Seal coating powder and preparation method of seal coating

Abstract

The invention relates to the technical field of coating materials, in particular to a preparation method of sealing coating powder and a preparation method of a sealing coating. The preparation method of the seal coating powder comprises the following steps: ball-milling and mixing diffusion phase powder and lubricating phase powder to obtain mixed powder; the diffusion phase powder is one or more of aluminum alloy, titanium alloy and nickel alloy, and the lubricating phase powder is polybenzoate, molybdenum disulfide, hexagonal boron nitride or bentonite; the mixed powder and structural phase powder are subjected to ball-milling mixing to obtain composite powder, so that an intermetallic compound layer is formed on the interface of the structural phase and the diffusion phase, and part of the structural phase wraps the periphery of the mixed powder; the structural phase powder is copper alloy; and the composite powder is subjected to high-temperature treatment, the powder subjected to high-temperature treatment is screened, and powder in a preset particle size range is selected as sealing coating powder. The problems that a sealing coating is poor in corrosion resistance and low in abradability can be solved.

Description

Technical Field

[0001] The present disclosure relates to the technical field of coating materials, and in particular to a method for preparing sealing coating powder and a method for preparing sealing coating. Background Art

[0002] The rapid development of the aviation industry has put forward higher requirements for the thrust-to-weight ratio and fuel efficiency of the engine. Therefore, the clearance control between the rotor blades and the casing inside the engine is particularly important. Too large a clearance will lead to reduced cycle efficiency and unstable airflow. Insufficient clearance will limit the flow of cooling airflow, cause friction between the blade tip and the casing, and even cause blade damage, resulting in a reduction in the service life of key components.

[0003] Sealing coating is applied to blade tip clearance as a sacrificial clearance control, which is of great significance for improving aircraft engine efficiency, reducing fuel consumption and extending component life.

[0004] It should be noted that the information disclosed in the above background technology section is only used to enhance the understanding of the background of the present disclosure, and therefore may include information that does not constitute the prior art known to ordinary technicians in the field. Summary of the invention

[0005] The purpose of the present disclosure is to provide a method for preparing sealing coating powder and a method for preparing sealing coating, aiming to solve the problems of poor corrosion resistance and low abradability of sealing coating.

[0006] Other features and advantages of the present disclosure will become apparent from the following detailed description, or may be learned in part by the practice of the present disclosure.

[0007] According to one aspect of the present disclosure, a method for preparing a sealing coating powder is provided, comprising: ball-milling a diffusion phase powder and a lubricating phase powder to obtain a mixed powder; the diffusion phase powder is one or more of an aluminum alloy, a titanium alloy, and a nickel alloy, and the lubricating phase powder is polyphenylene ester, molybdenum disulfide, hexagonal boron nitride or bentonite; ball-milling the mixed powder with a structural phase powder to obtain a composite powder, so that an intermetallic compound layer is formed at the interface between the structural phase and the diffusion phase, and part of the structural phase is wrapped around the periphery of the mixed powder; the structural phase powder is a copper alloy; high-temperature treating the composite powder, and sieving the powder after high-temperature treatment to select a powder in a preset particle size range as the sealing coating powder.

[0008] Optionally, the aluminum alloy is a 6-series aluminum alloy or a 7-series aluminum alloy, the titanium alloy is Ti6Al4V or Ti5Al2.5Sn, the nickel alloy is an Inconel alloy, and the copper alloy is CuAl6, CuSn8 or CuAl7Fe2.

[0009] Optionally, the diffusion phase powder accounts for 10-20% by mass, the structural phase powder accounts for 45-65% by mass, and the remainder is the lubricating phase powder.

[0010] Optionally, the particle size range of the diffusion phase powder is 40-100 μm, the particle size range of the lubricating phase powder is 5-10 μm, the particle size range of the structural phase powder is 5-15 μm, and the particle size range of the sealing coating powder is 30-75 μm.

[0011] Optionally, when the diffusion phase powder and the lubrication phase powder are ball-milled to obtain a mixed powder, the ball milling process parameters are: a ball-to-material ratio of 10:1 to 15:1, a ball milling speed of 400 to 800 rpm, and a ball milling time of 24 to 48 hours; when the mixed powder and the structural phase powder are ball-milled to obtain a composite powder, the ball milling process parameters are: a ball-to-material ratio of 5:1 to 8:1, a ball milling speed of 150 to 300 rpm, and a ball milling time of 48 to 72 hours, and the ball milling process is stopped for 10 minutes every 20 minutes.

[0012] Optionally, the method further comprises: adding a process control agent and a binder when the diffusion phase powder and the lubrication phase powder are ball-milled to obtain a mixed powder; the mass fraction of the process control agent is 2% to 3%, and the mass fraction of the binder is 2% to 5%.

[0013] Optionally, the composite powder is subjected to high temperature treatment, including: placing the composite powder in a tray and then putting it into an oven for high temperature treatment, the treatment temperature is 100-150° C., the insulation time is 1-5 hours, and then cooling to room temperature with the furnace.

[0014] According to a second aspect of the present disclosure, a method for preparing a sealing coating is provided, comprising: spraying MCrAlY powder as spraying powder on a metal substrate to obtain an MCrAlY base layer; wherein M is Co, Ni or a mixture of Co and Ni; pre-oxidizing the MCrAlY base layer, and spraying a sealing coating powder as spraying powder on the pre-oxidized MCrAlY base layer to obtain a sealing coating; wherein the sealing coating powder is prepared by the method for preparing a sealing coating powder as described in claims 1 to 7 above.

[0015] Optionally, the thickness of the MCrAlY bottom layer is 100-200 μm, and the thickness of the sealing coating is 800-1500 μm.

[0016] Optionally, the spraying process parameters when spraying to obtain the MCrAlY bottom layer are: argon flow rate 70-80L / min, hydrogen flow rate 10-15L / min, nitrogen flow rate 3-5L / min, spraying power 40-45kW, spray gun moving speed 100-500mm / s, spraying distance 100-200mm, and powder feeding rate 10-15g / min; the spraying process parameters when spraying to obtain the sealing coating are: argon flow rate 90-110L / min, hydrogen flow rate 6-10L / min, spraying power 15-25kW, spray gun moving speed 400-800mm / s, spraying distance 100-300mm, and powder feeding rate 20-35g / min.

[0017] The exemplary embodiments of the present disclosure may have some or all of the following beneficial effects:

[0018] In the technical solutions provided by some embodiments of the present disclosure, in the technical solutions provided by some embodiments of the present disclosure, on the one hand, the sealing coating powder generates intermetallic compounds through the interface reaction and diffusion of the diffusion phase and the structural phase during the ball milling process, thereby inhibiting the galvanic corrosion between different metals and improving the corrosion resistance of the coating; on the other hand, the corrosion rate of the coating is reduced by adding the corrosion-resistant diffusion phase, thereby further improving the corrosion resistance of the coating; on the other hand, by controlling the ball milling parameters, part of the structural phase is embedded in the powder surface, thereby inhibiting the oxidation of the added phase and the decomposition of the lubricating phase during the spraying process, so that the coating maintains excellent wear resistance.

[0019] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The drawings herein are incorporated into the specification and constitute a part of the specification, showing embodiments consistent with the present disclosure, and together with the specification, are used to explain the principles of the present disclosure. Obviously, the drawings described below are only some embodiments of the present disclosure, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. In the drawings:

[0021] Figure 1 A schematic diagram schematically shows a process flow diagram of a method for preparing a sealing coating powder in an exemplary embodiment of the present disclosure;

[0022] Figure 2 A schematic diagram schematically shows a process flow diagram of a method for preparing a sealing coating in an exemplary embodiment of the present disclosure;

[0023] Figure 3 The microscopic morphology of the sealing coating powder prepared by the exemplary embodiment 1 of the present disclosure is schematically shown;

[0024] Figure 4 The microscopic morphology of the sealing coating prepared according to exemplary embodiment 1 of the present disclosure is schematically shown. DETAILED DESCRIPTION

[0025] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be implemented in a variety of forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided so that this disclosure will be more comprehensive and complete and will fully convey the concept of the example embodiments to those skilled in the art.

[0026] In addition, the described features, structures or characteristics may be combined in one or more embodiments in any suitable manner. In the following description, many specific details are provided to provide a full understanding of the embodiments of the present disclosure. However, those skilled in the art will appreciate that the technical solutions of the present disclosure may be practiced without one or more of the specific details, or other methods, components, devices, steps, etc. may be adopted. In other cases, known methods, devices, implementations or operations are not shown or described in detail to avoid blurring the various aspects of the present disclosure.

[0027] The block diagrams shown in the accompanying drawings are merely functional entities and do not necessarily correspond to physically independent entities. That is, these functional entities may be implemented in software form, or in one or more hardware modules or integrated circuits, or in different networks and / or processor devices and / or microcontroller devices.

[0028] The flowcharts shown in the accompanying drawings are only exemplary and do not necessarily include all the contents and operations / steps, nor must they be executed in the order described. For example, some operations / steps can be decomposed, and some operations / steps can be combined or partially combined, so the actual execution order may change according to actual conditions.

[0029] The rapid development of the aviation industry has put forward higher requirements for the thrust-to-weight ratio and fuel efficiency of the engine. Therefore, the clearance control between the rotor blades and the casing inside the engine is particularly important. Too large a clearance will lead to reduced cycle efficiency and unstable airflow. Insufficient clearance will limit the flow of cooling airflow, cause friction between the blade tip and the casing, and even cause blade damage, resulting in a reduction in the service life of key components. Data show that the direct cost of aviation engines for fuel consumption accounts for about 53%, and the loss of fuel consumption due to tip clearance leakage accounts for about 30% of the loss of the entire engine. For every 0.02mm reduction in the tip clearance of a high-pressure turbine engine, fuel consumption can be reduced by 1% and engine efficiency can be increased by about 2%. Therefore, the clearance control between the rotor blades and the casing is the most effective way to improve the mechanical performance of the engine.

[0030] The abradable sealing coating is used as a sacrificial clearance control in the blade tip clearance, which is of great significance for improving the efficiency of aircraft engines, reducing fuel consumption and extending the life of components. The coating is generally composed of a composite of metal and non-metallic materials. Metallic materials in abradable sealing coatings mainly affect their sprayability, erosion resistance, and the bonding strength between the coating and the substrate and the cohesive strength of the coating, acting as a "bracket". Non-metallic materials are mainly divided into three parts according to their functions. One part mainly provides the abradability in the abradable sealing coating, and the materials in this part usually have good lubricity. The other part is responsible for bonding metal and some non-metallic materials, and acts as a binder in the preparation of composite powders and the spray preparation of coatings. Finally, non-metallic materials also act as pore formers in the preparation of some abradable sealing coatings, and can be used as an initial pore source to improve the abradability of the coating.

[0031] 90% of the time of the service life of aircraft engines is in a parking state. For aircraft engines serving in the ocean and coastal areas, the abradable sealing coating is in a high-humidity, high-salinity marine atmosphere. At this time, salt spray acts on the surface of the coating, which is prone to chemical or electrochemical corrosion, causing the coating to fail. In severe cases, it even endangers the safety of the engine. At the same time, due to the limitations of the design of the abradable sealing coating itself, the large number of pores in the coating will provide channels for the invasion of corrosive media and the occurrence of corrosion, accelerate the corrosion failure of the coating, and affect the service life of the engine. Therefore, it is urgent to develop new sealing coatings.

[0032] Therefore, in view of the deficiencies in the prior art, the present invention provides a corrosion-resistant and abradable sealing coating powder and a method for preparing the sealing coating, so that the obtained coating has both excellent abradability and good corrosion resistance and has broad application prospects.

[0033] The implementation details of the technical solution of the embodiment of the present disclosure are elaborated in detail below.

[0034] Figure 1 The following is a schematic diagram of a process for preparing a sealing coating powder in an exemplary embodiment of the present disclosure. Figure 1 As shown, the method for preparing the sealing coating powder includes steps S101 to S105:

[0035] Step S101, ball-milling a diffusion phase powder and a lubricating phase powder to obtain a mixed powder; the diffusion phase powder is one or more of an aluminum alloy, a titanium alloy, and a nickel alloy, and the lubricating phase powder is polyphenylene ester, molybdenum disulfide, hexagonal boron nitride or bentonite;

[0036] Step S103, ball-milling the mixed powder and the structural phase powder to obtain a composite powder, so that an intermetallic compound layer is formed at the interface between the structural phase and the diffusion phase, and part of the structural phase is wrapped around the periphery of the mixed powder; the structural phase powder is a copper alloy;

[0037] Step S105, subjecting the composite powder to high temperature treatment, and sieving the high temperature treated powder to select powder within a preset particle size range as sealing coating powder.

[0038] In the technical solutions provided in some embodiments of the present disclosure, the sealing coating powder, on the one hand, generates intermetallic compounds through the interface reaction and diffusion of the diffusion phase and the structural phase during the ball milling process, thereby inhibiting galvanic corrosion between different metals and improving the corrosion resistance of the coating; on the other hand, the corrosion rate of the coating is reduced by adding the corrosion-resistant diffusion phase, thereby further improving the corrosion resistance of the coating; on the other hand, by controlling the ball milling parameters, part of the structural phase is embedded in the powder surface, thereby inhibiting the oxidation of the added phase and the decomposition of the lubricating phase during the spraying process, so that the coating maintains excellent abradability.

[0039] Hereinafter, each step of the method for preparing the sealing coating powder in this exemplary embodiment will be described in more detail with reference to the accompanying drawings and examples.

[0040] In step S101, the diffusion phase powder and the lubrication phase powder are ball-milled to obtain a mixed powder.

[0041] Specifically, the diffusion phase powder is one or more of aluminum alloy, titanium alloy, and nickel alloy. Among them, the aluminum alloy is 6 series aluminum alloy or 7 series aluminum alloy, the titanium alloy is Ti6Al4V or Ti5Al2.5Sn, and the nickel alloy is Inconel alloy. The lubricating phase powder is polyphenyl ester, molybdenum disulfide (MoS2), hexagonal boron nitride (h-BN) or bentonite. The particle size range of the diffusion phase powder is 40 to 100 μm, and the particle size range of the lubricating phase powder is 5 to 10 μm.

[0042] In one embodiment of the present disclosure, a process control agent and a binder are added when the diffusion phase powder and the lubrication phase powder are ball-milled to obtain a mixed powder; the mass fraction of the process control agent is 2% to 3%, and the mass fraction of the binder is 2% to 5%.

[0043] In one embodiment of the present disclosure, when the diffusion phase powder and the lubrication phase powder are ball-milled to obtain a mixed powder, the ball-milling process parameters are: a ball-to-material ratio of 10:1 to 15:1, a ball-milling speed of 400 to 800 rpm, and a ball-milling time of 24 to 48 hours.

[0044] In step S103, the mixed powder and the structural phase powder are ball-milled to obtain a composite powder, so that an intermetallic compound layer is formed at the interface between the structural phase and the diffusion phase, and part of the structural phase is wrapped around the periphery of the mixed powder;

[0045] Specifically, the structural phase powder is a copper alloy, wherein the copper alloy is CuAl6, CuSn8 or CuAl7Fe2, and the particle size of the structural phase powder ranges from 5 to 15 μm.

[0046] In one embodiment of the present disclosure, when the mixed powder and the structural phase powder are ball-milled to obtain a composite powder, the ball-milling process parameters are: a ball-to-material ratio of 5:1 to 8:1, a ball-milling speed of 150 to 300 rpm, a ball-milling time of 48 to 72 h, and a 10-minute stop for every 20 minutes of ball-milling.

[0047] In the composite powder finally obtained, an intermetallic compound layer with a thickness of 5 to 10 μm is formed at the interface between the structural phase and the diffusion phase, and part of the structural phase is wrapped around the periphery of the mixed powder.

[0048] In step S105, the composite powder is subjected to high temperature treatment, and the powder after high temperature treatment is sieved to select powder within a preset particle size range as sealing coating powder.

[0049] Specifically, the composite powder is placed in a tray and then put into an oven for high-temperature treatment at a temperature of 100 to 150° C. for a holding time of 1 to 5 hours, and then cooled to room temperature in the oven.

[0050] The particle size range of the sealing coating powder is 30-75 μm, that is, during screening, powder with a particle size range of 30-75 μm can be selected for the preparation of the sealing coating.

[0051] In one embodiment of the present disclosure, the sealing coating powder is composed of diffusion phase powder, lubricating phase powder and structural phase powder, wherein the mass proportion of the diffusion phase powder is 10-20%, the mass proportion of the structural phase powder is 45-65%, and the remainder is lubricating phase powder.

[0052] Based on the above method, a sealing coating powder is prepared. On the one hand, intermetallic compounds are generated by interface reaction and diffusion between the diffusion phase and the structural phase during the ball milling process, which inhibits galvanic corrosion between different metals and improves the corrosion resistance of the coating. On the other hand, the corrosion rate of the coating is reduced by the addition of the corrosion-resistant diffusion phase, further improving the corrosion resistance of the coating.

[0053] In addition, by controlling the ball milling parameters, part of the structural phase is embedded in the powder surface, which inhibits the oxidation of the added phase and the decomposition of the lubricating phase during the spraying process, so that the coating maintains excellent abradability.

[0054] Figure 2 The following is a schematic diagram of a process for preparing a sealing coating in an exemplary embodiment of the present disclosure. Figure 2 As shown, the method for preparing the sealing coating includes steps S201 to S203:

[0055] Step S201, using MCrAlY powder as spray powder to spray on a metal substrate to obtain an MCrAlY bottom layer; wherein M is Co, Ni or a mixture of Co and Ni;

[0056] Step S202, pre-oxidizing the MCrAlY bottom layer, and spraying the sealing coating powder as spraying powder on the pre-oxidized MCrAlY bottom layer to obtain a sealing coating.

[0057] In step S201, MCrAlY powder is used as spraying powder and sprayed on a metal substrate to obtain an MCrAlY base layer.

[0058] Among them, M can be Co, Ni, or a mixture of the two. Then, MCrAlY powder is used as spray powder and plasma spraying is used to spray on the metal substrate. Specifically, the spraying process parameters when spraying the MCrAlY bottom layer are: argon flow rate 70-80L / min, hydrogen flow rate 10-15L / min, nitrogen flow rate 3-5L / min, spraying power 40-45kW, spray gun moving speed 100-500mm / s, spraying distance 100-200mm, powder feeding rate 10-15g / min. The thickness of the MCrAlY bottom layer is finally obtained to be 100-200μm.

[0059] In one embodiment of the present disclosure, the metal substrate may be pretreated before spraying, that is, the surface of the metal substrate is roughened by sandblasting, and the sand embedded in the substrate surface is removed, the sandblasting sand is 40-120 mesh brown corundum, and the sandblasting pressure is 0.4-0.6 MPa.

[0060] In step S202, the MCrAlY bottom layer is pre-oxidized, and a sealing coating powder is sprayed as a spraying powder on the pre-oxidized MCrAlY bottom layer to obtain a sealing coating.

[0061] Specifically, the MCrAlY bottom layer is first pre-oxidized, and the pre-oxidation parameters are: pre-oxidation temperature 1000 ~ 1100 ° C, pre-oxidation time 5 ~ 10h, pre-oxidation is carried out under vacuum, and the vacuum degree is ≤10 -3 Pa.

[0062] Then, the sealing coating powder is used as the spraying powder, and the sealing coating is prepared on the surface of the pre-oxidized MCrAlY bottom layer by plasma spraying. Specifically, the spraying process parameters when spraying the sealing coating are: argon flow rate 90-110L / min, hydrogen flow rate 6-10L / min, spraying power 15-25kW, spray gun moving speed 400-800mm / s, spraying distance 100-300mm, powder feeding rate 20-35g / min. The thickness of the sealing coating is finally 800-1500μm.

[0063] Based on the above method, pre-oxidation treatment is used to form a raised island-shaped Al2O3 structure on the surface of the bottom layer, which plays a pinning role on the surface layer and improves the bonding strength of the surface layer.

[0064] Example 1

[0065] The sealing coating powder of this embodiment is composed of structural phase powder, diffusion phase powder and lubricating phase powder, wherein the structural phase powder is 45% by mass, the diffusion phase powder is 20% by mass, and the remainder is lubricating phase powder. The structural phase powder is CuAl6, the diffusion phase powder is 6061 aluminum alloy, and the lubricating phase powder is polyphenylene ester.

[0066] In this embodiment, the sealing coating powder is first prepared in the following steps:

[0067] Step 1: ball-milling the diffusion phase powder with a particle size of 40 μm and the lubricating phase powder with a particle size of 5 μm, with a ball-to-material ratio of 10:1, a ball-milling speed of 400 rpm, and a ball-milling time of 24 h. During the ball-milling process, a process control agent with a mass fraction of 2% and a binder with a mass fraction of 2% are added;

[0068] Step 2: The obtained mixed powder and the structural phase powder with a particle size of 5 μm are ball-milled to obtain a composite powder, the ball-to-material ratio is 5:1, the ball milling speed is 150 rpm, the ball milling time is 48 h, and the ball milling process is stopped for 10 min every 20 min of ball milling, so that an intermetallic compound layer is formed at the interface of the structural phase and the diffusion phase, and part of the structural phase is wrapped around the periphery of the mixed powder;

[0069] Step 3, placing the above composite powder in a tray, putting it into an oven for high temperature treatment, the treatment temperature is 100°C, the heat preservation time is 5h, and then cooling to room temperature with the furnace;

[0070] Step 4: Screen the composite powder after high temperature treatment, and select powder with a particle size of 30 μm for preparation of sealing coating.

[0071] Then prepare the sealing coating, the steps are as follows:

[0072] Step 1: sandblasting the surface of the metal substrate to roughen it and remove the gravel embedded in the substrate surface. The sandblasting gravel is 120 mesh brown corundum and the sandblasting pressure is 0.4 MPa.

[0073] Step 2: Using MCrAlY (M is Co, Ni or a mixture of the two) powder as spray powder, plasma spraying is used to spray a bottom layer on the surface of the metal substrate treated in step 1, and the bottom layer thickness is 100 μm; the process parameters for preparing the MCrAlY bottom layer are: argon flow rate 70 L / min, hydrogen flow rate 10 L / min, nitrogen flow rate 3 L / min, spraying power 40 kW, spray gun moving speed 100 mm / s, spraying distance 100 mm, and powder feeding rate 10 g / min;

[0074] Step 3: pre-oxidation treatment of the MCrAlY bottom layer, the pre-oxidation treatment parameters are: pre-oxidation temperature 1000 ° C, pre-oxidation time 5h, pre-oxidation under vacuum, vacuum degree ≤ 10 -3 Pa;

[0075] Step 4: Using the sealing coating powder as the spraying powder, plasma spraying is used to prepare the sealing coating on the surface of the MCrAlY base layer pre-oxidized in step 3, and the coating thickness is 800 μm; the process parameters for spraying the sealing coating are: argon flow rate 90 L / min, hydrogen flow rate 6 L / min, spraying power 15 kW, spray gun moving speed 400 mm / s, spraying distance 100 mm, and powder feeding rate 20 g / min.

[0076] Figure 3 The microscopic morphology of the sealing coating powder prepared in the exemplary embodiment 1 of the present disclosure is schematically shown. It can be seen that part of the structural phase is wrapped around the periphery of the mixed powder, which effectively inhibits the decomposition of the lubricating phase during the spraying process.

[0077] Figure 4 The microscopic morphology of the sealing coating prepared by the exemplary embodiment 1 of the present disclosure is schematically shown. It can be seen that the structural phase, lubricating phase and diffusion phase are uniformly distributed in the coating.

[0078] After testing, the coating has a porosity of 36.7%, a bonding strength of 17.8MPa, a feed depth ratio of 7.83%, good abradability, a room temperature salt spray corrosion time of 96h, and excellent corrosion resistance.

[0079] Example 2

[0080] The sealing coating powder of this embodiment is composed of structural phase powder, diffusion phase powder and lubricating phase powder, wherein the structural phase powder is 65% by mass, the diffusion phase powder is 10% by mass, and the remainder is lubricating phase powder. The structural phase powder is CuSn8, the diffusion phase powder is 7075 aluminum alloy, and the lubricating phase powder is MoS2.

[0081] In this embodiment, the sealing coating powder is first prepared in the following steps:

[0082] Step 1: ball-milling the diffusion phase powder with a particle size of 100 μm and the lubricating phase powder with a particle size of 10 μm, with a ball-to-material ratio of 15:1, a ball-milling speed of 800 rpm, and a ball-milling time of 48 h. During the ball-milling process, a process control agent with a mass fraction of 3% and a binder with a mass fraction of 5% are added;

[0083] Step 2: The obtained mixed powder and the structural phase powder with a particle size of 15 μm are ball-milled to obtain a composite powder, the ball-to-material ratio is 8:1, the ball milling speed is 300 rpm, the ball milling time is 72 h, and the ball milling process is stopped for 10 min after every 20 min of ball milling, so that an intermetallic compound layer is formed at the interface of the structural phase and the diffusion phase, and part of the structural phase is wrapped around the periphery of the mixed powder;

[0084] Step 3, placing the above composite powder in a tray, putting it into an oven for high temperature treatment, the treatment temperature is 150°C, the heat preservation time is 1h, and then cooling to room temperature with the furnace;

[0085] Step 4: Screen the composite powder after high temperature treatment, and select powder with a particle size of 75 μm for preparing the sealing coating.

[0086] Then prepare the sealing coating, the steps are as follows:

[0087] Step 1: sandblast the surface of the metal substrate to roughen it and remove the gravel embedded in the substrate surface. The sandblasting gravel is 40 mesh brown corundum and the sandblasting pressure is 0.6 MPa.

[0088] Step 2: Using MCrAlY (M is Co, Ni or a mixture of the two) powder as spray powder, plasma spraying is used to spray a bottom layer on the surface of the metal substrate treated in step 1, and the bottom layer thickness is 200 μm; the process parameters for preparing the MCrAlY bottom layer are: argon flow rate 80 L / min, hydrogen flow rate 15 L / min, nitrogen flow rate 5 L / min, spraying power 45 kW, spray gun moving speed 500 mm / s, spraying distance 200 mm, and powder feeding rate 15 g / min;

[0089] Step 3: Pre-oxidation treatment of the MCrAlY bottom layer, the pre-oxidation treatment parameters are: pre-oxidation temperature 1100 ° C, pre-oxidation time 10h, pre-oxidation under vacuum, vacuum degree ≤ 10 -3 Pa;

[0090] Step 4: Using the sealing coating powder as the spraying powder, the sealing coating is prepared on the surface of the MCrAlY base layer pre-oxidized in step 3 by plasma spraying, and the coating thickness is 1500μm; the process parameters for spraying the sealing coating are: argon flow rate 110L / min, hydrogen flow rate 10L / min, spraying power 25kW, spray gun moving speed 800mm / s, spraying distance 300mm, and powder feeding rate 35g / min.

[0091] After testing, the coating has a porosity of 32.4%, a bonding strength of 18.9MPa, a feed depth ratio of 8.94%, good abradability, a room temperature salt spray corrosion time of 90h, and excellent corrosion resistance.

[0092] Example 3

[0093] The sealing coating powder of this embodiment is composed of structural phase powder, diffusion phase powder and lubricating phase powder, wherein the structural phase powder is 50%, the diffusion phase powder is 15%, and the remainder is lubricating phase powder by mass percentage. The structural phase powder is CuAl7Fe2, the diffusion phase powder is Inconel 625, and the lubricating phase powder is h-BN.

[0094] In this embodiment, the sealing coating powder is first prepared in the following steps:

[0095] Step 1: ball-milling the diffusion phase powder with a particle size of 50 μm and the lubricating phase powder with a particle size of 7 μm, with a ball-to-material ratio of 12:1, a ball-milling speed of 500 rpm, and a ball-milling time of 36 h. During the ball-milling process, a process control agent with a mass fraction of 2.5% and a binder with a mass fraction of 3% are added;

[0096] Step 2: The obtained mixed powder and the structural phase powder with a particle size of 10 μm are ball-milled to obtain a composite powder, the ball-to-material ratio is 6:1, the ball milling speed is 200 rpm, the ball milling time is 56 h, and the ball milling process is stopped for 10 min every 20 min of ball milling, so that an intermetallic compound layer is formed at the interface of the structural phase and the diffusion phase, and part of the structural phase is wrapped around the periphery of the mixed powder;

[0097] Step 3, placing the above composite powder in a tray, putting it into an oven for high temperature treatment, the treatment temperature is 110°C, the heat preservation time is 2h, and then cooling to room temperature with the furnace;

[0098] Step 4: Screen the composite powder after high temperature treatment, and select powder with a particle size of 40 μm for preparing the sealing coating.

[0099] Then prepare the sealing coating, the steps are as follows:

[0100] Step 1: sandblasting the surface of the metal substrate to roughen it and remove the gravel embedded in the substrate surface. The sandblasting gravel is 60-mesh brown corundum and the sandblasting pressure is 0.5 MPa.

[0101] Step 2: Using MCrAlY (M is Co, Ni or a mixture of the two) powder as spray powder, plasma spraying is used to spray a bottom layer on the surface of the metal substrate treated in step 1, and the bottom layer thickness is 150 μm; the process parameters for preparing the MCrAlY bottom layer are: argon flow rate 75 L / min, hydrogen flow rate 12 L / min, nitrogen flow rate 4 L / min, spraying power 42 kW, spray gun moving speed 200 mm / s, spraying distance 150 mm, and powder feeding rate 12 g / min;

[0102] Step 3: pre-oxidation treatment of the MCrAlY bottom layer, the pre-oxidation treatment parameters are: pre-oxidation temperature 1050 ° C, pre-oxidation time 8h, pre-oxidation under vacuum, vacuum degree ≤10 -3 Pa;

[0103] Step 4: Using the sealing coating powder as the spraying powder, plasma spraying is used to prepare the sealing coating on the surface of the MCrAlY base layer pre-oxidized in step 3, and the coating thickness is 900 μm; the process parameters for spraying the sealing coating are: argon flow rate 100 L / min, hydrogen flow rate 8 L / min, spraying power 20 kW, spray gun moving speed 500 mm / s, spraying distance 200 mm, and powder feeding rate 25 g / min.

[0104] After testing, the coating has a porosity of 38.5%, a bonding strength of 16.9 MPa, a feed depth ratio of 9.35%, good abradability, a room temperature salt spray corrosion time of 85 hours, and excellent corrosion resistance.

[0105] Example 4

[0106] The sealing coating powder of this embodiment is composed of structural phase powder, diffusion phase powder and lubricating phase powder, wherein the structural phase powder is 55% by mass, the diffusion phase powder is 18% by mass, and the remainder is lubricating phase powder. The structural phase powder is CuAl6, the diffusion phase powder is Ti6Al4V, and the lubricating phase powder is bentonite.

[0107] In this embodiment, the sealing coating powder is first prepared in the following steps:

[0108] Step 1: ball-milling the diffusion phase powder with a particle size of 60 μm and the lubricating phase powder with a particle size of 8 μm, with a ball-to-material ratio of 11:1, a ball-milling speed of 600 rpm, and a ball-milling time of 40 h. During the ball-milling process, a process control agent with a mass fraction of 2.8% and a binder with a mass fraction of 4% were added;

[0109] Step 2: The obtained mixed powder and the structural phase powder with a particle size of 8 μm are ball-milled to obtain a composite powder, the ball-to-material ratio is 7:1, the ball milling speed is 250 rpm, the ball milling time is 65 h, and the ball milling process is stopped for 10 min every 20 min, so that an intermetallic compound layer is formed at the interface of the structural phase and the diffusion phase, and part of the structural phase is wrapped around the periphery of the mixed powder;

[0110] Step 3: Place the composite powder on a tray and place it in an oven for high temperature treatment at 120°C for 3 hours, and then cool it to room temperature.

[0111] Step 4: Screen the composite powder after high temperature treatment, and select powder with a particle size range of 50 μm for sealing coating preparation.

[0112] Then prepare the sealing coating, the steps are as follows:

[0113] Step 1: sandblast the surface of the metal substrate to roughen it and remove the gravel embedded in the substrate surface. The sandblasting gravel is 80 mesh brown corundum and the sandblasting pressure is 0.45 MPa.

[0114] Step 2: Using MCrAlY (M is Co, Ni or a mixture of the two) powder as spray powder, plasma spraying is used to spray the bottom layer on the surface of the metal substrate treated in step 1, and the bottom layer thickness is 180 μm; the process parameters for preparing the MCrAlY bottom layer are: argon flow rate 78 L / min, hydrogen flow rate 13 L / min, nitrogen flow rate 3.5 L / min, spraying power 44 kW, spray gun moving speed 300 mm / s, spraying distance 160 mm, and powder feeding rate 13 g / min;

[0115] Step 3: Pre-oxidation treatment of the MCrAlY bottom layer, the pre-oxidation treatment parameters are: pre-oxidation temperature 1030 ° C, pre-oxidation time 9h, pre-oxidation under vacuum, vacuum degree ≤ 10 -3 Pa;

[0116] Step 4: Use sealing coating powder as spraying powder, and use plasma spraying to prepare sealing coating on the surface of MCrAlY base layer after pre-oxidation treatment in step 3, and the coating thickness is 1000μm; the process parameters for spraying sealing coating are: argon flow rate 105L / min, hydrogen flow rate 7L / min, spraying power 18kW, spray gun moving speed 600mm / s, spraying distance 250mm, and powder feeding rate 30g / min.

[0117] After testing, the coating has a porosity of 37.9%, a bonding strength of 18.6 MPa, a feed depth ratio of 7.65%, good abradability, a room temperature salt spray corrosion time of 80 h, and excellent corrosion resistance.

[0118] Example 5

[0119] The sealing coating powder of this embodiment is composed of structural phase powder, diffusion phase powder and lubricating phase powder, wherein the structural phase powder is 48% by mass, the diffusion phase powder is 18% by mass, and the remainder is lubricating phase powder. The structural phase powder is CuSn8, the diffusion phase powder is a mixture of 7050 aluminum alloy and Inconel718, and the lubricating phase powder is MoS2.

[0120] In this embodiment, the sealing coating powder is first prepared in the following steps:

[0121] Step 1: The diffusion phase powder with a particle size of 55 μm and the lubricating phase powder with a particle size of 6 μm are ball-milled and mixed, the ball-to-material ratio is 13:1, the ball milling speed is 460 rpm, the ball milling time is 29 h, and a process control agent with a mass fraction of 2.3% and a binder with a mass fraction of 4.8% are added during the ball milling process;

[0122] Step 2: The obtained mixed powder and the structural phase powder with a particle size of 11 μm are ball-milled to obtain a composite powder, the ball-to-material ratio is 6:1, the ball milling speed is 270 rpm, the ball milling time is 66 h, and the ball milling process is stopped for 10 min every 20 min, so that an intermetallic compound layer is formed at the interface of the structural phase and the diffusion phase, and part of the structural phase is wrapped around the periphery of the mixed powder;

[0123] Step 3: Place the above composite powder in a tray and put it into an oven for high temperature treatment at 115°C for 2 hours, and then cool it to room temperature in the oven;

[0124] Step 4: Screen the composite powder after high temperature treatment, and select powder with a particle size range of 36 μm for preparing the sealing coating.

[0125] Then prepare the sealing coating, the steps are as follows:

[0126] Step 1: sandblast the surface of the metal substrate to roughen it and remove the gravel embedded in the substrate surface. The sandblasting gravel is 120 mesh brown corundum and the sandblasting pressure is 0.42MPa.

[0127] Step 2: Using MCrAlY (M is Co, Ni or a mixture of the two) powder as spray powder, plasma spraying is used to spray the bottom layer on the surface of the metal substrate treated in step 1, and the bottom layer thickness is 135 μm; the process parameters for preparing the MCrAlY bottom layer are: argon flow rate 72 L / min, hydrogen flow rate 11 L / min, nitrogen flow rate 3.9 L / min, spraying power 42 kW, spray gun moving speed 460 mm / s, spraying distance 165 mm, and powder feeding rate 12 g / min;

[0128] Step 3: Pre-oxidation treatment is performed on the MCrAlY bottom layer. The pre-oxidation treatment parameters are: pre-oxidation temperature 1010°C, pre-oxidation time 7.5h, pre-oxidation is performed under vacuum, and the vacuum degree is ≤10 -3 Pa;

[0129] Step 4: Use sealing coating powder as spraying powder, and use plasma spraying to prepare a sealing coating on the surface of the MCrAlY base layer pre-oxidized in step 3, with a coating thickness of 1150 μm; the process parameters for spraying the sealing coating are: argon flow rate 108 L / min, hydrogen flow rate 7 L / min, spraying power 23 kW, spray gun moving speed 750 mm / s, spraying distance 140 mm, and powder feeding rate 31 g / min.

[0130] After testing, the coating has a porosity of 34.2%, a bonding strength of 16.3 MPa, a feed depth ratio of 7.59%, good abradability, a room temperature salt spray corrosion time of 87 hours, and excellent corrosion resistance.

[0131] Example 6

[0132] The sealing coating powder of this embodiment is composed of structural phase powder, diffusion phase powder and lubricating phase powder, wherein the structural phase powder is 48% by mass, the diffusion phase powder is 18% by mass, and the remainder is lubricating phase powder. The structural phase powder is CuSn8, the diffusion phase powder is a mixture of 6061 aluminum alloy and Ti5Al2.5Sn, and the lubricating phase powder is h-BN.

[0133] In this embodiment, the sealing coating powder is first prepared in the following steps:

[0134] Step 1: ball-milling the diffusion phase powder with a particle size of 95 μm and the lubricating phase powder with a particle size of 6 μm, with a ball-to-material ratio of 11:1, a ball-milling speed of 550 rpm, and a ball-milling time of 25 h. During the ball-milling process, a process control agent with a mass fraction of 2.9% and a binder with a mass fraction of 2.4% were added;

[0135] Step 2: The obtained mixed powder and the structural phase powder with a particle size of 6 μm are ball-milled to obtain a composite powder, the ball-to-material ratio is 5:1, the ball milling speed is 180 rpm, the ball milling time is 50 h, and the ball milling process is stopped for 10 min every 20 min, so that an intermetallic compound layer is formed at the interface of the structural phase and the diffusion phase, and part of the structural phase is wrapped around the periphery of the mixed powder;

[0136] Step 3: Place the composite powder on a tray and place it in an oven for high temperature treatment at 115°C for 1.5 hours, and then cool it to room temperature.

[0137] Step 4: Screen the composite powder after high temperature treatment, and select powder with a particle size range of 38 μm for preparing the sealing coating.

[0138] Then prepare the sealing coating, the steps are as follows:

[0139] Step 1: sandblast the surface of the metal substrate to roughen it and remove the gravel embedded in the substrate surface. The sandblasting gravel is 60 mesh brown corundum and the sandblasting pressure is 0.58 MPa.

[0140] Step 2: Using MCrAlY (M is Co, Ni or a mixture of the two) powder as spray powder, plasma spraying is used to spray the bottom layer on the surface of the metal substrate treated in step 1, and the bottom layer thickness is 125 μm; the process parameters for preparing the MCrAlY bottom layer are: argon flow rate 71 L / min, hydrogen flow rate 13 L / min, nitrogen flow rate 3 L / min, spraying power 43 kW, spray gun moving speed 350 mm / s, spraying distance 120 mm, and powder feeding rate 12 g / min;

[0141] Step 3: Pre-oxidation treatment is performed on the MCrAlY bottom layer. The pre-oxidation treatment parameters are: pre-oxidation temperature 1020°C, pre-oxidation time 8.5h, pre-oxidation is performed under vacuum, and the vacuum degree is ≤10 -3 Pa;

[0142] Step 4: Use sealing coating powder as spraying powder, and use plasma spraying to prepare sealing coating on the surface of MCrAlY base layer after pre-oxidation treatment in step 3, and the coating thickness is 1050μm; the process parameters for spraying sealing coating are: argon flow rate 101L / min, hydrogen flow rate 9L / min, spraying power 18kW, spray gun moving speed 560mm / s, spraying distance 230mm, and powder feeding rate 24g / min.

[0143] After testing, the coating has a porosity of 33.6%, a bonding strength of 12.5 MPa, a feed depth ratio of 7.31%, good abradability, a room temperature salt spray corrosion time of 92 hours, and excellent corrosion resistance.

[0144] Example 7

[0145] The sealing coating powder of this embodiment is composed of structural phase powder, diffusion phase powder and lubricating phase powder, wherein the structural phase powder is 58% by mass, the diffusion phase powder is 11% by mass, and the remainder is lubricating phase powder. The structural phase powder is CuAl7Fe2, the diffusion phase powder is a mixture of Ti6Al4V and Inconel718, and the lubricating phase powder is bentonite.

[0146] In this embodiment, the sealing coating powder is first prepared in the following steps:

[0147] Step 1: ball-milling the diffusion phase powder with a particle size of 52 μm and the lubricating phase powder with a particle size of 6 μm, with a ball-to-material ratio of 13:1, a ball-milling speed of 500 rpm, and a ball-milling time of 32 h. During the ball-milling process, a process control agent with a mass fraction of 2.8% and a binder with a mass fraction of 3.8% were added;

[0148] Step 2: The obtained mixed powder and the structural phase powder with a particle size of 8 μm are ball-milled to obtain a composite powder, the ball-to-material ratio is 7:1, the ball milling speed is 220 rpm, the ball milling time is 52 h, and the ball milling process is stopped for 10 min every 20 min of ball milling, so that an intermetallic compound layer is formed at the interface of the structural phase and the diffusion phase, and part of the structural phase is wrapped around the periphery of the mixed powder;

[0149] Step 3: Place the above composite powder in a tray and put it into an oven for high temperature treatment at 115°C for 2 hours, and then cool it to room temperature in the oven;

[0150] Step 4: Screen the composite powder after high temperature treatment, and select powder with a particle size range of 46 μm for preparing the sealing coating.

[0151] Then prepare the sealing coating, the steps are as follows:

[0152] Step 1: sandblast the surface of the metal substrate to roughen it and remove the gravel embedded in the substrate surface. The sandblasting gravel is 80 mesh brown corundum and the sandblasting pressure is 0.52MPa.

[0153] Step 2: Using MCrAlY (M is Co, Ni or a mixture of the two) powder as spray powder, plasma spraying is used to spray the bottom layer on the surface of the metal substrate treated in step 1, and the bottom layer thickness is 125 μm; the process parameters for preparing the MCrAlY bottom layer are: argon flow rate 79 L / min, hydrogen flow rate 13 L / min, nitrogen flow rate 3.5 L / min, spraying power 43 kW, spray gun moving speed 440 mm / s, spraying distance 160 mm, and powder feeding rate 12 g / min;

[0154] Step 3: Pre-oxidation treatment of the MCrAlY bottom layer, the pre-oxidation treatment parameters are: pre-oxidation temperature 1030 ° C, pre-oxidation time 9h, pre-oxidation under vacuum, vacuum degree ≤ 10 -3 Pa;

[0155] Step 4: Using sealing coating powder as spraying powder, plasma spraying is used to prepare sealing coating on the surface of MCrAlY base layer pre-oxidized in step 3, and the coating thickness is 980 μm; the process parameters for spraying sealing coating are: argon flow rate 103 L / min, hydrogen flow rate 9 L / min, spraying power 24 kW, spray gun moving speed 780 mm / s, spraying distance 290 mm, and powder feeding rate 33 g / min.

[0156] After testing, the coating has a porosity of 38.1%, a bonding strength of 14.8 MPa, a feed depth ratio of 6.58%, good abradability, a room temperature salt spray corrosion time of 90 h, and excellent corrosion resistance.

[0157] Those skilled in the art will readily appreciate other embodiments of the present disclosure after considering the specification and practicing the invention disclosed herein. The present disclosure is intended to cover any variations, uses or adaptations of the present disclosure that follow the general principles of the present disclosure and include common knowledge or customary technical means in the art that are not disclosed in the present disclosure.

[0158] It should be understood that the present disclosure is not limited to the exact structures that have been described above and shown in the drawings, and that various modifications and changes may be made without departing from the scope thereof. The scope of the present disclosure is limited only by the appended claims.

Claims

1. A method for preparing sealing coating powder, characterized in that: include: The diffusion phase powder and the lubricating phase powder are ball-milled to obtain a mixed powder; the diffusion phase powder is one or more of aluminum alloy, titanium alloy, and nickel alloy, and the lubricating phase powder is polyphenylene ester, molybdenum disulfide, hexagonal boron nitride or bentonite; The mixed powder and the structural phase powder are ball-milled to obtain a composite powder, so that an intermetallic compound layer is formed at the interface between the structural phase and the diffusion phase, and part of the structural phase is wrapped around the periphery of the mixed powder; the structural phase powder is a copper alloy; The composite powder is subjected to high temperature treatment, and the powder after high temperature treatment is sieved to select powder within a preset particle size range as sealing coating powder.

2. The method for preparing sealing coating powder according to claim 1, characterized in that: The aluminum alloy is a 6 series aluminum alloy or a 7 series aluminum alloy, the titanium alloy is Ti6Al4V or Ti5Al2.5Sn, the nickel alloy is an Inconel alloy, and the copper alloy is CuAl6, CuSn8 or CuAl7Fe2.

3. The method for preparing sealing coating powder according to claim 1, characterized in that: The mass proportion of the diffusion phase powder is 10-20%, the mass proportion of the structural phase powder is 45-65%, and the balance is the lubricating phase powder.

4. The method for preparing sealing coating powder according to claim 1, characterized in that: The particle size of the diffusion phase powder is in the range of 40 to 100 μm, the particle size of the lubricating phase powder is in the range of 5 to 10 μm, the particle size of the structural phase powder is in the range of 5 to 15 μm, and the particle size of the sealing coating powder is in the range of 30 to 75 μm.

5. The method for preparing sealing coating powder according to claim 1, characterized in that: The ball milling process parameters when the diffusion phase powder and the lubrication phase powder are ball milled to obtain a mixed powder are as follows: a ball-to-material ratio of 10:1 to 15:1, a ball milling speed of 400 to 800 rpm, and a ball milling time of 24 to 48 hours; the ball milling process parameters when the mixed powder and the structural phase powder are ball milled to obtain a composite powder are as follows: a ball-to-material ratio of 5:1 to 8:1, a ball milling speed of 150 to 300 rpm, a ball milling time of 48 to 72 hours, and the ball milling process is stopped for 10 minutes after every 20 minutes of ball milling.

6. The method for preparing sealing coating powder according to claim 1, characterized in that: The method further comprises: When the diffusion phase powder and the lubrication phase powder are ball-milled and mixed to obtain the mixed powder, a process control agent and a binder are added; the mass fraction of the process control agent is 2% to 3%, and the mass fraction of the binder is 2% to 5%.

7. The method for preparing sealing coating powder according to claim 1, characterized in that: The composite powder is subjected to high temperature treatment, comprising: The composite powder is placed in a tray and then put into an oven for high temperature treatment at a temperature of 100 to 150° C. for a heat preservation time of 1 to 5 hours, and then cooled to room temperature in the oven.

8. A method for preparing a sealing coating, characterized in that: include: The MCrAlY bottom layer is obtained by spraying MCrAlY powder as spray powder on a metal substrate, wherein M is Co, Ni or a mixture of Co and Ni; The MCrAlY bottom layer is pre-oxidized, and a sealing coating powder is sprayed as a spray powder on the pre-oxidized MCrAlY bottom layer to obtain a sealing coating; wherein the sealing coating powder is prepared by the preparation method of the sealing coating powder as described in claims 1-7 above.

9. The method for preparing the sealing coating according to claim 8, characterized in that: The thickness of the MCrAlY bottom layer is 100-200 μm, and the thickness of the sealing coating is 800-1500 μm.

10. The method for preparing the sealing coating according to claim 8, characterized in that: The spraying process parameters when spraying to obtain the MCrAlY bottom layer are: argon flow rate 70-80L / min, hydrogen flow rate 10-15L / min, nitrogen flow rate 3-5L / min, spraying power 40-45kW, spray gun moving speed 100-500mm / s, spraying distance 100-200mm, and powder feeding rate 10-15g / min; the spraying process parameters when spraying to obtain the sealing coating are: argon flow rate 90-110L / min, hydrogen flow rate 6-10L / min, spraying power 15-25kW, spray gun moving speed 400-800mm / s, spraying distance 100-300mm, and powder feeding rate 20-35g / min.

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