Aerosol deposition spraying system for online particle grading and high-density coating preparation method

Abstract

The invention discloses an aerosol deposition spraying system for particle online grading and a high-density coating preparing method.The system comprises an aerosol generating chamber, a grading device, a nozzle and a deposition chamber, the grading device is arranged between the aerosol generating chamber and the deposition chamber, and the nozzle is arranged in the deposition chamber; the aerosol generation chamber is used for mixing high-pressure carrier gas and raw material powder to form aerosol; the classifier is used for screening and intercepting powder particles and soft aggregates of which the particle sizes exceed a preset size in the aerosol output by the aerosol generation chamber; the nozzle is used for spraying powder particles in the aerosol screened by the classifier to the surface of a base material in the deposition chamber; and the deposition chamber is used for enabling the raw material powder in the aerosol to deposit a required film layer on the surface of the to-be-sprayed base material through a chemical gas phase reaction in a low-pressure environment so as to realize spraying of the to-be-sprayed base material. The method can effectively reduce the grain size in the coating and improve the density of the coating.

Description

Technical Field

[0001] This application belongs to the technical field of coating spraying, and particularly relates to an aerosol deposition spraying system with on-line particle classification and a method for preparing a highly dense coating. Background Art

[0002] In the aerosol deposition process flow, high-pressure carrier gas is mixed with submicron raw material powder in the aerosol generation chamber at room temperature to form an aerosol. The pressure difference between the aerosol generation chamber and the deposition chamber is used to drive the aerosol to accelerate through the nozzle and enter the deposition chamber. After leaving the nozzle, the powder particles in the aerosol fly towards and bombard the substrate under the action of inertia, and a coating is deposited.

[0003] The high-speed impact of dispersed powder particles on the substrate is crucial for coating formation. However, due to the small particle size of the powder particles (usually 0.2μm - 2μm), the powder particles form weak interactions due to Coulomb force (electrostatic adsorption), van der Waals force, etc., and form soft aggregates (aggregates of multiple particles). During the impact of the soft aggregates on the substrate, the powder particles directly contacting the substrate surface can be effectively deposited, while the powder particles indirectly colliding with the substrate surface cannot obtain sufficient energy and thus cannot be effectively deposited. In addition, in the raw material powder, there will inevitably be particles with larger sizes that cannot be deposited. Both the soft aggregates and the powder particles with larger sizes will affect the coating deposition effect, such as affecting the grain size and coating density in the coating.

[0004] Therefore, how to prevent large-sized powder particles and soft aggregates from entering the coating to reduce the grain size in the coating and improve the coating density is an urgent problem to be solved in this field currently. Summary of the Invention

[0005] To solve the above technical problems, this application provides an aerosol deposition spraying system with on-line particle classification and a method for preparing a highly dense coating, so as to solve the problem that large-sized powder particles and soft aggregates in the aerosol deposition process enter the coating and affect the grain size and coating density in the coating.

[0006] The first object of this application is to provide an aerosol deposition spraying system with on-line particle classification.

[0007] The above object one of this application is achieved through the following technical solutions:

[0008] An aerosol deposition spraying system with on-line particle classification includes an aerosol generation chamber, a classifier, a nozzle, and a deposition chamber. The classifier is arranged between the aerosol generation chamber and the deposition chamber, and the nozzle is arranged in the deposition chamber. Among them,

[0009] The aerosol generation chamber is used for mixing high-pressure carrier gas and the raw material powder to form an aerosol;

[0010] The classifier is used to screen and intercept powder particles and soft aggregates with particle sizes exceeding a preset size in the aerosol output from the aerosol generation chamber;

[0011] The nozzle is used to spray the powder particles in the aerosol passed through the screening of the classifier onto the surface of the substrate in the deposition chamber;

[0012] The deposition chamber is used to deposit a required thin film layer on the surface of the substrate to be sprayed by means of chemical vapor reaction of the aerosol in a low-pressure environment, so as to realize the spraying of the substrate to be sprayed.

[0013] Preferably, the aerosol deposition spraying system for online particle classification further includes a first aerosol delivery pipeline and a second aerosol delivery pipeline, wherein,

[0014] The aerosol outlet of the aerosol generation chamber is connected to the medium inlet of the classifier through the first aerosol delivery pipeline, and the medium outlet of the classifier is connected to the aerosol inlet end of the nozzle through the second aerosol delivery pipeline.

[0015] Preferably, the classifier includes at least one online particle classification unit, and each particle classification unit includes at least one particle sieve, wherein,

[0016] The particle sieve is used to screen and intercept powder particles and soft aggregates with particle sizes exceeding a preset size in the aerosol output from the aerosol generation chamber based on the action of gravity and / or sieve mesh.

[0017] Preferably, the classifier includes a plurality of online particle classification units connected in series, and the particle sieves of each online particle classification unit are different.

[0018] Preferably, the particle sieve in the same online particle classification unit adopts one of the following three structures:

[0019] Structure 1: It includes a classification tank with a containing cavity. The upper part of the classification tank is respectively provided with an inlet pipe and an outlet pipe communicating with the containing cavity on opposite sides, and the inlet pipe and the outlet pipe are at the same height;

[0020] Structure 2: It includes a classification tank with a containing cavity. The upper part of the classification tank is respectively provided with an inlet pipe and an outlet pipe communicating with the containing cavity on opposite sides, the outlet pipe is higher than the inlet pipe, and the height difference between the outlet pipe and the inlet pipe is greater than or equal to 1 time the pipe diameter of the inlet pipe;

[0021] Structure Three: It includes a grading tank with a receiving cavity. On the opposite sides of the upper part of the grading tank, an inlet pipe and an outlet pipe communicating with the receiving cavity are respectively provided. The outlet pipe is higher than the inlet pipe, and the height difference between the outlet pipe and the inlet pipe is greater than or equal to 1 time the pipe diameter of the inlet pipe. A screen is vertically arranged in the receiving cavity, and the screen divides the receiving cavity into a first cavity and a second cavity. The inlet pipe is connected to the first cavity, and the outlet pipe is connected to the second cavity.

[0022] Preferably, the classifier includes a pre - particle on - line grading unit, an intermediate particle on - line grading unit, and a post - particle on - line grading unit connected in series in sequence along the aerosol flow direction. Among them,

[0023] The particle sieve of the pre - particle on - line grading unit adopts the particle sieve of Structure One, the particle sieve of the intermediate particle on - line grading unit adopts the particle sieve of Structure Two, and the particle sieve of the post - particle on - line grading unit adopts the particle sieve of Structure Three.

[0024] Preferably, the grading tank is in the shape of a cuboid or a cylinder.

[0025] Preferably, the aerosol deposition spraying system for particle on - line grading further includes a gas cylinder, an X - Y - Z stage, a substrate fixture, and a vacuum pump group. Among them,

[0026] The gas cylinder is connected to the air inlet of the aerosol generation chamber and is used to transport high - pressure carrier gas to the aerosol generation chamber.

[0027] The substrate fixture is installed on the X - Y - Z stage and is used to clamp and fix the substrate to be sprayed.

[0028] The X - Y - Z stage is installed in the deposition chamber and is arranged opposite to the nozzle, and is used to drive the substrate to be sprayed to move so that the surface to be sprayed of the substrate to be sprayed is evenly sprayed.

[0029] The vacuum pump group is arranged outside the deposition chamber and is connected to the deposition chamber through a pipeline. The vacuum pump group is used to pump air from the deposition chamber to keep the pressure in the deposition chamber within a preset pressure range.

[0030] Preferably, the pressure in the deposition chamber is 50Pa - 2000Pa.

[0031] The second object of this application is to provide a method for preparing a highly dense coating.

[0032] The above - mentioned second application object of this application is achieved through the following technical solutions:

[0033] A method for preparing a highly dense coating of an aerosol deposition spraying system for online classification of particles based on the first purpose described above, comprising the following steps:

[0034] S1, Install the substrate to be sprayed on the X-Y-Z stage through the substrate fixture, and make the spraying surface of the substrate to be sprayed face the nozzle;

[0035] S2, Control the X-Y-Z stage to move along the Z direction to adjust the distance between the substrate to be sprayed and the nozzle to a preset spraying distance;

[0036] S3, Control the X-Y-Z stage to move to the initial working position in the X-Y plane;

[0037] S4, Add the raw material powder into the aerosol generation chamber;

[0038] S5, Control the vacuum pump group to start, and evacuate the deposition chamber through the vacuum pump group to make the pressure in the deposition chamber reach a preset pressure threshold;

[0039] S6, Open the gas cylinder to make the high-pressure carrier gas in the gas cylinder enter the aerosol generation chamber and mix with the raw material powder to form an aerosol. After the aerosol is screened by the classifier and the powder particles and soft agglomerates with a particle size exceeding the preset size are intercepted, the aerosol is sprayed onto the spraying surface of the substrate to be sprayed through the nozzle;

[0040] S7, Control the X-Y-Z stage to move uniformly along a preset movement trajectory in the X-Y plane so that the spraying surface of the substrate to be sprayed is evenly sprayed.

[0041] The above technical solution of the present application has the following advantages compared with the prior art:

[0042] In the present application, an aerosol generation chamber, a classifier, a nozzle and a deposition chamber are provided, and the classifier is arranged between the aerosol generation chamber and the deposition chamber. Before the aerosol output from the aerosol generation chamber enters the deposition chamber for spraying, the large-size powder particles and soft agglomerates in the aerosol are first screened and intercepted by the classifier. The powder particles in the aerosol passed through by the classifier are then sprayed through the nozzle into the deposition chamber onto the spraying surface of the substrate to be sprayed, thereby realizing the online classification of aerosol particles in the aerosol deposition system, avoiding the entry of large-size powder particles and soft agglomerates into the coating, effectively reducing the grain size in the coating, reducing the porosity, and improving the coating density. Description of the Drawings

[0043] To more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the accompanying drawings required for the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only some embodiments described in the present application. For those of ordinary skill in the art, without creative efforts, other accompanying drawings can be obtained based on these drawings.

[0044] Figure 1 It is a schematic structural diagram of an aerosol deposition spraying system for online classification of particles in an embodiment of the present application;

[0045] Figure 2 It is a schematic structural diagram of three kinds of particle sieves in an embodiment of the present application;

[0046] Figure 3 It is a process flow chart of a method for preparing a highly dense coating in an embodiment of the present application;

[0047] Figure 4 It is a TEM photograph (magnification: 125,000) of the cross-section of the coating prepared in Comparative Example 1 of the present application;

[0048] Figure 5 It is a TEM photograph (magnification: 125,000) of the cross-section of the coating prepared in Example 1 of the present application. Detailed implementation manners

[0049] In order to enable those skilled in the art to better understand the technical solutions in the present application, the following will clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope protected by the present application.

[0050] In the embodiments provided by the present application, it should be understood that the disclosed methods and systems can be implemented in other ways. The system embodiments described below are only illustrative. For example, the division of units and modules is only a logical function division. In actual implementation, there may be other division methods, such as: multiple units or modules can be combined, or can be integrated into another system, or some features can be ignored, or not executed. In addition, the coupling, direct coupling, or communication connection between the components shown or discussed with each other can be through some interfaces, and the indirect coupling or communication connection of devices or modules can be electrical, mechanical, or other forms.

[0051] In addition, in each embodiment of the present application, each functional unit can be entirely integrated in a processor, or each unit can be separately used as a device alone, or two or more units can be integrated in a device; each functional unit in each embodiment of the present application can be implemented in the form of hardware, or in the form of a combination of hardware and software functional units.

[0052] Those of ordinary skill in the art can understand that all or part of the steps of implementing the following method embodiments can be completed through program instructions and related hardware. The foregoing program instructions can be stored in a computer-readable storage medium. When the program instructions are executed, the steps of the following method embodiments are executed; and the foregoing storage medium includes: various media such as removable storage devices, read-only memory (ROM), magnetic disks, or optical discs that can store program codes.

[0053] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present application, the meanings of "a plurality" and "several" are two or more, unless otherwise specifically defined.

[0054] As Figure 1 shown, an embodiment of the present application provides an aerosol deposition spraying system for online particle classification. The aerosol deposition spraying system includes an aerosol generation chamber, a classifier, a nozzle, and a deposition chamber. The classifier is disposed between the aerosol generation chamber and the deposition chamber, and the nozzle is disposed in the deposition chamber. Among them,

[0055] The aerosol generation chamber is used to mix a high-pressure carrier gas and raw material powder to form an aerosol;

[0056] The classifier is used to screen and intercept powder particles and soft aggregates with particle sizes exceeding a preset size in the aerosol output from the aerosol generation chamber;

[0057] The nozzle is used to spray the powder particles in the aerosol screened by the classifier onto the surface of the substrate in the deposition chamber;

[0058] The deposition chamber is used to deposit a required thin film layer on the surface of the substrate to be sprayed by chemical vapor reaction in a low-pressure environment to realize spraying on the substrate to be sprayed.

[0059] In this embodiment, the working principle of the aerosol deposition spraying system for online particle classification is as follows:

[0060] High-pressure carrier gas and raw material powder are mixed in the aerosol generation chamber to form an aerosol. The aerosol generated in the aerosol generation chamber is output and enters the classifier. After the classifier screens and intercepts the powder particles and soft agglomerates with particle sizes exceeding the preset size in the aerosol output from the aerosol generation chamber, the aerosol enters the nozzle. The nozzle sprays the powder particles in the aerosol screened by the classifier onto the surface of the substrate in the deposition chamber. The deposition chamber deposits the required thin film layer of the raw material powder in the aerosol on the surface of the substrate to be sprayed through a chemical vapor reaction under a low-pressure environment, thereby realizing the spraying of the substrate to be sprayed.

[0061] In the aerosol deposition spraying system with on-line particle classification of this embodiment, by setting a classifier between the aerosol generation chamber and the deposition chamber, before the aerosol output from the aerosol generation chamber enters the deposition chamber for spraying, the large-size powder particles and soft agglomerates in the aerosol are first screened and intercepted by the classifier. The powder particles in the aerosol screened by the classifier are then sprayed through the nozzle onto the surface to be sprayed of the substrate to be sprayed in the deposition chamber, thereby realizing the on-line classification of aerosol particles in the aerosol deposition system, avoiding the entry of large-size powder particles and soft agglomerates into the coating, effectively reducing the grain size in the coating, reducing the porosity, and improving the coating density.

[0062] In one embodiment, the aerosol deposition spraying system with on-line particle classification further includes a first aerosol delivery pipeline and a second aerosol delivery pipeline, wherein,

[0063] The aerosol outlet of the aerosol generation chamber is connected to the medium inlet of the classifier through the first aerosol delivery pipeline, and the medium outlet of the classifier is connected to the aerosol inlet end of the nozzle through the second aerosol delivery pipeline.

[0064] In this embodiment, the aerosol generation chamber, the classifier, and the nozzle are connected through the first aerosol delivery pipeline and the second aerosol delivery pipeline, which facilitates arranging the position of the classifier as needed.

[0065] In one embodiment, the classifier includes at least one on-line particle classification unit, and each particle classification unit includes at least one particle sieve, wherein,

[0066] The particle sieve is used to screen and intercept the powder particles and soft agglomerates with particle sizes exceeding the preset size in the aerosol output from the aerosol generation chamber based on gravity and / or sieve mesh.

[0067] In this embodiment, the classifier passes through an online particle grading unit, and a particle screener is set in the online particle grading unit. The particle screener can screen and intercept powder particles and soft agglomerates with a particle size exceeding a preset size in the aerosol output from the aerosol generation chamber based on gravity and / or a screen, thereby preventing large-sized powder particles and soft agglomerates from entering the coating, thereby effectively reducing the grain size in the coating, reducing the porosity, and improving the density of the coating.

[0068] It should be noted that in order to improve the interception effect of powder particles and soft agglomerates with a particle size exceeding the preset size, and better prevent large-sized powder particles and soft agglomerates from entering the coating, the number of particle online grading units in the classifier and the number of particle screeners in each particle online grading unit can be set according to needs and interception effect.

[0069] In one embodiment, the classifier comprises a plurality of particle online classification units connected in series, and each particle online classification unit has a different particle sizer.

[0070] In this embodiment, the classifier realizes multi-stage series screening by setting up multiple online particle grading units connected in series, and the particle screeners of each online particle grading unit are different, so as to better ensure the screening and interception effect of powder particles and soft agglomerates with a particle size exceeding the preset size, and avoid large-sized powder particles and soft agglomerates from entering the coating as much as possible, thereby more effectively and reliably reducing the grain size in the coating, reducing the porosity, and improving the density of the coating.

[0071] like Figure 2 As shown in the figure (the direction of the arrow in the figure is the direction of air flow), in one embodiment, the particle screener in the same particle online classification unit adopts one of the following three structures:

[0072] Structure 1 (i.e. Figure 2 The particle sifter shown in (a) comprises a grading tank having a receiving chamber, wherein an inlet pipe and an outlet pipe communicating with the receiving chamber are respectively provided on opposite sides of the upper portion of the grading tank, and the inlet pipe and the outlet pipe are at the same height;

[0073] Structure 2 (i.e. Figure 2 The particle sifter shown in (b) comprises a grading tank having a receiving chamber, wherein an inlet pipe and an outlet pipe communicating with the receiving chamber are respectively provided on opposite sides of the upper portion of the grading tank, wherein the outlet pipe is higher than the inlet pipe, and the height difference between the outlet pipe and the inlet pipe is greater than or equal to 1 times the diameter of the inlet pipe;

[0074] Structure 3 (i.e. Figure 2The particle sieve shown in (c): It includes a classification tank with an accommodation cavity. On the opposite sides of the upper part of the classification tank, an inlet pipe and an outlet pipe communicating with the accommodation cavity are respectively provided. The outlet pipe is higher than the inlet pipe, and the height difference between the outlet pipe and the inlet pipe is greater than or equal to 1 times the pipe diameter of the inlet pipe. A sieve mesh is vertically arranged in the accommodation cavity. The sieve mesh divides the accommodation cavity into a first cavity and a second cavity. The inlet pipe is connected to the first cavity, and the outlet pipe is connected to the second cavity.

[0075] Specifically, in this embodiment, the pipe diameters of the inlet pipes and outlet pipes of the particle sieves of Structure One, Structure Two, and Structure Three are the same.

[0076] Specifically, Figure 2 For the particle sieve shown in (a), the inlet pipe and the outlet pipe are of the same height. This particle sieve realizes classification screening by relying on the different gravities of different particle sizes. The large-sized powder particles and soft agglomerate particles have greater gravity, and the acceleration effect of the large particles and soft agglomerates is weaker than that of the dispersed small particles. The large particles and soft agglomerates fall into the bottom of the classification tank during the horizontal movement process, while the dispersed fine particles enter the outlet pipe and then enter the deposition chamber through the nozzle to form a coating.

[0077] Figure 2 For the particle sieve shown in (b), the outlet pipe is higher than the inlet pipe, and the height difference between the outlet pipe and the inlet pipe is greater than or equal to 1 times the pipe diameter of the inlet pipe, thereby strengthening the gravity screening effect. The large-sized particles or soft agglomerate particles that cannot be fully suspended in the gas all fall to the bottom of the classification tank and cannot enter the outlet pipe and are intercepted.

[0078] Figure 2 For the particle sieve shown in (c), the outlet pipe is higher than the inlet pipe, and the height difference between the outlet pipe and the inlet pipe is greater than or equal to 1 times the pipe diameter of the inlet pipe; in addition, a sieve mesh is also installed in the accommodation cavity of the classification tank. The powder particles are screened by combining gravity screening and sieve mesh screening. On the one hand, the sieve mesh can block large-sized particles, and on the other hand, it can also assist in the dispersion of soft agglomerate particles, thereby realizing the utilization of soft agglomerate particles, improving the utilization rate of the raw material powder, and the sieve mesh can also more accurately and comprehensively screen and intercept the powder particles with a particle size exceeding the preset size and the powder particles in the soft agglomerate aerosol, thereby reducing the entry of large-sized powder particles and soft agglomerates into the coating to a greater extent.

[0079] In one embodiment, the classifier includes a pre-particle online classification unit, an intermediate particle online classification unit, and a post-particle online classification unit connected in series in the aerosol flow direction. Among them,

[0080] The particle sieve of the pre-particle online classification unit adopts the particle sieve of Structure 1, the particle sieve of the middle particle online classification unit adopts the particle sieve of Structure 2, and the particle sieve of the post-particle online classification unit adopts the particle sieve of Structure 3.

[0081] In this embodiment, by setting up three cascaded classification units, and in each of the three classification units, the particle sieves are different, the screening and interception effects on large-sized particles and soft agglomerates are effectively improved; in addition, the particle sieve with a screen in Structure 3 is placed at the very end of the classifier, and most large particles and soft agglomerates can be intercepted by the pre-particle online classification unit and the middle particle online classification unit, so as to minimize the adhesion of large particles and soft agglomerates to the screen, which may cause the screen to be blocked quickly and affect the normal ventilation effect, and reduce the maintenance frequency.

[0082] Through the above three cascaded classification units, large-sized powder particles and soft agglomerates can be efficiently prevented from entering the coating, thereby reducing the grain size in the coating to a greater extent, reducing the porosity, and improving the coating density.

[0083] Specifically, the outer shape of the classification tank can be rectangular or cylindrical.

[0084] In one embodiment, in order to improve the dispersion effect of the raw material powder, the pressure of the high-pressure carrier gas is maintained in the range of 0.1 MPa to 1 MPa, and in order to improve the coating deposition quality, the pressure of the deposition chamber is maintained in the range of 100 Pa to 2000 Pa.

[0085] In one embodiment, the aerosol deposition spraying system for particle online classification further includes a gas cylinder, an X-Y-Z stage, a substrate fixture, and a vacuum pump group, where

[0086] The gas cylinder is connected to the air inlet of the aerosol generation chamber and is used to supply high-pressure carrier gas to the aerosol generation chamber;

[0087] The substrate fixture is installed on the X-Y-Z stage and is used to clamp and fix the substrate to be sprayed;

[0088] The X-Y-Z stage is installed in the deposition chamber and is arranged opposite to the nozzle, and is used to drive the substrate to be sprayed to move so that the surface to be sprayed of the substrate to be sprayed is evenly sprayed;

[0089] The vacuum pump group is arranged outside the deposition chamber and is connected to the deposition chamber through a pipeline. The vacuum pump group is used to evacuate the deposition chamber to keep the pressure in the deposition chamber within a preset pressure range.

[0090] In this embodiment, the high-pressure carrier gas is released from the gas cylinder and enters the aerosol generation chamber. The gas is mixed with the raw material powder to form an aerosol, which enters the classifier. After screening by the classifier and intercepting the powder particles and soft agglomerates with particle sizes exceeding the preset size in the aerosol output from the aerosol generation chamber, the aerosol enters the deposition chamber through the nozzle. The powder particles in the aerosol impact the substrate to form a coating. The deposition chamber is connected to a vacuum pump group to maintain a vacuum state in the range of 50 - 2000 Pa, creating a pressure difference with the aerosol generation chamber (with a pressure of about 0.3 MPa). This pressure difference provides the driving force for accelerating the aerosol, enabling the gas to drive the particles to accelerate and impact the substrate to form a coating.

[0091] In one embodiment, specifically, the high-pressure carrier gas output from the gas cylinder can be air, nitrogen, helium, or hydrogen. In this embodiment, helium with low reactivity and low cost is used as the high-pressure carrier gas.

[0092] To better understand the advantages of the aerosol deposition spraying system with on-line particle classification in this application embodiment, the following shows and explains its technical effects through a comparative example and multiple embodiments:

[0093] Comparative Example 1: The aerosol generation chamber is directly connected to the nozzle through a pipeline, and no classifier is installed in the middle.

[0094] Raw material powder for spraying: Yttrium oxide spherical powder with an average single-particle size of 0.4 μm

[0095] Carrier gas: Helium

[0096] Carrier gas pressure: 300 kPa

[0097] Distance between the nozzle and the substrate: 5 mm

[0098] Substrate lateral (X - Y plane along the X or Y direction) movement speed: 1 mm / s

[0099] Pressure maintained in the deposition chamber during the experiment: 100 Pa

[0100] Material of the substrate: Alumina ceramic

[0101] Result detection: The particle size is tested by a laser particle size instrument, and the grain size and porosity of the coating are detected and analyzed through TEM photos of the coating cross-section (as Figure 4 shown). The average particle size of the powder at the nozzle, the main grain size of the prepared coating, and the coating porosity are shown in the test result comparison table.

[0102] Example 1. A classifier is installed between the aerosol generation chamber and the nozzle. The specific structure of the classifier is: a three-stage classification structure connected in series, including a pre-stage particle on-line classification unit, an intermediate particle on-line classification unit, and a post-stage particle on-line classification unit connected in series in the aerosol flow direction. Each particle on-line classification unit is provided with a particle sieve. Among them,

[0103] The particle sieve of the pre-stage particle on-line classification unit adopts the particle sieve with Structure 1 ( Figure 2 the structure shown in (a) in the figure), the particle sieve of the intermediate particle on-line classification unit adopts the particle sieve with Structure 2 ( Figure 2 the structure shown in (b) in the figure), and the particle sieve of the post-stage particle on-line classification unit adopts the particle sieve with Structure 3 ( Figure 2 the structure shown in (c) in the figure).

[0104] The sprayed raw material powder: spherical yttrium oxide powder with an average single-particle diameter of 0.4 μm

[0105] Carrier gas: helium

[0106] Carrier gas pressure: 300 kPa

[0107] The distance between the nozzle and the substrate: 5 mm

[0108] The moving speed of the substrate in the horizontal direction (along the X direction or Y direction in the X-Y plane): 1 mm / s

[0109] The pressure maintained in the deposition chamber during the experiment: 100 Pa

[0110] The material used for the substrate: alumina ceramic

[0111] Result detection: The particle size is tested by a laser particle size instrument, and the grain size and porosity of the coating are detected and analyzed through TEM photos of the coating cross-section (as Figure 5 shown). The average particle size of the powder at the nozzle, the main grain size of the prepared coating, and the coating porosity are shown in the test result comparison table.

[0112] Example 2. A classifier is installed between the aerosol generation chamber and the nozzle. The specific structure of the classifier is different from that in Example 1, and the other parameters are the same as those in Example 1. The specific structure of the classifier is: it includes one particle on-line classification unit, and this particle on-line classification unit is provided with a particle sieve adopting Structure 1.

[0113] Result detection: The particle size is tested by a laser particle size instrument, and the grain size and porosity of the coating are detected and analyzed through TEM photos of the coating cross-section. The average particle size of the powder particles at the nozzle, the main grain size of the prepared coating, and the coating porosity are shown in the test result comparison table.

[0114] Example 3: A classifier is installed between the aerosol generation chamber and the nozzle. The specific structure of the classifier is different from that of Example 1, and the remaining parameters are the same as those of Example 1. The specific structure of the classifier is as follows: It includes an on-line particle classification unit, and this on-line particle classification unit is provided with a particle sieve using Structure 2.

[0115] Result detection: The particle size is tested by a laser particle size instrument, and the grain size and porosity of the coating are detected and analyzed through TEM photos of the coating cross-section. The average particle size of the powder at the nozzle, the main grain size of the prepared coating, and the coating porosity are shown in the test result comparison table.

[0116] Example 4: A classifier is installed between the aerosol generation chamber and the nozzle. The specific structure of the classifier is different from that of Example 1, and the remaining parameters are the same as those of Example 1. The specific structure of the classifier is as follows: It includes an on-line particle classification unit, and this on-line particle classification unit is provided with a particle sieve using Structure 3.

[0117] Result detection: The particle size is tested by a laser particle size instrument, and the grain size and porosity of the coating are detected and analyzed through TEM photos of the coating cross-section. The average particle size of the powder at the nozzle, the main grain size of the prepared coating, and the coating porosity are shown in the test result comparison table.

[0118] Example 5: A classifier is installed between the aerosol generation chamber and the nozzle. The specific structure of the classifier is different from that of Example 1, and the remaining parameters are the same as those of Example 1. The specific structure of the classifier is as follows: It includes two on-line particle classification units. The previous on-line particle classification unit is provided with a particle sieve using Structure 1, and the latter on-line particle classification unit is provided with a particle sieve using Structure 2.

[0119] Result detection: The particle size is tested by a laser particle size instrument, and the grain size and porosity of the coating are detected and analyzed through TEM photos of the coating cross-section. The average particle size of the powder at the nozzle, the main grain size of the prepared coating, and the coating porosity are shown in the test result comparison table.

[0120] Example 6: A classifier is installed between the aerosol generation chamber and the nozzle. The specific structure of the classifier is different from that of Example 1, and the remaining parameters are the same as those of Example 1. The specific structure of the classifier is as follows: It includes two on-line particle classification units. The previous on-line particle classification unit is provided with a particle sieve using Structure 1, and the latter on-line particle classification unit is provided with a particle sieve using Structure 3.

[0121] Result detection: The particle size is tested by a laser particle size instrument, and the grain size and porosity of the coating are detected and analyzed through TEM photos of the coating cross-section. The average particle size of the powder at the nozzle, the main grain size of the prepared coating, and the coating porosity are shown in the test result comparison table.

[0122] Example 7: A classifier is installed between the aerosol generation chamber and the nozzle. The specific structure of the classifier is different from that of Example 1, and the remaining parameters are the same as those of Example 1. The specific structure of the classifier is as follows: It includes two on-line particle classification units. The previous on-line particle classification unit is provided with a particle sieve using Structure 2, and the latter on-line particle classification unit is provided with a particle sieve using Structure 3.

[0123] Result detection: The particle size is measured by a laser particle size instrument, and the grain size and porosity of the coating are detected and analyzed by TEM photos of the coating cross-section. The average particle size of the powder at the nozzle, the main grain size of the prepared coating, and the coating porosity are shown in the test result comparison table.

[0124] Example 8: A classifier is installed between the aerosol generation chamber and the nozzle. The specific structure of the classifier is different from that of Example 1, and the remaining parameters are the same as those of Example 1. The specific structure of the classifier is as follows: It includes two on-line particle classification units. The previous on-line particle classification unit is provided with a particle sieve using Structure 3, and the latter on-line particle classification unit is provided with a particle sieve using Structure 2.

[0125] Result detection: The particle size is measured by a laser particle size instrument, and the grain size and porosity of the coating are detected and analyzed by TEM photos of the coating cross-section. The average particle size of the powder at the nozzle, the main grain size of the prepared coating, and the coating porosity are shown in the test result comparison table.

[0126] The test results of the above Comparative Example 1 and Examples 1 to 8 are as follows in the table:

[0127] Test Result Comparison Table

[0128]

[0129] In the above Comparative Examples and Examples:

[0130] Comparative Example 1 uses an aerosol deposition spraying system without a classifier (i.e., the aerosol deposition spraying system in the prior art), and the raw material powder is mixed with a high-pressure carrier gas to form an aerosol and then directly enters the deposition chamber to spray the substrate.

[0131] Examples 1 to 8 use an aerosol deposition spraying system with a classifier (i.e., the innovative on-line particle classification aerosol deposition spraying system of the present application). After the raw material powder is mixed with a high-pressure carrier gas to form an aerosol, before entering the deposition chamber, the powder particles and soft aggregates with particle sizes exceeding the preset size in the aerosol output from the aerosol generation chamber are first sieved and intercepted by the classifier, and then the aerosol that passes through the sieving is transported to the deposition chamber to spray the substrate.

[0132] By comparing the average particle size of the powder at the nozzle and the main grain size of the prepared coating in the test results of Examples 1 to 8 and Comparative Example 1, it can be seen that when a classifier is installed in Examples 1 to 8, the average particle size of the powder at the nozzle and the main grain size of the coating are significantly reduced. The average particle size of the powder at the nozzle is close to the actual particle size of the powder particles (0.4 μm), and the main grain size of the prepared coating is significantly smaller than the actual particle size of the powder particles, indicating that the present application screens and classifies the aerosol by adding a classifier, avoiding large-sized powder particles and soft agglomerates from entering the coating, and can effectively reduce the grain size in the coating;

[0133] By comparing the coating porosity in the test results of Examples 1 to 8 and Comparative Example 1, it can be seen that when a classifier is installed in Examples 1 to 8, the coating porosity of the sprayed substrate is significantly reduced, indicating that the present application can effectively improve the coating quality of the low-pressure deposition process and enhance the density of the coating.

[0134] Furthermore,

[0135] By comparing the average particle size of the powder at the nozzle, the main grain size of the prepared coating, and the coating porosity in the test results of each example in Examples 1 to 8, it can be seen that the more the online particle classification units included in the classifier, the smaller the average particle size of the powder at the nozzle, the main grain size of the prepared coating, and the coating porosity. Among them, the test results of the three-stage classification structure adopted in Example 1 are the best.

[0136] Furthermore,

[0137] By comparing the average particle size of the powder at the nozzle, the main grain size of the prepared coating, and the coating porosity in the test results of Examples 7 and 8, it can be seen that in the classifier, placing the particle sieve of Structure III at the end has a better screening and retention effect than placing the particle sieve of Structure III at the front.

[0138] As Figure 3 shown, the embodiment of the present application also provides a method for preparing a high-density coating, which is realized based on the aerosol deposition spraying system with online particle classification in the embodiment shown in Figure 1 shown.

[0139] Specifically, the method for preparing a high-density coating may include the following steps:

[0140] S1, installing the substrate to be sprayed on the X-Y-Z stage through a substrate fixture, so that the spraying surface of the substrate to be sprayed faces the nozzle;

[0141] S2, controlling the X-Y-Z stage to move along the Z direction to adjust the distance between the substrate to be sprayed and the nozzle to a preset spraying distance;

[0142] S3. Control the X-Y-Z stage to move to the initial working position in the X-Y plane;

[0143] S4. Add the raw material powder into the aerosol generation chamber;

[0144] S5. Control the vacuum pump group to start, and evacuate the deposition chamber through the vacuum pump group so that the pressure in the deposition chamber reaches the preset pressure threshold;

[0145] S6. Open the gas cylinder to allow the high-pressure carrier gas in the gas cylinder to enter the aerosol generation chamber and mix with the raw material powder to form an aerosol. After the aerosol is sieved by the classifier and intercepts the powder particles and soft agglomerates with a particle size exceeding the preset size, it is sprayed onto the surface to be sprayed of the substrate to be sprayed through the nozzle;

[0146] S7. Control the X-Y-Z stage to move uniformly in the X-Y plane according to the preset movement trajectory, so that the surface to be sprayed of the substrate to be sprayed is evenly sprayed.

[0147] Specifically, in this embodiment, the Z direction is Figure 1 the up and down direction in

[0148] In the method for preparing the high-density coating of this embodiment, after the aerosol is formed, the powder particles and soft agglomerates with a particle size exceeding the preset size are sieved and intercepted by the classifier, and then sprayed onto the surface to be sprayed of the substrate to be sprayed through the nozzle to spray the surface to be sprayed. In this way, the on-line classification of aerosol particles in the aerosol deposition system during the spraying process is realized, avoiding the entry of large-size powder particles and soft agglomerates into the coating, thereby effectively reducing the grain size in the coating, reducing the porosity, and improving the coating density.

[0149] In this specification, each embodiment is described in a progressive manner. The key point of each embodiment is to describe the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the description of the method part.

[0150] Those skilled in the art can further realize that the units and algorithm steps of each example described in combination with the embodiments disclosed in this embodiment can be implemented by electronic hardware, computer software, or a combination of the two. To clearly illustrate the interchangeability of hardware and software, the composition and steps of each example have been generally described according to functions in the above description. Whether these functions are executed in a hardware or software manner depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of this application.

[0151] The steps of the methods or algorithms described in connection with the embodiments disclosed in this embodiment can be implemented directly in hardware, software modules executed by a processor, or a combination of both. The software modules can be placed in a random access memory (RAM), memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disk, removable disk, CD-ROM, or any other form of storage medium well known in the technical field

[0152] The foregoing description of the disclosed embodiments enables those skilled in the art to practice or use the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Thus, the present application is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein

Claims

1. An aerosol deposition spraying system for online classification of particles, characterized in that It includes an aerosol generation chamber, a classifier, a nozzle, and a deposition chamber. The classifier is disposed between the aerosol generation chamber and the deposition chamber, and the nozzle is disposed in the deposition chamber. Among them, the aerosol generation chamber is configured to mix a high-pressure carrier gas and the raw material powder to form an aerosol; the classifier is configured to screen and intercept powder particles and soft agglomerates with particle sizes exceeding a preset size in the aerosol output from the aerosol generation chamber; the nozzle is configured to spray the powder particles in the aerosol screened by the classifier onto the surface of a substrate in the deposition chamber; the deposition chamber is configured to deposit a required thin film layer on the surface of the substrate to be sprayed by the raw material powder in the aerosol through a chemical vapor reaction in a low-pressure environment so as to achieve spraying of the substrate to be sprayed.

2. The aerosol deposition spraying system for on-line classification of particles according to claim 1, characterized in that, It further includes a first aerosol delivery pipeline and a second aerosol delivery pipeline. Among them, the aerosol outlet of the aerosol generation chamber is connected to the medium inlet of the classifier through the first aerosol delivery pipeline, and the medium outlet of the classifier is connected to the aerosol inlet end of the nozzle through the second aerosol delivery pipeline.

3. The aerosol deposition spraying system for online classification of particles according to claim 2, wherein, The classifier includes at least one on-line particle classification unit, and each of the particle classification units includes at least one particle sieve. Among them, the particle sieve is configured to screen and intercept powder particles and soft agglomerates with particle sizes exceeding a preset size in the aerosol output from the aerosol generation chamber based on gravity and / or sieve mesh.

4. The aerosol deposition spraying system for online classification of particles according to claim 3, characterized in that, The classifier includes a plurality of on-line particle classification units connected in series, and the particle sieves of each of the on-line particle classification units are different.

5. The aerosol deposition spraying system for online classification of particles according to claim 3 or 4, characterized in that, The particle sieve in the same on-line particle classification unit adopts one of the following three structures: Structure 1: It includes a classification tank with a receiving cavity. Opposite sides of the upper part of the classification tank are respectively provided with an inlet pipe and an outlet pipe communicating with the receiving cavity, and the inlet pipe and the outlet pipe are at the same height; Structure 2: It includes a classification tank with a receiving cavity. Opposite sides of the upper part of the classification tank are respectively provided with an inlet pipe and an outlet pipe communicating with the receiving cavity, the outlet pipe is higher than the inlet pipe, and the height difference between the outlet pipe and the inlet pipe is greater than or equal to 1 time the pipe diameter of the inlet pipe; Structure 3: It includes a classification tank with a receiving cavity. Opposite sides of the upper part of the classification tank are respectively provided with an inlet pipe and an outlet pipe communicating with the receiving cavity, the outlet pipe is higher than the inlet pipe, and the height difference between the outlet pipe and the inlet pipe is greater than or equal to 1 time the pipe diameter of the inlet pipe; a sieve mesh is vertically arranged in the receiving cavity, the sieve mesh divides the receiving cavity into a first cavity and a second cavity, the inlet pipe is connected to the first cavity, and the outlet pipe is connected to the second cavity.

6. The aerosol deposition spraying system for online classification of particles according to claim 5, characterized in that, The classifier includes a pre-on-line particle classification unit, an intermediate on-line particle classification unit, and a post-on-line particle classification unit connected in series in the aerosol flow direction. Among them, The particle sieve of the pre-positioned particle on-line classification unit adopts the particle sieve of Structure 1, the particle sieve of the intermediate particle on-line classification unit adopts the particle sieve of Structure 2, and the particle sieve of the post-positioned particle on-line classification unit adopts the particle sieve of Structure 3.

7. The aerosol deposition spraying system for on-line classification of particles according to claim 5, characterized in that, The classification tank is rectangular parallelepiped-shaped or cylindrical.

8. The aerosol deposition spraying system for online classification of particles according to claim 1 or 2 or 3 or 4 or 6 or 7, characterized in that, It further includes a gas cylinder, an X-Y-Z stage, a substrate fixture, and a vacuum pump group, where the gas cylinder is connected to the air inlet of the aerosol generation chamber and is used to transport high-pressure carrier gas to the aerosol generation chamber; the substrate fixture is installed on the X-Y-Z stage and is used to clamp and fix the substrate to be sprayed; the X-Y-Z stage is installed in the deposition chamber and is arranged opposite to the nozzle, and is used to drive the substrate to be sprayed to move so that the surface to be sprayed of the substrate to be sprayed is evenly sprayed; the vacuum pump group is arranged outside the deposition chamber and is connected to the deposition chamber through a pipeline, and the vacuum pump group is used to evacuate the deposition chamber to keep the pressure in the deposition chamber within a preset pressure range.

9. The aerosol deposition spraying system for on-line classification of particles according to claim 8, characterized in that, The pressure in the deposition chamber is 50 Pa to 2000 Pa.

10. A method for preparing a highly dense coating of an aerosol deposition spraying system for online classification of particles according to claim 8, characterized in that, It includes the following steps: S1, install the substrate to be sprayed on the X-Y-Z stage through the substrate fixture, and make the spraying surface of the substrate to be sprayed face the nozzle; S2, control the X-Y-Z stage to move along the Z direction to adjust the distance between the substrate to be sprayed and the nozzle to a preset spraying distance; S3, control the X-Y-Z stage to move to the initial working position in the X-Y plane; S4, add raw material powder into the aerosol generation chamber; S5, control the vacuum pump group to start, and evacuate the deposition chamber through the vacuum pump group to make the pressure in the deposition chamber reach a preset pressure threshold; S6, open the gas cylinder to make the high-pressure carrier gas in the gas cylinder enter the aerosol generation chamber and mix with the raw material powder to form an aerosol. After the aerosol is sieved by the classifier and intercepts powder particles and soft agglomerates with a particle size exceeding a preset size, it is sprayed onto the surface to be sprayed of the substrate to be sprayed through the nozzle; S7, control the X-Y-Z stage to move uniformly along a preset movement track in the X-Y plane so that the surface to be sprayed of the substrate to be sprayed is evenly sprayed.

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