; (iv) the sample table was moved to a position 1400 mm away from the spray gun, and the spraying time was 3 min; (v) the sample table was moved to a position 1000 mm away from the spray gun, and the spraying time was 6 min; the powder feeding gas path was closed, the spray gun current and the plasma gas flow rate were gradually reduced, argon was filled to 60 mbar, the gun was turned off, the arc was extinguished, the vacuum pump was turned off after being cooled for 10 min to 20 min, and the sample was taken out after the chamber was balanced with the atmospheric pressure. The process can also refer to Figure 3 Figure (a) of the prior art shows a spraying distance-time relationship diagram for preparing the composite ceramic layer in Example 2. Figure 3(b) a micro cross-section electron backscatter image of the sealing coating prepared in Example 2.

[0170] From Figure 3 The structure of the composite ceramic layer in the abradable sealing coating (b) can be obtained, which comprises at least three sub-layers, the volume percentage of YSZ columnar crystals in the first sub-layer to the third sub-layer is about 82.82%, 70.44% and 64.56% respectively, the volume percentage of YSZ particles in the first sub-layer to the third sub-layer is about 6.22%, 15.23% and 17.70% respectively, the volume percentage of pores in the first sub-layer to the third sub-layer is 10.96%, 14.33% and 17.74% respectively, and the thickness of the first sub-layer to the third sub-layer is about 86.91 μm, 66.84 μm and 52.80 μm respectively.

[0171] Example 3

[0172] S1: GH4169 high-temperature alloy with a size of 20x20x2mm 3 is selected as the substrate, the high-temperature alloy substrate is pretreated, and the surface of the high-temperature alloy substrate is polished in sequence using 240#, 400# and 800# SiC sandpaper, the surface roughness Ra of the polished substrate is about 1 μm, the polished substrate is ultrasonically cleaned in acetone, anhydrous ethanol and deionized water in sequence, and the cleaning time is 10-15 min, and the cleaned substrate is dried.

[0173] S2: A NiAl metal bonding layer is prepared on the surface of the pretreated high-temperature alloy substrate by electron beam physical vapor deposition, and the target material is prepared by arc melting; during the preparation of the bonding layer, the electron beam voltage is 20 kV, the current is 1.5 A, the high-temperature alloy substrate is heated to 900℃, the substrate rotation speed is 15 r / min, and the deposition time is 30 min; the high-temperature alloy substrate with the prepared metal bonding layer is vacuum heat treated, the heat treatment temperature is 970℃, the heat treatment time is 4 h, the vacuum degree is 2.1x10-5mbar, and the sample is taken out after the treated sample is cooled to room temperature in the furnace.

[0174] S3: Place the high-temperature alloy sample with the NiAl metal binder layer in the fixture, fix the fixture to the sample stage of the plasma physical vapor deposition equipment, and set the deposition control program; load YSZ powder into the powder feeder; close the equipment chamber, check the equipment's airtightness, and then evacuate. When the vacuum level reaches below 0.1 mbar, fill with argon gas to 130 mbar; ignite the torch, and after the arc stabilizes, evacuate to below 2 mbar, start the control program, adjust the torch to face the sample, and move the sample stage to a position 1000 mm away from the torch; gradually increase the torch current to 1900 A, set the helium flow rate to 60 L / min and the argon flow rate to 35 L / min, and preheat the sample using the plasma jet. 800℃; Heat the powder feeder chamber to 60℃ and open the powder feeding gas path; (i) Set the powder feeding rate to 6g / min and the spraying time to 10min; (ii) Set the powder feeding rate to 12g / min and the spraying time to 3min; (iii) Set the powder feeding rate to 6g / min and the spraying time to 8min; (iv) Set the powder feeding rate to 12g / min and the spraying time to 3min; (v) Set the powder feeding rate to 6g / min and the spraying time to 6min; Close the powder feeding gas path, gradually reduce the spray gun current and plasma gas flow rate, fill with argon gas to 60mbar, then extinguish the gun and the arc. After cooling for 10-20min, turn off the vacuum pump. After the chamber reaches atmospheric pressure equilibrium, remove the sample. The process can also be referred to Figure 4 (a) shows the powder feed rate-time relationship during the preparation of the composite ceramic layer in Example 3. Figure 4 (b) is an electron backscatter photograph of the micro-section of the sealing coating prepared in Example 3.

[0175] from Figure 4 (b) can obtain the structure of the composite ceramic layer in the wearable sealing coating, which includes at least three sublayers. The volume percentages of YSZ columnar crystals in the first to third sublayers are approximately 82.47%, 68.02%, and 62.39%, respectively. The volume percentages of YSZ particles in the first to third sublayers are approximately 7.95%, 19.31%, and 21.11%, respectively. The volume percentages of pores in the first to third sublayers are 9.58%, 12.67%, and 16.50%, respectively. The thicknesses of the first to third sublayers are approximately 79.36 μm, 69.00 μm, and 56.90 μm, respectively.

[0176] Comparative Example 1

[0177] Comparative Example 1 was prepared in a similar manner to Example 1 except that in Comparative Example S3, the current of the spray gun was gradually increased to 1900 A for 6 min, then decreased to 1400 A for 3 min, then increased to 1900 A for 8 min, then decreased to 1400 A for 3 min, and then increased to 1900 A for 10 min. The microstructure of the ceramic layer of the abradable seal coating prepared in Comparative Example 1 is shown in FIG. 1 (b). The process can also be referred to FIG. 1 (a), which shows a current-time relationship diagram for preparing the composite ceramic layer in Comparative Example 1. Figure 5 The process can also be referred to FIG. 1 (a), which shows a current-time relationship diagram for preparing the composite ceramic layer in Comparative Example 1. Figure 5 The process can also be referred to FIG. 1 (a), which shows a current-time relationship diagram for preparing the composite ceramic layer in Comparative Example 1. Figure 5 The structure of the composite ceramic layer in the abradable seal coating prepared in Comparative Example 1 is shown in FIG. 1 (b). The composite ceramic layer comprises at least three sub-layers, and the volume percentage of YSZ columnar crystals in the first sub-layer to the third sub-layer is about 84.78%, 67.58% and 69.14%, respectively. The volume percentage of YSZ particles in the first sub-layer to the third sub-layer is about 6.11%, 16.68% and 17.11%, respectively. The volume percentage of pores in the first sub-layer to the third sub-layer is 9.11%, 15.74% and 13.75%, respectively. The thickness of the first sub-layer to the third sub-layer is about 37.04 μm, 55.36 μm and 131.99 μm, respectively.

[0178] Comparative Example 2

[0179] Comparative Example 2 was prepared in a similar manner to Example 1 except that in Comparative Example S3, the current of the spray gun was kept at 1900 A for 30 min. The process can also be referred to FIG. 2 (a), which shows a current-time relationship diagram for preparing the composite ceramic layer in Comparative Example 2. Figure 6 The process can also be referred to FIG. 2 (a), which shows a current-time relationship diagram for preparing the composite ceramic layer in Comparative Example 2. Figure 6 The microstructure of the ceramic layer of the abradable seal coating prepared in Comparative Example 2 is shown in FIG. 2 (b). It can be seen that the ceramic layer is a PS-PVD quasi-columnar crystal structure, complete columnar crystals run through the entire coating, and a small amount of particles exist in the interstitial space of the columnar crystals. There is no sub-layer in the ceramic layer. The volume percentage of YSZ columnar crystals is about 81.20%, and the volume percentage of YSZ particles is about 8.85%. The thickness of the ceramic layer is 230.43 μm.

[0180] The abrasive seal coating characterization results and properties of examples 1-3 and comparative examples 1-2 in table 1. The volume percentage of columnar crystal, particle and pore in sublayer were measured by area method, the area of each sublayer region was segmented by image processing software ImageJ under scanning electron microscope image, the area of columnar crystal region S2, particle region S3 and pore region S4 were calculated, the volume percentage of columnar crystal S2 / S1, particle S3 / S1 and pore S4 / S1 were calculated, the average value of multiple region sampling calculation obtained the volume percentage of columnar crystal, particle and pore. The measurement of sublayer thickness and total coating thickness was calculated by area method under scanning electron microscope image, that is, the area S of sublayer or coating in a certain length range along the direction parallel to the surface of the bonding layer was calculated by measurement software ImageJ, the thickness H of coating or sublayer was obtained by dividing the measured area S of sublayer or coating by the length range L in the measurement direction, here the measurement range in length direction is the area between two straight lines perpendicular to the surface of the bonding layer. The surface hardness test uses a Vickers hardness tester with a load of 50 gf and a force holding time of 10 s. The thermal shock test parameters for one cycle are: 1100℃ for 5 minutes, room temperature environment air cooling for 5 minutes. The surface roughness test uses a laser confocal device to measure, the average value of roughness of at least 3 sample points under the same magnification is taken.

[0181] From the performance, it can be compared that the thermal shock performance of the seal coating in comparative example 1 is not as good as that of the abrasive seal coating in examples 1-3, and the hardness is higher than that of the abrasive seal coating in examples 1-3. The possible reason is that in examples 1-3, the volume percentage of columnar crystal in the first sublayer to the third sublayer and the thickness of the sublayer gradually decrease and the volume percentage of particles gradually increases along the direction perpendicular to the metal bonding layer away from the metal substrate, while in comparative example 1, the distribution of the volume percentage of columnar crystal, the thickness of the sublayer and the volume percentage of particles in the first sublayer to the third sublayer is different from that in examples 1-3. The thermal shock performance of the seal coating in comparative example 2 is not as good as that of the abrasive seal coating in examples 1-3, and the roughness and hardness are higher than those of the abrasive seal coating in examples 1-3. The possible reason is that in examples 1-3, the volume percentage of columnar crystal in the first sublayer to the third sublayer and the thickness of the sublayer gradually decrease and the volume percentage of particles gradually increases along the direction perpendicular to the metal bonding layer away from the metal substrate, while in comparative example 2, there is no multiple sublayers in the ceramic layer, and the columnar crystal in the ceramic layer grows continuously from the interface between the metal bonding layer and the ceramic layer to the outer surface of the ceramic layer.

[0182] Table 1 abrasive seal coating characterization results and properties of examples 1-3 and comparative examples 1

[0183]

[0184] The preferred embodiments of the present application are described in detail above. It should be understood that those skilled in the art can make many modifications and variations without departing from the concept of the present application. Therefore, any technical solutions obtained by logical analysis, reasoning or limited experiments based on the concept of the present application and the prior art in the technical field of the present application should be considered as falling within the protection scope of the present application. For example, the ceramic material used in the preparation of the composite ceramic layer in the embodiments is yttria-stabilized zirconia powder material, but those skilled in the art can obtain other ceramic heat insulation materials such as gadolinium zirconate (Gd2Zr2O7), ytterbium-doped gadolinium zirconate ((Gd 0.9 Yb 0.1 )2Zr2O7) and the like for the preparation of a coating layer having the aforementioned sub-layer structure characteristics, all of which should be within the protection scope defined by the claims.

[0185] The technical features of the above-described embodiments can be combined in any manner. In order to make the description concise, all possible combinations of the technical features in the above-described embodiments are not described, but as long as the combinations of the technical features do not contradict each other, they should be considered as falling within the scope of the present application.

[0186] The above-described embodiments only express several implementation manners of the present application, and the description is specific and detailed, but it should not be understood as a limitation on the patent scope of the present application. It should be pointed out that those skilled in the art can make several modifications and improvements without departing from the concept of the present application, and these should all fall within the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims, and the description and drawings can be used to explain the content of the claims.

Claims

1. An abrasive sealing coating, characterized in that, The wear-resistant sealing coating is disposed on a metal substrate; the metal substrate is a high-temperature alloy substrate. The wear-resistant sealing coating includes a metal bonding layer and a composite ceramic layer; the metal bonding layer is disposed on the metal substrate, and the composite ceramic layer is disposed on the side of the metal bonding layer away from the metal substrate; The composite ceramic layer comprises columnar crystals and particles filling the gaps between the columnar crystals; the columnar crystals and the particles each independently comprise one or more of yttrium-stabilized zirconium oxide, gadolinium zirconate, and ytterbium-doped gadolinium zirconate. The direction from the surface of the composite ceramic layer near the surface of the metal bonding layer to the direction from the surface of the composite ceramic layer away from the surface of the metal bonding layer is denoted as the first direction; The composite ceramic layer includes several sublayers, which are distinguished by discontinuous regions between columnar crystal grains along the first direction. Each sublayer includes a range from the bottom of the columnar crystal in the first layer to the bottom of the columnar crystal in the next layer. Along the first direction, the volume percentage of columnar crystals in each sublayer decreases gradually, while the volume percentage of particles in each sublayer increases gradually. Between two adjacent sublayers, there are particles with a higher volume fraction, which serve as the boundary between adjacent sublayers.

2. The wear-resistant sealing coating according to claim 1, characterized in that, Each sublayer of the composite ceramic layer of the wearable sealing coating is composed of columnar crystals and particles, and the length of the columnar crystals decreases layer by layer along the direction perpendicular to the surface of the metal bonding layer, that is, the thickness of the sublayer gradually decreases, while the proportion of particles and pores gradually increases.

3. The wear-resistant sealing coating according to claim 1, characterized in that, The composite ceramic layer comprises at least i sublayers, where i ≥ 2; Each sublayer of the composite ceramic layer includes columnar crystals and particles filling the gaps between the columnar crystals; the columnar crystals and the particles each independently contain one or more of yttrium-stabilized zirconium oxide, gadolinium zirconate, and ytterbium-doped gadolinium zirconate. Along the first direction, the sublayers are numbered from smallest to largest, and the volume percentage of columnar crystals in the i-th sublayer and the (i+1)-th sublayer is denoted as A. i and A i+1 Let B be the volume percentage of particles in the i-th sublayer and the (i+1)-th sublayer, respectively. i and B i+1 Let C be the porosity, which is the percentage of pores in the volume of the i-th sublayer and the (i+1)-th sublayer. i and C i+1 Let D be the thickness of the i-th sublayer and the (i+1)-th sublayer. i and D i+1 Satisfying A i >A i+1 B i <B i+1 C i <C i+1 and D i >D i+1 One or more of the following conditions; the sublayer thickness refers to the shortest distance from the bottom of the columnar crystal in this layer to the bottom of the next columnar crystal in the first direction.

4. The wear-resistant sealing coating according to claim 3, characterized in that, Along the first direction, the composite ceramic layer includes at least a first sublayer and a second sublayer; The columnar crystals in the first sublayer account for 70% to 95% of the volume of the first sublayer, the particles in the first sublayer account for 5% to 30% of the volume of the first sublayer, and the thickness of the first sublayer is 8 μm to 120 μm; The columnar crystals in the second sublayer account for 60% to 85% of the volume of the second sublayer, the particles in the second sublayer account for 10% to 40% of the volume of the second sublayer, and the thickness of the second sublayer is 8 μm to 120 μm.

5. The wear-resistant sealing coating according to claim 1, characterized in that, It meets one or more of the following characteristics: The metal bonding layer includes one of MCrAlY, NiAl and NiPtAl, wherein the M element in MCrAlY is selected from at least one of Ni and Co; The thickness of the metal bonding layer is 30μm to 100μm.

6. The wear-resistant sealing coating according to claim 1, characterized in that, It meets one or more of the following characteristics: The thickness of the composite ceramic layer is 70μm to 300μm; The thickness of each sublayer of the composite ceramic layer is 8 μm to 120 μm; The width of the columnar crystals in each sublayer of the composite ceramic layer is 10 μm to 40 μm; The length of the columnar crystals in each sublayer of the composite ceramic layer is 8 μm to 120 μm; The average particle size of the particles in each sublayer of the composite ceramic layer is 0.5 μm to 10 μm.

7. The method for preparing the wear-resistant sealing coating according to any one of claims 1 to 6, characterized in that, Includes the following steps: Pretreatment of high-temperature alloy substrate: The high-temperature alloy substrate is pretreated, which includes grinding, polishing, ultrasonic cleaning and drying. Preparation of the metal bonding layer: A metal bonding layer is deposited on one side of the high-temperature alloy substrate and subjected to vacuum heat treatment to obtain the metal bonding layer; Preparation of the composite ceramic layer: A composite ceramic layer is deposited on the side of the metal bonding layer away from the high-temperature alloy substrate to obtain the composite ceramic layer; the composite ceramic layer includes at least two sublayers, each sublayer of the composite ceramic layer includes columnar crystals and particles filling the gaps between the columnar crystals; the columnar crystals and particles in each sublayer are gradient distributed along the first direction in the composite ceramic layer; the columnar crystals and the particles each independently contain one or more of yttrium-stabilized zirconium oxide, gadolinium zirconate, and ytterbium-doped gadolinium zirconate; a high volume fraction of particles is distributed between two adjacent sublayers as a boundary between adjacent sublayers.

8. The preparation method according to claim 7, characterized in that, It meets one or more of the following characteristics: The method for depositing the metal bonding layer on one side of the high-temperature alloy substrate is selected from one or more of multi-arc ion plating, electron beam physical vapor deposition, and electroplating-aluminizing. The method for depositing the composite ceramic layer on the side of the metal bonding layer away from the high-temperature alloy substrate is selected from plasma physical vapor deposition. When depositing the composite ceramic layer on the side of the metal bonding layer away from the high-temperature alloy substrate using plasma physical vapor deposition, by adjusting process parameters including powder feed rate, sample-to-spray gun distance, and spray gun current, a gradient abrasion-resistant sealing coating comprising multiple sublayers can be prepared, satisfying one or more of the following characteristics: The material used to deposit the composite ceramic layer includes ceramic material powder, the ceramic material powder having an average particle size D50 of 10 μm to 100 μm, and the ceramic material composition includes one or more of yttrium-stabilized zirconium oxide, gadolinium zirconate, and ytterbium oxide-doped gadolinium zirconate. The vacuum level is set to 1 mbar to 5 mbar. The sample preheating temperature was set to 600℃~800℃; The atmosphere is an inert gas, which is selected from at least one of argon and helium; When helium is used as the plasma gas, the flow rate of helium is 40 L / min to 80 L / min. When argon is used as the plasma gas, the flow rate of argon is 20 L / min to 40 L / min. Argon is used as the powder carrier gas, and the powder feeding rate is set to 4 g / min to 14 g / min. The distance between the spray gun and the deposition surface is set to 800mm to 1600mm; The current is set to 1200A~2200A; The power is set to 45kW to 65kW.

9. A turbine outer ring, characterized in that, The outer ring surface of the turbine is provided with a wearable sealing coating as described in any one of claims 1 to 6 or a wearable sealing coating prepared by the preparation method as described in any one of claims 7 to 8.

10. The application of an abrasive sealing coating according to any one of claims 1 to 6 or an abrasive sealing coating prepared by the preparation method according to any one of claims 7 to 8 in the manufacture of aero-engine components.

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