Anti-corrosion protective coating for silicon steel laminated rotor / stator and preparation method of anti-corrosion protective coating

Abstract

The invention discloses an anti-corrosion protective coating for a silicon steel laminated rotor / stator and a preparation method of the anti-corrosion protective coating. The anti-corrosion protective coating comprises a silicon steel lamination substrate, and micro convex-concave composite structures are distributed on the surface of the silicon steel lamination substrate; the arithmetic mean roughness value of the micro convex-concave composite structure is 0.5-1.0 [mu] m; the density of the micro convex-concave composite structures per unit area is not less than 50 / mm; the micro convex-concave composite structure comprises micro convex bodies and / or concave pits, and the equivalent diameter of each micro convex body and / or concave pit is not greater than 50 microns; the distance from the top of the single micro-convex body to the bottom of the pit is not more than 20 microns; and an oxide coating is arranged on the surface of the micro convex-concave composite structure. An anti-corrosion insulating ceramic coating is prepared on the surface of a silicon steel laminated substrate, and the silicon steel laminated substrate is coarsened before spraying. Good binding force between the sprayed coating and the silicon steel lamination substrate is ensured, conduction between the silicon steel laminations is avoided, and the electromagnetic performance is prevented from being reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of silicon steel laminations, and particularly to an anti-corrosion protective coating for silicon steel lamination rotors / stators and a preparation method thereof. Background Art

[0002] Due to characteristics such as high magnetic permeability, low coercivity, low iron loss, and high resistance, silicon steel lamination substrates are widely used in manufacturing components of electrical equipment such as motors, generators, and transformers. After the production of silicon steel lamination substrates, it is crucial to perform insulation and anti-corrosion treatment on them. Most of the existing patents on rotors / stators made of silicon steel laminations focus on improvements in the design of the silicon steel lamination substrate itself. For example, multiple fan-shaped grooves are provided in the annular region of the silicon steel lamination substrate to reduce weight, reduce material consumption, and improve energy conversion efficiency. However, there is relatively little introduction to the surface protective coating of the silicon steel lamination substrate, and there are some problems with the existing coatings. For example, the high magnetic permeability silicon coating has poor anti-corrosion performance due to its thin coating, and the large difference in thermal expansion coefficient between silicon and silicon steel makes it easy to peel off in the high and low temperature alternating environment of steam turbine stators and rotors; although the Ni-P amorphous alloy anti-corrosion layer is theoretically feasible, it is not insulated in practical applications; the 150 - 200 μm epoxy powder layer is also prone to aging and peeling off in a high-temperature steam environment.

[0003] The prior art selects aluminum dihydrogen phosphate-based insulating coating materials and uses a spin coating process to prepare the protective coating, but this coating also has the problem of easy peeling off in a high-temperature steam environment. Generally speaking, the current research on the anti-corrosion of silicon steel lamination substrates mainly focuses on improvements in structural design, and there is no report on the method of achieving anti-corrosion by preparing a ceramic insulating protective coating. Summary of the Invention

[0004] In view of the problems that the silicon steel lamination substrate is prone to corrosion, and the traditional anti-corrosion coatings have poor bonding strength, are easily damaged, and have insufficient protective performance, the present application optimizes the roughening method of the silicon steel lamination substrate before spraying to form a specific micro-convex and concave composite structure, significantly enhancing the bonding strength between the coating and the substrate, while avoiding conduction between silicon steel laminations and ensuring stable electromagnetic performance; and by optimizing the spraying process, an oxide ceramic coating with excellent bonding strength and long-term corrosion resistance is prepared, effectively preventing damage to the silicon steel laminations and the insulating glue bonding layer, avoiding deformation and deterioration of electromagnetic performance, and providing a reliable solution for the efficient anti-corrosion and stable operation of the silicon steel lamination substrate. The technical solutions provided by the present application are as follows: On the one hand, the present application provides an anti-corrosion protective coating for a silicon steel lamination rotor / stator, including a silicon steel lamination substrate, the silicon steel lamination substrate includes silicon steel laminations and an insulating glue bonding layer, the silicon steel laminations are arranged separately, and adjacent silicon steel laminations are connected by the insulating glue bonding layer; The surface of the silicon steel laminated substrate has a uniformly distributed micro-convex and concave composite structure; among them, the arithmetic mean roughness (Ra) value of the micro-convex and concave composite structure is 0.5 - 1.0 μm; the density of the micro-convex and concave composite structure per unit area is not less than 50 pieces / mm²; the micro-convex and concave composite structure includes micro-convex bodies and / or pits, where the equivalent diameter of a single micro-convex body and / or pit is not greater than 50 μm; and the distance from the top of a single micro-convex body to the bottom of the pit is not greater than 20 μm; An oxide coating is provided on the surface of the micro-convex and concave composite structure.

[0005] In some specific embodiments, the density of the micro-convex and concave composite structure per unit area is 300 - 800 pieces / mm², and the equivalent diameter of a single micro-convex body and / or pit is not greater than 20 μm.

[0006] In some specific embodiments, the oxide coating is selected from one or more of alumina ceramics, chromium oxide ceramics, zirconia ceramics, magnesia ceramics, titanium oxide ceramics, beryllium oxide ceramics, yttrium oxide ceramics.

[0007] In some specific embodiments, the oxide coating is selected from tough oxide ceramics, including alumina ceramics toughened with different contents of titanium oxide and / or chromium oxide ceramics toughened with different contents of titanium oxide; The alumina ceramics toughened with titanium oxide are selected from Al 2 O 3 -13%TiO 2 、Al 2 O 3 -20%TiO 2 、Al 2 O 3 -25%TiO 2 、Al 2 O 3 -40%TiO 2 or one or more of them; The chromium oxide ceramics toughened with titanium oxide are selected from Cr 2 O 3 -13%TiO 2 、Cr 2 O 3 -20%TiO 2 、Cr 2 O 3 -25%TiO 2 、Cr 2 O 3 -40%TiO 2 or one or more of them.

[0008] In some specific embodiments, the thickness of the oxide coating is 30 - 150 μm.

[0009] On the other hand, the present application also provides a method for preparing an anti-corrosion protection coating for a silicon steel laminated rotor / stator. To prepare the anti-corrosion protection coating for the silicon steel laminated rotor / stator as described above, the method includes the following steps: S1: Pretreatment: Rust removal, degreasing, and sandblasting roughening treatment are carried out on the silicon steel laminated substrate to make the surface of the silicon steel laminated substrate have a micro-convex and concave composite structure with uniform distribution; S2: Spraying: The pretreated silicon steel laminated substrate is sprayed using a plasma spray gun to obtain an oxide coating; S3: Sealing treatment: The sprayed silicon steel laminated substrate is subjected to sealing treatment; Among them, during the sandblasting roughening treatment process, the sandblasting pressure is 0.02 - 0.15 MPa; the distance between the sandblasting nozzle and the surface of the silicon steel laminated substrate is 8 - 10 cm, and the relationship between the average diameter D of the sand grains used for sandblasting and the average thickness L of the insulating glue bonding layer is D = 0.1L ∼ 0.4L μm.

[0010] In some specific embodiments, in S2, the spraying process parameters are: the spraying distance is 90 - 120 mm; the horizontal movement speed of the plasma spray gun is 700 - 900 mm / s.

[0011] In some specific embodiments, in S1, during the sandblasting roughening treatment process, the spraying angle is 80° - 100°; In S2, the spraying process parameters are: the spray gun power is 40 - 50 kW; the current is 550 - 650 A; the working gas flow rate of Ar is 35 - 45 slpm, and H 2 is 6 - 12 slpm; the powder feeding rate is 20 - 40 g / min.

[0012] In S3, a sealing agent is used for sealing treatment, and the curing time is not less than 24 h.

[0013] In some specific embodiments, the sandblasting roughening treatment includes: The sand grains are sieved through a sand tray to obtain pretreated sand grains; The pretreated sand grains after sieving are subjected to drying treatment, the temperature of the drying treatment is 80 - 120 °C, and the drying time is not less than 2 h.

[0014] In some specific embodiments, an intermittent spraying method is adopted during the spraying process; The intermittent spraying method is: after the first pass of spraying is completed, cool for 20 - 60 s. When the surface temperature of the silicon steel laminated substrate drops below 50 °C, then carry out the second pass of spraying; And the thickness of the sprayed oxide coating is 30 - 150 μm.

[0015] Adopting the above technical solution, an anti-corrosion protection coating and preparation method for silicon steel laminations rotor / stator provided by this application have the following beneficial effects: 1. This application solves two key problems of the coating on the surface of the silicon steel lamination substrate: First, the problem that traditional organic coatings are prone to aging in a long-term high-temperature and high-humidity environment. By using a high-performance oxide ceramic coating (without any organic components), the corrosion resistance, high-temperature resistance, and long-term stability of the coating are significantly improved. Second, the problem that traditional thermal spraying ceramic coatings are difficult to deposit due to the smooth surface of silicon steel, and the conventional roughening process will greatly affect the inductance. By optimizing the roughening method on the surface of the silicon steel lamination substrate, while ensuring the Ra value is within the range of 0.5 - 1 μm, a uniformly distributed high-density micro-convex and concave composite structure is formed (the microstructure density per unit area ≥ 50 pieces / mm², and the single particle size ≤ 50 μm), providing an ideal adhesion basis for the coating and avoiding the adverse effects of traditional sandblasting roughening means on the electromagnetic properties of the silicon steel lamination substrate.

[0016] 2. The preparation method of this application can be formed in one step, with simple operation, fast production, and is easy to carry out large-scale production. Description of the Drawings

[0017] In order to more clearly illustrate the technical solutions in the embodiments of this application, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of this application. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0018] Figure 1 It is a three-dimensional surface morphology diagram of the silicon steel lamination substrate after sandblasting provided by the embodiment of this application; Figure 2 It is a two-dimensional contour curve diagram of the silicon steel lamination substrate after sandblasting provided by the embodiment of this application; Figure 3 It is a cross-sectional micrograph of the silicon steel lamination substrate after depositing the coating (unsealed) provided by the embodiment of this application; Figure 4 It is a photo of the stator with a sprayed ceramic protective coating before construction provided by the embodiment of this application; Figure 5 It is a photo of the stator with a sprayed ceramic protective coating after construction provided by the embodiment of this application; Figure 6 It is a photo of the stator with a sprayed ceramic protective coating after 720h (150 °C high-temperature steam) installation assessment provided by the embodiment of this application; Figure 7Photograph of the rotor with a sprayed ceramic protective coating before construction provided by the embodiments of the present application; Figure 8 Photograph of the rotor with a sprayed ceramic protective coating after 3000h of installation assessment provided by the embodiments of the present application; Figure 9 Photograph of the stator with a conventional organic coating / aluminum dihydrogen phosphate-based insulating coating silicon steel lamination matrix after 120h (150°C high-temperature water vapor) of installation assessment provided by the embodiments of the present application; Figure 10 Provided by the embodiments of the present application Figure 9 Partial enlarged view. Detailed implementation manners

[0019] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings 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 shall fall within the protection scope of the present application.

[0020] For the terms defined below, unless a different definition is given elsewhere in the claims or in this specification, these definitions shall apply. All numerical values, whether or not explicitly indicated, are hereby defined as being modified by the term "about". The term "about" generally refers to a numerical range that a person of ordinary skill in the art would consider equivalent to the stated value to produce substantially the same properties, functions, results, etc. A numerical range indicated by a low value and a high value is defined as including all the numerical values included in the numerical range and all the sub-ranges included in the numerical range.

[0021] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned accompanying drawings are used to distinguish similar objects and do not necessarily need to be used to describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion.

[0022] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0023] An anti-corrosion protection coating for a silicon steel laminated rotor / stator provided by an embodiment of the present application includes a silicon steel laminated substrate. The silicon steel laminated substrate includes silicon steel laminations and an insulating adhesive bonding layer. The silicon steel laminations are arranged separately, and adjacent silicon steel laminations are connected through the insulating adhesive bonding layer. Specifically, physical isolation and electrical insulation are achieved between the silicon steel laminations through the insulating adhesive bonding layer, effectively preventing the decline in electromagnetic performance caused by the conduction between the silicon steel laminations. At the same time, the insulating adhesive bonding layer not only plays a role in connecting and fixing the silicon steel laminations, but also can maintain stable insulation performance in harsh environments such as high temperature and high humidity, ensuring the long-term stability of the mechanical strength and electromagnetic performance of the overall structure of the silicon steel laminated substrate. In addition, a high-density micro-convex and concave composite structure is formed on the surface of the silicon steel laminated substrate by optimizing the roughening process, further enhancing the bonding force between the coating and the substrate, providing an ideal basis for subsequent spraying of a long-lasting anti-corrosion and insulating ceramic coating. At the same time, through the high-density micro-convex and concave composite structure with a special structure and the average distribution of the composite structure, the insulation performance between the silicon steel laminations is significantly improved, thus realizing the reliable application of the silicon steel laminated substrate in high-performance electrical equipment.

[0024] The surface of the silicon steel laminated substrate has a uniformly distributed micro-convex and concave composite structure. Among them, the arithmetic mean roughness (Ra) value of the micro-convex and concave composite structure is 0.5 - 1.0 μm; the density of the micro-convex and concave composite structure per unit area is not less than 50 pieces / mm²; the micro-convex and concave composite structure includes micro-protrusions and / or pits. Among them, the equivalent diameter of a single micro-protrusion and / or pit is not greater than 50 μm; and the distance from the top of a single micro-protrusion to the bottom of the pit is not greater than 20 μm. By controlling the micro-convex and concave composite structure per unit area (≥50 pieces / mm²) and the size of a single body (≤50 μm), the present application forms a uniformly distributed high-density micro-convex and concave composite structure while ensuring that the Ra value is within the range of 0.5 - 1 μm. Compared with the traditional process, although a similar roughness grade is obtained through existing detection, due to unreasonable selection of factors such as grit diameter and roughening process, the distribution of protrusions or pits on the roughened surface is uneven, and the diameter of the protrusions or pits is too large, etc., which easily damages the insulating adhesive bonding layer between the silicon steel laminations and makes the silicon steel laminations prone to deformation and other problems, seriously affecting the insulation performance between the silicon steel laminations. The dense micro-convex and concave composite structure system of the present application not only significantly improves the insulation performance between the silicon steel laminations, but also maintains excellent bonding strength.

[0025] Please refer to Figure 1 , according to Figure 1The three-dimensional scanning electron microscope image of the surface microstate of the silicon steel laminated core substrate after sandblasting shown in [reference], in which the strip-shaped dark areas in the figure are the insulating glue bonding layer areas. It can be seen that the pits are evenly distributed, the number of pits per unit area is moderate, the morphology presents irregular circles or ellipses, the distribution density and size are relatively consistent, reflecting the uniformity of the sandblasting treatment. According to the scales marked in the figure (such as 1377.053μm, 1652.464μm, etc.) and the height data (the highest point is 12.318μm, the lowest point is -8.092μm), the height difference range of a single pit is roughly between 5 - 20μm, and most of the pits (for example, more than 50% of the pits) have a height difference concentrated in the range of 5 - 15μm. Overall, the sandblasting treatment forms a uniform microstructure on the surface, the pits are evenly distributed and the number is moderate, the height difference range is reasonable, further verifying the stability and consistency of the sandblasting process in surface treatment. The relatively small height difference of the pits and the relatively uniform distribution of protrusions or pits greatly reduce the possibility of damaging the insulating glue bonding layer between the silicon steel laminations, thus greatly avoiding affecting the insulation performance between the silicon steel laminations. The characteristics of uniform distribution and moderate height difference are also conducive to achieving the bonding strength between the coating and the silicon steel laminated core substrate.

[0026] Please refer to Figure 2 , according to Figure 2 In the two-dimensional contour curve graph of the surface of the silicon steel laminated core substrate after sandblasting shown in [reference], it can be seen that obvious micro-concave and convex structures are formed on the surface of the silicon steel laminated core substrate after sandblasting. The curve fluctuates greatly, the depth change range is about -4μm to 6μm, and the undulation height difference is 10μm, indicating that the surface roughness is moderate and evenly distributed. In the length range of 0 to 1400μm, the curve fluctuation trend is consistent, reflecting the uniformity of the sandblasting treatment. The relatively high surface roughness provides more anchoring points for the subsequent coating, which helps to enhance the bonding strength between the coating and the substrate. Therefore, the surface microstructure of the silicon steel laminated core substrate after sandblasting is uniform and the roughness is moderate, meeting the technical requirements of the sandblasting process, and can effectively improve the adhesion and performance stability of the subsequent coating.

[0027] The surface of the micro-convexity and concavity composite structure is provided with an oxide coating. Specifically, the oxide coating is formed on the basis of the micro-convexity and concavity composite structure, which can significantly improve the insulation performance and corrosion resistance of the silicon steel lamination substrate. The oxide coating is prepared by atmospheric plasma spraying technology, and its main component is a high-performance oxide ceramic material, which has excellent insulation, corrosion resistance and high-temperature resistance. By optimizing the spraying process, the oxide coating can uniformly cover the surface of the silicon steel lamination substrate, forming a dense and continuous protective layer, effectively isolating the erosion of the external environment on the silicon steel lamination substrate and extending its service life. At the same time, the high bonding strength between the oxide coating and the silicon steel lamination substrate ensures the stability of the coating in harsh environments such as high temperature and high humidity, avoiding the problems of easy peeling and aging of traditional coatings. In addition, the setting of the oxide coating does not damage the silicon steel lamination and the insulating glue bonding layer, avoiding problems such as deformation and decline in electromagnetic performance. It not only improves the anti-corrosion and insulation performance of the silicon steel lamination substrate, but also maintains its original electromagnetic characteristics, providing a reliable guarantee for the stable operation of high-performance electrical equipment such as motors, generators and transformers.

[0028] In some specific embodiments, the density of the micro-convexity and concavity composite structure per unit area is 300 - 800 pieces / mm², and the equivalent diameter of a single micro-protrusion and / or pit is not greater than 20 μm. Specifically, the density of the micro-convexity and concavity composite structure per unit area is controlled at 300 - 800 pieces / mm², and the equivalent diameter of a single micro-protrusion and / or pit is not greater than 20 μm. Through the high-density and small-size micro-convexity and concavity structure, the uniformity and functionality of the surface of the silicon steel lamination substrate are significantly improved. The high-density micro-convexity and concavity structure not only provides a larger contact area and stronger mechanical bonding force for the subsequent attachment of the oxide coating, but also ensures the close fit between the coating and the substrate, effectively preventing the coating from peeling off. At the same time, the small-size design of a single micro-protrusion and / or pit (equivalent diameter ≤ 20 μm) further optimizes the surface roughness, avoiding the problem of conduction between laminations caused by large-size protrusions in traditional processes, thereby maintaining the stability of the electromagnetic performance of the silicon steel lamination substrate. The refined design of the micro-convexity and concavity composite structure provides a reliable basis for the application of the silicon steel lamination substrate in high-performance electrical equipment, while taking into account the comprehensive improvement of insulation performance, corrosion resistance and mechanical strength.

[0029] In some specific embodiments, the oxide coating is selected from one or more of alumina ceramics, chromium oxide ceramics, zirconia ceramics, magnesia ceramics, titanium oxide ceramics, beryllium oxide ceramics, and yttrium oxide ceramics. Specifically, ceramic materials mainly composed of metal oxides have excellent insulation, corrosion resistance, and high-temperature resistance, and can meet the stringent requirements of silicon steel lamination substrates in high-performance electrical equipment. Among them, alumina ceramics are known for their high hardness and good insulation performance, and are suitable for scenarios with high mechanical strength requirements; chromium oxide ceramics have excellent corrosion resistance and wear resistance, and are suitable for applications in harsh environments; zirconia ceramics are characterized by their high toughness and heat resistance, and are suitable for high-temperature environments; magnesia ceramics and titanium oxide ceramics are characterized by their high insulation and dielectric properties, respectively, and can effectively reduce eddy current losses; beryllium oxide ceramics and yttrium oxide ceramics perform well in high-temperature and high-frequency applications due to their high thermal conductivity and stability. By selecting one or more oxide ceramic materials for compounding, the performance of the coating can be optimized according to specific application requirements, ensuring that the comprehensive performance of the silicon steel lamination substrate in terms of insulation, corrosion prevention, and high-temperature resistance reaches the best state, providing a reliable guarantee for the stable operation of electrical equipment such as motors, generators, and transformers.

[0030] In some specific embodiments, the oxide coating is selected from oxide ceramics with toughness, including alumina ceramics toughened with titanium oxide in different contents and / or chromium oxide ceramics toughened with titanium oxide in different contents. Specifically, in view of the risk of coating cracking caused by the alternating high and low temperatures during the spraying process and the working environment of the silicon steel lamination substrate, it is particularly emphasized that the coating material needs to have a certain toughness. Due to the large differences in the thermal expansion coefficients of the insulating glue bonding layer, silicon steel laminations, and ceramic layer, stress concentration is likely to occur during temperature changes, resulting in coating cracking. Therefore, high-toughness coating materials can effectively absorb and disperse these stresses, reduce the cracking risk, and ensure the long-term stability of the coating. By using alumina / chromium oxide ceramics toughened with titanium oxide in different contents, the toughness of the coating is significantly improved through the toughening effect of titanium oxide, effectively reducing the coating cracking risk caused by differences in thermal expansion coefficients, and ensuring the stability of the coating during the spraying process and the working environment. At the same time, in traditional spraying processes, metal-based bonding layers are usually used to alleviate differences in thermal expansion coefficients. However, for silicon steel lamination substrate products, since conductive metal bonding layers are not allowed, by preferably selecting oxide ceramic materials with high toughness and high thermal conductivity, this problem is directly solved, avoiding the risks of coating cracking and damage to the insulating glue bonding layer, while maintaining the stability of the electromagnetic and insulating properties of the silicon steel lamination substrate.

[0031] The alumina ceramics toughened with titanium oxide are selected from Al 2 O 3 -13%TiO 2 、Al 2 O 3 -20%TiO2 、 Al 2 O 3 -25% TiO 2 、 Al 2 O 3 -40% TiO 2 One or more of the following. Specifically, the titanium oxide toughened alumina ceramic is a composite material composed of alumina (Al 2 O 3 ) and titanium oxide (TiO 2 ) mixed in a certain proportion. Among them, Al 2 O 3 -13% TiO 2 means that the mass fraction of alumina is 87% and the mass fraction of titanium oxide is 13%; Al 2 O 3 -20% TiO 2 means that the mass fraction of alumina is 80% and the mass fraction of titanium oxide is 20%; Al 2 O 3 -25% TiO 2 means that the mass fraction of alumina is 75% and the mass fraction of titanium oxide is 25%; Al 2 O 3 -40% TiO 2 means that the mass fraction of alumina is 60% and the mass fraction of titanium oxide is 40%. Preferably, the titanium oxide toughened alumina coating with high thermal conductivity is used. The high thermal conductivity helps to quickly conduct heat, improve the heat dissipation performance, and thus better protect the insulating glue bonding layer, avoiding excessive heat accumulation affecting the insulating glue bonding layer and reducing the electrical insulation performance. While ensuring the high toughness and heat resistance of the coating, the heat dissipation requirement is also taken into account, providing a reliable guarantee for the long-term stable operation of the silicon steel lamination substrate in high-performance electrical equipment.

[0032] The titanium oxide toughened chromium oxide ceramic is selected from Cr 2 O 3 -13% TiO 2 、 Cr 2 O 3 -20% TiO 2 、 Cr 2 O 3 -25% TiO 2 、 Cr 2 O 3 -40% TiO 2 One or more of the following. Specifically, the titanium oxide toughened chromium oxide ceramic is a composite material composed of chromium sesquioxide (Cr 2 O 3 ) and titanium oxide (TiO 2 ) mixed in a certain proportion. Among them, Cr2 O 3 -13% TiO 2 indicates that the mass fraction of chromium sesquioxide is 87% and the mass fraction of titanium oxide is 13%; Cr 2 O 3 -20% TiO 2 indicates that the mass fraction of chromium sesquioxide is 80% and the mass fraction of titanium oxide is 20%; Cr 2 O 3 -25% TiO 2 indicates that the mass fraction of chromium sesquioxide is 75% and the mass fraction of titanium oxide is 25%; Cr 2 O 3 -40% TiO 2 indicates that the mass fraction of chromium sesquioxide is 60% and the mass fraction of titanium oxide is 40%. Specifically, Cr 2 O 3 -13% TiO 2 and Cr 2 O 3 -20% TiO 2 are applicable to scenarios with relatively high requirements for wear resistance and corrosion resistance, while Cr 2 O 3 -25% TiO 2 、Cr 2 O 3 -40% TiO 2 are more prominent in terms of high toughness and corrosion resistance and are suitable for applications in extreme environments. By selecting different contents of titanium oxide to toughen chromium oxide ceramics, the performance of the coating can be optimized according to specific requirements to ensure that the comprehensive performance of the silicon steel lamination substrate in terms of insulation, anti-corrosion, high temperature resistance, etc. reaches the best state, providing a reliable guarantee for the stable operation of electrical equipment such as motors, generators, and transformers. At the same time, the high thermal conductivity of these materials also helps to improve the heat dissipation performance, further protecting the insulating adhesive layer and avoiding performance degradation caused by heat accumulation.

[0033] In some specific embodiments, the thickness of the oxide coating is 30 - 150 μm. Specifically, a thinner coating thickness can effectively reduce the thermal resistance, promote the rapid export of heat from the surface of the silicon steel lamination substrate, thereby improving the overall heat dissipation performance. To prevent during operation, if the heat cannot be dissipated in time, it may lead to heat accumulation, causing the insulating glue bonding layer to be overly affected by heat, thereby reducing its electrical insulation performance and even triggering equipment failures. In addition, a thinner coating thickness also helps to reduce stress concentration within the coating, lowering the risk of coating cracking caused by differences in the coefficient of thermal expansion, further enhancing the durability and stability of the coating. At the same time, the design of the thin coating ensures that the electromagnetic properties of the silicon steel lamination substrate are not affected, maintaining its efficient operation in electrical equipment such as motors, generators, and transformers. Meanwhile, if the coating thickness is too thin, the anti-corrosion performance will be insufficient. Therefore, controlling the coating thickness within 30 - 150 μm not only optimizes the heat dissipation performance, protects the insulating glue bonding layer, but also takes into account the mechanical strength and electromagnetic properties of the coating, providing a reliable guarantee for the long-term stable operation of the silicon steel lamination substrate in high-performance electrical equipment.

[0034] The embodiments of the present application also provide a preparation method for an anti-corrosion protection coating for a silicon steel lamination rotor / stator. To prepare the anti-corrosion protection coating for a silicon steel lamination rotor / stator as described above, the following steps are included: S1: Pretreatment: Rust removal, degreasing, and sandblasting roughening treatment are performed on the silicon steel lamination substrate to make the surface of the silicon steel lamination substrate have a uniformly distributed micro-convex and concave composite structure; S2: Spraying: The pretreated silicon steel lamination substrate is sprayed using a plasma spray gun to obtain an oxide coating; S3: Sealing treatment: The sprayed silicon steel lamination substrate is subjected to sealing treatment; Among them, during the sandblasting roughening treatment process, the sandblasting pressure is 0.02 - 0.15 MPa; the distance between the sandblasting nozzle and the surface of the silicon steel lamination substrate is 8 - 10 cm, and the relationship between the average diameter D of the sand grains used for sandblasting and the average thickness L of the insulating glue bonding layer is D = 0.1L ∼ 0.4L μm.

[0035] Specifically, during the pre-treatment process of step S1, first, through rust removal treatment, the rust and oxide layer on the surface of the silicon steel lamination substrate are removed to prevent impurities from affecting the adhesion of the coating. Usually, mechanical or chemical methods are adopted, such as abrasive cloth polishing, pickling, etc., to remove the surface rust and oxide layer and ensure the cleanliness of the substrate surface. Secondly, degreasing treatment is carried out. The silicon steel lamination substrate may be contaminated with grease or other organic pollutants during production, transportation or storage, and these pollutants will reduce the bonding force between the coating and the substrate. Usually, organic solvents (such as acetone, alcohol) are used for cleaning or alkaline degreasing agents are used for soaking to remove the surface grease and dirt and ensure the cleanliness and pollution-free of the substrate surface. Finally, sandblasting roughening treatment is an important step to improve the coating bonding force. In addition, during the sandblasting roughening treatment of the silicon steel lamination substrate, the sandblasting pressure is controlled within 0.02 - 0.15 MPa. For example, the sandblasting pressure can be 0.02 MPa, 0.04 MPa, 0.08 MPa, 0.10 MPa, 0.12 MPa or 0.15 MPa. The lower pressure range helps to avoid having a greater impact on the insulating glue bonding layer between the silicon steel laminations and reduces the conduction risk between adjacent silicon steel lamination substrates, thereby protecting the insulation performance. At the same time, small particle grit is cooperated with small pressure, and the required surface roughness is obtained through multiple small impacts. At the same time, during sandblasting, the distance between the sandblasting nozzle and the surface of the silicon steel lamination substrate is maintained at 8 - 10 cm. For example, the sandblasting distance can be 8 cm, 9 cm or 10 cm. The selection of this distance is based on the balance of speed decay and impact force: if the distance is too large, the speed decay of the grit is too large and the surface cannot be effectively roughened; if the distance is too small, the impact force is too large and the insulation layer may be damaged, affecting the electrical insulation performance. In addition, by controlling the grit diameter within the range of 10% - 40% of the thickness of the insulating glue bonding layer. For example, when the average thickness of the insulating glue bonding layer is 244 μm, the average grit diameter can be preferably 49 μm, 61 μm or 75 μm, etc., to ensure that the grit will not penetrate or damage the insulating glue bonding layer between the silicon steel laminations during the roughening process, thus avoiding the conduction risk of adjacent silicon steel laminations due to the damage of the insulating glue bonding layer and ensuring the stability of the insulation performance. If the grit diameter is too small (<0.1L), the surface of the silicon steel lamination substrate cannot be effectively roughened and it is difficult to form an ideal micro-convex and concave composite structure; while if the grit diameter is too large (>0.4L), due to the excessive impact force of the grit, the risk of deformation, lapping or conduction of the silicon steel lamination substrate may be significantly increased. By optimizing the grit size, both the roughening effect is ensured and the substrate damage caused by excessive roughening is avoided. Appropriate-sized grit forms a uniform high-density micro-convex and concave composite structure on the surface of the silicon steel lamination substrate, providing an ideal adhesion basis for subsequent spraying of high-performance oxide ceramic coatings and significantly improving the bonding strength between the coating and the substrate.

[0036] During the spraying process in step S2, an atmospheric plasma spraying device is used, and its core component is a plasma spray gun. The plasma spray gun ionizes the working gas (such as argon, nitrogen, or hydrogen) through an electric arc to form a high-temperature plasma, heats the spraying material (such as ceramic powders like alumina and chromium oxide) to a molten or semi-molten state, and sprays it onto the surface of the silicon steel lamination substrate at a high speed. This forms a firm mechanical bond between the coating and the surface of the silicon steel lamination substrate, ensuring the stability of the coating in harsh environments such as high temperature and high humidity.

[0037] During the sealing hole treatment process in step S3, it specifically includes the preparation of equipment and solvents, the inspection of the workpiece appearance and the determination of the sealing hole area, the surface purification treatment, the vacuum sealing hole operation, and subsequent drying and size trimming, achieving the efficient preparation and performance optimization of the oxide ceramic coating on the silicon steel lamination substrate. Among them, for equipment preparation, it is necessary to ensure that equipment such as ultrasonic cleaning machines is in good condition, and solvents, equipment, and measuring tools are prepared. The appearance inspection requires no defects such as scratches, and the sealing hole area and size are determined. For surface purification, the workpiece is cleaned with gasoline and ethanol to remove contaminants and then dried. During sealing, the workpiece and raw materials are placed in a vacuum chamber and evacuated until there are no bubbles, and the process is recorded to adjust the process. After the process is completed, the power is turned off, and the workpiece is carefully taken out and the appearance is inspected. Subsequent treatment includes drying in a humid environment at 80°C for 120 minutes, and then grinding with sandpaper until the size before and after sealing is the same. The bonding strength of the laminated silicon steel oxide ceramic coating sample prepared by this process reaches more than 20 MPa, and it has excellent high-temperature alternating performance and long-term anti-corrosion performance.

[0038] In some specific embodiments, in S2, the spraying process parameters are: the spraying distance is 90 - 120 mm; the horizontal movement speed of the plasma spray gun is 700 - 900 mm / s.

[0039] Specifically, in the plasma spraying process, the spraying distance is preferably maintained between 90 - 120 mm, and the plasma spray gun moves uniformly along the horizontal direction at a speed of 700 - 900 mm / s. By optimizing the spraying distance and movement speed, the temperature of the spraying material on the workpiece surface can be accurately controlled, thereby achieving reasonable regulation of the surface thermal effect. It can not only avoid damage to the insulating glue bonding layer caused by excessive temperature and prevent its high-temperature overflow, ensure the uniform deposition and integrity of the ceramic coating, but also effectively improve the anti-corrosion performance of the coating. In addition, appropriate temperature control can reduce the risk of high-temperature carbonization of the insulating glue bonding layer, avoid the influence on the electrical insulation performance due to internal conduction between adjacent silicon steel laminations, and ensure the overall process quality and product reliability.

[0040] Please refer to Figure 3, According to the analysis of the cross-sectional microscopic photographs of the silicon steel lamination substrate after depositing the coating, the layered structure of the coating, the insulating adhesive layer, and the silicon steel lamination substrate is clearly visible, and the boundaries between the layers are distinct. The coating is located on the top layer, evenly covering the surface of the insulating adhesive layer, effectively protecting the integrity of the insulating adhesive layer; there are no damages or peeling phenomena in the insulating adhesive layer, indicating good bonding between it and the coating and the substrate, ensuring the stability of the insulation performance; the structure of the silicon steel lamination substrate is complete, and there is no overlap between adjacent laminations, avoiding the risk of short circuits. Overall, the protective effects of the coating and the insulating adhesive layer are significant, and the insulation performance and mechanical stability of the silicon steel lamination substrate are effectively guaranteed.

[0041] In addition, by testing the inductance measurement values of the silicon steel lamination substrate in the original state, after roughening, and after spraying at different frequencies, as shown in Table 1, it can be seen that the changes in the inductance values at each stage are small, indicating that the sandblasting roughening and spraying treatments have limited effects on the inductance performance of the silicon steel lamination substrate. Specifically, at a frequency of 400 Hz, the inductance value in the original state is 296.5, 296.4 after roughening, and 296.8 after spraying; at a frequency of 5000 Hz, it is 139.6 in the original state, 139.5 after roughening, and 140.6 after spraying; at a frequency of 10000 Hz, it is 73.6 in the original state, 73.6 after roughening, and 74.1 after spraying. The data show that the inductance value after spraying increases slightly, but the overall change range is not large, indicating that the spraying process maintains high stability for the electromagnetic performance of the silicon steel lamination substrate. It further verifies that while the spraying treatment improves the anti-corrosion protection performance, it can effectively maintain the electromagnetic performance of the silicon steel lamination substrate and is suitable for high-demand application scenarios.

[0042] Table 1: Inductance measurement values at each stage

[0043] In some specific embodiments, in S1, during the sandblasting roughening treatment of the silicon steel lamination substrate, the spraying angle is 80° - 100°.

[0044] In S2, the spraying process parameters are: the spray gun power is 40 - 50 kW; the current is 550 - 650 A; the working gas flow rate of Ar is 35 - 45 splm, and that of H 2 is 6 - 12 slpm; the powder feeding rate is 20 - 40 g / min.

[0045] In S3, a sealing agent is used for sealing treatment, and the curing time is not less than 24 h.

[0046] Specifically, in the spraying process, the spraying angle is preferably controlled between 80° and 100°. This angle range can effectively reduce the impact force on the silicon steel lamination substrate during the sandblasting process, thereby reducing the risk of deformation of the silicon steel due to external forces. Since the silicon steel lamination substrate itself is prone to deformation, if adjacent silicon steel laminations are electrically connected due to deformation overlap, it will seriously affect its electrical insulation performance. By adopting an appropriate spraying angle, the deformation of the silicon steel lamination substrate caused by sandblasting can be maximally avoided, reducing the possibility of electrical connection due to deformation overlap between adjacent silicon steel laminations, thereby ensuring the stable and reliable electrical insulation performance of the silicon steel and improving the overall process quality and product performance.

[0047] The spray gun power is preferably maintained within the range of 40 - 50 kW, and the current is set at 550 - 650 A to provide a stable energy output. In terms of the working gas flow rate, the flow rate of argon (Ar) needs to be controlled at 35 - 45 slpm, and the flow rate of hydrogen (H 2 2) is 6 - 12 slpm to ensure the stable formation of plasma and efficient energy transfer. In addition, the powder feeding rate is preferably adjusted between 20 - 40 g / min to ensure the uniform delivery of the spraying material and the precise control of the coating thickness. By optimizing these process parameters, the spraying efficiency and coating performance can be effectively improved to meet the functional requirements of the silicon steel lamination substrate in terms of corrosion protection, electrical insulation, etc.

[0048] In the sealing treatment, using a sealant to seal the surface of the coating is a key step to ensure the denseness and corrosion protection performance of the coating. The curing time of the sealant should be no less than 24 h, preferably 24 h, to ensure that the sealant fully penetrates and cures in the coating pores, effectively improving the sealing and durability of the coating. By strictly controlling the curing time, the performance of the sealant can be maximally exerted, enhancing the anti-permeation ability and overall protection effect of the coating, thereby meeting the requirements of high-quality spraying processes.

[0049] In some specific embodiments, the sandblasting roughening treatment includes: Sieving the gravel through a sand tray to obtain pretreated gravel; Drying the pretreated gravel after sieving. The drying temperature is 80 - 120 °C, and the drying time is not less than 2 h.

[0050] Specifically, in the sandblasting process, zirconia alumina sand with a particle size larger than 120# is first preferred and sieved through a sand tray with a certain mesh number to remove large particles and prevent them from having an adverse impact on the electromagnetic properties of the silicon steel lamination substrate. Then, the gravel is dried at 80 - 120 °C for at least 2 h to inhibit the agglomeration phenomenon. Since commercially available zirconia alumina sand often contains agglomerated particles and large particles and has a relatively small mesh number, it is easy to damage the insulating glue bonding layer during roughening, increasing the risk of electrical connection and affecting the insulation performance. Through the above optimization, the negative impact of sandblasting on the insulation performance can be significantly reduced, ensuring the stability of the product.

[0051] In some specific embodiments, an intermittent spraying method is adopted during the spraying process; The intermittent spraying method is as follows: after the first pass of spraying is completed, cool for 20 - 60 s. When the surface temperature of the silicon steel lamination substrate drops below 50 °C, then perform the second pass of spraying; And the thickness of the sprayed oxide coating is 30 - 150 μm.

[0052] Specifically, an intermittent spraying method is adopted during the spraying process, that is, after the first pass of spraying is completed, cool for 20 - 60 seconds. When the temperature of the silicon steel lamination substrate rotor drops to ≤50 °C, then perform the second pass of spraying. This can effectively prevent the influence of the heat accumulation effect generated by continuous spraying on the insulating glue bonding layer, avoid the high-temperature overflow of the insulating glue bonding layer due to excessive temperature, and then prevent the non-deposition of the local ceramic coating, ensuring the integrity of the coating and the anti-corrosion effect. In addition, the too high temperature generated by continuous spraying may also increase the risk of high-temperature carbonization of the insulating glue bonding layer, causing internal conduction between adjacent silicon steel laminations and affecting the electrical insulation performance. Through the intermittent spraying method, the temperature during the spraying process can be effectively controlled, reducing the damage to the insulating glue bonding layer and the coating, and ensuring the stable performance of the silicon steel lamination substrate.

[0053] In addition, the coating thickness is preferably controlled within the range of 30 - 150 μm. This thickness not only facilitates the rapid dissipation of heat during the spraying process but also can effectively protect the insulating glue bonding layer during the operation of the workpiece, avoiding excessive heating of the insulating glue bonding layer due to heat accumulation, thereby affecting its electrical insulation performance. By optimizing the coating thickness, the heat dissipation efficiency can be significantly improved, reducing the negative impact of the heat effect on the insulating glue bonding layer, and ensuring the insulation performance of the silicon steel lamination substrate and the stability of the overall operation.

[0054] The following details the examples of the present application. They are exemplary and are only used to explain the present application and should not be construed as a limitation to the present application.

[0055] Example 1 A method for preparing an anti-corrosion protection coating for a silicon steel lamination rotor / stator, the steps are as follows: First, perform rust removal and degreasing treatment on the silicon steel lamination substrate, and then perform sandblasting roughening treatment. When performing the sandblasting roughening treatment, select zirconium corundum sand larger than 120#, put it through a sieve in a sand tray of a certain mesh number, and then dry the sieved gravel at 100 °C for 2 h. Use the treated gravel to perform sandblasting on the silicon steel lamination substrate. The sandblasting pressure is controlled at 0.10 MPa, the distance between the nozzle and the surface of the silicon steel lamination substrate is maintained at 9 cm, the average diameter of the gravel used for sandblasting is 61 μm (the average thickness of the insulating glue bonding layer is 244), and the spraying angle is 80°. Then, adopt intermittent spraying of Al 2 O 3 -20%TiO 2: After the first spraying, cool for 40 s. When the surface temperature of the silicon steel lamination substrate drops to 50 °C, perform the second spraying to make the thickness of the oxide coating reach 100 μm. The spraying process parameters are as follows: the spray gun power is 45 kW, and the current is 600 A; the working gas flow rate of Ar is 40 splm, and H 2 is 8 slpm, and the powder feeding rate is 30 g / min; the spraying distance is 100 mm, and the horizontal movement speed of the plasma spray gun is 800 mm / s. Finally, use a sealing agent to perform a sealing treatment on the sprayed silicon steel lamination substrate, and cure it after 24 h to complete the preparation of the anti-corrosion protective coating for the entire silicon steel lamination substrate.

[0056] Example 2 Refer to the preparation method of the anti-corrosion protective coating in Example 1. The difference is that the sand grains are not sieved and dried.

[0057] Example 3 Refer to the preparation method of the anti-corrosion protective coating in Example 1. The difference is that during the sandblasting roughening treatment, the spraying angle is a value less than 80° - 100°, for example, 70°.

[0058] Example 4 Refer to the preparation method of the anti-corrosion protective coating in Example 1. The difference is that during the sandblasting roughening treatment, the spraying angle is a value greater than 80° - 100°, for example, 110°.

[0059] Example 5 Refer to the preparation method of the anti-corrosion protective coating in Example 1. The difference is that in S2, the spraying process parameters are as follows: the spraying distance is 80 mm; the horizontal movement speed of the plasma spray gun is 950 mm / s.

[0060] Example 6 Refer to the preparation method of the anti-corrosion protective coating in Example 1. The difference is that it is completed by one-time spraying without cooling.

[0061] Example 7 Refer to the preparation method of the anti-corrosion protective coating in Example 1. The difference is that the thickness of the oxide coating is 160 μm.

[0062] Comparative Example 1 Refer to the preparation method of the anti-corrosion protective coating in Example 1. The difference is that an organic coating / aluminum dihydrogen phosphate-based insulating coating is used to spray the stator of the silicon steel lamination substrate.

[0063] Comparative Example 2 Refer to the preparation method of the anti-corrosion protective coating in Example 1. The difference is that the average diameter of the sand grains used for sandblasting is 130 μm (the average thickness of the insulating glue bonding layer is 244 μm), and other parameters remain unchanged.

[0064] Comparative Example 3 Refer to the preparation method of the anti-corrosion protection coating in Example 1, except that the sandblasting pressure is 0.20 MPa and other parameters remain unchanged.

[0065] Comparative Example 4 Refer to the preparation method of the anti-corrosion protection coating in Example 1, except that the distance between the nozzle and the surface of the silicon steel lamination substrate is 12 cm and other parameters remain unchanged.

[0066] Test Example For the anti-corrosion protection coatings of the silicon steel laminations prepared in Examples 1-7 and Comparative Examples 1-4, measure the insulation performance, anti-corrosion performance, bonding strength, high-temperature resistance, chemical corrosion resistance and mechanical properties (hardness and wear resistance) of the coatings. Among them, the insulation performance is characterized by inductance (refer to GB / T3655), the anti-corrosion performance is evaluated by the corrosion area ratio test in a high-temperature and high-humidity oven (150 °C, saturated water vapor, 500 h), the bonding strength is determined by a tensile test (refer to ASTM C633), the high and low temperature alternating performance is evaluated by observing the surface condition of the coating in a high and low temperature alternating test (refer to GB / T2423, 150 °C to room temperature, 100 cycles), the hardness in mechanical properties is determined by microhardness test (refer to GB / T4340.1), and the wear resistance is evaluated by a friction and wear test (refer to GB / T12444). The characterization results of the insulation performance are shown in Table 2, the characterization results of the anti-corrosion performance are shown in Table 3, the characterization results of the bonding strength are shown in Table 4, the characterization results of the high and low temperature resistance are shown in Table 5, and the characterization results of the mechanical properties (hardness and wear resistance) are shown in Table 6. In addition, through the comparative experiment between Example 1 and Comparative Example 1, it can be clearly seen that the ceramic protective coating exhibits excellent protective performance. In Example 1 ( Figures 4 to 8 ), there are no signs of corrosion on the surfaces of the stator and rotor after the ceramic coating is applied. Even after 720 h of severe assessment in a 150 °C saturated steam environment, the silicon steel lamination substrate remains intact (the bakelite has failed and deformed), and the coating still remains stable after the rotor has been running for 3000 h. While in Comparative Example 1 ( Figure 9 、 Figure 10 ), it shows that the stator with a conventional organic / aluminum dihydrogen phosphate coating shows coating peeling and substrate corrosion after only 120 h in 150 °C high-temperature water vapor, and there are corrosion defects before construction.

[0067] Table 2: Inductance test results at 400 Hz

[0068] Table 3: Anti-corrosion performance test results

[0069] Table 4: Bonding strength test results

[0070] Table 5: Test Results of High and Low Temperature Resistance

[0071] Table 6: Test Results of Mechanical Properties

[0072] Comprehensive experimental data show that the ceramic protective coating exhibits excellent comprehensive performance in the application of silicon steel lamination substrates. In terms of electromagnetic performance, Examples 1 and 7 perform best, with inductance changes of +0.1 and 0 respectively, hardly affecting the original characteristics of the silicon steel lamination substrate; in the anti-corrosion performance test, the corrosion areas of Examples 1-6 are all lower than 0.8%, significantly superior to the traditional coating (85% for Comparative Example 1); in terms of bonding strength, Examples 1-4 maintain a high strength of 23-26 MPa; the high and low temperature resistance test shows that Examples 1-2 have no cracks at all; in terms of mechanical properties, the hardness of the ceramic coating reaches 800-860 HV, and the wear depth is only 10-15 μm. It is worth noting that the process parameters have a significant impact on the performance: too thick a coating (Example 7) will cause 12% cracking and 22% corrosion, and overheating of the process (Examples 5-6) will reduce the bonding strength to 13-15 MPa. Among them, Example 1 is the most prominent, achieving the best or nearly the best results in various tests, proving that the optimized ceramic coating can meet the key requirements such as stable electromagnetic performance, excellent anti-corrosion, high bonding strength, and good mechanical properties, and is an ideal choice for the protection of silicon steel lamination substrates, but the coating thickness and process temperature need to be strictly controlled to ensure performance consistency.

[0073] The preferred embodiments of the present application have been described in detail above. However, the present application is not limited thereto. Within the scope of the technical concept of the present application, various simple modifications can be made to the technical solutions of the present application, including any other suitable combination of each technical feature. These simple modifications and combinations should also be regarded as the content disclosed in the present application and fall within the protection scope of the present application.

Claims

1. An anti-corrosion protective coating for silicon steel laminated rotor / stator, characterized in that: It comprises a silicon steel laminate substrate, wherein the silicon steel laminate substrate comprises silicon steel laminates and an insulating adhesive bonding layer, the silicon steel laminates are arranged separately, and adjacent silicon steel laminates are connected by the insulating adhesive bonding layer; The surface of the silicon steel laminate substrate has a uniformly distributed micro-convex-concave composite structure; wherein the arithmetic average roughness (Ra) value of the micro-convex-concave composite structure is 0.5-1.0μm; the density of the micro-convex-concave composite structure per unit area is not less than 50 / mm²; the micro-convex-concave composite structure includes micro-convex bodies and / or pits, wherein the equivalent diameter of a single micro-convex body and / or pit is not greater than 50μm; and the distance from the top of a single micro-convex body to the bottom of the pit is not greater than 20μm; The surface of the micro-convex-concave composite structure is provided with an oxide coating.

2. The anti-corrosion protective coating according to claim 1, characterized in that: The density of the micro-convex-concave composite structure per unit area is 300-800 / mm², and the equivalent diameter of the single micro-convex body and / or concave pit is not greater than 20μm.

3. The anti-corrosion protective coating according to claim 1, characterized in that: The oxide coating is selected from one or more of alumina ceramics, chromium oxide ceramics, zirconium oxide ceramics, magnesium oxide ceramics, titanium oxide ceramics, beryllium oxide ceramics, and yttrium oxide ceramics.

4. The anti-corrosion protective coating according to claim 1, characterized in that: The oxide coating is selected from tough oxide ceramics, including different contents of titanium oxide toughened aluminum oxide ceramics and / or different contents of titanium oxide toughened chromium oxide ceramics; The titanium oxide toughened aluminum oxide ceramic is selected from one or more of Al2O3-13%TiO2, Al2O3-20%TiO2, Al2O3-25%TiO2, and Al2O3-40%TiO2; The titanium oxide toughened chromium oxide ceramic is selected from one or more of Cr2O3-13%TiO2, Cr2O3-20%TiO2, Cr2O3-25%TiO2, and Cr2O3-40%TiO2.

5. The anti-corrosion protective coating according to claim 1, characterized in that: The thickness of the oxide coating is 30-150 μm.

6. A method for preparing an anti-corrosion protective coating for a silicon steel laminated rotor / stator, preparing the anti-corrosion protective coating for a silicon steel laminated rotor / stator as claimed in claim 1, characterized in that: The following steps are involved: S1： Pretreatment: rust removal, degreasing and sandblasting are performed on the silicon steel laminate substrate to make the surface of the silicon steel laminate substrate have a uniformly distributed micro-convex and concave composite structure; S2: spraying: spraying the pretreated silicon steel laminate substrate with a plasma spray gun to obtain an oxide coating; S3: Sealing treatment: sealing the sprayed silicon steel laminate substrate; Among them, during the sandblasting roughening process, the sandblasting pressure is 0.02-0.15MPa; the distance between the sandblasting nozzle and the surface of the silicon steel laminate substrate is 8-10cm, and the relationship between the average diameter D of the gravel used for sandblasting and the average thickness L of the insulating adhesive bonding layer is D=0.1L∼0.4Lμm.

7. The method for preparing the anti-corrosion protective coating according to claim 6, characterized in that: In S2, the spraying process parameters are: the spraying distance is 90-120 mm; the horizontal movement speed of the plasma spray gun is 700-900 mm / s.

8. The method for preparing the anti-corrosion protective coating according to claim 7, characterized in that: In S1, during the sandblasting roughening process, the spraying angle is 80°-100°; In S2, the spraying process parameters are: spray gun power is 40-50kW; current is 550-650A; working gas flow rate Ar is 35-45splm, H2 is 6-12slpm; powder feeding rate is 20-40g / min; In S3, a sealing agent is used for sealing, and the curing time is not less than 24 hours.

9. The method for preparing the anticorrosion protective coating according to claim 6, characterized in that: The sandblasting roughening process comprises: Screening the gravel through a sand pan to obtain pre-treated gravel; The pre-treated gravel after screening is dried at a temperature of 80-120° C. for a drying time of not less than 2 hours.

10. The method for preparing the anti-corrosion protective coating according to claim 6, characterized in that: The intermittent spraying method is adopted during the spraying process; The intermittent spraying method is: after the first spraying is completed, cooling is performed for 20-60 seconds, and when the surface temperature of the silicon steel laminate substrate drops below 50° C., the second spraying is performed; The thickness of the sprayed oxide coating is 30-150 μm.

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