Anti-icing coating, preparation method and application thereof and anti-icing system

Abstract

The invention belongs to the technical field of chemical material engineering, and particularly relates to an anti-icing coating, a preparation method and application thereof and an anti-icing system. The anti-icing coating comprises nano ferrite particles and a polymer; and the nano ferrite particles are dispersed and fixed in the polymer through chemical action. The preparation method comprises the following steps: carrying out hydrolytic polymerization reaction on a polymer precursor to form polymer sol; the preparation method comprises the following steps: mixing nano ferrite particles with polymer sol to prepare mixed sol, applying the mixed sol to the surface of a base material, and completing condensation reaction through heat treatment to form an anti-icing coating. The system comprises equipment coated with a coating; and the magnetic field generating device is used for applying an alternating magnetic field to the coating. According to the anti-icing coating provided by the invention, the nano ferrite particles are dispersed and fixed on the polymer through a chemical effect, and the magnetic hysteresis and eddy current effect of the nano ferrite are excited by an external alternating magnetic field so as to generate heat, so that efficient heat production and active anti-icing are realized, and the anti-icing coating can be widely applied to various base materials.

Description

Technical Field

[0001] This invention belongs to the field of chemical materials engineering technology, specifically relating to an anti-icing coating, its preparation method and application, and an anti-icing system. Background Technology

[0002] In low-temperature, high-humidity environments, especially in cold climates, icing frequently occurs on the surfaces of high-voltage transmission lines, communication lines, and wind power generation equipment. Icing not only hinders equipment power recovery but can also cause mechanical damage and even shutdowns. Therefore, employing effective anti-icing technologies is crucial for improving equipment stability and safety.

[0003] Existing anti-icing technologies typically include mechanical heating, electric heating, heat pipe heating, and chemical anti-icing methods. Electric heating anti-icing technology uses an electric heater to transfer heat to the equipment surface, but this method is sensitive to heat and prone to failure in extreme environments. In contrast, technologies that achieve anti-icing through the thermal conductivity or electrothermal properties of coating materials have significant advantages, especially with the application of nanomaterials to improve thermal efficiency and anti-icing performance.

[0004] Currently, common anti-icing / de-icing technologies are mainly divided into two categories: active and passive.

[0005] 1. Active anti-icing technologies (such as thermal melting and mechanical de-icing) typically consume a lot of energy, have complex systems, and their reliability decreases in extreme environments.

[0006] 2. Passive anti-icing technology mainly relies on the properties of the coating material itself. Its low cost, low energy consumption, and ease of implementation have made it a key research focus. Passive anti-icing coatings mainly include the following categories:

[0007] Superhydrophobic coatings refer to coating materials where the static contact angle of water on their surface is greater than 150° and the roll-off angle is less than 10°. Their anti-icing principle primarily relies on a special micro / nano rough structure to adsorb air, forming an air film that delays ice crystal nucleation, reduces ice adhesion, and causes water droplets to roll off before freezing. The core superhydrophobic properties are highly dependent on the fragile and easily worn micro / nano structures. After mechanical wear, UV aging, or multiple freeze-thaw cycles, the microstructure is damaged, leading to a sharp decline in anti-icing performance or even permanent failure. Studies show that as icing / de-icing cycles continue, the ice adhesion strength of the superhydrophobic coating gradually increases, and the contact angle gradually decreases, eventually achieving anti-icing performance comparable to ordinary hydrophobic coatings. Poor environmental adaptability: Under conditions of continuous freezing rain, high humidity (such as fog), or impact from supercooled water droplets, water droplets easily penetrate and fill the recesses between the micro / nano structures, destroying the air film and causing a "pinning" effect, which in turn increases ice adhesion and may even cause the coating to fail completely. Superhydrophobic coatings primarily function to "delay" icing and "facilitate" ice removal; they cannot actively generate heat to prevent ice formation. Under extreme low temperatures or continuous icing conditions, ice will eventually accumulate, failing to address the root cause of the problem.

[0008] Photothermal coatings: By adding photothermal materials (such as carbon nanotubes, iron oxide, etc.) to the coating, solar energy is converted into heat energy, raising the surface temperature to achieve anti-icing / de-icing. Photothermal coatings rely entirely on solar radiation intensity for their energy source. Under conditions of insufficient or no sunlight, such as at night, on cloudy days, in foggy weather, or during polar winters, their anti-icing effectiveness will significantly decrease or even completely fail, failing to meet all-weather, all-time application requirements. The photothermal conversion efficiency is limited by the material itself and lighting conditions; the heating may not be rapid or uniform, making it difficult to handle scenarios involving rapid cooling or large-area icing.

[0009] Other Magnetic Heating Coatings: These coatings utilize the hysteresis or eddy current effects of magnetic fillers (such as micron-sized ferrite or metal alloy powders) under an alternating magnetic field to generate heat. The hysteresis and eddy current losses of micron-sized magnetic particles are far lower than those of nanoscale materials, resulting in a significantly lower specific absorptivity (SAR). To achieve effective anti-icing temperatures, a stronger magnetic field is often required, leading to high energy consumption and complex equipment. To ensure sufficient heat generation, a large amount of magnetic filler (high filler ratio) is often needed, which degrades the coating's mechanical properties (such as toughness and adhesion), making it prone to cracking and peeling. If metal alloy fillers are used, there is also a risk of electrochemical corrosion, affecting the coating's lifespan and reliability.

[0010] Transparent anti-icing coatings: These employ a composite structure of a hydrophilic bottom layer and a hydrophobic top layer, balancing light transmittance with some anti-icing functionality. However, their anti-icing ability still relies on the traditional superhydrophobic principle (hydrophobic top layer) and hygroscopic principle (hydrophilic bottom layer), and they cannot actively generate heat, resulting in limited anti-icing effectiveness under severe icing conditions. The multi-layered composite structure places high demands on the manufacturing process, and the bonding strength and long-term stability between the layers, especially their performance durability under temperature variations, remain unknown.

[0011] In summary, existing anti-icing coatings are insufficient to meet the demands of modern industrial equipment for efficient, reliable, low-energy-consumption, and all-weather active anti-icing.

[0012] Existing magnetothermal anti-icing or de-icing coatings have the following significant drawbacks:

[0013] Micron-sized ferrite / polymer composites: have low heating efficiency, with hysteresis and eddy current losses of micron-sized particles being much lower than those of nano-sized particles, resulting in significantly lower SAR values; require high-strength magnetic fields, and to achieve effective heat generation, stronger alternating magnetic fields are often required, leading to high energy consumption and complex equipment; there is a contradiction between the mechanical properties and heating performance of the coating, and although high filler content (30-40 parts) increases heating, it reduces coating toughness and adhesion, making it prone to cracking and peeling.

[0014] Metal alloy magnetic fillers, using metallic magnetic materials such as iron-manganese alloys, generate heat through the eddy current effect. However, they pose a risk of corrosion: in humid environments, metal alloy fillers are prone to electrochemical corrosion, leading to coating failure. Their high density also causes sedimentation: the high density of the metal particles makes them prone to sedimentation during coating preparation and curing, resulting in uneven distribution. Furthermore, some low Curie point materials lose magnetism and cease heating after reaching a specific temperature, limiting the maximum temperature.

[0015] Ferrites are a special type of magnetic material composed of iron, oxygen, and one or more other metallic elements (such as manganese and nickel), exhibiting rich magnetic properties and practical value. Ferrites can be classified into soft magnetic ferrites and hard magnetic ferrites, based on their magnetic characteristics. Soft magnetic ferrites are easily magnetized and demagnetized, while hard magnetic ferrites remain magnetized. They are also named based on their specific structures and compositions, such as spinel and perovskite. Since the late 20th century, nanoscale ferrites (especially Fe3O4) have generated heat under alternating magnetic fields, finding applications in the biomedical field. The most typical application is magnetohydrodynamic (MHD) therapy, where nanoparticles are injected into tumor areas and heated by an external alternating magnetic field to kill cancer cells.

[0016] Chinese patent application CN119081541A discloses a magnetronically controlled active anti-icing / de-icing coating, its preparation method, and its de-icing method. This coating uses silicone oil as the lubricating or functional phase, which inevitably suffers from migration, volatilization, and loss. Under temperature changes, wind and rain, or ultraviolet radiation, its performance rapidly degrades, and the anti-icing effect becomes unsustainable. While high levels of micron / nano fillers can increase heat generation, they severely disrupt the continuity of the polymer matrix, leading to brittle coatings, reduced adhesion, and easy cracking. There is an irreconcilable contradiction between performance and reliability. Most existing methods focus on passive mechanisms such as "reducing ice adhesion" or "delaying icing," or attempt to remove ice after it has formed through energy input. Summary of the Invention

[0017] (a) Technical problems to be solved

[0018] In view of the above-mentioned shortcomings and deficiencies of the prior art, the present invention provides an anti-icing coating, which disperses and fixes nano-ferrite particles in a polymer through chemical action, and generates heat by stimulating the hysteresis and eddy current effect of the nano-ferrite through an external alternating magnetic field, so as to achieve efficient heat generation and active anti-icing; and solves the problem of filler migration and detachment, thereby maintaining the long-term stable dispersion of magnetic fillers.

[0019] Accordingly, the present invention also provides a method for preparing an anti-icing coating and its application;

[0020] Accordingly, the present invention also provides an anti-icing system.

[0021] (II) Technical Solution To achieve the above objectives, the main technical solutions adopted by this invention include:

[0022] In a first aspect, the present invention provides an anti-icing coating comprising nano-ferrite and a polymer; wherein the nano-ferrite particles are dispersed and fixed in the polymer by chemical action.

[0023] This invention specifically addresses the challenges of long-term stability, anti-migration, anti-volatilization, anti-aging, and mechanical properties under high filler content by chemically binding nano-ferrite particles. However, the chemical bonding method employed in this invention is relatively complex and requires higher standards for cost and process control. As demonstrated in Chinese patent application CN119081541A, which uses a physical blending method with silicone rubber and silicone oil as dispersants, this approach is simpler and lower in cost, illustrating the existence of technological bias and path dependence in this field.

[0024] The excellent dispersibility of the polymer in this invention allows the nano-ferrite particles, as fillers, to be uniformly distributed in micro- and nano-scale clusters, avoiding macroscopic agglomeration. This ensures that the nano-ferrite particles are fully exposed to the alternating magnetic field, greatly improving the heat generation efficiency per unit mass of filler. The nano-ferrite particles, as fillers, are firmly anchored in the three-dimensional network of the polymer through chemical bonds, resulting in extremely strong resistance to erosion, aging, and shedding. No easily migrating liquid additives are required.

[0025] Meanwhile, the robust polymer allows for a higher proportion of filler without sacrificing mechanical properties. This invention significantly improves active heating efficiency while simultaneously enhancing the mechanical strength and adhesion of the coating. It breaks the conventional wisdom held by those skilled in the art that "high filler content inevitably leads to deterioration of mechanical properties," resulting in a synergistic effect of "1+1>2."

[0026] Optionally, the chemical interaction between the nano-ferrite and the polymer includes one or more combinations of covalent bonds, coordination bonds, and hydrogen bonds.

[0027] The technical solution of this invention provides multiple chemical pathways to achieve firm fixation, among which covalent bonds provide the strongest and most durable force, ensuring optimal effect and stability.

[0028] Optionally, the polymer is a weather-resistant polymer resin.

[0029] Optionally, the polymer matrix is ​​a polysiloxane resin.

[0030] Optionally, the polysiloxane resin is an organic-inorganic hybrid polysiloxane prepared by the sol-gel method.

[0031] In this invention, the sol-gel method is the optimal method for chemical bonding. Its advantage lies in achieving uniform dispersion and fixation of nanoparticles at the molecular level, forming a novel and stable hybrid material, rather than a simple mixture.

[0032] Optionally, the organic-inorganic hybrid polysiloxane is prepared by hydrolysis and condensation of an alkoxysilane precursor.

[0033] Optionally, the alkoxysilane precursor is selected from one or more of methyltrimethoxysilane (MTMS), methyltriethoxysilane (MTES), and tetraethyl orthosilicate (TEOS).

[0034] Optionally, the polymer is an epoxy resin, a polyurethane resin, or an acrylic resin, and the surface of the nano-ferrite particles is treated with a silane coupling agent.

[0035] This technical solution uses lower-cost and more widely applicable resins. Through silane coupling agents, it can also significantly improve filler dispersibility and interfacial bonding, greatly enhancing the durability of these traditional resin-based magnetothermal coatings. Although the effect is lower than that of sol-gel systems, it still represents a significant improvement over physical blending.

[0036] Optionally, the hydrolysis products of the polymer undergo a condensation reaction with the hydroxyl groups on the surface of the nano-ferrite.

[0037] In this technical solution, the strongest Si-O-Fe covalent bond is formed through a condensation reaction, resulting in the strongest binding force and the highest stability.

[0038] Optionally, the nano-ferrite particles are Fe2O4 or MFe2O4, wherein M is a divalent metal ion selected from Ni. 2+ Co 2+ Zn 2+ Mn 2+ One or more of them.

[0039] This technical solution provides a variety of high-performance magnetic materials. Different ferrites exhibit optimal heating performance under alternating magnetic fields of different frequencies and intensities. This invention allows for the selection of the most suitable and energy-efficient ferrite material based on the parameters of the external magnetic field equipment, thereby achieving customization and maximizing the efficiency of the anti-icing system.

[0040] Optionally, the average particle size of the nano-ferrite particles is 5 nm to 100 nm.

[0041] In the nanoscale range, the material exhibits a significant size effect, its magnetocaloric mechanism is more efficient, and its SAR value is much higher than that of micron-scale fillers, thereby achieving the technical effects of low-energy consumption and fast-response heating de-icing and anti-icing.

[0042] Optionally, the mass fraction of the nano-ferrite particles in the coating is 5% to 40%.

[0043] In the technical solution of this invention, if the mass fraction of nano-ferrite particles is <5%, the heat generation is insufficient; if it is >40%, it is difficult to guarantee good dispersibility and mechanical properties. Within this range, sufficient heat generation power can be provided while ensuring excellent dispersibility and mechanical properties of the coating.

[0044] Secondly, the present invention also provides a method for preparing the anti-icing coating described in any of the above embodiments, the steps of which include:

[0045] The polymer precursor is hydrolyzed and polymerized to form a polymer sol;

[0046] A mixed sol was prepared by mixing the nano-ferrite particle dispersion with the polymer sol.

[0047] The mixed sol is applied to the surface of the substrate, and the condensation reaction is completed through heat treatment to form the anti-icing coating.

[0048] Optionally, the polymer precursor is an alkoxysilane precursor, which is formed by hydrolysis and polymerization.

[0049] Optionally, the alkoxysilane precursor is methyltrimethoxysilane.

[0050] Thirdly, the present invention also provides the application of the anti-icing coating described in any of the above embodiments in substrate anti-icing, including the following steps: applying an alternating magnetic field to the substrate coated with the anti-icing coating.

[0051] Optionally, the frequency of the alternating magnetic field is 10kHz to 1MHz, and the magnetic field strength is 1kA / m to 100kA / m.

[0052] This invention achieves true "preventative" active anti-icing: due to the coating's high efficiency, stability, and rapid response, it can actively maintain the surface temperature above 0°C when icing conditions occur, thus completely preventing the formation and accumulation of ice crystals. This represents a fundamental strategic leap compared to existing technologies that typically perform "de-icing" after icing has occurred. It also results in lower energy consumption and stronger protection for equipment safety. Energy is transferred via a magnetic field, solving the problem of difficult wiring and power supply for high-voltage and rotating equipment. This ensures extremely high safety, strong energy targeting, and minimal energy loss.

[0053] In particular, by utilizing an alternating magnetic field to excite the magnetocaloric effect of nano-ferrites, electromagnetic energy is efficiently converted into thermal energy, thereby achieving proactive and preventative anti-icing.

[0054] Thirdly, the present invention also provides an anti-icing system, comprising:

[0055] Equipment coated with the anti-coating coating of any of the above schemes;

[0056] And a magnetic field generating device for applying an alternating magnetic field to the coating;

[0057] The frequency of the alternating magnetic field is 10kHz to 1MHz, and the magnetic field strength is 1kA / m to 100kA / m.

[0058] The system provided by this invention is applicable to equipment coated with the anti-icing coating described in any of the above-mentioned schemes. It solves the last-mile problem from materials to equipment, enabling this high-performance active anti-icing technology to be truly implemented in key sectors of the national economy, such as power grids, aviation, and wind power.

[0059] Optionally, the equipment includes high-voltage transmission lines, wind turbine blades, communication antennas, and aircraft wings.

[0060] (III) Beneficial Effects

[0061] The beneficial effects of this invention are:

[0062] The anti-icing coating provided by the present invention disperses and fixes nano-ferrite particles in a polymer through chemical action, and generates heat by stimulating the hysteresis and eddy current effect of the nano-ferrite through an external alternating magnetic field, so as to achieve efficient heat generation and active anti-icing.

[0063] Among them, the chemical bonding between nano-ferrite particles and polymers can solve the problem of filler migration and detachment, thereby maintaining the long-term stable dispersion of magnetic fillers. Detailed Implementation

[0064] To illustrate the possible application scenarios, technical principles, implementable specific solutions, and achievable objectives and effects of this application in detail, the following description is provided in conjunction with the specific embodiments listed. The embodiments described herein are merely illustrative of the technical solutions of this application and are therefore intended only as examples, not as limiting the scope of protection of this application.

[0065] In this document, the term "embodiment" means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The term "embodiment" appearing in various places throughout the specification does not necessarily refer to the same embodiment, nor does it specifically limit its independence or connection with other embodiments. In principle, in this application, as long as there are no technical contradictions or conflicts, the technical features mentioned in each embodiment can be combined in any way to form corresponding implementable technical solutions.

[0066] Unless otherwise defined, the technical terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the use of related terms herein is merely for the purpose of describing particular embodiments and is not intended to limit this application.

[0067] In the description of this application, the term "and / or" is used to describe the logical relationship between objects, indicating that three relationships can exist. For example, A and / or B means: A exists, B exists, and A and B exist simultaneously. Additionally, the character " / " in this document generally indicates that the preceding and following objects have an "or" logical relationship.

[0068] In this application, terms such as “first” and “second” are used only to distinguish one entity or operation from another, and do not necessarily require or imply any actual quantity, hierarchy or order relationship between these entities or operations.

[0069] Unless otherwise specified, the use of terms such as “comprising,” “including,” “having,” or other similar expressions in this application is intended to cover non-exclusive inclusion, which does not exclude the presence of additional elements in a process, method, or product that includes the stated elements, such that a process, method, or product that includes a list of elements may include not only those defined elements but also other elements not expressly listed, or elements inherent to such a process, method, or product.

[0070] Similar to the understanding in the Examination Guidelines, in this application, expressions such as "greater than," "less than," and "exceeding" are understood to exclude the stated number; expressions such as "above," "below," and "within" are understood to include the stated number. Furthermore, in the description of the embodiments in this application, "multiple" means two or more (including two), and similar expressions related to "multiple" are also understood in this way, such as "multiple groups" and "multiple times," unless otherwise explicitly specified.

[0071] In the description of the embodiments of this application, the space-related expressions used, such as "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "vertical," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential," indicate the orientation or positional relationship based on the orientation or positional relationship shown in the specific embodiments. They are only for the purpose of describing the specific embodiments of this application or for the reader's understanding, and do not indicate or imply that the device or component referred to must have a specific position, a specific orientation, or be constructed or operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0072] In the embodiments of this invention, the parameters (such as reactant mass, solution volume, and reaction time) are not fixed. Those skilled in the art will understand that the preparation method can be scaled up or down proportionally according to production needs. Process parameters (such as concentration, pH, temperature, and time) can be adjusted within the given range. These adjustments are all based on the same chemical reaction principle and fall within the scope of what those skilled in the art can determine through conventional experiments, without requiring creative effort.

[0073] Example 1

[0074] This invention provides a method for preparing Fe3O4 nano-ferrites for use in anti-icing coatings, the steps of which are as follows:

[0075] Preparation of S1 precursor solution:

[0076] Soluble ferric salts, such as ferric chloride hexahydrate (FeCl3·6H2O), are dissolved in deionized water to prepare ferric ion solutions with a concentration of 0.05 mol / L to 0.5 mol / L.

[0077] S2 coprecipitation reaction:

[0078] Under stirring and an inert atmosphere, a precipitant, which can be selected from ammonia, sodium hydroxide solution, or urea solution, is slowly added to the iron ion solution. The pH value of the reaction is adjusted to the range of 8.5 to 11; the reaction temperature is maintained at 60℃ to 90℃, and the reaction is continuously stirred for 1 to 4 hours to generate a reddish-brown precipitate of iron hydroxide Fe(OH)3.

[0079] S3 Washing and Purification: After the reaction, the obtained ferric hydroxide Fe(OH)3 precipitate was filtered and repeatedly washed and centrifuged with deionized water and ethanol until the filtrate was neutral and no chloride ions were detected by silver nitrate solution, to ensure the complete removal of excess anions (such as Cl-). - ) and salt.

[0080] This invention provides a more specific method for preparing Fe3O4 nano-ferrites for use in anti-icing coatings, the steps of which are as follows:

[0081] Preparation of S1 precursor solution: Dissolve 10g of ferric chloride (FeCl3) solution in 100mL of deionized water to prepare a 0.1mol / L FeCl3 solution.

[0082] S2 coprecipitation reaction: Ammonia water is added to the above FeCl3 solution, the pH value is adjusted to 9, and the reaction is maintained at 70℃ with stirring for 2 hours to generate a reddish-brown Fe(OH)3 precipitate.

[0083] S3 filtration and washing: The precipitate is washed multiple times with deionized water to avoid unnecessary salt.

[0084] S4 High-Temperature Calcination: The washed precipitate is calcined at 500℃ for 4 hours to transform it into Fe3O4 nano-ferrite.

[0085] S5 Post-processing and dispersion: Cool to granulation, disperse the granules using a sieve and a dispersant (such as PVP) to obtain uniform nano Fe3O4 granules.

[0086] The nano-Fe3O4 particles prepared by the above method in this embodiment have an average particle size that can be controlled between 10 nm and 100 nm, and have good crystallinity and magnetism, making them suitable for the preparation of high-performance magnetothermal anti-icing coatings.

[0087] Example 2

[0088] This invention discloses a method for preparing NiFe2O4 nano-ferrites for use in anti-icing coatings, comprising the following steps:

[0089] Preparation of S1 precursor solution: Dissolve 0.05 mol ferric chloride (FeCl3) and 0.025 mol nickel chloride (NiCl2) in 100 mL of deionized water and mix thoroughly;

[0090] S2 coprecipitation reaction: Add ammonia to adjust the pH to 9, maintain the reaction temperature at 80℃, stir for 3 hours to generate granular precipitate;

[0091] S3 filtration and washing: Wash the precipitate repeatedly with deionized water;

[0092] S4 calcination: The precipitate was calcined at 550℃ for 5 hours to obtain NiFe2O4 nano-ferrite;

[0093] S5 Post-processing and dispersion: After cooling the product, it is sieved to obtain NiFe2O4 nano-ferrite powder with uniform particle size.

[0094] Example 3

[0095] This invention provides a method for preparing an anti-icing coating.

[0096] Alkoxysilane precursor: 10-20 parts; the preferred alkoxysilane precursor is methyltrimethoxysilane.

[0097] Alcohol solvent: 50-75 parts; the alcohol solvent is selected from one or more of ethanol and isopropanol, and is used to dissolve the precursor and control the rate of hydrolysis-condensation reaction;

[0098] Water: 8–20 parts; used for hydrolysis reaction;

[0099] Acidic catalyst: 0.5–2 parts; the acidic catalyst is a dilute hydrochloric acid or dilute acetic acid solution, used to catalyze the hydrolysis reaction. Its concentration is preferably 0.05 M–0.5 M.

[0100] Nano-ferrite particles prepared in Example 1 or Example 2: 5-15 parts; the nano-ferrites are Fe3O4 or NiFe2O4 particles with surface pretreatment and an average particle size of 10nm-50nm. Their surface can be treated with a silane coupling agent to improve compatibility with the matrix;

[0101] (Optional addition) Dispersant: 0.5 to 3 parts; the preferred dispersant is polyvinylpyrrolidone (PVP) or BYK series polymeric dispersants, used to promote the stable dispersion of nanoparticles in the sol;

[0102] (Optional addition) Surface performance modifier: 0 to 2 parts; the modifier may be fluorosilane, etc., used to further adjust the surface energy of the coating.

[0103] The specific steps are as follows:

[0104] S1 Preparation of polysiloxane sol: In a reaction vessel, add 70% to 80% of the weight of the alcohol solvent, all the weight of water, and slowly add all the weight of the acid catalyst. Stir until homogeneous. While stirring, slowly add the alkoxysilane precursor. Maintain the temperature at 20°C to 40°C and continue stirring for 0.5 to 2 hours to allow it to fully hydrolyze and obtain the polysiloxane sol.

[0105] S2 Preparation of Nanocomposite Sol: Ferrite nanoparticles and an optional dispersant are pre-dispersed in an alcohol solvent at 20%–30% by weight by ultrasonic treatment for 30 minutes to form a uniform slurry. Under stirring conditions, the slurry is slowly added to the polysiloxane sol prepared in all steps of S1, and stirring is continued for 1–2 hours to ensure uniform mixing, thus obtaining the nanocomposite sol for coating.

[0106] S3 Coating and Curing: The substrate is pretreated by cleaning, sanding, and drying. The obtained nanocomposite sol is applied to the substrate surface using dip coating, dip coating, or spray coating. The coated substrate is then aged at room temperature for 0.5 hours, followed by heat treatment at 80℃~150℃ for 1~2 hours to allow the sol to fully gel and complete the condensation reaction, ultimately forming a dense and uniform anti-icing coating on the substrate surface. The dry film thickness can be controlled between 20μm and 200μm by the number of coatings.

[0107] In this embodiment, the substrate pretreatment method is as follows: the substrate surface is cleaned with photons to remove cosmetics and grease. Hot air or vacuum drying is then used to ensure the substrate surface is completely dry.

[0108] In this embodiment, the dip coating method is as follows: the substrate is immersed in the sol, left for a few seconds, and then slowly pulled out to avoid air bubbles.

[0109] The spraying method involves using a spray gun to evenly spray the sol, controlling the spraying speed and distance.

[0110] The brush coating method is suitable for small-area coatings and uses a brush to apply the solution.

[0111] The anti-icing coating obtained in this embodiment contains nano-ferrite particles. When an external alternating magnetic field is applied, these nano-ferrite particles, acting as magnetic particles, undergo hysteresis, leading to energy loss. Eddy current loss and hysteresis loss generate heat within the coating material. Due to the ultra-fine size and high insulation of the nano-ferrite particles in the coating, hysteresis loss and eddy current loss are effectively increased, thereby enhancing heat generation. At specific frequencies and intensities, the coating can convert electromagnetic energy into heat energy, reaching the equipment surface and preventing the condensation and accumulation of ice and snow.

[0112] Examples 4-6 provide a more specific method for preparing an anti-icing coating compared to Example 3. The steps are the same as in Example 3, except that the values ​​of each parameter are as shown in Table 1.

[0113] Table 1

[0114]

[0115]

[0116] The heating of nano-ferrites under a magnetic field typically originates from hysteresis loss, Néel relaxation, and Brownian relaxation in an alternating magnetic field (AMF). When the magnetic field is 0.3T (3000 Gauss), the heating power is typically expressed as SAR (in W / g), which is then converted to power per unit area (W / m²) based on material density and coating area. 2 The calculation formula is as follows:

[0117] SAR = P / m (where P is the heating power and m is the mass of the nanoparticles);

[0118] Heat output per unit area (W / m) 2 ) = SAR × ρ × h (ρ is the coating density, h is the coating thickness).

[0119] Experimental measurements showed that:

[0120] SAR values ​​of nano-ferrites (such as Fe3O4) under alternating magnetic fields:

[0121] Under magnetic field strengths of 15–48 kA / m (approximately 0.02–0.06 T) and frequencies of 123–430 kHz, the SAR values ​​of 8–18 nm Fe3O4 nanoparticles range from 30 W / g to 326 W / g.

[0122] Larger Fe3O4 nanoparticles (>20 nm) exhibit near-theoretical SAR (1000 W / g) at higher frequencies and magnetic field strengths. Under an alternating magnetic field of 0.3 T amplitude and in the frequency range of 100–500 kHz (common in magnetocaloric studies), the SAR ranges from 100 to 500 W / g, with the specific value depending on particle size and optimization. This translates to a heat output per unit area of ​​SAR = 200 W / g (a moderate estimate); the density of the nano-ferrite coating ρ ≈ 5 g / cm³. 3 (Typical density of Fe3O4, 5000 kg / m³) 3 );

[0123] Thickness h = 100 nm (10 -7 Coating calculation for m (typical thin coating),

[0124] Mass surface density = ρ × h = 5000 kg / m 3 ×10 -7 m = 0.0005 kg / m 2 ;

[0125] Heat generation power per unit area = SAR × surface density = 200 W / g × 0.0005 kg / m³ 2 =100W / m 2 ;

[0126] If the coating is thicker (e.g., 1μm, 10) -6 If m), then: surface density = 0.005 kg / m³ 2 Heating power

[0127] = 200W / g × 0.005kg / m 2 =1000W / m 2 .

[0128] Compared with traditional micron-scale materials, nano-ferrite materials have higher specific surface area and magnetic responsiveness, especially at the nanoscale, where hysteresis loss and relaxation mechanisms are more efficient.

[0129] In summary, this invention can achieve an anti-icing coating of 100 W / m by controlling the properties (particle size, SAR value) of the nano-ferrite material and the coating design (thickness). 2 ~1000W / m 2 Even higher, with a wide range of flexibly adjustable heating power per unit area.

[0130] Example 7

[0131] This embodiment provides a porous anti-icing coating compared to Embodiment 4. The steps are the same as in Embodiment 4, but the difference is:

[0132] The prepared polysiloxane sol contains 0.5 to 5 parts by weight of a pore-forming agent. When the pore-forming agent is added, it is stirred until it is completely dissolved or uniformly dispersed. The pore-forming agent is polyethylene glycol (PEG, molecular weight 400-6000).

[0133] In other specific embodiments, heat treatment at higher temperatures can be performed under a specific atmosphere to stabilize the pore structure.

[0134] In other specific embodiments, the pore-forming agent may be selected from polyethylene glycol (PEG, molecular weight 400-6000), hexadecyltrimethylammonium bromide (CTAB), or thermally decomposable polymer microspheres.

[0135] In other specific embodiments, the amount of pore-forming agent added is 0.5 parts by weight, 2 parts by weight, 3 parts by weight, and 5 parts by weight.

[0136] This embodiment features a porous anti-icing coating. Experiments have shown that the coating contains uniformly distributed micron or nano-sized pores with a porosity between 10% and 40%.

[0137] Experimental results showed that, under identical conditions, the porous anti-icing coating prepared with the addition of a pore-forming agent, compared to the coating without the addition of a pore-forming agent, exhibited the following performance:

[0138] Under the same alternating magnetic field conditions (300 kHz, 24 kA / m), the SAR value increased by 15% to 30%. This may be because the porosity reduces the dielectric constant of the material, reduces the shielding of the external magnetic field by eddy currents, and improves the utilization rate of the magnetic field.

[0139] Ice adhesion is reduced by about 20% to 50%, and combined with its active heating function, it exhibits superior anti-icing and de-icing effects.

[0140] This embodiment provides an anti-icing coating with a porous structure. By reducing the equivalent dielectric constant of the coating, the eddy current shielding effect is reduced, allowing the alternating magnetic field to penetrate the coating more deeply and excite more nanoparticles to generate heat. At the same time, the porous structure can reduce ice adhesion and produce a synergistic anti-icing effect with the active heating mechanism.

[0141] Example 8

[0142] This embodiment provides a multi-layer composite anti-icing coating, which includes a top layer, an intermediate layer, and a bottom layer arranged sequentially from top to bottom.

[0143] The bottom layer is an adhesive and thermally conductive layer, accounting for 20% of the total thickness. It contains a small amount of nano-ferrite. Its main function is to provide strong adhesion to the substrate and rapidly conduct heat from the heating layer to the substrate interface.

[0144] The middle layer is the heating layer, accounting for 60% of the total thickness. It is a high-load nano-ferrite / polysiloxane composite layer (ferrite content can reach 30-40%, which is the main magnetocaloric conversion functional layer).

[0145] The surface layer is a wear-resistant and ice-repellent layer, accounting for 20% of the total thickness. This layer does not contain magnetic fillers; in some other specific embodiments, it can be modified by adding wear-resistant particles (such as nano-Al2O3) or low surface energy substances (such as fluorosilanes) to give the coating excellent wear resistance, weather resistance and a certain degree of hydrophobicity.

[0146] The specific preparation method is as follows:

[0147] S1. Prepare each layer of sol separately:

[0148] Preparation of the bottom sol: 15 parts by weight of MTMS, 65 parts by weight of ethanol, 15 parts by weight of water, and 1.5 parts by weight of 0.1M hydrochloric acid were mixed and stirred for 1 hour for hydrolysis. 5 parts by weight of nano-boron nitride were added, and the mixture was ultrasonically dispersed for 30 minutes to obtain the bottom sol.

[0149] Preparation of the intermediate layer sol: 15 parts by weight of MTMS, 60 parts by weight of ethanol, 14 parts by weight of water, and 1.5 parts by weight of 0.1M hydrochloric acid were mixed and stirred for 1 hour for hydrolysis. 15 parts by weight of nano-Fe3O4 particles and 1.5 parts by weight of PVP dispersant were added, and the mixture was ultrasonically dispersed for 30 minutes to obtain the intermediate layer sol.

[0150] Preparation of the surface sol: 15 parts by weight of MTMS, 65 parts by weight of ethanol, 15 parts by weight of water, and 1.5 parts by weight of 0.1M hydrochloric acid were mixed and stirred for 1 hour for hydrolysis. 3 parts by weight of nano-Al2O3 were added and ultrasonically dispersed for 30 minutes to obtain the wear-resistant surface sol.

[0151] S2 Layer-by-Layer Coating and Pre-Cure: Aluminum alloy plate is used as the substrate for standard cleaning and pre-treatment, followed by ultrasonic cleaning with acetone and ethanol and drying.

[0152] Undercoating: Using a dip-coating method, the substrate is immersed in the undercoating sol and then pulled out at a uniform speed of 100 mm / min. Heat treatment at 80℃ for 15 minutes allows the sol to gel, forming a stable undercoating gel film.

[0153] Applying the intermediate layer: After the bottom gel film has cooled to room temperature, the intermediate layer sol is evenly sprayed onto the bottom layer using a spraying method. Pre-curing is then performed by heat treatment at 80°C for 15 minutes.

[0154] Surface coating: After the intermediate layer has cooled to room temperature, the substrate is immersed in the surface sol using the dip coating method and then pulled out at a uniform speed of 100 mm / min.

[0155] S3. Final Co-curing: The substrate coated with the base layer, intermediate layer, and top layer is placed in a programmed temperature oven for final curing: the temperature is increased from room temperature to 150°C at a rate of 2°C / min, and held at 150°C for 2 hours. During the curing process, strong chemical bonds are formed between the layers through the condensation reaction of silanol groups, ultimately resulting in a uniform gradient coating with no obvious interfaces between layers and extremely strong adhesion. The total dry film thickness is controlled at 100μm to obtain an anti-icing coating.

[0156] The anti-icing coating prepared in this embodiment was tested for adhesion using the cross-cut adhesion test according to ASTM D3359 standard. The results showed that the adhesion of the multilayer structure reached the highest level, grade 0 (no peeling).

[0157] Thermal management efficiency: Under the same alternating magnetic field (300 kHz, 24 kA / m), the surface heating process was monitored using an infrared thermal imager. Compared with a single coating, the gradient coating showed a more uniform surface temperature distribution and reduced the time to reach the target temperature (50 °C) by approximately 20%. This demonstrates that the thermally conductive filler (BN) in the underlayer effectively improves lateral heat diffusion and reduces localized overheating.

[0158] This embodiment successfully prepared a multilayer composite anti-icing coating with excellent comprehensive performance. This coating is not a simple stacking of layers, but rather forms an organic whole through chemical bonding, perfectly achieving a balance of high-strength adhesion, efficient heat generation, excellent wear resistance, and long-term stability. It solves a long-standing technical problem in this field and achieves unexpected technical results.

[0159] Example 9

[0160] In a high-voltage transmission line, the anti-icing coating prepared according to Examples 3-8 of this invention was applied. The coating thickness was set to 100 micrometers. By applying an alternating magnetic field with a frequency of 50Hz to the transmission line, the coating effectively generated heat under the influence of the magnetic field, keeping the surface of the transmission line above 0°C and successfully preventing the coverage of ice and snow.

[0161] Example 10

[0162] The anti-icing coatings prepared according to Examples 3-8 of this invention were coated on the surface of a wind turbine blade, with a coating thickness of 200 micrometers for each coating. Experimental results showed that the coatings effectively prevented icing on the wind turbine blades under extremely cold weather conditions, improving the generator's operating efficiency and reducing the cost of manual de-icing.

[0163] The anti-icing coating provided by this invention utilizes the hysteresis eddy current effect of nano-ferrite materials to generate heat efficiently under the action of an external electromagnetic field, effectively preventing ice formation on equipment surfaces. This coating has advantages such as low coating thickness, high-efficiency anti-icing, and strong stability, making it suitable for various equipment, and particularly promising for applications in extremely cold and snow-covered insulation fields.

[0164] The anti-icing coatings prepared in Examples 4, 7, and 8 of this invention were subjected to low-temperature anti-icing performance tests.

[0165] 1.1 Test Samples

[0166] Substrate material: bare aluminum alloy conductor. Cable coating preparation: anti-icing coatings prepared in Examples 4, 7, and 8. Ensure coating uniformity and optimize thickness.

[0167] Control group: Same substrate but without coating, used as a reference group for comparison.

[0168] 1.2 Low Temperature Environment Simulation

[0169] Ambient temperature control:

[0170] A low-temperature incubator or liquid nitrogen cooling system is used, with temperature gradients set (-10℃, -20℃, -30℃, and -40℃). Humidity control: relative humidity is set (50%-90%) to simulate humidity changes in the natural environment.

[0171] Cooling time: Pre-cool the sample to the set temperature to ensure consistent experimental conditions.

[0172] 1.3 Water droplet spraying and ice layer measurement

[0173] Water droplet spraying method

[0174] Dynamic spraying method: Using an ultrasonic atomizer to spray micron-sized water droplets (10-50μm) to simulate the freezing of natural fog droplets.

[0175] Ice thickness measurement

[0176] Optical microscopy: After the ice layer has formed, a high-resolution microscope is used to measure the thickness of the ice layer.

[0177] Laser confocal microscopy: This non-contact method measures the three-dimensional morphology of ice layers and analyzes the thickness distribution of ice layers.

[0178] Mass measurement method: First, weigh the sample (ice-free), then spray water droplets and let it freeze before weighing again. Calculate the ice layer mass: Ice layer mass = m_{coating + ice} - m_{coating} Then, calculate the ice layer thickness using density: h = mρAh = m Ah = ρAm Where: mm is the ice layer mass, ρ is the density of ice (0.92 g / cm³). 3 ), where AAA is the sample surface area.

[0179] 2. Results Analysis

[0180] 2.1 Changes in ice thickness

[0181] Table 2 shows the variation of ice thickness at different temperatures:

[0182] Table 2

[0183]

[0184]

[0185] Applicable devices:

[0186] This coating is suitable for surfaces of equipment prone to ice and snow evaporation, such as high-voltage transmission lines, communication equipment, wind turbines, solar photovoltaic panels, and aircraft wings.

[0187] It is particularly suitable for power transmission lines in extremely cold regions, high-pressure areas with ice and snow, and cold and humid coastal areas.

[0188] advantage:

[0189] Low refractive index: Due to the frictional magnetoresistance loss and eddy current loss of the nano ferrite coating, electromagnetic energy can be effectively converted into heat energy, reducing the high refractive index problem of traditional electric heating anti-icing systems.

[0190] Highly efficient anti-icing: The nano-ferrite generates heat, which can rapidly increase the surface temperature of the equipment, prevent ice and snow from depositing, and reduce the burden caused by ice and snow accumulation.

[0191] Robust: The coating material is a composite of nano-ferrite and high-temperature resistant resin, which has corrosion resistance, oxidation resistance and mechanical strength, adapts to chronic climatic conditions and extends service life.

[0192] Environmental protection: The anti-icing coating of the present invention can work under a variety of climate and environmental conditions, and is particularly suitable for cold regions and high humidity environments.

[0193] Comparative Example 1

[0194] This comparative example describes a method for preparing an anti-icing coating, which employs a physical blending process. The specific method is as follows:

[0195] S1. 15 parts by weight of the nano-iron particles prepared in Example 1 and 10 parts by weight of silicone oil are initially mixed in a beaker.

[0196] S2 grinds the above mixture three times on a three-roll mill to obtain a relatively uniform paste;

[0197] S3 blending: Mix the ground paste with 100 parts by weight of RTV-2 silicone rubber in a mixer for 1 hour;

[0198] S4 dilution coating: Add 50 parts by weight of n-heptane to the blend and continue stirring for 0.5 hours to reduce the viscosity and obtain a coatable mixture.

[0199] S5 Curing: Apply the mixture to the pretreated substrate (aluminum alloy plate) and cure at room temperature for 24 hours to form a coating with a dry film thickness of approximately 100 μm.

[0200] Comparative Example 2

[0201] This comparative example describes a method for preparing an anti-icing coating. The steps are the same as in Example 4, except that a non-alternating magnetic field is used to apply the coating.

[0202] Comparative Example 3

[0203] This comparative example describes a method for preparing an anti-icing coating, with the same steps as in Example 4, except that the average particle size of the nano-ferrite particles is 3 nm.

[0204] Comparative Example 4

[0205] This comparative example describes a method for preparing an anti-icing coating, with the same steps as in Example 4, except that the average particle size of the nano-ferrite particles is 120 nm.

[0206] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An anti-icing coating, characterized in that: It comprises nano-ferrite particles and a polymer; the nano-ferrite particles are dispersed and immobilized in the polymer through chemical action.

2. The anti-icing coating as described in claim 1, characterized in that, The chemical interactions between the nano-ferrite and the polymer include one or more combinations of covalent bonds, coordination bonds, and hydrogen bonds.

3. The anti-icing coating as described in claim 1, characterized in that: The nano-ferrite particles are Fe2O4 or MFe2O4, where M is a divalent metal ion selected from Ni. 2+ Co 2+ Zn 2+ Mn 2+ One or more of the following; optionally, the polymer is a weather-resistant polymer resin.

4. The anti-icing coating as described in claim 1, characterized in that: The average particle size of the nano-ferrite particles is 5 nm to 100 nm.

5. The anti-icing coating as described in claim 1, characterized in that: The mass fraction of the nano-ferrite particles in the coating is 5% to 40%.

6. A method for preparing an anti-icing coating as described in any one of claims 1-5, characterized in that, The steps include: The polymer precursor is hydrolyzed and polymerized to form a polymer sol; A mixed sol was prepared by mixing nano-ferrite particles with the polymer sol. The mixed sol is applied to the surface of the substrate, and the condensation reaction is completed through heat treatment to form the anti-icing coating.

7. The method for preparing the anti-icing coating as described in claim 6, characterized in that: The alkoxysilane precursor is methyltrimethoxysilane.

8. An application of the anti-icing coating according to any one of claims 1-5 in preventing icing of a substrate, characterized in that, Includes the following steps: An alternating magnetic field is applied to the substrate coated with the anti-icing coating.

9. The application of the anti-icing coating as described in claim 8 in preventing icing of a substrate, characterized in that: The frequency of the alternating magnetic field is 10kHz to 1MHz, and the magnetic field strength is 1kA / m to 100kA / m.

10. An anti-icing system, characterized in that, include: Equipment coated with an anti-icing coating as described in any one of claims 1-3; And a magnetic field generating device for applying an alternating magnetic field to the coating; The frequency of the alternating magnetic field is 10kHz to 1MHz, and the magnetic field strength is 1kA / m to 100kA / m.

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