A self-repairing low-temperature enamel coating, a low-temperature enamel composite siloxane hydrophobic coating, and preparation methods and applications thereof

Abstract

The present invention discloses a self-repairing low-temperature enamel coating, a low-temperature enamel composite silicone hydrophobic coating, and a preparation method and application thereof. The enamel coating utilizes mica flakes and graphene quasi-two-dimensional materials to assemble into a scalloped laminate structure. While enhancing mechanical properties, it uses kaolin to adsorb nano-rare earths. When the coating is damaged, it can quickly passivate the substrate, achieving an intelligent corrosion inhibition effect. As a primer for the low-temperature enamel composite silicone hydrophobic coating, it has good compatibility with a silica sol-modified silicone topcoat, so that the coating comprehensively combines the characteristics of high thermal hardness, high strength, good wear resistance, and self-repairing performance of the enamel primer and the characteristics of corrosion resistance, good toughness, and hydrophobicity of the silicone topcoat. It also breaks through the thickness limit of a single coating and is suitable for applications in environmentally friendly coated pots, marine anti-corrosion, and anti-fouling coatings. When preparing the coating, the primer and topcoat are wet-sprayed separately, and only a single baking and curing process is required, which greatly reduces energy consumption, has high production efficiency, and is simple in process.

Description

Technical Field

[0001] The present invention belongs to the technical field of functional coatings, and in particular relates to a self-repairing low-temperature enamel coating, a low-temperature enamel composite silicone hydrophobic coating, and a preparation method and application thereof. Background Art

[0002] Most non-stick pans on the market are coated with Teflon, which offers excellent hydrophobic and non-stick properties. However, the organic fluorine in Teflon coatings has a low melting point. When heated above 260°C, the organic fluorine in the coating evaporates and is absorbed by food and the human body, potentially harming human health. Furthermore, when heated, Teflon organic coatings have a low pencil hardness of only 1H at 200°C, making the coating less wear-resistant. After wear, the coating's hydrophobic properties deteriorate, and the non-stick effect becomes less than ideal.

[0003] With growing environmental awareness, coatings formed by hydrolyzing and polymerizing siloxane and applying it to metal surfaces have emerged. These coatings, based on a Si-O-Si inorganic network structure with various organic groups such as methyl, ethyl, and propyl attached to the framework, combine the corrosion resistance of inorganic coatings with the plasticity and hydrophobicity of organic coatings. These coatings are non-toxic and harmless, thus offering broad application prospects in the coatings field. Prior art uses a silica-alumina sol composite siloxane coating. After curing at 120-640°C, the coating has a pencil hardness of 3H-6H at 200°C measured at room temperature. Using a scouring pad as the abrasion tester, the coating wears through after 2000-6000 rubbings, exposing the substrate. Iron black, carbon black, whisker silicon, etc. are added as fillers to the silica-alumina sol composite siloxane coating for modification. When used for electric iron flat plate coating, its pencil 200℃ thermal hardness can be increased to 9H. However, when rubbed 5000 times with a scouring pad, the coating is worn through and the substrate is exposed. The main reason is that the coating thickness is less than 50μm and the thickness is limited. But overall, its wear resistance needs to be further improved. Summary of the Invention

[0004] In order to overcome the deficiencies of the prior art, the first object of the present invention is to provide a self-repairing low-temperature enamel coating having the characteristics of high thermal hardness, high strength, good wear resistance and self-repairing performance.

[0005] The second object of the present invention is to provide a low-temperature enamel composite silicone hydrophobic coating.

[0006] The third object of the present invention is to provide a method for preparing the above-mentioned low-temperature enamel composite silicone hydrophobic coating.

[0007] The fourth object of the present invention is to provide an application of the above-mentioned self-repairing low-temperature enamel paint or low-temperature enamel composite silicone hydrophobic coating.

[0008] The first object of the present invention can be achieved by adopting the following technical solutions:

[0009] A self-repairing low-temperature enamel coating comprises the following components in parts by weight: 40-50 parts of silica sol, 5-10 parts of aluminum sol, 2-5 parts of glass powder, 5-10 parts of SiC, 0.1-0.5 part of graphene, 2-6 parts of aluminum silicate, 1-3 parts of mica flakes, 0.2-1 part of cobalt black, 1.0-1.5 parts of NiO, 1.0-1.5 parts of MoO3, 2-6 parts of kaolin, 1-2 parts of rare earth filler; and XX to XX parts of nano-alumina.

[0010] Furthermore, the rare earth filler is adsorbed on the kaolin.

[0011] Furthermore, the rare earth filler is a cerium salt, preferably cerium nitrate and / or cerium acetate.

[0012] Furthermore, the particle size of the SiC is 10 to 50 μm.

[0013] Furthermore, the mica sheet diameter-to-thickness ratio is 50-70.

[0014] The second object of the present invention can be achieved by adopting the following technical solutions:

[0015] A low-temperature enamel composite silicone hydrophobic coating comprises any of the above-mentioned self-repairing low-temperature enamel coatings as a primer and a topcoat.

[0016] Furthermore, the topcoat comprises the following components in parts by weight:

[0017] 50-60 parts of siloxane, 3-7 parts of silicone oil, 1-3 parts of mica flakes, 0.1-0.5 parts of graphene, 20-25 parts of polyethylene glycol, and 2-5 parts of water.

[0018] Furthermore, the siloxane is a short-chain alkylsiloxane; preferably, the siloxane is one or a combination of two or more of methyltrimethoxysilane, methyltriethoxysilane, phenyltrimethoxysilane, tetraethoxysilane, and polydimethylsiloxane.

[0019] Furthermore, the silicone oil is one or a combination of two or more of hydroxy silicone oil, methyl silicone oil, and dimethyl silicone oil.

[0020] The third object of the present invention can be achieved by adopting the following technical solutions:

[0021] The method for preparing any of the above-mentioned low-temperature enamel composite silicone hydrophobic coatings comprises the following steps:

[0022] S1: first adsorbing the rare earth filler on the kaolin; then fully mixing the various components of the self-repairing low-temperature enamel coating to obtain the self-repairing low-temperature enamel coating;

[0023] S2: fully mixing the various components in the topcoat to obtain the topcoat;

[0024] S3: spraying the self-repairing low-temperature enamel coating obtained in step S1 on the surface of the substrate as a primer, and spraying the topcoat obtained in step S2 on the primer to form a coating;

[0025] S4: curing the coating formed in step S3 to obtain the low-temperature enamel composite silicone hydrophobic coating.

[0026] Furthermore, in step S1, the rare earth filler is adsorbed on the kaolin. The specific process is: immersing the kaolin in a rare earth filler solution for adsorption; after the adsorption is completed and solid-liquid separation is performed, the solid is dried.

[0027] Furthermore, the substrate is a metal substrate; preferably, the substrate is any one of an aluminum alloy substrate, a copper alloy substrate, a tinplate substrate, a Q235 steel substrate, a stainless steel substrate or a titanium alloy.

[0028] Furthermore, the coating is cured under the following conditions: heating at a temperature of 250 to 480° C. for 10 to 30 minutes.

[0029] The fourth object of the present invention can be achieved by adopting the following technical solutions:

[0030] The use of the low-temperature enamel composite siloxane hydrophobic coating prepared by any of the above-mentioned low-temperature enamel coatings or any of the above-mentioned low-temperature enamel composite siloxane hydrophobic coatings or any of the above-mentioned methods for preparing a low-temperature enamel composite siloxane hydrophobic coating in the preparation of cookware, metal marine corrosion protection, and metal anti-fouling.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] 1. The self-repairing low-temperature enamel coating of the present invention has inorganic and fluorine-free ingredients; a coating with silica and alumina as the main components is formed, and silicon carbide is added to enhance the compatibility and bonding with the topcoat; and the three together with mica flakes and graphene form a unique scallop-like stacking structure, which enhances the strength and fracture toughness of the coating; and the combination of kaolin and rare earth fillers can quickly passivate the substrate when the coating is damaged, achieving a nano self-repairing effect and improving the corrosion resistance of the coating; the coating has the characteristics of high thermal hardness, high strength, good wear resistance and self-repairing performance.

[0033] 2. The low-temperature enamel composite silicone hydrophobic coating of the present invention has a primer raw material mainly of low-temperature enamel and a topcoat of silica sol-modified silicone. The primer and the topcoat have good compatibility and comprehensively combine the characteristics of high thermal hardness, high strength, good wear resistance and self-repairing performance of the enamel primer and the characteristics of corrosion resistance, good toughness and hydrophobicity of the silicone topcoat, and breaks through the thickness limit of a single coating, making it suitable for application in environmentally friendly coated pots.

[0034] 3. The preparation method of the low-temperature enamel composite silicone hydrophobic coating of the present invention only requires one baking and curing step after the primer and topcoat are wet-sprayed separately, which greatly reduces energy consumption, has high production efficiency and simple process. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is an optical microscope microscopic morphology image of the coating cross section of Example 5;

[0036] Figure 2 is a SEM image of the coating cross section of Example 5;

[0037] Figure 3 is a SEM image of the coating plane before corrosion in Example 5;

[0038] Figure 4 This is the SEM image of the coating plane after corrosion in Example 5

[0039] Figure 5 is a water contact angle diagram of the coating of Example 5;

[0040] Figure 6 The TGA (a) and DSC (b) curves of the aluminosilicate of the present invention are shown;

[0041] Figure 7 DSC (b) and TGA (a) graphs of kaolin of the present invention;

[0042] Figure 8 SEM image of SiC of the present invention;

[0043] Figure 9 SEM image of the mica sheet of the present invention

[0044] Figure 10 This is the EDS diagram of the mica sheet of the present invention;

[0045] Figure 11 This is a schematic diagram of the self-repairing effect of kaolin@rare earth filler on the coating of the present invention.

[0046] A—intact coating containing kaolin and rare earth fillers; B—damaged coating; C—release of rare earth fillers at the damaged coating; D—rare earth fillers promoting passivation of the metal substrate; 1—metal substrate; 2—coating; 3—kaolin and rare earth fillers; 31—adsorbed rare earth fillers; 32—released Ce(NO3)3 or Ce(AC)3; 33—kaolin fragments; 4—corrosive medium; 5—passivation film;

[0047] Figure 12 This is a schematic diagram of the unique structure of the "mica sheet / (SiO2+Al2O3+SiC) / graphene" scallop-like stacking of the present invention, where 1-mica sheet; 2-SiC; 3-SiO2; 4-graphene; 5-enamel particles.

[0048] Figure 13 is an SEM image of the coating plane before corrosion in Comparative Example 4;

[0049] Figure 14 This is the SEM image of the coating plane after corrosion in Comparative Example 4

[0050] Figure 15 This is the water contact angle diagram of the coating of Comparative Example 4. DETAILED DESCRIPTION

[0051] The technical solutions of the present invention will be described clearly and completely below with reference to specific embodiments. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without inventive effort are also within the scope of protection of the present invention.

[0052] The present invention provides a self-repairing low-temperature enamel coating, comprising the following components in parts by weight: 40-50 parts of silica sol, 5-10 parts of aluminum sol, 2-5 parts of glass powder, 5-10 parts of SiC, 0.1-0.5 part of graphene, 2-6 parts of aluminum silicate, 1-3 parts of mica flakes, 0.2-1 part of cobalt black, 1.0-1.5 parts of NiO, 1.0-1.5 parts of MoO3, 2-6 parts of kaolin, 1-2 parts of rare earth filler; and XX to XX parts of nano-alumina.

[0053] As one embodiment, the present invention includes the following components in parts by weight: 42-48 parts of silica sol, 7-9 parts of aluminum sol, 3-4 parts of glass powder, 6-8 parts of SiC, 0.25-0.45 parts of graphene, 3-5 parts of aluminum silicate, 1.5-2 parts of mica flakes, 0.5-0.8 parts of cobalt black, 1.2-1.4 parts of NiO, 1.2-1.4 parts of MoO3, 3-5 parts of kaolin, 1.5-2 parts of rare earth filler; and XX to XX parts of nano-alumina.

[0054] The alumina sol of the present invention is a precursor for Al2O3. The silica sol, glass powder, and alumina sol, after sol-gelation, form a coating primarily composed of inorganic silica and alumina. The alumina sol is particularly capable of forming nano-Al2O3. This nano-Al2O3 can fully fill the voids in the silica powder, reducing porosity and increasing the thermal expansion coefficient of the enamel coating. Due to its small size, the nano-alumina has numerous interfaces, providing short-range diffusion pathways and a high diffusion rate for the coating. This increases the driving force for sintering, effectively lowering the enamel softening point and facilitating sintering. Furthermore, the resulting nano-alumina has a particle size of 50 to 100 nm. This 50 to 100 nm alumina particle size allows some Al2O3 particles to suspend above the coating. Because alumina has a higher thermal hardness at 200°C than silica, the Al2O3 film enhances the wear resistance of the coating. If the alumina particle size is less than 50nm, the internal stress of the coating will be too large after film formation, which will easily cause cracks; since the density of alumina is 1.5 times that of silicon oxide, if the alumina particle size is greater than 100nm, it will be difficult to form an alumina film on the coating surface.

[0055] Silicon carbide is an inorganic material with high high temperature strength, high hardness at 200℃ and good wear resistance. It has a smooth surface and sharp edges (such as Figure 8 The SiC used in the coating of the present invention is a particle reinforcement. The addition of SiC particles can also enhance the bonding strength between the primer and topcoat. This is primarily due to the close proximity of the Si-C bond in the SiC molecule and the Si-O bond in the siloxane of the topcoat. The Si-O bonds between the SiC and polysiloxane form a connection during the hydrolysis-dehydration-polymerization process, improving the compatibility between the primer and topcoat.

[0056] As one embodiment, the SiC particle size is 10 to 50 μm.

[0057] Aluminosilicate consists of two parts: solid phase gel and liquid phase. The micelle is an amorphous substance, which contains four-membered rings, six-membered rings, etc. of silicon-oxygen tetrahedron and aluminum-oxygen tetrahedron and disordered silicon-aluminum-oxygen skeleton. The liquid phase contains Na + , K + 、H3 + O、OH - Plasma. On the one hand, aluminosilicate undergoes continuous polycondensation and dehydration during the heating process (such as Figure 6 The aluminum silicate shown in a loses weight continuously during the heating process); on the other hand, it releases heat during the heating process (such as Figure 6b), when the temperature reaches 350°C, some of the chemical bonds between the aluminum oxide tetrahedron and the silicon oxide tetrahedron in the aluminosilicate are broken, where the four-membered ring unit of the aluminum oxide tetrahedron is larger than that of the silicon oxide tetrahedron, which can create larger structural gaps, effectively connecting and bonding with other silicon dioxide crystals, self-condensing and bonding with silicon dioxide, thereby improving the integrity of the network in the coating structure.

[0058] Mica is a layered silicate with a structure consisting of two layers of silicon-oxygen tetrahedrons sandwiched between a layer of aluminum-oxygen octahedrons. Its general chemical composition is SiO2, Al2O3, K2O, Na2O: 9-11% and biocarbon carbide (such as Figure 10 As shown). Before the paint film solidifies, the mica wafers automatically lie flat due to the surface tension and form an oriented structure that is substantially parallel to the outer surface of the coating. The penetration of water and other corrosive substances into the coating is strongly blocked, thereby improving the corrosion resistance of the coating. In particular, the two-dimensional material graphene of the present invention is used in conjunction with the quasi-two-dimensional mica sheet to form a unique structure of "mica sheet / (SiO2+Al2O3+SiC) / graphene" imitating scallop stacking (as shown). Figure 11 As shown in Figure 2, the enamel coating has a multi-layered structure, and its biomimetic multi-layered structure effect is used to achieve toughening of the coating. The introduction of mica flakes and two-dimensional graphene creates a stacking effect of strong and weak interfaces. When a crack propagates to the "mica flake / (SiO2+Al2O3+SiC) / graphene" or "graphene / SiO2+Al2O3+SiC" interface, the direction of crack propagation deflects. After extending for a distance along the surface of a quasi-two-dimensional material such as mica flakes or graphene, it continues to propagate toward a (SiO2+Al2O3+SiC) layer, deflecting again upon reaching a weak interface, causing the crack to propagate in a step-like manner. This greatly increases the crack's repeated deflection at the quasi-two-dimensional interface, allowing it to absorb more energy, significantly increasing the work of fracture, and improving the fracture toughness of the coating.

[0059] As one embodiment, the mica sheet diameter-to-thickness ratio is 50-70. Figure 9 As shown, mica sheets with a large aspect ratio are quasi-two-dimensional materials. They will form a basically parallel oriented flat arrangement in the coating, and form a unique scallop-like stacking structure of "mica sheets / (SiO2+Al2O3+SiC) / graphene" with two-dimensional graphene, which has the effect of strong and weak interface stacking.

[0060] The present invention introduces cobalt black, NiO and MoO3 as adhesion agents, which promotes mutual melting and good bonding between the coating and the substrate, thereby obtaining good adhesion performance.

[0061] Rare earth fillers can delay the corrosion process, and the combination of rare earth fillers and kaolin can achieve intelligent corrosion inhibition.

[0062] As one embodiment, the rare earth filler is adsorbed on the kaolin. Kaolin has excellent adsorption properties. Kaolin adsorbs nano rare earth fillers to achieve a storage function. If the coating is damaged, under the action of the corrosive medium, the kaolin disintegrates and releases the rare earth filler, thereby playing an intelligent corrosion inhibition role. The principle diagram is shown as follows: Figure 11 shown.

[0063] As one embodiment, kaolin is immersed in a rare earth filler solution for adsorption; after the adsorption is completed and solid-liquid separation is performed, the solid is dried.

[0064] In this embodiment, the rare earth filler solution is a saturated solution; the immersion is performed under a vacuum negative pressure environment; the immersion and adsorption time is 20-50 minutes, preferably 20-40 minutes, and more preferably 30 minutes. The solid-liquid separation method is not limited to centrifugation, filtration, and suction filtration; centrifugation is preferred. After solid-liquid separation, the solid is collected and dried, which can be air-dried or oven-dried; the drying temperature is 250-480°C.

[0065] from Figure 7 DSC( Figure 7 a) and TGA( Figure 7 b) The curve shows that when the heating temperature is 500℃, the weight loss rate of kaolin is 6.42%, and there is an obvious endothermic peak, so the decomposition reaction occurs: Al4Si4O 10 (OH)8→2Al2O3+4SiO2+4H2O, the crystal structure of kaolin shrinks severely, which will affect the storage, caching and sustained-release effects of rare earth fillers.

[0066] In one embodiment, the rare earth filler is a cerium salt, preferably cerium nitrate and / or cerium acetate. When a coating primarily composed of silicon oxide and aluminum oxide is damaged, the cerium salt slows down the corrosion process. Cerium nitrate and / or cerium acetate, when combined with kaolin, allows for better storage and release of corrosive media.

[0067] The self-healing low-temperature enamel coating of this invention is inorganic and fluorine-free, highly compatible with ecological principles, and beneficial to human health and environmental protection. Its quasi-two-dimensional structure, composed of mica flakes and graphene, creates a scalloped structure, further enhancing its mechanical properties. Kaolin adsorbs nano-rare earths, which rapidly passivate the substrate when the coating is damaged, achieving a nano-self-healing effect and improving the coating's corrosion resistance. As a result, the coating exhibits high thermal hardness, strength, wear resistance, and self-healing properties.

[0068] The present invention also provides a low-temperature enamel composite silicone hydrophobic coating, comprising any of the above-mentioned self-repairing low-temperature enamel coatings as a primer and a topcoat.

[0069] As one embodiment thereof, the topcoat comprises the following components in parts by weight:

[0070] 50-60 parts of siloxane, 3-7 parts of silicone oil, 1-3 parts of mica flakes, 0.1-0.5 parts of graphene, 20-25 parts of polyethylene glycol, and 2-5 parts of water.

[0071] As one embodiment, the topcoat includes the following components in parts by weight: 55-58 parts of siloxane, 4-6 parts of silicone oil, 1.5-2.5 parts of mica flakes, 0.25-0.4 parts of graphene, 22-24 parts of polyethylene glycol, and 3-4 parts of water.

[0072] After curing, the siloxane forms a topcoat. To further enhance the surface hydrophobicity of the topcoat, the present invention adds silicone oil to the topcoat. The molecular structure of the silicone oil is similar to that of the film-forming agent, siloxane. The silicone oil can be evenly distributed in the organosilicon coating and does not participate in the crosslinking and curing reaction of the organosilicon, remaining as a liquid dispersed in the cured three-dimensional network of cross-linked silica. During curing, some of the organic coating components volatilize to form a microporous structure, providing channels for the migration and exudation of the silicone oil. Due to the action of the silicone oil, the water contact angle of the coating reaches above 100°, improving the coating's hydrophobicity and non-stick properties.

[0073] To enhance the corrosion resistance of the topcoat, mica flakes with a diameter-to-thickness ratio of 50-70 and 0.1-0.5% graphene are added to the topcoat. During the coating process, surface tension forces the mica flakes and graphene to flatten before the paint film solidifies, forming a substantially parallel alignment with the coating's outer surface. This strongly blocks the penetration of water and other corrosive substances, thereby improving the coating's corrosion resistance. During the topcoat application process, the mica flakes spread across different planes along the thickness direction, and SiO2 particles are distributed between the mica flakes and graphene, forming a unique multilayer structure reminiscent of a scallop, which toughens the coating. Polyethylene glycol and water serve as dispersants for the topcoat.

[0074] As one embodiment, the siloxane is a short-chain alkylsiloxane; preferably, the siloxane is one or a combination of two or more of methyltrimethoxysilane, methyltriethoxysilane, phenyltrimethoxysilane, tetraethoxysilane, and polydimethylsiloxane.

[0075] As one embodiment, the silicone oil is one or a combination of two or more of hydroxy silicone oil, methyl silicone oil, and dimethyl silicone oil.

[0076] The topcoat of this invention utilizes a polysiloxane composite inorganic material, exhibiting excellent hydrophobicity, wear resistance, and corrosion resistance. The primer is a self-healing, low-temperature enamel coating with high thermal hardness up to 200°C, high strength, wear resistance, and self-healing properties. This invention utilizes two layers of coatings with different compositions to form a film, leveraging the respective performance advantages of enamel and siloxane coatings while exceeding the thickness limit of a single coating, making it particularly suitable for use in environmentally friendly coated pots.

[0077] The present invention provides a method for preparing a low-temperature enamel composite siloxane hydrophobic coating, comprising the following steps:

[0078] S1: first adsorbing the rare earth filler on the kaolin; then fully mixing the various components of the self-repairing low-temperature enamel coating to obtain the self-repairing low-temperature enamel coating;

[0079] S2: fully mixing the various components in the topcoat to obtain the topcoat;

[0080] S3: spraying the self-repairing low-temperature enamel coating obtained in step S1 on the surface of the substrate as a primer, and spraying the topcoat obtained in step S2 on the primer to form a coating;

[0081] S4: curing the coating formed in step S3 to obtain the low-temperature enamel composite silicone hydrophobic coating.

[0082] The preparation method of the low-temperature enamel composite silicone hydrophobic coating of the present invention requires only one baking and curing step after wet-spraying the primer and the topcoat, which greatly reduces energy consumption, has high production efficiency and simple process.

[0083] As one embodiment, in step S1, the rare earth filler is adsorbed on the kaolin. The specific process is: immersing the kaolin in a rare earth filler solution for adsorption; after the adsorption is completed and solid-liquid separation is performed, the solid is dried.

[0084] As one embodiment, the substrate is a metal substrate; preferably, the substrate is any one of an aluminum alloy substrate, a copper alloy substrate, a tinplate substrate, a Q235 steel substrate, a stainless steel substrate or a titanium alloy.

[0085] As one embodiment, the coating is cured under the following conditions: heating at a temperature of 250 to 480° C. for 10 to 30 minutes.

[0086] If the curing temperature is below 250°C, the coating surface is smooth and non-porous; if the curing temperature is above 480°C, cracks of varying degrees will appear. Therefore, the present invention adopts a curing temperature of 250-480°C, which allows some of the organic coating components to volatilize and form a microporous structure, providing channels for the migration and seepage of silicone oil. Due to the action of the silicone oil, the hydrophobicity and non-stick properties of the coating are improved.

[0087] The use of the low-temperature enamel composite siloxane hydrophobic coating prepared by any of the above-mentioned low-temperature enamel coatings or any of the above-mentioned low-temperature enamel composite siloxane hydrophobic coatings or any of the above-mentioned methods for preparing a low-temperature enamel composite siloxane hydrophobic coating in the preparation of cookware, metal marine corrosion protection, and metal anti-fouling.

[0088] The following is a further description with reference to specific embodiments.

[0089] Example 1

[0090] This case provides a low-temperature enamel composite siloxane coating, including a primer and a topcoat;

[0091] The primer uses a self-repairing low-temperature enamel paint, including the following components in parts by weight: 40 parts of silica sol, 10 parts of aluminum sol, 2 parts of glass powder, 5 parts of SiC, 0.1 parts of graphene, 6 parts of aluminum silicate, 1 part of mica flakes, 0.2 parts of cobalt black, 1.5 parts of NiO, 1.0 part of MoO3, 2 parts of kaolin, and 1 part of Ce(NO3)3;

[0092] The topcoat comprises the following components in parts by weight: 50 parts of siloxane, 7 parts of silicone oil, 1 part of mica flakes, 0.1 parts of graphene, 20 parts of polyethylene glycol, and 2 parts of water;

[0093] The two parts of kaolin are immersed in one part of saturated Ce(NO3)3 solution under vacuum pressure for 30 minutes for adsorption, and the kaolin adsorbed with Ce(NO3)3 is separated by centrifugal technology. After drying at 300°C, it is fully mixed with other components of the self-repairing low-temperature enamel coating to prepare a primer coating;

[0094] The various components of the topcoat are fully mixed to obtain a topcoat coating;

[0095] The primer coating is sprayed on the surface of the base metal substrate using a spray gun as a primer, and then the coating is cured at 250° C. for 30 minutes to obtain the low-temperature enamel composite siloxane hydrophobic coating.

[0096] Example 2

[0097] This case provides a low-temperature enamel composite siloxane coating, including a primer and a topcoat;

[0098] The primer adopts a self-repairing low-temperature enamel coating, which includes the following components in parts by weight: 50 parts of silica sol, 5 parts of aluminum sol, 5 parts of glass powder, 10 parts of SiC, 0.5 parts of graphene, 2 parts of aluminum silicate, 3 parts of mica flakes, 1 part of cobalt black, 1.0 part of NiO, 1.5 parts of MoO3, 6 parts of kaolin, and 2 parts of Ce(NO3)3;

[0099] The topcoat comprises the following components in parts by weight: 60 parts of siloxane, 3 parts of silicone oil, 3 parts of mica flakes, 0.5 parts of graphene, 25 parts of polyethylene glycol, and 5 parts of water;

[0100] The 6 parts of kaolin are immersed in 2 parts of saturated Ce(NO3)3 solution under vacuum pressure for 20 minutes for adsorption, and the kaolin adsorbed with Ce(NO3)3 is separated by centrifugal technology. After drying at 250°C, it is fully mixed with other components of the self-repairing low-temperature enamel coating to prepare a primer coating;

[0101] The various components of the topcoat are fully mixed to obtain a topcoat coating;

[0102] The primer coating is sprayed on the surface of the base metal substrate using a spray gun as a primer, and then the coating is cured at 480° C. for 10 minutes to obtain the low-temperature enamel composite siloxane hydrophobic coating.

[0103] Example 3

[0104] This case provides a low-temperature enamel composite siloxane coating, including a primer and a topcoat;

[0105] The primer uses a self-repairing low-temperature enamel paint, including the following components by weight: 42 parts of silica sol, 7 parts of aluminum sol, 3 parts of glass powder, 6 parts of SiC, 0.25 parts of graphene, 3 parts of aluminum silicate, 1.5 parts of mica flakes, 0.5 parts of cobalt black, 1.2 parts of NiO, 1.2 parts of MoO3, 3 parts of kaolin, and 1.5 parts of Ce(NO3)3;

[0106] The topcoat comprises the following components in parts by weight: 55 parts of siloxane, 4 parts of silicone oil, 1.5 parts of mica flakes, 0.25 parts of graphene, 22 parts of polyethylene glycol, and 3 parts of water;

[0107] The 3 parts of kaolin are soaked in 1.5 parts of saturated Ce(NO3)3 solution under vacuum pressure for 40 minutes for adsorption, and the kaolin adsorbed with Ce(NO3)3 is separated by centrifugal technology. After drying at 480°C, it is fully mixed with other components of the self-repairing low-temperature enamel coating to prepare a primer coating;

[0108] The various components of the topcoat are fully mixed to obtain a topcoat coating;

[0109] The primer coating is sprayed on the surface of the base metal substrate using a spray gun as a primer, and then the coating is cured at 450° C. for 20 minutes to obtain the low-temperature enamel composite siloxane hydrophobic coating.

[0110] Example 4

[0111] This case provides a low-temperature enamel composite siloxane coating, including a primer and a topcoat;

[0112] The primer adopts a self-repairing low-temperature enamel paint, which includes the following components in parts by weight: 48 parts of silica sol, 9 parts of aluminum sol, 4 parts of glass powder, 8 parts of SiC, 0.45 parts of graphene, 5 parts of aluminum silicate, 2 parts of mica flakes, 0.8 parts of cobalt black, 1.4 parts of NiO, 1.4 parts of MoO3, 5 parts of kaolin, and 2 parts of Ce(AC)3;

[0113] The topcoat comprises the following components in parts by weight: 58 parts of siloxane, 6 parts of silicone oil, 2.5 parts of mica flakes, 0.4 parts of graphene, 24 parts of polyethylene glycol, and 4 parts of water;

[0114] The 5 parts of kaolin were immersed in 2 parts of saturated Ce(AC)3 solution under vacuum pressure for 50 minutes for adsorption, and the kaolin adsorbed with Ce(AC)3 was separated by centrifugal technology. After drying at 350°C, the mixture was fully mixed with other components of the self-repairing low-temperature enamel coating to prepare a primer coating.

[0115] The various components of the topcoat are fully mixed to obtain a topcoat coating;

[0116] The primer coating is sprayed on the surface of the base metal substrate using a spray gun as a primer, and then the coating is cured at 300° C. for 30 minutes to obtain the low-temperature enamel composite siloxane hydrophobic coating.

[0117] Example 5

[0118] This case provides a low-temperature enamel composite siloxane coating, including a primer and a topcoat;

[0119] The primer uses a self-repairing low-temperature enamel paint, including the following components in parts by weight: 45 parts of silica sol, 8 parts of aluminum sol, 3.5 parts of glass powder, 7 parts of SiC, 0.3 parts of graphene, 4 parts of aluminum silicate, 1.8 parts of mica flakes, 0.6 parts of cobalt black, 1.3 parts of NiO, 1.3 parts of MoO3, 4 parts of kaolin, and 1.8 parts of Ce(AC)3;

[0120] The topcoat comprises the following components in parts by weight: 56 parts of siloxane, 5 parts of silicone oil, 2 parts of mica flakes, 0.3 parts of graphene, 23 parts of polyethylene glycol, and 3.5 parts of water;

[0121] The 4 parts of kaolin were immersed in 1.8 parts of saturated Ce(AC)3 solution under vacuum pressure for 30 minutes for adsorption, and the kaolin adsorbed with Ce(AC)3 was separated by centrifugal technology. After drying at 400°C, the mixture was fully mixed with other components of the self-repairing low-temperature enamel coating to prepare a primer coating.

[0122] The various components of the topcoat are fully mixed to obtain a topcoat coating;

[0123] The primer coating is sprayed on the surface of the base metal substrate using a spray gun as a primer, and then the coating is cured at 420° C. for 25 minutes to obtain the low-temperature enamel composite siloxane hydrophobic coating.

[0124] Comparative Example 1

[0125] Compared with Example 5, the self-repairing low-temperature enamel coating used in the primer of Comparative Example 1 does not contain cobalt black, NiO, or MoO3 adhesives; the topcoat has the same components as Example 5, and the preparation process is also consistent with the preparation method of Example 5.

[0126] Comparative Example 2

[0127] Compared with Example 5, Comparative Example 2 is the self-repairing low-temperature enamel coating used in the primer of Comparative Example 2, in which mica flakes and graphene are not added; mica flakes and graphene are not added to the topcoat; the other components are the same as those in Example 5, and the preparation process is also consistent with the preparation method of Example 5.

[0128] Comparative Example 3

[0129] Compared with Example 5, the self-repairing low-temperature enamel coating used in the primer of Comparative Example 3 does not contain aluminum silicate; the topcoat has the same components as Example 5, and the preparation process is also consistent with the preparation method of Example 5.

[0130] Comparative Example 4

[0131] Compared with Example 5, the self-repairing low-temperature enamel coating used in the primer of Comparative Example 4 does not contain silicon carbide; the topcoat has the same components as Example 5, and the preparation process is also consistent with the preparation method of Example 5.

[0132] Comparative Example 5

[0133] Compared with Example 5, Comparative Example 5 does not add kaolin to the self-repairing low-temperature enamel coating used in the primer of Comparative Example 5; the topcoat has the same components as in Example 5. During preparation, all components of the self-repairing low-temperature enamel coating are fully mixed with the primer coating; other preparation processes are also consistent with the preparation method of Example 5.

[0134] Comparative Example 6

[0135] Compared with Example 5, the primer of Comparative Example 6 does not add Ce(AC)3 to the self-repairing low-temperature enamel coating used in the primer of Comparative Example 6; the components of the topcoat are the same as those in Example 5. During preparation, all components of the self-repairing low-temperature enamel coating are fully mixed with the primer coating; other preparation processes are also consistent with the preparation method of Example 5.

[0136] Comparative Example 7

[0137] Compared with Example 5, the primer of Comparative Example 7 uses the same components as Example 5 of the self-repairing low-temperature enamel coating; the topcoat does not contain silicone oil, and the preparation process of other components is also consistent with the preparation method of Example 5.

[0138] Comparative Example 8

[0139] Compared with Example 5, the primer of Comparative Example 8 adopts a self-repairing low-temperature enamel coating, and the topcoat has the same components as Example 5. During preparation, the curing temperature is 200°C and the curing time is 25 minutes; other preparation processes are also consistent with the preparation method of Example 5.

[0140] Comparative Example 9

[0141] Compared with Example 5, the primer of Comparative Example 9 adopts a self-repairing low-temperature enamel coating, and the topcoat has the same components as Example 5. During preparation, the curing temperature is 510°C and the curing time is 25 minutes; other preparation processes are also consistent with the preparation method of Example 5.

[0142] The composition and content of the self-repairing low-temperature enamel coating primer in Examples 1-5 and Comparative Examples 1-9 are shown in Table 1; the composition and content of the topcoat are shown in Table 2.

[0143] Table 1 Composition and content of self-repairing low-temperature enamel paint primer in Examples 1-5 and Comparative Examples 1-9

[0144]

[0145] Table 2 Composition and content of topcoat in Examples 1-5 and Comparative Examples 1-9

[0146]

[0147] Coating micromorphology, composition analysis and performance testing methods:

[0148] Micromorphology and composition: Scanning electron microscopy was used to analyze the micromorphology and element content of the coating interface of Example 5. The results are as follows: Figure 1-2 As shown;

[0149] Figure 1Be the embodiment 5 coating cross section micromorphology that optical microscope is taken, wherein the left side is carbon steel matrix, and the right side is coating, formed the entangled structure of inlay at carbon steel / coating interface, this is in the curing heating process, the existence of cobalt black, NiO, molybdenum oxide contained in the enamel paint of coating, promoted the mutual melting of coating and carbon steel matrix, formed good chemical metallurgy combination.Coating is divided into primer and topcoat, fails to see the obvious boundary of two kinds of coatings from the figure, shows that the compatibility of two kinds of coatings is fine.Some apertures 1,2,3 appear in the topcoat, and three apertures are the structure of diameter crooked and secluded, and this porous structure is interconnected but tortuous and hidden structure is conducive to the storage of silicone oil in coating, and the release rate of silicone oil is also slowed down.

[0150] Figure 2 This thermal field electron scanning microscope captures the cross-sectional micromorphology of the example coating. The primer is dense and non-porous, while the topcoat is dotted with holes of varying sizes and depths. The dense structure of the primer protects the carbon steel substrate from corrosive media, while the porous structure of the topcoat allows for the storage and slow release of silicone oil.

[0151] Thickness: The coating was cut along the thickness direction, and the coating cross section was observed using an electron scanning microscope to measure its thickness range. The results are shown in Table 3.

[0152] Hydrophilicity test: The water contact angle of the coating was measured using a TEP-1000A video optical contact angle meter. The results are shown in Table 3. The water contact angle image of the coating of Example 5 is shown in Table 3. Figure 5 As shown;

[0153] from Figure 5 As can be seen in the figure, the left contact angle is 103.23° and the right contact angle is 103.50°, indicating that the coating is a hydrophobic coating.

[0154] 200°C Hot Hardness: The coating's 200°C hot hardness was measured using a cart according to the test method specified in national standard GB6739-88. The 200°C hot hardness was determined by measuring the mark left by a pencil across the coating. The results are shown in Table 3.

[0155] Wear resistance: The wear resistance of the coating was tested using an abrasion tester. A scouring pad was used as the friction head. The abrasion tester rubbed the coating 500 times, replacing the scouring pad. The number of frictions required for the coating to be worn through and the substrate to be exposed was used to characterize the wear resistance of the coating. The results are shown in Table 3.

[0156] Adhesion: The WS-2005 automatic scratch technology was used to test the adhesion between the coating and the substrate. The results are shown in Table 3.

[0157] Corrosion resistance: The coating was placed in a 5% citric acid solution, and the anodic polarization curve of the coating in the citric acid solution was measured using the IM6 electrochemical workstation three-electrode method. The open circuit potential and breakdown potential were analyzed to characterize the corrosion resistance of the coating. The results are shown in Table 3.

[0158] Table 3 Performance data of coatings of examples and comparative examples

[0159]

[0160] As can be seen from Table 3, the total thickness of the low-temperature enamel composite silicone hydrophobic coating prepared in Examples 1 to 5 is 55 to 70 μm, wherein the film-forming agents of the primer self-repairing low-temperature enamel coating are silica sol and glass powder, and the film thickness is greater when the silica sol content is high; the film-forming agent of the topcoat is siloxane, and the greater the proportion of siloxane, the greater the thickness of the topcoat film.

[0161] The topcoat of Examples 1 to 5 uses siloxane as a film-forming agent, and the contact angle of the coating with water is 102.2 to 105.4°. The water contact angle graph is shown in FIG. Figure 5 As shown, it is a hydrophobic coating; the thermal hardness of the pencils of the five embodiments reaches 9H at 200℃, which is high; the surface resistance to rubbing with a scouring pad is greater than 50,000 times, and the wear resistance is good; the bonding force between the coating and the substrate is greater than 26.23N, and it has good bonding force with the substrate; the breakdown voltage in citric acid is greater than 1.42V, indicating good corrosion resistance; among them, the comprehensive performance of Example 5 is the best. The surface of the coating of Example 5 was observed before and after corrosion. The surface before corrosion is shown in the figure below. Figure 3 As shown, the surface after corrosion is as follows Figure 4 As shown, Figure 3 and Figure 4 There is no obvious change, which shows that the coating of Example 5 has good corrosion resistance and the coating surface is not damaged after corrosion by citric acid.

[0162] In Comparative Example 1, the primer does not contain cobalt black, NiO, or MoO3 adhesive, and the composition of the topcoat has not changed. The bonding strength between the prepared coating and the substrate is only 5.21 N. This is because without the effect of the adhesive, the substances in the primer coating and the substrate cannot melt into each other and bond well. The decrease in bonding strength also makes the coating easy to peel off during the scouring pad wear test, which also reduces the wear resistance of the coating.

[0163] In comparative example 2, the primer and topcoat components do not contain mica flakes and graphene. During the wear resistance test with a scouring pad, the coating was worn through after only 5,000 frictions, exposing the substrate. The breakdown potential was 1.05V, indicating that the corrosion resistance and wear resistance of the coating have decreased. This is because the main function of mica flakes in the coating is to improve the corrosion resistance and wear resistance of the coating. On the one hand, the mica flakes with a large diameter-to-thickness ratio are quasi-two-dimensional materials. Before the paint film is cured, the mica chips automatically lie flat due to the surface tension and form an oriented arrangement structure that is basically parallel to the outer surface of the coating. The penetration of water and other corrosive substances into the coating is strongly blocked, thereby improving the corrosion resistance of the coating. On the other hand, the two-dimensional material graphene of the present invention is used in conjunction with the quasi-two-dimensional mica flakes to form a unique structure of "mica flakes / (SiO2+Al2O3+SiC) / graphene" imitating scallop stacking (such as Figure 12 The enamel coating has a multi-layer structure, and the toughening of the coating is achieved by utilizing its bionic multi-layer structure effect.

[0164] The primer of Comparative Example 3 does not contain aluminum silicate, and the mechanical properties of the coating, including 200°C thermal hardness, wear resistance and adhesion, are significantly reduced. The aluminum silicate in the coating can ensure the integrity of the network in the enamel primer structure; without aluminum silicate, the enamel coating network of the primer is incomplete, resulting in deterioration of the mechanical properties of the primer.

[0165] The primer of Comparative Example 4 does not contain SiC, and the mechanical properties and corrosion resistance of the coating are deteriorated. This is because the Si-C bond in the SiC molecule is very close to the Si-O bond of the siloxane in the topcoat. The Si-O bonds of SiC and polysiloxane are connected during the hydrolysis-dehydration-polymerization process, making the compatibility of the primer and the topcoat better, thereby enhancing the bonding strength between the primer and the topcoat.

[0166] The primer of Comparative Example 5 does not contain kaolin, resulting in a decrease in the corrosion resistance of the coating. Kaolin is added to the primer primarily to adsorb the rare earth fillers Ce(NO3)3 or Ce(AC)3. If kaolin is not adsorbed, the rare earth fillers Ce(NO3)3 or Ce(AC)3 are directly added. During the coating formation process, the rare earth fillers are dispersed and diluted into the coating, making it difficult to quickly passivate the substrate into a passivation film to improve corrosion resistance based on whether the coating is damaged. Therefore, the intelligent corrosion inhibition effect cannot be achieved.

[0167] The coating of Comparative Example 5 was corroded in a 5% citric acid solution for a period of time. The coating was observed microscopically before and after corrosion. The micrograph before corrosion was as follows: Figure 13 As shown in the micrograph after corrosion, Figure 14 As shown, compared Figure 13 and Figure 14 , it was found that after a period of corrosion, the brightness and number of mica flakes on the surface of the material decreased. This was mainly because the surface coating was corroded and dissolved. Figure 15 For comparative example 4, the contact angle of the coating after corrosion dropped sharply from 103.36° to 63.72°, and the hydrophobicity was destroyed.

[0168] The primer of Comparative Example 6 does not contain rare earth fillers, which leads to a significant decrease in the corrosion resistance of the coating, indicating that the main function of the rare earth filler is to slow down the corrosion.

[0169] The primer composition of Comparative Example 7 is consistent with that of Example 5, and the topcoat does not contain silicone oil. When the silicone in the topcoat is heated to 420°C, a pore structure will appear. When silicone oil is present, the silicone oil is stored in the pores and can be effectively released, making the topcoat surface hydrophobic. When there is no silicone oil, the hydrophobic effect brought by the silicone oil is reduced, and the formed pores further reduce the hydrophobicity of the surface, thereby causing the contact angle of the coating to decrease to only 67.2°.

[0170] Compared with Example 5, the content of the primer and topcoat components in Comparative Example 8 is consistent with that in Example 5, but its curing temperature is 200°C and the curing time is 25 minutes; due to the low curing temperature, the siloxane organic coating of the topcoat forms a dense non-porous structure, and the silicone oil in the topcoat has no escape channel, resulting in a contact angle between the coating and water lower than that in Example 5, only 85.2°; the mechanical properties of the coating are also severely reduced, because the curing temperature is too low, and the enamel raw materials of the primer are not well reacted to form a film, resulting in the coating degree, wear resistance, corrosion resistance and bonding strength being worse than those in Example 5.

[0171] Comparative Example 9, compared with Example 5, employed the same primer and topcoat composition as in Example 5, with a curing temperature of 510°C and a curing time of 25 minutes. Due to the high curing temperature, cracks appeared in the silicone coating of the topcoat. The silicone oil in Coating B evaporated during heating, resulting in a very low water contact angle of only 56.1°. The kaolin in the primer also shrank significantly at high temperatures, reducing the coating's expansion coefficient during film formation, thus affecting the coating's wear and corrosion resistance.

[0172] In summary, the low-temperature enamel composite silicone hydrophobic coating of the present invention includes a self-repairing low-temperature enamel paint primer and a silicone topcoat. On the one hand, the primer utilizes mica sheets and graphene quasi-two-dimensional materials to assemble into a scallop stacking structure, which makes its mechanical properties dimension even higher; at the same time, kaolin is used to adsorb nano rare earths, and the substrate can be quickly passivated when the coating is damaged, thereby realizing intelligent corrosion inhibition and improving the corrosion resistance of the coating; and the topcoat adopts medium-temperature curing to promote the pore formation of some organic coating components, providing a channel for the migration and seepage of silicone oil, which is conducive to improving the water contact angle, and the coating has excellent hydrophobicity and non-stick properties; and it is fluorine-free, highly harmoniously integrated with the ecology, and is beneficial to human health and environmental protection.

[0173] The above embodiments are only preferred embodiments of the present invention and cannot be used to limit the scope of protection of the present invention. Any non-substantial changes and replacements made by technicians in this field on the basis of the present invention fall within the scope of protection required by the present invention.

Claims

1. A low-temperature enamel composite silicone hydrophobic coating, characterized in that: Includes self-healing low-temperature enamel paint as a primer and topcoat; The self-repairing low-temperature enamel coating comprises the following components in parts by weight: 40-50 parts of silica sol, 5-10 parts of aluminum sol, 2-5 parts of glass powder, 5-10 parts of SiC, 0.1-0.5 parts of graphene, 2-6 parts of aluminum silicate, 1-3 parts of mica flakes, 0.2-1 parts of cobalt black, 1.0-1.5 parts of NiO, 1.0-1.5 parts of MoO3, 2-6 parts of kaolin, and 1-2 parts of rare earth filler; The topcoat comprises the following components in parts by weight: 50-60 parts of siloxane, 3-7 parts of silicone oil, 1-3 parts of mica flakes, 0.1-0.5 parts of graphene, 20-25 parts of polyethylene glycol, and 2-5 parts of water.

2. The low-temperature enamel composite silicone hydrophobic coating according to claim 1, characterized in that: The rare earth filler is adsorbed on the kaolin; the rare earth filler is cerium salt.

3. The low-temperature enamel composite silicone hydrophobic coating according to claim 2, wherein the cerium salt is cerium nitrate and / or cerium acetate.

4. The low-temperature enamel composite silicone hydrophobic coating according to claim 1, characterized in that: The particle size of the SiC is 10 to 50 μm; the diameter-to-thickness ratio of the mica sheet is 50 to 70.

5. The low-temperature enamel composite silicone hydrophobic coating according to claim 1, characterized in that: The siloxane is a short-chain alkylsiloxane; the silicone oil is one of hydroxy silicone oil, methyl silicone oil, and dimethyl silicone oil, or a combination of two or more thereof.

6. The low-temperature enamel composite silicone hydrophobic coating according to claim 5, characterized in that: The siloxane is one or a combination of two or more of methyltrimethoxysilane, methyltriethoxysilane, phenyltrimethoxysilane, tetraethoxysilane and polydimethylsiloxane.

7. The method for preparing the low-temperature enamel composite silicone hydrophobic coating according to any one of claims 1 to 6, characterized in that: The following steps are involved: S1: first adsorbing the rare earth filler on the kaolin; then fully mixing the various components of the self-repairing low-temperature enamel coating to obtain the self-repairing low-temperature enamel coating; S2: fully mixing the components of the topcoat to obtain the topcoat; S3: spraying the self-repairing low-temperature enamel coating obtained in step S1 on the surface of the substrate as a primer, and spraying the topcoat obtained in step S2 on the primer to form a coating; S4: curing the coating formed in step S3 to obtain the low-temperature enamel composite silicone hydrophobic coating.

8. The method for preparing a low-temperature enamel composite silicone hydrophobic coating according to claim 7, wherein: In step S1, the rare earth filler is adsorbed on the kaolin. The specific process is: immersing the kaolin in a rare earth filler solution for adsorption; after the adsorption is completed, solid-liquid separation is performed, and then the solid is dried.

9. The method for preparing a low-temperature enamel composite siloxane hydrophobic coating according to claim 7 or 8, characterized in that: The substrate is a metal substrate; the coating curing condition is: heating at a temperature of 250-480° C. for 10-30 minutes.

10. The method for preparing a low-temperature enamel composite silicone hydrophobic coating according to claim 9, characterized in that: The substrate is any one of an aluminum alloy substrate, a copper alloy substrate, a tinplate substrate, a Q235 steel substrate, a stainless steel substrate or a titanium alloy.

11. Use of the low-temperature enamel composite siloxane hydrophobic coating prepared by the method for preparing the low-temperature enamel composite siloxane hydrophobic coating according to any one of claims 1 to 6 or the low-temperature enamel composite siloxane hydrophobic coating according to any one of claims 7 to 10 in the preparation of cookware, metal marine corrosion protection, and metal antifouling.

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