Sealing coating and method for producing the same

Abstract

The application provides a sealing coating and a preparation method thereof. The sealing coating comprises a high-temperature alloy base, a metal bonding layer and a ceramic layer which are sequentially arranged on the high-temperature alloy base, wherein the metal bonding layer comprises at least one etching area on the surface of the side close to the ceramic layer, and the etching area contains ceramic particles. The sealing coating provided by the application has good high-temperature resistance and wear resistance.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of seal coating, in particular to a seal coating and a preparation method thereof. BACKGROUND

[0002] With the development of aero-engines towards high thrust-to-weight ratio, it is urgent to improve the service performance and working efficiency of the engine. In addition to improving the service temperature, improving the dynamic seal between rotating parts and fixed parts has become one of the important directions for the development of high-performance engines. Research shows that the seal coating can effectively reduce the radial airflow loss and reduce oil consumption by reducing the gap between the casing and the blade tip. At the same time, factors such as thermal expansion of the blade and changes in centrifugal force during service will cause changes in the gap between the blade tip and the casing, so the seal coating should have characteristics such as abradability and low hardness to avoid wear of the blade tip.

[0003] Commonly used alloy materials such as NiAl and MCrAlY for seal coating will sinter and harden and partially fall off under high-temperature service conditions (above 1000℃), and will cause serious wear to the blade. Therefore, in order to cope with the increasing service temperature, ceramic-based seal coatings need to be developed. ZrO2 stabilized by 6wt.%~8wt.%Y2O3 (referred to as YSZ) is of great concern in the field of ceramic-based seal coatings due to its high melting point, good thermal stability, and high thermal expansion coefficient. However, YSZ itself has high hardness, and the abradability of YSZ coating is one of the main factors limiting its large-scale application as a high-temperature seal coating. In addition, due to the generally large thickness design of the seal coating, new challenges are posed to the bonding performance of the coating and the substrate and the thermal shock resistance of the coating. Therefore, it is urgent to develop a seal coating that can meet the performance requirements of high-temperature resistance, abradability, low hardness, good bonding between the coating and the substrate, etc., and the preparation process of the coating is easy to control and has high production efficiency. SUMMARY

[0004] Based on this, the present application provides a seal coating and a preparation method thereof, which can improve the high-temperature resistance and grinding performance of the seal coating.

[0005] The first aspect of the present application provides a seal coating, comprising: a high-temperature alloy substrate, and a metal bonding layer and a ceramic layer sequentially stacked on the high-temperature alloy substrate, wherein the metal bonding layer comprises at least one etching area on the surface of the side relatively close to the ceramic layer, and the etching area contains ceramic particles.

[0006] In some embodiments of the present application, the etching depth of the etching area is 5μm~30μm, and the width of the etching area is 5μm~30μm;

[0007] Optionally, the ceramic particles comprise YSZ particles;

[0008] Further optionally, the average particle size of the YSZ particles is 0.5 μm to 10 μm.

[0009] In some embodiments of the present application, the seal coating satisfies at least one of the following conditions:

[0010] (1) the thickness of the metal bonding layer is 40 μm to 150 μm;

[0011] (2) the metal bonding layer comprises MCrAlY or NiAl, M comprising at least one of Ni and Co.

[0012] In some embodiments of the present application, the ceramic layer comprises YSZ columnar crystals and YSZ particles, wherein the YSZ particles are located in the gaps formed by the YSZ columnar crystals;

[0013] Optionally, the width of the YSZ columnar crystals is 10 μm to 40 μm;

[0014] Optionally, the average particle size of the YSZ particles is 0.5 μm to 10 μm.

[0015] In some embodiments of the present application, the ceramic layer satisfies at least one of the following conditions:

[0016] (1) the volume ratio of the YSZ columnar crystals in the ceramic layer is 40% to 80%;

[0017] (2) the volume ratio of the YSZ particles in the ceramic layer is 10% to 50%;

[0018] (3) the porosity of the ceramic layer is 10% to 35%.

[0019] The second aspect of the present application provides a method for preparing a seal coating, characterized in that it comprises:

[0020] providing a high-temperature alloy substrate and a metal bonding layer arranged on one side of the high-temperature alloy substrate;

[0021] performing etching treatment on the metal bonding layer to form at least one etching area on the surface of the metal bonding layer away from the high-temperature alloy substrate;

[0022] preparing a ceramic layer on the surface of the metal bonding layer comprising the etching area, forming ceramic particles inside and above the etching area, and forming columnar crystals above the unetched area, to obtain the seal coating.

[0023] In some embodiments of the present application, the method for preparing the metal bonding layer comprises:

[0024] pre-treating the high-temperature alloy substrate;

[0025] depositing the metal bonding layer on the surface of the pre-treated high-temperature alloy substrate;

[0026] vacuum heat-treating the metal bonding layer;

[0027] Optionally, the method of preparing the metal bonding layer comprises at least one of multi-arc ion plating, electron beam physical vapor deposition, and electroplating-embedded infiltration;

[0028] Optionally, the temperature of the vacuum heat-treatment is 900-1050℃;

[0029] Optionally, the vacuum degree of the vacuum heat-treatment is (2x10 -5 )mbar-(7x10 -5 )mbar;

[0030] Optionally, the time of the vacuum heat-treatment is 2-6h.

[0031] In some embodiments of the present application, the etching treatment of the metal bonding layer comprises:

[0032] pulsed laser etching treatment of the metal bonding layer,

[0033] Optionally, the laser central wavelength of the pulsed laser is 355nm;

[0034] Optionally, the laser focusing spot diameter of the pulsed laser is 5-20μm;

[0035] Optionally, the laser pulse width of the pulsed laser is 5-20ns;

[0036] Optionally, the laser power of the pulsed laser is 1-5W;

[0037] Optionally, the repetition frequency of the pulsed laser is 1-30kHz;

[0038] Optionally, the scanning speed of the pulsed laser is 10-200mm / s;

[0039] Optionally, the scanning repetition number of the pulsed laser is 1-5.

[0040] In some embodiments of the present application, the method of preparing the ceramic layer comprises plasma physical vapor deposition;

[0041] Optionally, the material of preparing the ceramic layer comprises YSZ powder;

[0042] Optionally, the vacuum degree of the plasma physical vapor deposition is 1 mbar to 5 mbar.

[0043] Optionally, the working gas used in the plasma physical vapor deposition comprises argon and helium.

[0044] Optionally, the distance between the sample and the spray gun during the plasma physical vapor deposition is 1000 mm to 1400 mm.

[0045] Optionally, the current of the plasma physical vapor deposition is 1800 A to 2100 A.

[0046] Optionally, the power of the plasma physical vapor deposition is 55 kW to 65 kW.

[0047] Optionally, the preheating temperature of the sample during the plasma physical vapor deposition is 600 DEG C to 800 DEG C.

[0048] In some embodiments of the present application, the method satisfies at least one of the following conditions:

[0049] (1) the average particle size D50 of the YSZ powder is 20 μm to 100 μm;

[0050] (2) the gas flow rate of the helium is 40 L / min to 80 L / min;

[0051] (3) the gas flow rate of the argon is 20 L / min to 40 L / min.

[0052] The sealing coating provided by the present application comprises a high-temperature alloy substrate, a metal bonding layer and a ceramic layer, wherein the metal bonding layer is provided with an etching area on the surface of the side relatively close to the ceramic layer, the etching area is arranged to induce the aggregation of ceramic particles, so that the etching area contains more ceramic particles inside and above; the etching area forms an interface pinning effect, which is beneficial to improve the bonding force between the metal bonding layer and the ceramic layer, improve the thermal shock resistance of the sealing coating, and prolong the service life thereof.

[0053] In addition, the metal bonding layer is etched by pulse laser etching in the present application, in particular, the metal bonding layer is etched by ultraviolet short pulse laser, which can realize the accurate control of the periodic structure on the microscale according to the existing double-temperature model of energy transmission in the metal; at the same time, the metal bonding layer is etched by pulse laser etching, the energy utilization efficiency of the pulse laser is high, the processing speed is fast, and large-scale rapid processing of the surface of the metal bonding layer can be realized. BRIEF DESCRIPTION OF DRAWINGS

[0054] Figure 1 is a structural schematic diagram of the sealing coating of an embodiment of the present application.

[0055] Figure 2 is a schematic diagram of a grid-like periodic structure etched on the surface of a metal bond layer (Figure (a)) and a photograph of the surface of the metal bond layer after pulsed laser etching (Figure (b)) of an embodiment of the present application.

[0056] Figure 3 is a micro-section electron backscatter diffraction pattern of a seal coating prepared in Example 1.

[0057] Figure 4 is a schematic diagram of a line-like periodic structure etched on the surface of a metal bond layer (Figure (a)) and a photograph of the surface of the metal bond layer after laser etching (Figure (b)) of an embodiment of the present application.

[0058] Figure 5 is a micro-section electron backscatter diffraction pattern of a seal coating prepared in Example 2. DETAILED DESCRIPTION

[0059] In order to facilitate the understanding of the present application, a more complete understanding of the present application can be had by reference to the following description when read in conjunction with the accompanying drawings, in which the preferred embodiments of the present application are illustrated. However, it is to be understood that the application can be carried out in a multitude of different forms and that the application is to be considered as not limited to the embodiments described and depicted herein. Rather, the embodiments are provided as illustrative of the application so as to provide a thorough understanding to those skilled in the art.

[0060] For simplicity, only some numerical ranges are explicitly disclosed herein. However, any lower limit can be combined with any upper limit to form a range not explicitly recited; and any lower limit can be combined with any other lower limit to form a range not explicitly recited, as can any upper limit with any other upper limit to form a range not explicitly recited. Furthermore, although a range of endpoints is recited, each point or individual value within the range is also included within the range. Thus, each point or individual value can be combined as its own lower limit or upper limit with any other point or individual value or with other lower or upper limits to form a range not explicitly recited.

[0061] 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 herein is for describing particular embodiments only and is not intended to be limiting of the application. It is to be understood that unless otherwise indicated, the terms "and / or" includes any and all combinations of one or more of the associated listed items. The articles "a," "an," and "the" each contain the meaning of "one or more" unless otherwise specified. The terms "plurality" and "multiple" each contain the meaning of two or more unless otherwise specified.

[0062] The above disclosure of the present application is not intended to describe every disclosed embodiment or every implementation in the present application. The following description more specifically illustrates exemplary embodiments. In many places throughout the application, guidance is provided through a series of examples, which can be used in various combinations. In each example, the enumeration is intended only as a representative group and should not be construed as exhaustive.

[0063] The first aspect of the present application provides a sealing coating, such as Figure 1 As shown, it includes: a high-temperature alloy substrate 1, and a metal bonding layer 2 and a ceramic layer 3 stacked in sequence on the high-temperature alloy substrate 1, wherein the metal bonding layer 2 includes at least one etching area 21 on the surface relatively close to the ceramic layer, and the etching area 21 contains ceramic particles.

[0064] It is understood that the shape and arrangement of the above-mentioned etching areas are not particularly limited. As a non-limiting example, the etching areas can be grid-shaped or in other geometric shapes; they can be multiple periodically arranged, for example, multiple grids arranged periodically (such as Figure 1 It can also be a combination of multiple shapes arranged non-periodically.

[0065] The sealing coating provided in the present application includes a high-temperature alloy substrate, a metal bonding layer and a ceramic layer, wherein the metal bonding layer is provided with an etching area on the surface of the side relatively close to the ceramic layer. The setting of the etching area can induce the aggregation of ceramic particles so that the etching area contains more ceramic particles; the etching area forms an interface pinning effect, which is beneficial to improve the bonding force between the metal bonding layer and the ceramic layer, improve the thermal shock resistance of the sealing coating, and extend its service life.

[0066] In some embodiments, the etching depth of the etched area is 5 μm to 30 μm, and the width of the etched area is 5 μm to 30 μm. For example, the etching depth of the etched area can be 5 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, or within a range of any of the above values. The width of the etched area can be 5 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, or within a range of any of the above values.

[0067] It can be understood that the etching depth of the etching zone described in this application refers to the height from the surface of the metal bonding layer relatively close to the ceramic layer to the deepest height etched downward in a direction perpendicular to the surface; the width of the etching zone refers to the longest straight line length of the etching zone along the direction parallel to the surface of the metal bonding layer.

[0068] The etching depth and width of the etched area are within the above ranges, which is conducive to forming an interface pinning effect between the metal bonding layer and the ceramic layer, thereby further improving the bonding strength between the metal bonding layer and the ceramic layer.

[0069] In some embodiments, the ceramic particles include YSZ particles.

[0070] It is understood that the YSZ mentioned in this application refers to zirconium oxide doped with the rare earth element yttrium, i.e., yttria-stabilized zirconium oxide (Y2O3-stabilized ZrO2), wherein the yttria doping amount is 6 wt.% to 8 wt.%, which can be adjusted according to the application requirements.

[0071] In some embodiments, the average particle size of the YSZ particles is 0.5 μm to 10 μm. For example, the average particle size of the YSZ particles can be 0.5 μm, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, or any range thereof.

[0072] In some embodiments, the thickness of the metal bonding layer is 40 μm to 150 μm. For example, the thickness of the metal bonding layer can be 40 μm, 60 μm, 80 μm, 100 μm, 120 μm, 140 μm, 150 μm, or any range thereof.

[0073] In some embodiments, the metal bonding layer comprises MCrAlY or NiAl, and M comprises at least one of Ni and Co.

[0074] In some embodiments, as Figure 1 As shown, the ceramic layer 3 includes YSZ columnar crystals 31 and YSZ particles 32 , wherein the YSZ particles are located in the gaps formed by the YSZ columnar crystals.

[0075] In the sealing coating of the present application, the YSZ columnar crystal structure in the ceramic layer can serve as a "skeleton" to provide sufficient mechanical support; at the same time, the YSZ particles filling the gaps between the columnar crystals and the pores between the YSZ particles can provide good grinding performance for the sealing coating.

[0076] In some embodiments, the width of the YSZ columnar crystals is 10 μm to 40 μm. For example, the width of the YSZ columnar crystals can be 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, or any range thereof.

[0077] It can be understood that the width of the YSZ columnar crystals described in this application refers to the maximum radial length of each YSZ columnar crystal.

[0078] In some embodiments, the average particle size of the YSZ particles is 0.5 μm to 10 μm. For example, the average particle size of the YSZ particles can be 0.5 μm, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, or within a range between any of the above values.

[0079] In some embodiments, the volume fraction of the YSZ columnar crystals in the ceramic layer is 40% to 80%. For example, the volume fraction of the YSZ columnar crystals in the ceramic layer can be 40%, 50%, 60%, 70%, 80%, or within a range between any of the above values.

[0080] The volume fraction of the YSZ columnar crystals in the ceramic layer within the above range can control the hardness and friction and wear properties of the ceramic layer while ensuring appropriate mechanical support of the ceramic layer, so as to match the design requirements of the seal coating.

[0081] In some embodiments, the volume fraction of the YSZ particles in the ceramic layer is 10% to 50%. For example, the volume fraction of the YSZ particles in the ceramic layer can be 10%, 20%, 30%, 40%, 50%, or within a range between any of the above values.

[0082] In some embodiments, the porosity of the ceramic layer is 10% to 35%. For example, the porosity of the ceramic layer can be 10%, 15%, 20%, 25%, 30%, 35%, or within a range between any of the above values.

[0083] The volume fraction of the YSZ particles in the ceramic layer and the porosity of the ceramic layer within the above range can control the hardness and friction and wear properties of the ceramic layer while ensuring appropriate mechanical support of the ceramic layer, so as to match the design requirements of the seal coating.

[0084] In the seal coating of the present application, the volume fraction of the YSZ columnar crystals in the ceramic layer, the volume fraction of the YSZ particles in the ceramic layer, and the porosity of the ceramic layer are associated with each other, and can be cooperatively controlled to control the mechanical properties and thermal shock resistance of the ceramic layer and the seal coating.

[0085] The second aspect of the present application provides a method for preparing the seal coating of the first aspect of the present application, which can comprise the following steps:

[0086] S10, providing a high-temperature alloy substrate and a metal bonding layer arranged on one side of the high-temperature alloy substrate;

[0087] S30, etching the metal bonding layer to form at least one etching area on the surface of the metal bonding layer away from the high-temperature alloy substrate.

[0088] S50, preparing a ceramic layer on the surface of the metal bonding layer including the etched area, forming ceramic particles inside and above the etched area, and forming columnar crystals above the unetched area to obtain the sealing coating.

[0089] This application etches an etched area on the surface of the metal bonding layer. On the one hand, the etched area can induce the aggregation of ceramic particles during the subsequent deposition process. By adjusting the processing parameters of the etching process, the shape of the etched area can be adjusted, thereby achieving flexible adjustment of the proportion of YSZ columnar crystals, YSZ particles, and pores in the ceramic layer. By adjusting the composition of the ceramic layer, the design requirements of coatings with different hardness and wear properties can be met. On the other hand, the periodic etching structure of the metal bonding layer can enhance the bonding strength of the ceramic layer, improve the thermal shock resistance of the sealing coating, and extend its service life. In addition, this method is process-stable, highly flexible, highly controllable, and has high production efficiency.

[0090] It is understood that the shape and arrangement of the above-mentioned etched areas are not particularly limited. As a non-limiting example, the etched areas may be in a grid shape or other geometric shapes (e.g., a triangle shape); or may be a plurality of periodically arranged areas, such as a plurality of periodically arranged grid structures (e.g., a plurality of periodically arranged grid structures). Figure 2 As shown), it can also be a periodically arranged strip structure (as shown Figure 4 ), or a combination of multiple shapes arranged non-periodically (for example, a combination of a grid shape and a triangular shape).

[0091] In some embodiments, the etching process on the metal bonding layer may include step S300: performing pulse laser etching process on the metal bonding layer.

[0092] In some embodiments, the pulse laser etching may be ultraviolet short pulse laser etching.

[0093] The present application uses pulsed laser etching to etch the metal bonding layer, especially uses ultraviolet short-pulse laser to etch the metal bonding layer, which can achieve accurate control of the periodic structure on a microscopic scale based on the existing dual-temperature model of internal energy transfer in the metal; at the same time, the metal bonding layer is etched using pulsed laser etching, and the energy utilization efficiency of the pulsed laser is high, and the processing speed is fast, which can realize large-scale and rapid processing of the surface of the metal bonding layer.

[0094] In some embodiments, the pulsed laser has a central wavelength of 355 nm.

[0095] In some embodiments, the pulsed laser has a laser focus spot diameter of 5-20 μm. For example, the laser focus spot diameter can be 5 μm, 10 μm, 15 μm, 20 μm, or within a range defined by any of the above values.

[0096] In some embodiments, the pulsed laser has a laser pulse width of 5-20 ns. For example, the laser pulse width can be 5 ns, 10 ns, 15 ns, 20 ns, or within a range defined by any of the above values.

[0097] In some embodiments, the pulsed laser has a laser power of 1-5 W. For example, the pulsed laser can have a laser power of 1 W, 2 W, 3 W, 4 W, 5 W, or within a range defined by any of the above values.

[0098] In some embodiments, the pulsed laser has a repetition frequency of 1-30 kHz. For example, the pulsed laser can have a repetition frequency of 1 kHz, 5 kHz, 10 kHz, 15 kHz, 20 kHz, 25 kHz, 30 kHz, or within a range defined by any of the above values.

[0099] In some embodiments, the pulsed laser has a scanning speed of 10-200 mm / s. For example, the pulsed laser can have a scanning speed of 10 mm / s, 30 mm / s, 50 mm / s, 100 mm / s, 150 mm / s, 200 mm / s, or within a range defined by any of the above values.

[0100] In some embodiments, the pulsed laser has a repetition number of 1-5. For example, the pulsed laser can have a repetition number of 1, 2, 3, 4, 5, or within a range defined by any of the above values.

[0101] In some embodiments, the method for preparing the metal bonding layer can comprise the following steps:

[0102] S100, pretreating the high-temperature alloy substrate;

[0103] S110, depositing a metal bonding layer on the surface of the pretreated high-temperature alloy substrate;

[0104] S120, vacuum heat treating the metal bonding layer.

[0105] In some embodiments, the method for depositing the metal bonding layer comprises at least one of multi-arc ion plating, electron beam physical vapor deposition, and electroplating-embedded infiltration.

[0106] It can be understood that the multi-arc ion plating, electron beam physical vapor deposition and electroplating-embedding infiltration described above are all known preparation methods in the art, and will not be described herein.

[0107] In some embodiments, the temperature of the vacuum heat treatment is 900-1050℃. For example, the temperature of the vacuum heat treatment can be 900℃, 950℃, 1000℃, 1050℃ or within a range formed by any of the above values.

[0108] In some embodiments, the vacuum degree of the vacuum heat treatment is (2x10 -5 )mbar-(7x10 -5 )mbar. For example, the vacuum degree of the vacuum heat treatment can be (2x10 -5 )mbar, (3x10 -5 )mbar, (4x10 -5 )mbar, (5x10 -5 )mbar, (6x10 -5 )mbar, (7x10 -5 )mbar or within a range formed by any of the above values.

[0109] In some embodiments, the time of the vacuum heat treatment is 2-6h. For example, the time of the vacuum heat treatment can be 2h, 3h, 4h, 5h, 6h or within a range formed by any of the above values.

[0110] As a non-limiting example, the pretreatment of the superalloy substrate in step S100 can include the following steps: sequentially polishing the surface of the superalloy substrate with 60#, 240#, 400# and 800# SiC sandpaper, and sequentially cleaning the polished substrate with acetone, anhydrous ethanol and deionized water by ultrasonic cleaning, with a cleaning time of 10-15min.

[0111] In some embodiments, the method for preparing the ceramic layer includes a plasma physical vapor deposition method. It can be understood that the plasma physical vapor deposition method described herein is a known method in the art, and will not be described herein.

[0112] The ceramic layer is prepared by the plasma physical vapor deposition method in the present application, which has a wide process window, a high controllability and repeatability of the deposition process, and a high efficiency of the coating deposition process, compared with the existing method of preparing a coating by solid-liquid-gas three-phase co-deposition.

[0113] In some embodiments, the material for preparing the ceramic layer includes YSZ powder.

[0114] In some embodiments, the vacuum degree of the plasma physical vapor deposition is 1 mbar to 5 mbar.

[0115] In some embodiments, the working gas used in the deposition includes argon and helium.

[0116] In some embodiments, the distance between the sample and the spray gun during the plasma physical vapor deposition is 1000 mm to 1400 mm. For example, the distance between the sample and the spray gun during the deposition can be 1000 mm, 1100 mm, 1200 mm, 1300 mm, 1400 mm, or within a range between any of the foregoing.

[0117] In some embodiments, the current during the plasma physical vapor deposition is 1800 A to 2100 A. For example, the current during the deposition can be 1800 A, 1900 A, 2000 A, 2100 A, or within a range between any of the foregoing.

[0118] In some embodiments, the power during the plasma physical vapor deposition is 55 kW to 65 kW. For example, the power during the deposition can be 55 kW, 57 kW, 59 kW, 61 kW, 63 kW, 65 kW, or within a range between any of the foregoing.

[0119] In some embodiments, the preheating temperature of the sample during the plasma physical vapor deposition is 600℃ to 800℃. For example, the preheating temperature of the sample during the deposition can be 600℃, 650℃, 700℃, 750℃, 800℃, or within a range between any of the foregoing.

[0120] In some embodiments, the average particle size D50 of the YSZ powder used to deposit the ceramic layer is 20 μm to 100 μm. For example, the average particle size D50 of the YSZ powder can be 20 μm, 40 μm, 60 μm, 80 μm, 100 μm, or within a range between any of the foregoing.

[0121] In some embodiments, the flow rate of the helium gas is 40 L / min to 80 L / min. For example, the flow rate of the helium gas can be 40 L / min, 50 L / min, 60 L / min, 70 L / min, 80 L / min, or within a range between any of the foregoing.

[0122] In some embodiments, the flow rate of the argon gas is 20 L / min to 40 L / min. For example, the flow rate of the argon gas can be 20 L / min, 25 L / min, 30 L / min, 35 L / min, 40 L / min, or within a range between any of the foregoing.

[0123] The above-mentioned method for preparing a sealing coating provided in the present application adopts a method of combining pulsed laser etching with plasma physical vapor deposition (PS-PVD) to prepare the sealing coating. By adjusting the laser scanning pattern and scanning parameters in the pulsed laser etching, periodic structures of different shapes (i.e., etching areas) can be etched on the surface of the metal bonding layer, and then PS-PVD is used to deposit a ceramic layer with a micro-nano composite structure on the surface of the metal bonding layer. During the PS-PVD deposition process, the etching area on the surface of the metal bonding layer can induce YSZ particles to aggregate, while the ceramic layer deposited above the area not scanned by the laser is mainly composed of YSZ columnar crystals. By adjusting the preparation process parameters of the ceramic layer, the proportion and distribution of micro-nano structures in the ceramic layer (i.e., the volume proportion of YSZ columnar crystals in the ceramic layer, the volume proportion of YSZ particles in the ceramic layer, and the porosity of the ceramic layer) can be flexibly controlled. This preparation method has stable process, high flexibility, strong controllability and high production efficiency.

[0124] Example

[0125] The following are specific examples, which describe the present disclosure in more detail. These examples are intended for illustrative purposes only, as various modifications and variations within the scope of the present disclosure will be apparent to those skilled in the art. Unless otherwise stated, all parts, percentages, and ratios reported in the following examples are by weight, and all reagents used in the examples are commercially available or synthesized according to conventional methods and can be used directly without further processing. The instruments used in the examples are also commercially available.

[0126] Example 1

[0127] S1: The size is 10×10×1mm 3 The K3 high-temperature alloy was used as the matrix, and the high-temperature alloy matrix was pretreated. The surface of the high-temperature alloy matrix was polished in sequence with 240#, 400# and 800# SiC sandpaper. The surface roughness Ra of the matrix after polishing was about 1μm. The polished matrix was ultrasonically cleaned in acetone, anhydrous ethanol and deionized water in sequence. The cleaning time was 10min to 15min, and the cleaned matrix was dried.

[0128] S2: A NiAl bonding layer was prepared on the surface of a pretreated high-temperature alloy substrate using electron beam physical vapor deposition. The target material was prepared by arc melting. During the bonding layer preparation process, the electron beam voltage was 20 kV, the current was 1.5 A, the high-temperature alloy substrate was heated to 900°C, the substrate rotation speed was 15 rpm, and the deposition time was 30 min. The high-temperature alloy substrate with the metal bonding layer was vacuum heat treated to improve the bonding strength. The heat treatment temperature was 970°C, the heat treatment time was 4 h, and the vacuum degree was 2.1×10-5 mbar, the processed sample was taken out after the furnace cooling to room temperature.

[0129] S3: using CAD software to draw the grid-like periodic structure as shown in Figure 2 (a) and import it into the ultraviolet laser control software, the overall size of the periodic structure is consistent with the surface area of the adhesive layer; the sample is placed on the laser processing platform, and the position of the processing platform is adjusted so that the laser spot is focused on the surface of the metal adhesive layer, and the diameter of the focused laser spot is about 15 μm.

[0130] S4: setting the processing parameters of the laser to process the metal adhesive layer, wherein the laser pulse width is 10 ns, the laser power is 2.5 W, the repetition frequency is 10 kHz, the scanning speed is 20 mm / s, and the scanning repetition number is 4 times; the surface of the processed sample is shown in Figure 2 (b), wherein the laser-processed grid etching depth is about 40 μm. The laser-etched sample is sequentially ultrasonically cleaned with acetone, anhydrous ethanol and deionized water and dried.

[0131] S5: placing the laser-etched high-temperature alloy sample with metal adhesive layer in a clamp, then fixing the clamp to the sample table of the plasma physical vapor deposition device and setting the deposition control program; filling the YSZ powder in the powder feeder; closing the device chamber, checking the device sealing, then vacuumizing, filling argon to 130 mbar when the vacuum degree reaches below 0.1 mbar; igniting the arc, vacuumizing to below 2 mbar after the arc is stable, moving the sample table to a position 1200 mm away from the spray gun, and adjusting the spray gun to face the sample; gradually increasing the spray gun current to 1800 A, setting the helium flow rate to 60 L / min, the argon flow rate to 35 L / min, the spraying power to 60 kW, and preheating the sample to 800℃ using the plasma jet; heating the temperature in the powder feeder chamber to 60℃, opening the powder feeding gas path, adjusting the powder feeding carrier gas flow rate to 8 L / min, the spraying time to 30 min, and the deposited coating thickness to about 200 μm; closing the powder feeding gas path, gradually reducing the spray gun current and plasma gas flow rate, filling argon to 60 mbar, then extinguishing the gun and extinguishing the arc, cooling for 10-20 min, then closing the vacuum pump, and taking out the sample after the chamber is balanced with the atmospheric pressure.

[0132] Example 2

[0133] S1: selecting a Φ25x1mm 3GH3230 high-temperature alloy as the substrate, the high-temperature alloy substrate was pretreated, and the surface of the high-temperature alloy 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 10-15 min, and the cleaned substrate was dried.

[0134] S2: A NiCrAlY bonding layer was prepared on the surface of the pretreated high-temperature alloy 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%, the deposition time was 40 min; the high-temperature alloy substrate with the prepared metal bonding layer was vacuum heat treated to improve the bonding force, 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 cooling to room temperature in the furnace; the sample surface 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.

[0135] S3: A line-shaped periodic structure as shown in Figure 4 (a) was drawn using CAD software and imported into the control software of the ultraviolet laser, the overall size of the periodic structure was consistent with the surface area of the bonding layer; the sample was placed on the laser processing platform, the position of the processing platform was adjusted so that the laser spot was focused on the surface of the metal bonding layer, and the diameter of the focused laser spot was about 15 μm.

[0136] S4: The processing parameters of the laser were set to process the metal bonding layer, wherein the laser pulse width was 10 ns, the laser power was 2.5 W, the repetition frequency was 10 kHz, the scanning speed was 50 mm / s, and the scanning repetition number was 2; the surface of the processed sample was as shown in Figure 4 (b), wherein the etching depth of the laser-processed grid was about 30 μm. The laser-etched sample was ultrasonically cleaned in acetone, anhydrous ethanol and deionized water in turn and dried.

[0137] S5: The laser-etched high-temperature alloy sample with a metal bonding layer is placed in a clamp, and then the clamp is fixed to a sample table of a plasma physical vapor deposition device and a deposition control program is set; YSZ powder is loaded in a powder feeder; the device chamber is closed, the sealing of the device is checked, and then vacuum is pumped, and when the vacuum degree reaches below 0.1 mbar, argon is filled to 130 mbar; the gun is ignited, and when the arc is stable, vacuum is pumped to below 2 mbar, the control program is started, the sample table is moved to a position 1200 mm away from the spray gun, and the spray gun is adjusted to face the sample; the spray gun current is gradually increased to 1800 A, the helium flow rate is set to 60 L / min, the argon flow rate is set to 35 L / min, the spraying power is 60 kW, and the sample is preheated to 800°C by using a plasma jet; the temperature in the powder feeder chamber is heated to 60°C, the powder feeding gas path is opened, the powder feeding carrier gas flow rate is adjusted to 8 L / min, the spraying time is 30 min, and the deposited coating thickness is about 200 μm; the powder feeding gas path is closed, the spray gun current and the plasma gas flow rate are gradually reduced, argon is filled to 60 mbar, the gun is turned off, the arc is extinguished, and after cooling for 10-20 min, the vacuum pump is turned off, and after the chamber is balanced with the atmospheric pressure, the sample is taken out.

[0138] Example 3

[0139] The preparation method of Example 3 is similar to that of Example 1, except that in step S4, the laser power is 8 W.

[0140] Example 4

[0141] The preparation method of Example 4 is similar to that of Example 1, except that in step S4, the laser power is 0.5 W.

[0142] Example 5

[0143] The preparation method of Example 5 is similar to that of Example 1, except that in step S4, the repetition frequency is 35 kHz.

[0144] Example 6

[0145] The preparation method of Example 6 is similar to that of Example 1, except that in step S4, the repetition frequency is 0.5 kHz.

[0146] Example 7

[0147] The preparation method of Example 7 is similar to that of Example 1, except that in step S4, the scanning repetition number is 8.

[0148] Comparative Example 1

[0149] The preparation method of Comparative Example 1 is similar to that of Example 1, except that steps S3 and S4 are omitted, that is, the etching step of the metal bonding layer is omitted, and the surface of the prepared metal bonding layer has no etched area.

[0150] The various performance parameters of the sealing coatings in Examples 1 to 7 and Comparative Example 1 are shown in Tables 1 and 2. The test conditions or test standards for each performance test item are as follows:

[0151] (1) Bonding strength between metal bonding layer and ceramic layer

[0152] The bonding strength test between the metal bonding layer and the ceramic layer was carried out in accordance with HB5476-1991 "Test Method for Bond Strength of Thermal Sprayed Thermal Barrier Coatings". The adhesive type was FM-1000 thin film resin glue, the testing equipment was SABA electronic tensile testing machine, the tensile speed was 1 mm / min, and the number of samples was ≥3.

[0153] (2) Hardness of sealing coating

[0154] The sample surface hardness test was carried out in accordance with GB / T 4340 "Vickers Hardness Test for Metallic Materials". The test equipment was the Yinuo FALCON511 fully automatic (micro) Vickers hardness tester. The test parameters were a load of 20 N, a loading time of 5 s, and the number of sample points ≥ 3.

[0155] (3) Wear resistance of sealing coating

[0156] An MPX-3G pin-on-disc friction and wear tester was used with test parameters of 500g, a turntable of 1000r / min, an intrusion rate of 0.02mm / s, and a loading time of 10min. The change in coating weight per unit area before and after the test was used as an indicator for evaluating wear resistance. The number of test samples in each group was ≥3.

[0157] (4) High temperature resistance of sealing coating

[0158] Thermal shock resistance testing of coatings was conducted in accordance with HB7269-96, "Quality Inspection of Thermal Sprayed Thermal Barrier Coatings." The test method involves heating a Φ25.4mm x 5mm sample to 1000°C, holding it for 5 minutes, quickly removing it from the heat, quenching it to room temperature in room temperature (25°C), and then drying it. The coating's surface morphology was then observed. Failure was considered when the surface area of ​​the coating peeled off by more than 20%. The number of thermal shock cycles at this point was recorded to indicate the coating's thermal shock resistance. Each test group consisted of ≥3 samples.

[0159] Table 1

[0160]

[0161] Table 2

[0162]

[0163] As can be seen from the above table, compared with Comparative Example 1, the bonding strength between the metal bonding layer and the ceramic layer and the number of thermal shock cycles of the sealing coating in the embodiment are higher than those in Comparative Example 1. At the same time, the change in coating weight per unit area and the hardness of the sealing layer are lower than those in Comparative Example 1, indicating that the etching area set in the sealing coating in the present application can enhance the bonding strength between the metal bonding layer and the metal layer, reduce the hardness of the coating, and at the same time improve the wear resistance and high temperature resistance of the coating.

[0164] In addition, from Figure 3 and Figure 5 It can be seen that after laser etching, a periodic undulating structure forms on the surface of the metal bonding layer, namely the etched area. The etched area and the coating above the etched area are filled with micron-nanoscale YSZ particles, while the unetched area forms micron-scale columnar crystals, and the two are distributed alternately along the horizontal direction.

[0165] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0166] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art could make various modifications and improvements without departing from the spirit of the present application, all of which fall within the scope of protection of the present application. Therefore, the scope of protection of the present patent application shall be determined by the appended claims.

Claims

1. A sealing coating, characterized in that: include: High temperature alloy substrate; and A metal bonding layer and a ceramic layer are sequentially stacked on the high-temperature alloy substrate, wherein the metal bonding layer includes at least one etched region on a surface relatively close to the ceramic layer, wherein ceramic particles are contained within and above the etched region, the etched region has an etch depth of 5 μm to 30 μm, a width of 5 μm to 30 μm, and a porosity of 13.56% to 35%; The etched area and the coating above the etched area are filled with micron-scale YSZ particles, and the unetched area generates micron-scale YSZ columnar crystals, and the two are alternately distributed in the horizontal direction; the volume of the YSZ columnar crystals in the ceramic layer accounts for 40% to 80%, and the volume of the YSZ particles in the ceramic layer accounts for 10% to 50%.

2. The sealing coating according to claim 1, characterized in that: The average particle size of the YSZ particles is 0.5 μm to 10 μm.

3. The sealing coating according to claim 1 or 2, characterized in that: The sealing coating satisfies at least one of the following conditions: (1) The thickness of the metal bonding layer is 40 μm to 150 μm; (2) The metal bonding layer comprises MCrAlY or NiAl, and M comprises at least one of Ni and Co.

4. The sealing coating according to claim 1 or 2, characterized in that: The YSZ particles are located in the gaps formed by the YSZ columnar crystals.

5. The sealing coating according to claim 1 or 2, characterized in that: One or more of the following conditions are met: (1) The width of the YSZ columnar crystal is 10 μm to 40 μm; (2) The average particle size of the YSZ particles is 0.5 μm to 10 μm.

6. A method for preparing a sealing coating, characterized in that: include: Providing a high-temperature alloy substrate and a metal bonding layer disposed on one side of the high-temperature alloy substrate; Etching the metal bonding layer to form at least one etched area on a surface of the metal bonding layer relatively away from the high-temperature alloy substrate; A ceramic layer is prepared on the surface of the metal bonding layer including the etched area, ceramic particles are formed inside and above the etched area, and columnar crystals are formed above the unetched area to obtain the sealing coating, wherein the etched area has an etch depth of 5 μm to 30 μm, a width of 5 μm to 30 μm, and a porosity of 13.56% to 35%; The etched area and the coating above the etched area are filled with micron-scale YSZ particles, and the unetched area generates micron-scale YSZ columnar crystals, and the two are alternately distributed in the horizontal direction; the volume of the YSZ columnar crystals in the ceramic layer accounts for 40% to 80%, and the volume of the YSZ particles in the ceramic layer accounts for 10% to 50%.

7. The method according to claim 6, characterized in that The method for preparing the metal bonding layer comprises: Pretreating the high-temperature alloy substrate; Depositing the metal bonding layer on the surface of the pretreated high-temperature alloy substrate; The metal bonding layer is subjected to vacuum heat treatment.

8. The method according to claim 7, characterized in that One or more of the following conditions are met: (1) The method of depositing the metal bonding layer includes at least one of multi-arc ion plating, electron beam physical vapor deposition, and electroplating-embedded infiltration; (2) The temperature of the vacuum heat treatment is 900°C to 1050°C; (3) The vacuum degree of the vacuum heat treatment is (2×10 -5 )mbar~(7×10 -5 )mbar; (4) The vacuum heat treatment time is 2h~6h.

9. The method according to any one of claims 6 to 8, characterized in that The etching process on the metal bonding layer includes: The metal bonding layer is subjected to pulse laser etching treatment.

10. The method according to claim 9, characterized in that One or more of the following conditions are met: (1) The central wavelength of the pulsed laser is 355 nm; (2) The laser focus spot diameter of the pulsed laser is 5 μm to 20 μm; (3) The pulse width of the pulse laser is 5 ns to 20 ns; (4) The laser power of the pulsed laser is 1W~5W; (5) The repetition frequency of the pulsed laser is 1 kHz to 30 kHz; (6) The scanning speed of the pulse laser is 10 mm / s to 200 mm / s; (7) The pulse laser scanning is repeated 1 to 5 times.

11. The method according to any one of claims 6 to 8, characterized in that The method for preparing the ceramic layer includes plasma physical vapor deposition.

12. The method according to claim 11, characterized in that One or more of the following conditions are met: (1) The material for preparing the ceramic layer includes YSZ powder; (2) The vacuum degree of the plasma physical vapor deposition is 1 mbar to 5 mbar; (3) The working gases used in the plasma physical vapor deposition process include argon and helium; (4) The distance between the sample and the spray gun during the plasma physical vapor deposition process is 1000 mm to 1400 mm; (5) The current of the plasma physical vapor deposition is 1800A~2100A; (6) The power of the plasma physical vapor deposition is 55kW~65kW; (7) The preheating temperature of the sample during the plasma physical vapor deposition process is 600°C~800°C.

13. The method according to claim 12, characterized in that The method satisfies at least one of the following conditions: (1) The average particle size D50 of the YSZ powder is 20 μm to 100 μm; (2) The helium gas flow rate is 40 L / min to 80 L / min; (3) The gas flow rate of the argon gas is 20 L / min to 40 L / min.

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