Magnetization coating method

Abstract

The invention provides a magnetization coating method, and belongs to the field of railway vehicle coating. The method comprises the following steps: carrying out magnetization degreasing treatment on a to-be-degreased base material to obtain a degreased base material; the degreased base material is magnetized, polished and ground, scrap iron generated in the magnetizing, polishing and grinding process is magnetized and fixed to the surface of the degreased base material, and a polished base material is obtained; carrying out base material magnetization treatment on the polished base material to obtain a magnetized base material; coating magnetization treatment is conducted on the coating, and the surface of the magnetized base material is coated with the coating subjected to magnetization treatment; the magnetized base material coated with the coating is magnetized and dried, and a dried coating is obtained; and the dried coating is demagnetized, and a coating product is obtained. By means of magnetization collaborative design of the whole coating process, paint mist pollution is reduced, the technological process is simplified, and meanwhile the performance of the coating is improved.

Description

Technical Field

[0001] This application relates to the field of railway vehicle painting technology, and in particular to a magnetization painting method. Background Technology

[0002] The main painting processes for railway vehicles include manual brushing, air spraying, and high-pressure airless spraying. All of these processes require pretreatment and grinding. However, the grinding process can leave iron filings on the surface of the substrate. Therefore, a special cleaning process must be added to remove the iron filings. This not only increases the complexity of the process and the production cost, but the residual iron filings may also affect the adhesion and integrity of the subsequent paint film, thereby reducing the coating quality.

[0003] Meanwhile, various traditional processes also have their own significant drawbacks: manual brushing relies on tools such as brushes and rollers for manual application, resulting in low coating efficiency and high labor intensity. It is prone to uneven coating thickness, brush marks, and runs, severely affecting coating quality and appearance. While air spraying achieves higher coating efficiency and a more uniform coating by utilizing compressed air, it generates a large amount of paint mist, polluting the environment and harming the health of operators. Furthermore, it suffers from low paint utilization and significant waste. High-pressure airless spraying uses high pressure to propel paint at high speed onto the workpiece surface, offering high coverage and good adhesion, suitable for large-area coating. However, its paint atomization effect is poor, resulting in a less smooth coating surface compared to air spraying. Additionally, it involves high equipment costs and difficult maintenance. In summary, existing railway vehicle coating processes struggle to simultaneously achieve paint mist pollution control, process simplification, and coating performance improvement. Therefore, there is an urgent need for a coating technology that can reduce paint mist pollution, simplify the process, and effectively improve coating performance. Summary of the Invention

[0004] This application provides a magnetized coating method to solve the following technical problem: how to reduce paint mist pollution and simplify the process while improving coating performance during the coating process.

[0005] This application provides a magnetization coating method, the method comprising: The substrate to be degreased is subjected to magnetization degreasing treatment to obtain a degreased substrate; The degreased substrate is magnetized and polished, and the iron filings generated during the magnetization and polishing process are magnetized and fixed on the surface of the degreased substrate to obtain a polished substrate. The polished substrate is subjected to substrate magnetization treatment to obtain a magnetized substrate; The coating is magnetized, and the magnetized coating is then applied to the surface of the magnetized substrate. The magnetized substrate coated with the coating is subjected to magnetization and drying treatment to obtain a dried coating. The dried coating is demagnetized to obtain the coated product.

[0006] Optionally, the magnetization degreasing treatment of the substrate to be degreased includes: The substrate to be degreased is placed in a magnetic field with a first set magnetic field strength, and an alkaline degreasing agent is sprayed onto the surface of the substrate to be degreased. After spraying the alkaline degreasing agent, allow it to stand, and then rinse the surface of the substrate to be degreased with deionized water.

[0007] Optionally, the first set magnetic field strength is 0.1T to 0.5T; The settling time is 5s to 15s.

[0008] Optionally, the step of magnetizing and polishing the degreased substrate includes: The degreased substrate is placed in a magnetic field with a second set magnetic field strength, and the surface of the degreased substrate is polished in multiple stages using a variety of magnetic abrasives with different mesh sizes.

[0009] Optionally, the second set magnetic field strength is 0.1T to 0.5T.

[0010] Optionally, multi-stage polishing of the surface of the degreased substrate using a variety of magnetic abrasives with different mesh sizes includes: The surface of the degreased substrate is first-stage polished for 20s to 40s using 80-mesh magnetic abrasive. The surface of the degreased substrate is polished in two stages for 50s to 70s using 325-mesh magnetic abrasive. The surface of the degreased substrate was polished in three stages for 4 to 6 minutes using 1000-mesh magnetic abrasive. The polished degreased substrate is placed in a magnetic field with a strength of 4T to 6T for 4s to 6s to perform demagnetization.

[0011] Optionally, the magnetic field strength for the substrate magnetization treatment is 1T to 15T.

[0012] Optionally, the process of magnetizing the coating includes: A magnetic field is applied along the flight path of the coating as it is sprayed from the spray gun onto the magnetized substrate; the length of the flight path is 0.1m to 1.0m.

[0013] Optionally, the magnetization drying process of the magnetized substrate coated with the coating includes: The magnetized substrate coated with the coating is placed in a magnetic field with a third set magnetic field strength, and the coating is heated to a set temperature and held at the set temperature for a set time.

[0014] Optionally, the third set magnetic field strength is 0.1T to 1T.

[0015] Optionally, the set temperature is 50℃~70℃, and the set time is 15min~60min.

[0016] Optionally, the magnetic field strength of the demagnetization treatment is 1T to 15T, and the duration of the demagnetization treatment is 1s to 10s.

[0017] Optionally, the magnetic fields involved in the magnetization degreasing treatment, the magnetization polishing, the substrate magnetization treatment, the coating magnetization treatment, the magnetization drying treatment, and the demagnetization treatment are all generated by superconducting magnets.

[0018] Optionally, the superconducting magnet comprises a magnetic core and wires; The magnetic core is made of silicon steel with a silicon content of 3.5% to 5%. The material of the conductor is yttrium barium copper oxide superconducting material.

[0019] Optionally, the superconducting magnet is equipped with a directional current switch, which is used to change the direction of the magnetic field generated by the superconducting magnet.

[0020] Optionally, the coating product includes a substrate and a coating covering the surface of the substrate, wherein the coating contains magnetized and embedded iron filings.

[0021] The technical solutions provided in this application have the following advantages compared with the prior art: This application provides a magnetized coating method. Through the magnetization-coordinated design of the entire coating process, it reduces paint mist pollution and simplifies the process while improving coating performance. Its core logic is closely integrated with the process steps.

[0022] In terms of reducing paint mist pollution, the polished substrate is magnetized before coating to obtain a magnetized substrate. At the same time, the paint is magnetized. The magnetized paint droplets are polarized to form magnetic dipoles during the process of being sprayed from the spray gun onto the magnetized substrate. The directional magnetic attraction force generated by the magnetized substrate will precisely pull the polarized paint droplets, causing the paint droplets to adhere to the substrate surface in an orientation. This avoids the disorderly escape of paint after atomization in traditional spraying, thus effectively reducing paint mist pollution.

[0023] In terms of simplifying the process, the key lies in the design of the magnetized polishing and grinding process. This process is carried out in a magnetic field environment. The iron filings generated during grinding are instantly magnetized and fixed on the surface of the degreased substrate. Unlike traditional processes, there is no need to add a separate iron filings cleaning process, which directly saves the operation and time costs of the cleaning process. This makes the entire coating process simpler and more efficient, and the magnetization processes are smoothly connected without the need for additional complex steps.

[0024] In terms of improving coating performance, on the one hand, the iron filings fixed on the substrate surface are encapsulated by the coating during the subsequent coating process, eventually embedding into the coating to form a composite structure. The presence of the iron filings fills the tiny gaps inside the coating, enhancing the physical integrity and structural strength of the coating. On the other hand, the magnetization drying treatment after coating can guide the resin, pigment molecules and embedded iron filings inside the coating to arrange in an orderly manner under the action of a magnetic field, promoting the cross-linking reaction between molecules and forming a more dense and stable coating microstructure. This improves the hardness, adhesion and corrosion resistance of the coating, ultimately achieving the simultaneous reduction of pollution, simplification of the process and improvement of performance. Attached Figure Description

[0025] 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.

[0026] 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.

[0027] Figure 1 This is a schematic flowchart of a magnetization coating method provided in an embodiment of this application. Detailed Implementation

[0028] 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.

[0029] The range descriptions used herein, such as numerical ranges and proportional ranges, include all possible sub-ranges and single numerical values ​​within that range. For example, the range descriptions of "1 to 6" or "1 to 6" cover all sub-ranges (such as 1 to 3, 2 to 5, etc.) and single numbers (such as 1, 2, 3, 4, 5, 6) between 1 and 6. Unless otherwise specified, the terms "including" and "contains" as used herein mean "including but not limited to"; relational terms such as "first" and "second" are used only to distinguish different entities or operations and do not imply an actual order or relationship; "and / or" indicates that multiple situations can exist individually or simultaneously; expressions such as "at least one," "multiple," and "at least one" refer to any combination of the corresponding objects, including combinations of single or multiple objects. The proportional relationships mentioned herein, such as mass ratios and molar ratios, should be understood as the correspondence between the first and second terms of a proportional formula, according to the order of description. The raw materials, reagents, instruments, and equipment used herein can all be obtained through commercial purchase or prepared using existing methods.

[0030] Figure 1 This is a schematic flowchart of a magnetization coating method provided in an embodiment of this application.

[0031] like Figure 1 As shown in the figure, this application provides a magnetization coating method, the method comprising: S1. The substrate to be degreased is subjected to magnetization degreasing treatment to obtain a degreased substrate; S2. The degreased substrate is magnetized and polished, and the iron filings generated during the magnetization and polishing process are magnetized and fixed on the surface of the degreased substrate to obtain a polished substrate. S3. The polished substrate is subjected to substrate magnetization treatment to obtain a magnetized substrate; S4. Magnetize the coating and apply the magnetized coating to the surface of the magnetized substrate. S5. The magnetized substrate coated with the coating is subjected to magnetization and drying treatment to obtain a dried coating. S6. Demagnetize the dried coating to obtain the coated product.

[0032] The magnetization coating method provided in this application systematically solves many technical problems in the traditional railway vehicle coating process by introducing a magnetic field throughout the entire coating process.

[0033] The magnetization degreasing treatment in step S1 is a fundamental pretreatment process in the magnetized coating process. Its core function is to provide a clean and contamination-free substrate surface for subsequent coating processes. When the substrate to be degreased is placed in a magnetic field of a set intensity, the magnetic field alters the physicochemical properties of the sodium hydroxide alkaline degreaser, significantly enhancing its penetration and oil-decomposing ability. This allows the degreaser to more quickly and thoroughly remove grease, dust, and other impurities from the substrate surface. Allowing the substrate to stand for a specific period after spraying the degreaser ensures a full reaction between the degreaser and impurities. Multiple rinsings with deionized water thoroughly remove any reaction residues, ultimately resulting in a clean, oil-free degreased substrate. This lays a crucial foundation for subsequent magnetized polishing and coating adhesion.

[0034] The magnetized polishing process in step S2 is a core innovative step that achieves resource utilization and process simplification, serving the dual purpose of mechanical processing and resource transformation. On the one hand, the degreased substrate is placed in a magnetic field of a set intensity, and multi-mesh magnetic abrasives are used for gradual polishing, which effectively removes the oxide layer on the surface of the degreased substrate and creates a suitable surface roughness, forming an anchoring structure that is conducive to coating adhesion. On the other hand, the iron filings generated during the polishing process are instantly magnetized under the action of the magnetic field. The magnetized iron filings are firmly adsorbed and fixed on the surface of the degreased substrate, which not only completely solves the problem of iron filings remaining and requiring additional cleaning in traditional processes, eliminating the need for a separate cleaning process and shortening the working time, but also transforms the iron filings, which were originally waste, into components of the subsequent coating, realizing in-situ recycling of resources, and finally obtaining a polished substrate with a surface treatment that meets the standards and has iron filings fixed in place.

[0035] The core function of substrate magnetization in step S3 is to create stable magnetic adsorption conditions for coating. By applying a strong magnetic field of a set intensity to the polished substrate, the substrate itself and the iron filings fixed on its surface are deeply magnetized to saturation, forming a magnetized substrate with uniform magnetism and stable adsorption force. The deeply magnetized substrate generates a directional and strong magnetic field. This magnetic field environment can form a strong magnetic interaction with the subsequently polarized coating droplets, providing "magnetic anchor points" for the directional adsorption of the coating droplets. This fundamentally reduces the rebound and scattering of coating droplets during the coating process, providing a key guarantee for improving coating utilization and coating uniformity.

[0036] Step S4, paint magnetization and coating, is the core process for achieving low-pollution, high-utilization coating. Its role is reflected in two key aspects: paint polarization and directional coating. A magnetic field is applied along the flight path of the paint as it travels from the spray gun to the magnetized substrate. Paint droplets are polarized in the magnetic field, forming tiny magnetic dipoles. These dipoles repel each other during flight, achieving more uniform atomization and avoiding uneven coating caused by droplet agglomeration. When the polarized paint droplets approach the magnetized substrate, they are attracted by the substrate's magnetic field. This "magnetically guided" effect significantly reduces paint droplet escape (i.e., paint mist generation), reducing paint loss, improving material utilization, and reducing environmental pollution at the source. Simultaneously, it ensures uniform paint coverage on the magnetized substrate surface, forming the initial coating structure.

[0037] The purpose of the magnetization drying process in step S5 is to achieve rapid curing and performance optimization of the coating. By placing the magnetized substrate coated with the paint in a magnetic field of a set intensity and heating it to a set temperature and holding it there, the magnetic field guides the resin, pigment molecules, and embedded iron filings within the coating to align in an orderly manner, promoting cross-linking reactions between molecules. Compared to traditional drying methods, the magnetic field-assisted drying process accelerates solvent evaporation, shortens drying time, and simultaneously enables the coating to form a denser and more stable microstructure. This significantly improves the density, hardness, adhesion, and corrosion resistance of the dried coating, ensuring excellent performance and ultimately resulting in a dried coating that meets performance standards.

[0038] Step S6, the demagnetization process, is the final step to ensure the reliability of the coated product. Its core function is to eliminate residual magnetism in the dried coating and substrate. After multiple magnetization processes, the coating intermediates (dried coating and substrate) will have oriented magnetic domains, resulting in residual magnetism in the product. By applying a reverse magnetic field of a set intensity, the oriented arrangement of the magnetic domains can be disrupted, achieving overall demagnetization. This process prevents the coated product from adsorbing ferromagnetic dust from the environment during subsequent use, ensuring the cleanliness of the product's appearance. It also prevents residual magnetism from interfering with the normal operation of railway vehicle equipment, ultimately resulting in a reliable coated product free from hysteresis.

[0039] In summary, this magnetized coating method constructs a complete and innovative technological system through six interconnected steps and the synergistic effect of a magnetic field. It not only eliminates the traditional cleaning process and realizes the resource utilization of waste iron filings, but also significantly reduces environmental pollution through magnetron spraying. Finally, through magnetized drying and demagnetization treatment, it yields high-quality coated products with superior performance and free from hysteresis effects.

[0040] In some embodiments, the magnetization degreasing treatment of the substrate to be degreased includes: The substrate to be degreased is placed in a magnetic field with a first set magnetic field strength, and an alkaline degreasing agent is sprayed onto the surface of the substrate to be degreased. After spraying the alkaline degreasing agent, allow it to stand, and then rinse the surface of the substrate to be degreased with deionized water.

[0041] In some embodiments, the first set magnetic field strength is 0.1T to 0.5T; The settling time is 5s to 15s.

[0042] The initial magnetic field strength in the magnetization degreasing treatment is set to 0.1T to 0.5T. This strength range precisely matches the physicochemical properties of the alkaline degreasing agent, effectively enhancing its penetration ability and oil-decomposing activity on the substrate surface, ensuring that the degreasing agent quickly acts on the grease and impurities on the substrate surface. Simultaneously, this strength range balances the economy and safety of the process, eliminating the need for excessively high magnetic field generation costs and avoiding unnecessary impacts of strong magnetic fields on the initial state of the substrate. For example, the initial magnetic field strength can be 0.1T, 0.15T, 0.2T, 0.25T, 0.3T, 0.35T, 0.4T, 0.45T, etc.

[0043] The settling time after spraying the alkaline degreasing agent is set to 5-15 seconds. This timeframe provides sufficient reaction time for the degreasing agent to react with the oil and dirt on the substrate surface, ensuring that the oil and dirt are fully emulsified and decomposed. This lays the foundation for the subsequent deionized water rinsing process and guarantees the cleanliness of the substrate surface after degreasing. For example, the settling time can be 5 seconds, 6 seconds, 7 seconds, 8 seconds, 10 seconds, 11 seconds, 12 seconds, 15 seconds, etc.

[0044] In some embodiments, the magnetizing polishing of the degreased substrate includes: The degreased substrate is placed in a magnetic field with a second set magnetic field strength, and the surface of the degreased substrate is polished in multiple stages using a variety of magnetic abrasives with different mesh sizes.

[0045] In some embodiments, the second set magnetic field strength is 0.1T to 0.5T.

[0046] The second set magnetic field strength for magnetized polishing is limited to 0.1T to 0.5T. This strength enables the magnetic abrasive to form a stable and uniform magnetic brush structure on the substrate surface, ensuring full contact between the abrasive and the substrate surface. Simultaneously, it firmly adsorbs iron filings generated during polishing, achieving in-situ fixation of the iron filings. For example, the second set magnetic field strength can be 0.1T, 0.15T, 0.2T, 0.25T, 0.3T, 0.35T, 0.4T, 0.45T, etc.

[0047] In some embodiments, multi-stage polishing of the surface of the degreased substrate using multiple magnetic abrasives with different mesh sizes includes: The surface of the degreased substrate is first-stage polished for 20s to 40s using 80-mesh magnetic abrasive. The surface of the degreased substrate is polished in two stages for 50s to 70s using 325-mesh magnetic abrasive. The surface of the degreased substrate was polished in three stages for 4 to 6 minutes using 1000-mesh magnetic abrasive. The polished degreased substrate is placed in a magnetic field with a strength of 4T to 6T for 4s to 6s to perform demagnetization.

[0048] In the multi-stage polishing process, 80-mesh magnetic abrasive combined with a 20-40 second primary polishing stage can quickly remove the oxide layer and protruding impurities from the substrate surface, completing the basic smoothing treatment and creating conditions for subsequent fine polishing. A 325-mesh magnetic abrasive, after a 50-70 second secondary polishing stage, further refines the surface roughness of the substrate and eliminates traces left by the primary polishing stage. A 1000-mesh magnetic abrasive, through a 4-6 minute tertiary polishing stage, achieves a fine finishing treatment of the substrate surface, obtaining a smooth surface suitable for coating adhesion. After polishing, a magnetic field of 4-6T is continuously applied for 4-6 seconds for demagnetization. This parameter combination effectively eliminates residual magnetism accumulated on the substrate during magnetization polishing, preventing residual magnetism from interfering with subsequent processes and ensuring the stability of the polished substrate. For example, the primary polishing time for 80-mesh magnetic abrasive can be 20s, 23s, 26s, 29s, 32s, 35s, 38s, 40s, etc.; the secondary polishing time for 325-mesh magnetic abrasive can be 50s, 53s, 56s, 59s, 62s, 65s, 68s, 70s, etc.; the tertiary polishing time for 1000-mesh magnetic abrasive can be 4.0min, 4.3min, 4.6min, 4.9min, 5.2min, 5.5min, 5.8min, 6.0min, etc.; the magnetic field strength for demagnetization after polishing can be 4.0T, 4.3T, 4.6T, 4.9T, 5.2T, 5.5T, 5.8T, 6.0T, etc.; and the duration of demagnetization after polishing can be 4.0s, 4.3s, 4.6s, 4.9s, 5.2s, 5.5s, 5.8s, 6.0s, etc.

[0049] In some embodiments, the magnetic field strength for the substrate magnetization treatment is 1T to 15T.

[0050] The magnetic field strength for the substrate magnetization treatment is set to 1T to 15T. This range provides sufficient magnetization saturation for the polished substrate, ensuring that both the substrate itself and the iron filings fixed on its surface achieve a stable magnetization state, forming a magnetic environment with suitable strength and uniform distribution. This fully magnetized state provides a reliable "magnetic substrate" for the subsequent coating magnetization process, ensuring that the polarized coating droplets are subject to stable magnetic attraction, thus providing a key guarantee for improving coating utilization and coating uniformity. For example, the magnetic field strength for the substrate magnetization treatment can be 1T, 3T, 5T, 7T, 9T, 11T, 13T, 15T, etc.

[0051] In some embodiments, the magnetization treatment of the coating includes: A magnetic field is applied along the flight path of the coating as it is sprayed from the spray gun onto the magnetized substrate; the length of the flight path is 0.1m to 1.0m.

[0052] In the coating magnetization process, the flight path length of the coating from the spray gun to the magnetized substrate is set to 0.1m to 1.0m. This length range provides sufficient space for the coating droplets to undergo magnetization, ensuring that the droplets can fully pass through the magnetic field region during flight and complete the polarization process to form tiny magnetic dipoles. Fully polarized coating droplets not only achieve a more uniform atomization effect but also adhere precisely to the surface of the magnetized substrate under magnetic attraction, ensuring the stability of the coating process and the uniformity of the coating. For example, the flight path length for coating magnetization can be 0.1m, 0.2m, 0.3m, 0.4m, 0.6m, 0.7m, 0.9m, 1.0m, etc.

[0053] In some embodiments, the magnetization drying process of the magnetized substrate coated with the coating includes: The magnetized substrate coated with the coating is placed in a magnetic field with a third set magnetic field strength, and the coating is heated to a set temperature and held at the set temperature for a set time.

[0054] In some embodiments, the third set magnetic field strength is 0.1T to 1T.

[0055] The third set magnetic field strength for the magnetization drying process is specified to be 0.1T to 1.0T. This strength can continuously guide the resin, pigment molecules, and embedded iron filings within the coating to arrange themselves in an orderly manner during the drying process, promoting intermolecular cross-linking reactions and helping to form a dense coating microstructure. For example, the third set magnetic field strength can be 0.1T, 0.2T, 0.3T, 0.4T, 0.6T, 0.7T, 0.9T, 1.0T, etc.

[0056] In some embodiments, the set temperature is 50°C to 70°C, and the set time is 15 min to 60 min.

[0057] A heating temperature of 50℃ to 70℃ provides a suitable thermal environment for coating curing, accelerating the evaporation of solvents within the coating while preventing adverse effects of high temperatures on coating performance. A holding time of 15 to 60 minutes ensures the coating undergoes a complete curing reaction, resulting in a stable structure and excellent mechanical properties and corrosion resistance. For example, the set temperature for magnetization drying can be 50℃, 53℃, 56℃, 59℃, 62℃, 65℃, 68℃, or 70℃; the set time for magnetization drying can be 15 minutes, 21 minutes, 28 minutes, 34 minutes, 41 minutes, 47 minutes, 54 minutes, or 60 minutes.

[0058] In some embodiments, the magnetic field strength of the demagnetization treatment is 1T to 15T, and the duration of the demagnetization treatment is 1s to 10s.

[0059] The magnetic field strength for demagnetization is set to 1T–15T, and the treatment time is set to 1s–10s, creating a reverse magnetic field sequence with precise intensity-time matching. This parameter combination effectively disrupts the oriented magnetic domain structure within the coated product, causing the magnetic domains to redistribute randomly, thereby achieving complete demagnetization of the product and ensuring that the final coated product is free of residual magnetism, guaranteeing its stability and reliability during subsequent use. For example, the magnetic field strength for demagnetization can be 1T, 3T, 5T, 7T, 9T, 11T, 13T, 15T, etc.; the duration of demagnetization can be 1.0s, 2s, 3s, 4s, 6s, 7s, 8s, 10s, etc.

[0060] In some embodiments, the magnetic fields involved in the magnetization degreasing treatment, the magnetization polishing, the substrate magnetization treatment, the coating magnetization treatment, the magnetization drying treatment, and the demagnetization treatment are all generated by superconducting magnets.

[0061] In some embodiments, the superconducting magnet comprises a magnetic core and wires; The magnetic core is made of silicon steel with a silicon content of 3.5% to 5%. The material of the conductor is yttrium barium copper oxide superconducting material.

[0062] The magnetic field source uses superconducting magnets, providing a stable and continuous high-intensity magnetic field for each magnetization step in the coating process, meeting the varying magnetic field strength requirements of different steps. The core of the superconducting magnet is made of silicon steel with a silicon content of 3.5%–5%. This silicon content range gives the core the dual characteristics of low eddy current loss and high permeability, effectively improving magnetic field conversion efficiency and reducing energy loss. The conductor uses yttrium barium copper oxide superconducting material, whose excellent superconducting properties ensure that the magnetic field source maintains efficient and stable magnetic field output even under high load operation, reducing operating energy consumption. For example, the silicon content of the superconducting magnet core can be 3.5%, 3.7%, 3.9%, 4.1%, 4.3%, 4.5%, 4.8%, 5.0%, etc.

[0063] In some embodiments, the superconducting magnet is equipped with a directional current switch for changing the direction of the magnetic field generated by the superconducting magnet.

[0064] The superconducting magnet is equipped with a directional current switch, which enables rapid and precise switching of the magnetic field direction, providing different magnetic fields required for the magnetization and demagnetization processes, ensuring smooth connection between each process and the desired process effect.

[0065] In some embodiments, the coated product includes a substrate and a coating covering the surface of the substrate, wherein the coating contains magnetized and embedded iron filings.

[0066] It should be noted that the iron filings embedded in the coating originate from the magnetization polishing process of the magnetized coating. In this process, the degreased substrate is placed in a magnetic field of a set intensity and polished sequentially using magnetic abrasives of multiple mesh sizes, including 80 grit, 325 grit, and 1000 grit. Iron filings are naturally generated during the polishing process. Because the entire polishing process is under the influence of a magnetic field, these newly generated iron filings are instantly magnetized, forming magnetic iron filings. At the same time, the attraction force generated by the magnetic field firmly fixes the magnetized iron filings to the surface of the degreased substrate, preventing them from falling off or scattering. After subsequent substrate magnetization treatment, the substrate and the iron filings fixed on the surface reach a stable magnetization state. In the coating magnetization coating process, polarized paint droplets are evenly covered on the substrate surface and the iron filings. After magnetization drying, the paint droplets solidify to form the coating matrix, and the magnetized iron filings originally fixed on the substrate surface are completely embedded inside the coating, ultimately becoming part of the coating. Furthermore, due to the use of multi-mesh magnetic abrasives for gradual polishing, the size of the iron filings will be naturally optimized during the polishing process, and their distribution will be more uniform, laying the foundation for a tight bond with the coating matrix.

[0067] Meanwhile, the embedded iron filings play a crucial role in enhancing the performance of coated products in several key ways. First, the iron filings form a tightly bonded composite structure with the coating matrix. Their uniform distribution fills the tiny gaps within the coating matrix, enhancing the overall physical integrity of the coating and reducing the risk of cracking and peeling during use. Second, the iron filings themselves possess high hardness and wear resistance. Embedded in the coating, they act as a "micro-skeleton" within the coating, significantly increasing its overall hardness, enhancing its resistance to external friction and impact, and extending its wear life. Third, the tight bond between the iron filings and the coating matrix forms a denser protective barrier, slowing the penetration of corrosive media (such as moisture and salt) into the substrate surface, effectively improving the coating's corrosion resistance and thus extending the overall service life of the coated product. Furthermore, these iron filings, originally waste generated during grinding, are embedded in the coating through magnetic field action, achieving resource utilization. This avoids the disposal problems of iron filings waste in traditional processes and eliminates the need for additional reinforcing fillers, achieving efficient resource recovery and simultaneous improvement in coating performance, thus balancing economic efficiency and practicality.

[0068] In summary, the magnetization coating method provided in this application has significant advantages in resource utilization. This method uses the directional adsorption effect of a magnetic field to magnetize and fix iron filings generated during magnetization polishing and grinding onto the substrate surface in situ. This transforms iron filings, which were originally process waste, into a functional component of the coating, achieving in-situ recycling and efficient utilization of resources and avoiding the waste and disposal problems associated with iron filings in traditional processes.

[0069] In terms of environmental performance, this process demonstrates outstanding value. After being polarized by a magnetic field during its flight path, the paint droplets adhere directionally to the magnetized substrate under the magnetic attraction force, significantly reducing paint mist escape and minimizing environmental pollution from the coating process at its source. It also avoids the health risks of operators being exposed to excessive paint mist. In addition, the in-situ fixation of iron filings eliminates the need for a separate cleaning process for iron filings residue in traditional processes, reducing pollutant emissions generated during cleaning and further enhancing the environmental friendliness of the process.

[0070] In terms of product performance enhancement, this method offers unique advantages. The magnetic field operates throughout the entire coating process. During magnetization and drying, the magnetic field guides the orderly arrangement of resin, pigments, and embedded iron filings within the coating, promoting molecular cross-linking to form a dense and stable composite coating structure. This significantly enhances the coating's integrity, hardness, wear resistance, and corrosion resistance. Simultaneously, the final demagnetization treatment completely eliminates residual magnetism in the coated product, preventing the adsorption of ferromagnetic dust during use and ensuring the product's long-term reliability and clean appearance.

[0071] In terms of process optimization, this method achieves high efficiency and simplification. In-situ fixation of iron filings eliminates the necessary cleaning process in traditional coating, reducing process steps and operations; magnetic field-assisted degreasing and drying processes can achieve the target effect more efficiently, shortening the overall process cycle, reducing labor and time costs in the production process, and improving the overall efficiency of coating production.

[0072] In terms of equipment adaptation and process implementation, this method offers reliable support advantages. Using a superconducting magnet as the magnetic field source, coupled with a silicon steel core with a specific silicon content and yttrium barium copper oxide superconducting wire, it can stably output the magnetic field strength required for each process, ensuring consistent process results. The configuration of a directional current switch enables precise switching of the magnetic field direction, meeting the differentiated needs of magnetization and demagnetization processes, and providing solid equipment and technical support for the large-scale and standardized implementation of the process.

[0073] The present application is further illustrated below with reference to specific embodiments. Experimental methods in the following embodiments that do not specify specific conditions are generally determined according to national standards / industry standards / the disclosure herein; if there are no corresponding national standards / industry standards / the disclosure herein, they are performed according to generally accepted international standards, conventional conditions, or conditions recommended by the manufacturer.

[0074] Example 1 This embodiment provides a magnetization coating method, which achieves efficient coating of railway vehicle substrates by introducing a magnetic field control mechanism. The specific implementation steps are as follows: (1) Magnetization degreasing treatment: Place the substrate to be degreased in a magnetic field environment with a magnetic field strength of 0.3T, spray sodium hydroxide alkaline degreasing agent evenly on the surface of the substrate to be degreased, let it stand for 10s, and then rinse the surface of the substrate with deionized water 3 times to obtain a clean degreased substrate.

[0075] (2) Magnetized Polishing: The degreased substrate was placed in a magnetic field with a strength of 0.5T and subjected to three-stage polishing. First, 80-mesh magnetic abrasive was used for primary polishing for 30 seconds, followed by 325-mesh magnetic abrasive for secondary polishing for 1 minute, and finally 1000-mesh magnetic abrasive for tertiary polishing for 5 minutes. After polishing, the substrate was placed in a magnetic field with a strength of 5T for demagnetization for 5 seconds, resulting in a smooth polished substrate. During this process, the iron filings generated during polishing were magnetized under the influence of the magnetic field and firmly adhered to the surface of the substrate.

[0076] (3) Substrate magnetization treatment: The polished substrate is placed in a magnetic field with a magnetic field strength of 5T for magnetization treatment, so that the substrate reaches a fully magnetized state and obtains a magnetized substrate.

[0077] (4) Magnetization treatment and coating of coating: A magnetic field is set in the flight path of the coating as it is sprayed from the spray gun to the magnetized substrate, and the distance of the magnetization interval is 0.5m. The magnetized coating is uniformly coated on the surface of the magnetized substrate.

[0078] (5) Magnetization drying treatment: The magnetized substrate coated with the coating is placed in a magnetic field environment, and the coating temperature is raised to 60°C by magnetic heating and maintained at this temperature for 0.5h to allow the coating to fully cure and obtain a dry coating.

[0079] (6) Demagnetization treatment: The substrate with the dry coating is placed in a magnetic field with a magnetic field strength of 5T for demagnetization treatment for 5 seconds, and finally a non-magnetic coating product is obtained.

[0080] In this embodiment, the magnetic fields involved in the magnetization degreasing treatment, magnetization polishing, substrate magnetization treatment, coating magnetization treatment, magnetization drying treatment, and demagnetization treatment are all generated by superconducting magnets; the core of the superconducting magnet is silicon steel with a silicon content of 4.2%, the wire is yttrium barium copper oxide superconducting material, and it is equipped with a directional current switch.

[0081] In the coating product prepared in this embodiment, the coating contains uniformly distributed magnetized and firmly embedded iron filings. These iron filings, which originate from the polishing process, have become an effective component of the coating, effectively improving the overall performance of the coating.

[0082] Example 2 This embodiment provides a magnetization coating method, and the specific implementation steps are as follows: (1) Magnetization degreasing treatment: Place the substrate to be degreased in a magnetic field environment with a magnetic field strength of 0.2T, spray sodium hydroxide alkaline degreasing agent evenly on the surface of the substrate, let it stand for 8s, and then rinse the surface of the substrate with deionized water 3 times to obtain a clean degreased substrate.

[0083] (2) Magnetized polishing: The degreased substrate was placed in a magnetic field with a strength of 0.3T and polished in three stages. First, 80-mesh magnetic abrasive was used for primary polishing for 25 seconds, followed by 325-mesh magnetic abrasive for secondary polishing for 50 seconds, and finally 1000-mesh magnetic abrasive for tertiary polishing for 4.5 minutes. After polishing, the substrate was placed in a magnetic field with a strength of 4T for demagnetization for 4 seconds to obtain a smooth polished substrate.

[0084] (3) Substrate magnetization treatment: The polished substrate is placed in a magnetic field with a magnetic field strength of 8T for magnetization treatment, so that the substrate reaches a fully magnetized state and obtains a magnetized substrate.

[0085] (4) Magnetization treatment and coating of coating: A magnetic field is set in the flight path of the coating as it is sprayed from the spray gun to the magnetized substrate, and the distance of the magnetization interval is 0.3m. The magnetized coating is uniformly coated on the surface of the magnetized substrate.

[0086] (5) Magnetization drying treatment: The magnetized substrate coated with the coating is placed in a magnetic field environment, and the coating temperature is raised to 55°C by magnetic heating and maintained at this temperature for 45 minutes to fully cure the coating and obtain a dry coating.

[0087] (6) Demagnetization treatment: The substrate with the dry coating is placed in a magnetic field with a magnetic field strength of 8T for demagnetization treatment for 8 seconds, and finally a non-magnetic coating product is obtained.

[0088] In this embodiment, all magnetic fields are generated by superconducting magnets; the core of the superconducting magnet is silicon steel with a silicon content of 4.0%, the wire is yttrium barium copper oxide superconducting material, and it is equipped with a directional current switch.

[0089] Example 3 This embodiment provides a magnetization coating method, and the specific implementation steps are as follows: (1) Magnetization degreasing treatment: Place the substrate to be degreased in a magnetic field environment with a magnetic field strength of 0.4T, spray sodium hydroxide alkaline degreasing agent evenly on the surface of the substrate to be degreased, let it stand for 12s, and then rinse the surface of the substrate with deionized water 3 times to obtain a clean degreased substrate.

[0090] (2) Magnetized polishing: The degreased substrate was placed in a magnetic field with a strength of 0.4T and polished in three stages. First, 80-mesh magnetic abrasive was used for primary polishing for 35 seconds, followed by 325-mesh magnetic abrasive for secondary polishing for 65 seconds, and finally 1000-mesh magnetic abrasive for tertiary polishing for 5.5 minutes. After polishing, the substrate was placed in a magnetic field with a strength of 5.5T for demagnetization for 6 seconds to obtain a smooth polished substrate.

[0091] (3) Substrate magnetization treatment: The polished substrate is placed in a magnetic field with a magnetic field strength of 12T for magnetization treatment, so that the substrate reaches a fully magnetized state and obtains a magnetized substrate.

[0092] (4) Magnetization treatment and coating of coating: A magnetic field is set in the flight path of the coating as it is sprayed from the spray gun to the magnetized substrate, and the distance of the magnetization interval is 0.8m. The magnetized coating is uniformly coated on the surface of the magnetized substrate.

[0093] (5) Magnetization drying treatment: The magnetized substrate coated with the coating is placed in a magnetic field environment, and the coating temperature is raised to 65°C by magnetic heating and maintained at this temperature for 20 minutes to fully cure the coating and obtain a dry coating.

[0094] (6) Demagnetization treatment: The substrate with the dry coating is placed in a magnetic field with a magnetic field strength of 12T for demagnetization treatment for 6 seconds, and finally a non-magnetic coating product is obtained.

[0095] In this embodiment, all magnetic fields are generated by superconducting magnets; the core of the superconducting magnet is silicon steel with a silicon content of 4.5%, the wire is yttrium barium copper oxide superconducting material, and it is equipped with a directional current switch.

[0096] Comparative Example 1 This comparative example provides a conventional painting method, employing traditional railway vehicle painting processes. The specific steps are as follows: (1) Pretreatment process: First, the substrate to be coated is surface treated, including mechanical grinding to remove the surface oxide layer and contaminants, and using an alkaline degreasing agent to thoroughly clean the substrate surface to remove oil and iron filings generated during grinding.

[0097] (2) Primer application: The primer is applied using an air spraying process. Compressed air is used to atomize the paint and deliver it to the substrate surface. The amount of primer used per car body section is 100 kg.

[0098] (3) Drying treatment: After the coating is completed, the workpiece is placed in a conventional baking equipment for curing treatment. The paint film drying process takes 1 hour.

[0099] (4) Topcoat application and curing: After the primer is completely dry, the same air spraying process is used to apply the topcoat. After the topcoat is applied, it is dried again.

[0100] Comparative Example 2 This comparative example is modified from the one disclosed in Example 1 as follows: The magnetic field effect in the magnetization degreasing process is eliminated, i.e., the first set magnetic field strength is 0T, and the remaining steps and parameters are completely consistent with those in Example 1.

[0101] Comparative Example 3 This comparative example is modified from the one disclosed in Example 1 as follows: The magnetic field effect in the magnetization polishing process is canceled, that is, the second set magnetic field strength is 0T, and the remaining steps and parameters are completely consistent with those in Example 1.

[0102] Comparative Example 4 This comparative example is based on the disclosure in Example 1, with the following modifications: the substrate magnetization treatment step is omitted, while other steps and parameters remain consistent with Example 1.

[0103] Comparative Example 5 Based on the disclosure in Example 1, this comparative example is modified as follows: the magnetic field effect in the magnetization drying process is removed, that is, the third set magnetic field strength is 0T, and the remaining steps and parameters are completely consistent with Example 1.

[0104] The coating process parameters of Examples 1-3 and Comparative Examples 1-5 were compared. The substrate of the examples and comparative examples was a car body. The results are shown in Table 1.

[0105] Table 1. Indicators of the coating processes in Examples 1-3 and Comparative Examples 1-5

[0106] As shown in Table 1, Examples 1 to 3 all adopted the complete magnetization coating process, and the data indicators were significantly better than those of the traditional process (Comparative Example 1), which proves the comprehensive superiority of the technology system.

[0107] In terms of resource utilization efficiency, the amount of primer used in this embodiment (82-88 kg) is reduced by more than 12% compared to the traditional process (100 kg), and the amount of alkaline degreasing agent used (47-54 kg) is reduced by nearly half. This is directly attributed to the intervention of the magnetic field: in the degreasing stage (S1), the magnetic field enhances the activity of the degreasing agent, achieving efficient cleaning; in the spraying stage (S4), the directional adsorption force of the magnetized substrate on the polarized coating significantly reduces coating splashing and improves utilization.

[0108] In terms of process efficiency, the advantages are even more pronounced. The total polishing time in this embodiment is reduced to less than 10 minutes, while the traditional process takes up to 4 hours (240 minutes). The fundamental reason is that the iron filings generated during magnetization polishing (S2) are instantly attracted and fixed to the substrate surface by the magnetic field, eliminating the indispensable and time-consuming independent cleaning step in the traditional process. At the same time, the magnetization drying (S5) time (0.3~0.75h) is also significantly shorter than that of traditional thermal drying (1.0h), and the magnetic field accelerates the curing of the internal structure of the coating.

[0109] Ultimately, in terms of core performance, the coatings in the examples all achieved a neutral salt spray resistance time exceeding 700 hours (706–732 hours), with a maximum of 732 hours, far surpassing the 600 hours of traditional processes. This indicates that the magnetization effect throughout the entire process, from substrate pretreatment and coating application to drying and curing, synergistically contributes to the final results of stronger coating adhesion, denser microstructure, and superior corrosion resistance.

[0110] Comparative Example 2 (without S1 magnetization degreasing): The amount of degreasing agent used surged to 102 kg, comparable to Comparative Example 1, demonstrating that the magnetic field is crucial for improving the penetration and decomposition efficiency of the degreasing agent. Although the subsequent magnetization step was still performed, the initial cleanliness was insufficient, affecting the bonding interface between the coating and the substrate. This resulted in a salt spray resistance performance (614 h) that was relatively high but still significantly inferior to the examples, highlighting that a "clean substrate" is the primary prerequisite for high-performance coatings.

[0111] Comparative Example 3 (S2 magnetization polishing and grinding cancelled): The most significant change is that the total polishing and grinding time is extended to 13.0 minutes (although still far superior to the traditional process). This is because without the magnetic field's adsorption and fixation of the iron filings, an additional step must be added to handle the loose iron filings, verifying the core contribution of this step in simplifying the process and realizing in-situ resource utilization of iron filings. At the same time, its salt spray resistance (651h) decreases, indicating that the iron filings that fail to embed in the coating lose their function as a reinforcing phase to improve the coating's density and corrosion resistance.

[0112] Comparative Example 4 (without S3 substrate magnetization treatment): This set of data reveals a key shortcoming. The amount of primer used in the coating increased significantly to 98 kg, approaching the level of traditional processes. This directly proves that the "magnetic anchor points" provided by the deeply magnetized substrate are crucial for reducing coating rebound and ensuring high utilization. More seriously, its salt spray resistance (583h) is the lowest among all comparisons, indicating a lack of strong magnetic adsorption guidance. This makes it difficult for the coating to adhere evenly and firmly, severely impairing the protective performance of the coating. This is the most critical aspect of this technical system.

[0113] Comparative Example 5 (S5 magnetization drying omitted): The drying time was extended to 1.1 hours, returning to the level of traditional hot drying, indicating that magnetization drying can effectively guide the orderly arrangement and cross-linking of coating molecules, thereby accelerating the curing process. Its salt spray resistance (662h) is better than that of the traditional process and Comparative Example 4, but significantly lower than that of the example, confirming the indispensability of magnetization drying for forming a denser and more stable coating microstructure.

[0114] In summary, the data in Table 1 strongly demonstrates that the superior performance of this magnetized coating method does not stem from a single step, but rather from the synergistic and cumulative effects of the magnetic fields in steps S1 to S6. The absence of any key magnetization step will result in significant shortcomings in material consumption, labor time, or the final coating performance. Comparative examples 2 to 5 systematically demonstrate, from the opposite perspective, the completeness, necessity, and advancement of this end-to-end magnetization technology system. Through the core means of magnetic fields, it systematically solves multiple challenges in cleanliness, efficiency, environmental protection, and performance inherent in traditional coating processes.

[0115] Furthermore, one or more technical solutions in the embodiments of this application have at least the following technical effects or advantages: In this embodiment, the principle of magnetization is adopted. By adding a magnetic field in the painting space, the problem of extra cleaning and wasted labor is addressed by the magnetic field. The magnetic field can magnetize the iron filings generated by grinding, so that these iron filings directly become part of the paint film. There is no need to remove the iron filings by cleaning, thus completely eliminating the cleaning process and avoiding labor waste.

[0116] In this embodiment of the application, in order to address the difficulties in handling waste iron filings and the problem of paint film defects caused by iron filings dust, the waste iron filings are transformed into part of the paint film material through the magnetization effect of a magnetic field, thereby improving the properties of the paint film and effectively reducing paint film defects caused by iron filings dust.

[0117] In this embodiment of the application, in order to address the problem of paint mist escaping and polluting the environment during the spraying process, a magnetic field is applied to the spraying site to polarize the paint droplets after spraying, which significantly reduces the amount of paint escaping after atomization, thereby reducing environmental pollution.

[0118] 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 magnetization painting method characterized by, The method comprises: magnetizing and degreasing the substrate to be degreased to obtain a degreased substrate; magnetizing and polishing the degreased substrate, and the iron filings generated during the magnetizing and polishing process are magnetized and fixed on the surface of the degreased substrate to obtain a polished substrate; magnetizing the substrate to obtain a magnetized substrate; magnetizing the paint and coating the magnetized paint on the surface of the magnetized substrate; magnetizing and drying the magnetized substrate coated with the paint to obtain a dry coating; demagnetizing the dry coating to obtain a coated product.

2. The method of claim 1, wherein, The magnetizing and degreasing the substrate to be degreased comprises: placing the substrate to be degreased in a magnetic field with a first set magnetic field strength, and spraying an alkaline degreasing agent on the surface of the substrate to be degreased; after spraying the alkaline degreasing agent, standing for a period of time, and then rinsing the surface of the substrate to be degreased with deionized water.

3. The method of claim 2, wherein, The first set magnetic field strength is 0.1T-0.5T; The standing time is 5s-15s.

4. The method of claim 1, wherein, The magnetizing and polishing the degreased substrate comprises: placing the degreased substrate in a magnetic field with a second set magnetic field strength, and using magnetic abrasives with different mesh sizes to polish the surface of the degreased substrate in multiple stages.

5. The method of claim 4, wherein, The second set magnetic field strength is 0.1T-0.5T.

6. The method of claim 4, wherein, Polishing the surface of the degreased substrate in multiple stages using magnetic abrasives with different mesh sizes comprises: using a magnetic abrasive with a mesh size of 80 to polish the surface of the degreased substrate in the first stage for 20s-40s; using a magnetic abrasive with a mesh size of 325 to polish the surface of the degreased substrate in the second stage for 50s-70s; using a magnetic abrasive with a mesh size of 1000 to polish the surface of the degreased substrate in the third stage for 4min-6min; placing the degreased substrate after polishing in a magnetic field with a magnetic field strength of 4T-6T for 4s-6s for demagnetization.

7. The method of claim 1, wherein, The magnetic field strength of the substrate magnetization process is 1T-15T.

8. The method of claim 1, wherein, The magnetizing the paint comprises: applying a magnetic field to the flight path of the paint from the spray gun to the magnetized substrate; the length of the flight path is 0.1m-1.0m.

9. The method of claim 1, wherein, The magnetizing and drying the magnetized substrate coated with the paint comprises: placing the magnetized substrate coated with the paint in a magnetic field with a third set magnetic field strength, and heating the coating of the paint to a set temperature and keeping it at the set temperature for a set time.

10. The method of claim 9, wherein, The third set magnetic field strength is 0.1T-1T.

11. The method of claim 9, wherein, The set temperature is 50℃-70℃, and the set time is 15min-60min.

12. The method of claim 1, wherein, The magnetic field strength of the demagnetization process is 1T-15T, and the duration of the demagnetization process is 1s-10s.

13. The method of claim 1, wherein, The magnetic fields involved in the magnetizing and degreasing, the magnetizing and polishing, the substrate magnetization, the paint magnetization, the magnetizing and drying, and the demagnetization are generated by superconducting electromagnets.

14. The method of claim 13, wherein, The superconducting electromagnet comprises a magnetic core and a wire; The material of the magnetic core is silicon steel with a silicon content of 3.5%-5%; The material of the wire is yttrium barium copper oxide superconducting material.

15. The method of claim 13, wherein, The superconducting electromagnet is configured with a current reversing switch for changing the direction of the magnetic field generated by the superconducting electromagnet.

16. The method of claim 1, wherein, The coated product includes a substrate and a coating covering the surface of the substrate, and the coating contains magnetized and embedded iron filings particles.

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