A method for preparing a non-uniform spray coating

Abstract

This application relates to the field of spray coating technology, and more particularly to a method for preparing a non-uniform spray coating. The method includes: igniting an electric arc between continuously fed first and second filaments located in the same plane to obtain molten filaments; wherein the first and second filaments are made of different materials; subjecting the molten filaments to a first atomization to obtain atomized filaments; the atomized filaments forming a beam that flies towards the surface of a substrate; the beam moving in the direction of the first filament within the plane containing the first and second filaments to spray coating, thereby obtaining a non-uniform spray coating. This application solves the technical problem of the difficulty in spraying coatings with high Mg content onto substrate surfaces, and can further increase the Mg content of the coating surface compared to homogeneous coatings.

Description

Technical Field

[0001] This application relates to the field of spray coating protection technology, and in particular to a method for preparing a non-uniform spray coating. Background Technology

[0002] Arc spraying is a process that uses an electric arc burning between two continuously fed metal wires to melt the metal. A high-speed gas stream atomizes the molten metal, and the atomized metal particles are accelerated and sprayed onto the substrate to form a coating. Arc spraying is characterized by low cost and high efficiency, and is widely used in industry, primarily for applications requiring resistance to high-temperature oxidation, wear, and corrosion. In contrast, traditional spraying methods, where the two metal wires have the same diameter and feed speed, result in a relatively uniform coating composition. The performance of the coating depends mainly on the composition of the metal wires, the spraying process, and the coating thickness.

[0003] Currently, Mg is added to the metal wires used for spraying to ensure the corrosion resistance of the coating, but this can easily lead to reduced drawing performance and wire breakage during drawing. Summary of the Invention

[0004] This application provides a method for preparing a non-uniform spray coating to solve the existing technical problem of difficulty in spraying coatings with high Mg content onto the surface of a substrate.

[0005] In a first aspect, this application provides a method for preparing a non-uniform sprayed coating, the method comprising:

[0006] Located in the same plane, an electric arc is ignited between continuously fed first and second wires to obtain molten wire; wherein, the first and second wires are made of different materials;

[0007] The molten filament is first atomized to obtain atomized filament;

[0008] The atomized filaments form a beam that flies toward the surface of the substrate;

[0009] The beam moves in the direction of the first filament within the plane containing the first and second filaments to perform spraying, resulting in a non-uniform spray coating.

[0010] Optionally, the first wire is fed into the first conductor tube via the first wire feeding mechanism, and the second wire is fed into the second conductor tube via the second wire feeding mechanism; wherein the first conductor tube and the second conductor tube are respectively connected to the two ends of the power supply.

[0011] Optionally, the beam has an asymmetric structure, wherein,

[0012] In the beam below the first filament, the atomized particles of the second filament are more numerous than those of the first filament;

[0013] In the beam below the second filament, the atomized particles of the first filament are more numerous than those of the second filament.

[0014] Optionally, in the component content distribution of the non-uniform sprayed coating,

[0015] The coating is applied to the side closest to the substrate, where the content of the second filament is greater than that of the first filament.

[0016] The coating is applied to the side closest to the surface, where the content of the first filament is greater than that of the second filament.

[0017] Optionally, the radius and feeding speed of the first filament satisfy the following relationship with the radius and feeding speed of the second filament:

[0018] 0.8*r2≤r1≤1.2*r2,

[0019] 0.8*v2≤v1≤1.2*v2,

[0020] 0.5*r1 2 v1≤r2 2 v2≤1.7*r1 2 v1,

[0021] In the formula, r1 represents the radius of the first filament, v1 represents the feeding speed of the first filament, r2 represents the radius of the second filament, and v2 represents the feeding speed of the second filament.

[0022] Optionally, the radius and feeding speed of the first filament satisfy the following relationship with the radius and feeding speed of the second filament:

[0023] 0.9*r2≤r1≤1.1*r2,

[0024] 0.9*v2≤v1≤1.1*v2,

[0025] 0.8*r1 2 v1≤r2 2 v2≤1.2*r1 2 v1,

[0026] In the formula, r1 represents the radius of the first filament, v1 represents the feeding speed of the first filament, r2 represents the radius of the second filament, and v2 represents the feeding speed of the second filament.

[0027] Optionally, the coating thickness is ≥10μm.

[0028] Optionally, the atomization of the molten filament to obtain atomized filament includes:

[0029] The high-speed airflow is accelerated by a nozzle method to atomize the molten filament, thereby obtaining atomized filament.

[0030] Optionally, the nozzle method is a converging nozzle method or a Laval nozzle method.

[0031] Optionally, when the nozzle is a converging nozzle, the molten wire is atomized a second time between the electric arc and the conductor.

[0032] The technical solutions provided in this application have the following advantages compared with the prior art:

[0033] The method for preparing a non-uniform sprayed coating provided in this application embodiment utilizes two metal wires with different compositions in the spraying direction. By leveraging the non-uniformity of the spray beam in the spraying direction, a coating with a higher Mg content is sprayed onto the substrate surface. The Mg content on the coating surface can be controlled to ≥1.9% by weight, thus achieving a non-uniform sprayed coating. The spraying direction points towards the first wire, and in the final coating, the composition of the first wire is biased towards the upper part of the coating, while the composition of the second wire is biased towards the lower part. This method can complete the preparation of a non-uniform coating in a single spraying operation, resulting in high production efficiency. Furthermore, by employing a control method combining heterogeneous twin wires and the spraying direction, the equipment and process costs are low. Attached Figure Description

[0034] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0035] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0036] Figure 1 A flowchart illustrating a method for preparing a non-uniform spray coating provided in this application embodiment;

[0037] Figure 2 This is a schematic diagram of a method for preparing a non-uniform spray coating provided in Embodiment 1 of this application;

[0038] Figure 3 This is a schematic diagram of a method for preparing a non-uniform spray coating provided in Embodiment 2 of this application;

[0039] Figure 4 This is a schematic diagram of a method for preparing a non-uniform spray coating provided in Embodiment 3 of this application;

[0040] Figure 5 This is a schematic diagram of a method for preparing a non-uniform sprayed coating according to an embodiment of this application; wherein, the reference numerals are:

[0041] 1-Power source, 2-First filament, 3-Second filament, 4-First filament feeding mechanism, 5-Second filament feeding mechanism, 6-First lead tube, 7-Second lead tube, 8-Nozzle, 9-Substrate, 10-Electric arc, 11-Beam, 12-Coating, 13-Cover plate. Detailed Implementation

[0042] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0043] Various embodiments of this application may exist in the form of a range; it should be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as a hard limitation on the scope of this application; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values ​​within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. Furthermore, whenever a numerical range is referred to herein, it means including any referenced number (fraction or integer) within the referred range.

[0044] In this application, unless otherwise stated, directional terms such as "upper" and "lower" specifically refer to the drawing directions in the accompanying drawings. Furthermore, in the description of this application, terms such as "comprising" and "including" mean "including but not limited to." In this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. In this document, "and / or" describes the relationship between related objects, indicating that three relationships can exist; for example, A and / or B can represent: A alone, A and B simultaneously, or B alone. A and B can be singular or plural. In this document, "at least one" means one or more, and "more than one" means two or more. "At least one," "at least one of the following," or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, "at least one of a, b, or c" or "at least one of a, b, and c" can both mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be a single or multiple.

[0045] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this application can be purchased from the market or prepared by existing methods.

[0046] To improve the corrosion resistance of metal substrates, zinc-aluminum-magnesium coated steel sheets have been developed. A hot-dip galvanizing process is used to deposit a zinc-aluminum-magnesium coating of a certain thickness onto the surface of the steel sheet. Typically, the corrosion resistance of zinc-aluminum-magnesium coated steel sheets is more than three times that of traditional pure zinc coated steel sheets. However, during hot working processes (such as welding), the zinc-aluminum-magnesium coating around the weld seam can be damaged. Spraying the weld area is the primary means of effective protection, but the corrosion resistance of traditional sprayed pure zinc coatings or sprayed aluminum-zinc coatings is lower than that of the original zinc-aluminum-magnesium coating.

[0047] The main reason is that the addition of Mg can inhibit the rise of the pH in the corrosive environment, thereby preventing the protective corrosion product Zn5(OH)8Cl2·H2O from transforming into the non-protective corrosion product ZnO under high pH conditions. This forms a stable and dense corrosion product layer, inhibiting further corrosion and improving corrosion resistance. However, adding Mg to metal wires used for spraying reduces drawing performance and causes wire breakage during drawing, making it difficult to prepare zinc-aluminum-magnesium metal wires for spraying.

[0048] Furthermore, the corrosion resistance of zinc-aluminum-magnesium (ZAM) spray coatings is closely related to the Mg content on the coating surface. In the embodiments of this application, the Mg content on the coating surface can be controlled at ≥1.9% by weight. The positive effects of controlling it within this range are that Mg can inhibit the increase of pH value in the corrosive environment and generate protective corrosion products containing Zn5(OH)8Cl2·H2O. Generally, the higher the Mg content, the better the corrosion resistance.

[0049] In this embodiment, a non-uniform coating is obtained by acquiring a composition different from that at the coating / substrate interface on the coating surface. The beneficial effects of the non-uniform coating are: in a spraying system composed of two heterogeneous filaments, with the filament containing Mg as the first filament, a higher Mg content can be obtained on the surface of the sprayed coating. In contact with the external environment, the sprayed coating with a higher Mg content on the surface can achieve better corrosion resistance. This also takes into account spraying efficiency and cost.

[0050] Firstly, this application provides a method for preparing a non-uniform sprayed coating; please refer to [link to relevant documentation]. Figure 1 The method includes:

[0051] S1. Located in the same plane, an electric arc is ignited between the continuously fed first and second wires to obtain molten wire; wherein the first and second wires are made of different materials;

[0052] In this embodiment of the application, an electric arc 10 is ignited between a first wire 2 and a second wire 3 that are continuously fed in the same plane.

[0053] The first wire 2 is composed of an AlMg alloy, with Al accounting for 96% and Mg accounting for 4% by mass percentage; the second wire 3 is composed of Zn.

[0054] In some embodiments, the first filament is fed into the first conductor tube via a first filament feeding mechanism, and the second filament is fed into the second conductor tube via a second filament feeding mechanism; wherein the first conductor tube and the second conductor tube are respectively connected to the two ends of the power supply.

[0055] In this embodiment of the application, the first wire 2 is fed into the first conductor tube 6 via the first wire feeding mechanism 4, and the second wire 3 is fed into the second conductor tube 7 via the second wire feeding mechanism 5; wherein the first conductor tube 6 and the second conductor tube 7 are respectively connected to the two ends of the power supply 1.

[0056] Both the first conduit 6 and the second conduit 7 are made of conductive materials, specifically a copper alloy in this embodiment. The voltage across the power supply 1 is transmitted between the first wire 2 and the second wire 3 using the above method. In this embodiment, the first wire feeding mechanism 4 and the second wire feeding mechanism 5 are each composed of paired rollers. Driven by a servo motor, the rollers rotate to feed the first wire 2 and the second wire 3. In this embodiment, the feeding speeds of the first wire 2 and the second wire 3 can be adjusted independently.

[0057] S2. The molten filament is first atomized to obtain atomized filament;

[0058] In some embodiments, the atomization of the molten filament to obtain atomized filament includes:

[0059] The high-speed airflow is accelerated by a nozzle method to atomize the molten filament, thereby obtaining atomized filament.

[0060] In some embodiments, the nozzle method is a converging nozzle method or a Laval nozzle method.

[0061] In this embodiment, the high-speed airflow is compressed air, which is further accelerated by a nozzle method. The positive effects are: more complete atomization results in smaller particle diameters, higher flight speeds, and a denser coating formed upon impact. Furthermore, for suppressing dual-wire spraying, the smaller diameter particles formed after complete atomization are more easily mixed.

[0062] In some embodiments, when the nozzle is a converging nozzle, the molten filament is atomized a second time between the electric arc and the conductor.

[0063] In this embodiment, when the nozzle is a converging nozzle, a cover plate 13 is provided between the electric arc and the wire tube. The cover plate 13 has a secondary airflow to perform a second atomization on the molten wire, thereby improving the atomization effect.

[0064] S3. The atomized filament forms a beam that flies toward the surface of the substrate;

[0065] S4. The beam moves in the direction of the first filament within the plane containing the first and second filaments to perform spraying, resulting in a non-uniform spray coating. A schematic diagram of this coating can be found in [reference needed]. Figure 5 .

[0066] In some embodiments, the beam has an asymmetric structure, wherein,

[0067] In the beam below the first filament, the atomized particles of the second filament are more numerous than those of the first filament;

[0068] In the beam below the second filament, the atomized particles of the first filament are more numerous than those of the second filament.

[0069] In this embodiment, the beam 11 has an asymmetric structure. In the beam 11 below the first filament 2, there are more atomized particles of the second filament 3 than atomized particles of the first filament 2. In the beam 11 below the second filament 3, there are more atomized particles of the first filament 2 than atomized particles of the second filament 3.

[0070] In some embodiments, in the component content distribution of the non-uniform spray coating, the component content of the second filament is greater than that of the first filament on the side of the coating closer to the substrate; and the component content of the first filament is greater than that of the second filament on the side of the coating closer to the surface.

[0071] In this embodiment, the coating 12 near the substrate 9 has a higher content of second filament 3 than first filament 2; the coating 12 near the surface has a higher content of first filament 2 than second filament 3.

[0072] like Figure 2 As shown, in this embodiment of the application, the centerline ( Figure 2 (As shown by the dashed line) The beam 11 is divided into region I below the first filament 2 and region II below the second filament 3. The study found that the atomized droplets from the second filament 3 are more numerous in region I than in region II; the atomized droplets from the first filament 2 are more numerous in region II than in region I. That is, the atomized AlMg alloy droplets are more numerous in region II than in region I, and the atomized Zn droplets are more numerous in region I than in region II.

[0073] During the spraying process, the beam 11 is controlled to move at a speed V, and the direction of movement is as follows: Figure 2 As indicated by the arrow representing the medium velocity V, the beam 11 moves in the direction of the first filament 2, while the first filament 2 and the second filament 3 are in a plane, performing spraying and ultimately forming a coating 12 on the substrate. At the same location on the substrate 9, region I of the beam 11 always passes through first, and is subsequently covered by region II. The final coating is as follows... Figure 5 As shown in the figure, the position where the coating thickness is half is indicated by a dashed line. The coating 12 above the dashed line is region ①, and the coating 12 below the dashed line is region ②. Analysis shows that the content of Mg and Al elements is higher in region ① than in region ②, while the content of Zn is higher in region ② than in region ①.

[0074] In some embodiments, the radius and feeding speed of the first filament are related to the radius and feeding speed of the second filament as follows:

[0075] 0.8*r2≤r1≤1.2*r2,

[0076] 0.8*v2≤v1≤1.2*v2,

[0077] 0.5*r1 2 v1≤r2 2 v2≤1.7*r1 2 v1,

[0078] In the formula, r1 represents the radius of the first filament, v1 represents the feeding speed of the first filament, r2 represents the radius of the second filament, and v2 represents the feeding speed of the second filament.

[0079] When the diameters of the first wire 2 and the second wire 3 are different, the instability of the electric arc 10 can be avoided by adjusting the speeds of the first wire feeding mechanism 4 and the second wire feeding mechanism 5. In this case, the wire diameter and the wire feeding speed should satisfy the above-mentioned relationship.

[0080] In some embodiments, the radius and feeding speed of the first filament are related to the radius and feeding speed of the second filament as follows:

[0081] 0.9*r2≤r1≤1.1*r2,

[0082] 0.9*v2≤v1≤1.1*v2,

[0083] 0.8*r1 2 v1≤r2 2 v2≤1.2*r1 2 v1,

[0084] In the formula, r1 represents the radius of the first filament, v1 represents the feeding speed of the first filament, r2 represents the radius of the second filament, and v2 represents the feeding speed of the second filament.

[0085] The above are preferred relationships between the radius of the first filament and the feeding speed of the first filament, and the radius of the second filament and the feeding speed of the first filament.

[0086] When the difference in melting point between the first wire 2 and the second wire 3 causes the electric arc 10 to be unstable or frequently interrupted, the feeding speed of the first wire 2 and the second wire 3 can be appropriately adjusted to optimize the situation.

[0087] In some embodiments, the coating thickness is ≥10 μm.

[0088] The positive effects of controlling the coating thickness to ≥10μm are twofold: firstly, thicker coatings exhibit better corrosion resistance; secondly, for coatings thinner than 10μm, microscopic inhomogeneities cause fluctuations in the thickness gradient. Specifically, the coating thickness can be 10μm, 11μm, 12μm, etc.

[0089] The present application is further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the application. Experimental methods in the following embodiments that do not specify specific conditions are generally determined according to national standards. If there is no corresponding national standard, then general international standards, conventional conditions, or conditions recommended by the manufacturer are followed.

[0090] Example steps:

[0091] S1. Located in the same plane, an electric arc is ignited between the continuously fed first and second wires to obtain molten wire; wherein the first and second wires are made of different materials;

[0092] S2. The molten filament is first atomized to obtain atomized filament;

[0093] S3. The atomized filament forms a beam that flies toward the surface of the substrate;

[0094] S4. The beam moves in the direction of the first filament within the plane containing the first filament and the second filament to perform spraying, thereby obtaining a non-uniform spray coating.

[0095] Example 1

[0096] The radius of the first filament is r1 = 1 mm, and the radius of the second filament is r2 = 1 mm. The spraying process is as follows: voltage 30V, current 120A, high-speed airflow is compressed air, pressure 0.6MPa, filament feed speed v1 = v2, and the electric arc is stable. The beam moves in the plane containing the first and second filaments, towards the direction of the first filament.

[0097] like Figure 2 As shown, nozzle 8 is a converging nozzle, meaning that the outlet diameter of nozzle 8 is smaller than the inlet diameter of nozzle 8. At this time, the high-speed airflow passes through the converging nozzle 8, is accelerated, and then atomizes the electric arc 10.

[0098] At this point, the thickness of the sprayed coating 12 is 30 μm. The Mg content in region ① of coating 12 is 2.2%, and the Mg content in region ② of coating 12 is 1.7%. In addition to Zn, Al, and Mg, O was also detected in the coating elements. The O element was mainly introduced by the oxidation of the atomized droplets during the spraying process.

[0099] Example 2

[0100] The radius of the first filament is r1 = 1 mm, and the radius of the second filament is r2 = 1 mm. The spraying process is as follows: voltage 30V, current 120A, high-speed airflow is compressed air, pressure 0.6MPa, filament feed speed v1 = v2, and the electric arc is stable. The beam moves in the plane containing the first and second filaments, towards the direction of the first filament.

[0101] like Figure 3 As shown, nozzle 8 is a converging nozzle, meaning the outlet diameter of nozzle 8 is smaller than the inlet diameter of nozzle 8. Unlike embodiment 1, a cover plate 13 is added. On one hand, the high-speed airflow passes through the converging nozzle 8, is accelerated, and then atomizes the electric arc 10; on the other hand, the high-speed airflow passes through the gap between the cover plate 13 and the conduit, further atomizing the electric arc 10 and atomizing the droplets.

[0102] At this point, the thickness of the sprayed coating 12 is 30 μm. The Mg content in region ① of coating 12 is 1.9%, and the Mg content in region ② of coating 12 is 1.6%.

[0103] Example 3

[0104] The radius of the first filament is r1 = 1 mm, and the radius of the second filament is r2 = 1 mm. The spraying process is as follows: voltage 30V, current 120A, high-speed airflow is compressed air, pressure 0.6MPa, filament feed speed v1 = v2, and the electric arc is stable. The beam moves in the plane containing the first and second filaments, towards the direction of the first filament.

[0105] like Figure 4 As shown: Nozzle 8 is a Laval nozzle, meaning that the orifice of nozzle 8 first contracts and then expands to increase the speed of the high-speed airflow. At this time, the high-speed airflow passes through the Laval nozzle 8, is accelerated, and then performs a second atomization on the electric arc 10.

[0106] At this point, the thickness of the sprayed coating 12 is 30 μm. The Mg content in region ① of coating 12 is 1.9%, and the Mg content in region ② of coating 12 is 1.7%.

[0107] In the above three embodiments, adding Mg to the coating 12 can improve the corrosion resistance of the coating 12.

[0108] Comparative Example 1:

[0109] The radius of the first wire is r1 = 1 mm, and the radius of the second wire is r2 = 1 mm. The spraying process is as follows: voltage 30V, current 120A, high-speed airflow is compressed air, pressure 0.6MPa, wire feeding speed v1 = v2, and the electric arc is stable. The plane containing the first and second wires is perpendicular to the direction of motion.

[0110] Nozzle 8 is a Laval nozzle, meaning that the orifice of nozzle 8 first contracts and then expands to increase the speed of the high-speed airflow. At this time, the high-speed airflow passes through the Laval nozzle 8, is accelerated, and then performs a second atomization on the electric arc 10.

[0111] At this point, the thickness of the sprayed coating 12 is 30 μm. The Mg content in region ① of coating 12 is 1.8%, and the Mg content in region ② of coating 12 is also 1.8%. The coating content is basically uniform along the thickness direction.

[0112] The disadvantage of Comparative Example 1 is that, although the comparative example also adopted the heterogeneous dual-wire spraying method of this application, the beam movement direction did not follow the requirement of this invention that "the beam moves in the plane where the first wire and the second wire are located, in the direction of the first wire". Therefore, the Mg content in the thickness direction of the resulting coating 12 is relatively uniform, and it is not possible to obtain a higher Mg content than the coating average on the surface layer in contact with the atmospheric environment (the Mg content on the coating surface is 1.8%, which is equal to the average Mg content of coating 12). Therefore, it is impossible to further improve the corrosion resistance of coating 12. In Embodiments 1, 2, and 3 of this application, since the beam movement direction satisfies "the beam moves in the direction of the first filament within the plane containing the first and second filaments", a non-uniform coating 12 is obtained. Furthermore, the surface layer in contact with the atmospheric environment has a higher Mg content than the average coating (the Mg content on the coating surface in Embodiment 1 is 2.1%, higher than the average Mg content of 1.95% in coating 12; the Mg content on the coating surface in Embodiment 2 is 1.9%, higher than the average Mg content of 1.75% in coating 12; and the Mg content on the coating surface in Embodiment 3 is 1.9%, higher than the average Mg content of 1.8% in coating 12), which further enhances the corrosion resistance of coating 12.

[0113] If the wire containing Zn-Al-Mg elements is directly prepared, it will break during the drawing process to the specified diameter, making it difficult to achieve direct preparation through drawing.

[0114] The method in this embodiment of the application achieves the preparation of Zn-Al-Mg coating 12 by using zinc metal wire and AlMg alloy metal wire respectively. Even so, it is difficult to increase the Mg element in AlMg alloy wire, and Mg element is also subject to some burn-off during subsequent spraying. This method utilizes the non-uniformity of the spray beam in the travel direction to achieve a non-uniform sprayed coating. With the travel direction pointing towards AlMg alloy wire, the upper region of the final coating 12 contains a higher Mg element, which offsets the Mg element burn-off during spraying, resulting in a coating 12 with a relatively high Mg element on the surface.

[0115] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this 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 this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A method for preparing a non-uniform sprayed coating, characterized in that, The method includes: Located in the same plane, an electric arc is ignited between the continuously fed first and second wires to obtain molten wire; wherein the first and second wires are made of different materials and the first wire is an aluminum-magnesium alloy; The molten filament is first atomized to obtain atomized filament; The atomized filaments form a beam that flies toward the surface of the substrate; The beam moves in the direction of the first filament within the plane containing the first and second filaments to perform spraying, resulting in a non-uniform spray coating. The beam has an asymmetric structure, wherein, In the beam below the first filament, the atomized particles of the second filament are more numerous than those of the first filament; In the beam below the second filament, the atomized particles of the first filament are more numerous than those of the second filament.

2. The method according to claim 1, characterized in that, The first wire is fed into the first conductor tube via the first wire feeding mechanism, and the second wire is fed into the second conductor tube via the second wire feeding mechanism; wherein the first conductor tube and the second conductor tube are respectively connected to the two ends of the power supply.

3. The method according to claim 1, characterized in that, In the component content distribution of the non-uniform sprayed coating, The coating is applied to the side closest to the substrate, where the content of the second filament is greater than that of the first filament. The coating is applied to the side closest to the surface, where the content of the first filament is greater than that of the second filament.

4. The method according to claim 1, characterized in that, The radius and feeding speed of the first filament satisfy the following relationship with the radius and feeding speed of the second filament: 0.8*r2≤r1≤1.2*r2， 0.8*v2≤v1≤1.2*v2, 0.5*r1 2 v1≤r2 2 v2≤1.7*r1 2 v1, In the formula, r1 represents the radius of the first filament, v1 represents the feeding speed of the first filament, r2 represents the radius of the second filament, and v2 represents the feeding speed of the second filament.

5. The method according to claim 1 or 4, characterized in that, The radius and feeding speed of the first filament satisfy the following relationship with the radius and feeding speed of the second filament: 0.9*r2≤r1≤1.1*r2， 0.9*v2≤v1≤1.1*v2, 0.8*r1 2 v1≤r2 2 v2≤1.2*r1 2 v1, In the formula, r1 represents the radius of the first filament, v1 represents the feeding speed of the first filament, r2 represents the radius of the second filament, and v2 represents the feeding speed of the second filament.

6. The method according to claim 1, characterized in that, The coating thickness is ≥10μm.

7. The method according to claim 2, characterized in that, The first atomization includes: The high-speed airflow is accelerated by a nozzle method to atomize the molten filament, thereby obtaining atomized filament.

8. The method according to claim 7, characterized in that, The nozzle method is either the contraction nozzle method or the Laval nozzle method.

9. The method according to claim 8, characterized in that, When the nozzle method is a shrink-type nozzle method, a cover plate is set between the electric arc and the first and second conductor tubes, and a secondary airflow is provided in the cover plate to perform a second atomization on the molten wire.

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