Non-stick coating and method for its production, non-stick cookware

Abstract

The application provides a non-stick coating and a preparation method thereof, and a non-stick cooker. The preparation method of the non-stick coating comprises the following steps: hot spraying raw magnetite to form an initial non-stick layer with an amorphous structure; and modifying the initial non-stick layer by using an organic silicon modifier, so as to obtain the non-stick coating. The main components of the raw magnetite include 90%-95% of ferroferric oxide, 0.1%-1% of silicate minerals and a remainder of harmless metal ions. According to the preparation method of the non-stick coating, the non-stick coating with excellent initial non-stickness, long-lasting non-stickness, hardness, corrosion resistance and actual use test can be obtained.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of cookware non-stick technology, and more particularly, to a method for preparing a non-stick coating, a non-stick coating, and a non-stick cookware. BACKGROUND

[0002] In the art, fluorine coating is a common non-stick coating. However, the non-stick coating manufactured by using fluorine coating has excellent initial non-stick property, but is easily damaged by a spatula and is easily aged or decomposed at high temperature during use. These problems have seriously affected the service life of the coating formed by fluorine coating, resulting in the general persistent non-stick property of the coating formed by fluorine coating.

[0003] In order to ensure the scratch resistance and high temperature resistance, in some pots, a coating formed by plasma spraying inorganic ceramic is used, and the initial non-stick property of the coating is poor, and generally needs to be modified by a material with good non-stick property (for example, fluorinated material) to meet the initial non-stick property required by the national standard.

[0004] Therefore, it is necessary to explore a new non-stick coating to meet the requirements of pots for initial non-stick property, persistent non-stick property, hardness, and resistance to external force impact and the like. SUMMARY

[0005] Therefore, the purpose of the present application is to provide a non-stick coating and a preparation method thereof, and a non-stick cookware to meet the requirements of pots for persistent non-stick property, hardness, corrosion resistance, and actual use test and the like.

[0006] According to a first aspect of the present application, a method for preparing a non-stick coating is provided, wherein the method for preparing a non-stick coating comprises: hot spraying raw magnetite to form an initial non-stick layer with an amorphous structure; and modifying the initial non-stick layer by using an organic silicon modifier, so as to obtain the non-stick coating, wherein, based on the total weight of the raw magnetite being 100%, the main components of the raw magnetite include: 90%-95% of ferroferric oxide, 0.1%-1% of silicate minerals, and the balance of harmless metal ions.

[0007] According to the method for preparing the non-stick coating according to the present application, the raw magnetite has low surface energy, certain wear resistance and hardness, and thus the initial non-stick layer with excellent properties and amorphous structure can be formed by thermal spraying of the raw magnetite. Although the initial non-stick layer has good initial non-stickness, generally grade II, it may still not be able to obtain higher user experience and improve the competitiveness of the product. The inventors found that the surface of the formed initial non-stick layer has hydroxyl groups, and the initial non-stick layer can be modified by using a silicone modifier, thereby obtaining a non-stick coating of the cookware. Specifically, the silanol groups in the silicone modifier hydrolyze to form silicon hydroxyl groups, which then undergo dehydration condensation reaction with the hydroxyl groups on the surface of the initial non-stick layer to form relatively firm bonds, thereby grafting a very thin layer of organic groups on the surface of the initial non-stick layer, which can improve the performance of the initial non-stick layer. For example, the initial non-stickness, corrosion resistance and hardness of the initial non-stick layer can be improved, and the affinity effect of the non-stick layer to cooking oil can be improved, making the non-stick effect of the coating more durable and stable.

[0008] In embodiments, the step of modifying the initial non-stick layer with the silicone modifier includes contacting and reacting a modification solution including the silicone modifier and an aqueous solvent with the initial non-stick layer, thereby obtaining the initial non-stick layer modified by the silicone modifier as the non-stick coating.

[0009] In these embodiments, the silicone modifier itself has lower surface energy than the raw magnetite, and the surface modification treatment of the initial non-stick layer by the modification solution including the silicone modifier and the aqueous solvent can further optimize the initial non-stickness of the overall coating.

[0010] Specifically, the silicone modifier includes a fluorosilane material, and the surface layer of the initial non-stick layer modified by the silicone modifier is the product after the hydrolysis product of the fluorosilane material reacts with the initial non-stick layer; or the silicone modifier includes a silane coupling agent, and the surface layer of the initial non-stick layer modified by the silicone modifier is the product after the hydrolysis product of the silane coupling agent reacts with the initial non-stick layer.

[0011] In these embodiments, the silicone modifier is a silane coupling agent or a fluorosilane material, and the fluorosilane material or the silane coupling agent itself has lower surface energy than the raw magnetite, so that the fluorosilane material or the silane coupling agent is grafted on the surface of the initial non-stick layer, which can further optimize the initial non-stickness of the overall coating. The method for preparing the non-stick coating not only utilizes the excellent properties of the raw magnetite, but also further optimizes the non-stickness of the non-stick coating by introducing a material with lower surface energy, so that the cookware with the coating can meet the requirements of persistent non-stickness, hardness, corrosion resistance and actual use test, etc.

[0012] In embodiments, the method for preparing the non-stick coating further comprises at least pickling and roasting the natural magnetite powder to obtain the raw material magnetite.

[0013] In these embodiments, in the pickling and high-temperature roasting steps, harmful metal ions in the natural magnetite can be removed as much as possible to obtain the raw material magnetite according to the present application which can be suitable for cookware.

[0014] In embodiments, the thermal spraying raw material magnetite comprises controlling the particle size of the raw material magnetite and spraying parameters, so as to form an initial non-stick layer with a predetermined pore structure.

[0015] In these embodiments, the initial non-stick layer with a predetermined pore structure can facilitate the modification of the organosilicon modifier and improve the modification degree, so as to further optimize the non-stick property.

[0016] Specifically, the particle size of the raw material magnetite is 300-500 mesh, and the spraying parameters are as follows: powder feeding speed 20-50 g / min; spraying distance 80-100 mm; arc current 450-650 A; hydrogen pressure 0.2-0.4 MPa; voltage 50-70 V; hydrogen flow 6-15 L / min, argon pressure 2.5-4.0 MPa, argon flow 1000-1500 L / min, spraying angle 45-80°; and workpiece temperature normal temperature or -15-0°C.

[0017] According to a second aspect of the present application, a non-stick coating is provided, wherein the non-stick coating is prepared by the method for preparing the non-stick coating according to the above embodiments.

[0018] Specifically, the surface energy of the non-stick coating is 18-40 dynes; the porosity of the non-stick coating is 1-3%; the pore size of the non-stick coating is 0.1-1 μm; the hardness of the non-stick coating is 400-800 HV; the volume fraction of amorphous phase in the non-stick coating is 60-90%; and the color of the non-stick coating is black.

[0019] According to a third aspect of the present application, a non-stick cookware is provided, wherein the non-stick cookware comprises a substrate and a non-stick coating formed on the substrate, and the non-stick coating comprises the non-stick coating according to the above embodiments.

[0020] In embodiments, the substrate is a metal substrate, and the non-stick cookware further comprises a metal primer layer formed between the substrate and the non-stick coating.

[0021] In these embodiments, the metal primer layer formed between the base and the non-stick coating can increase the bonding force between the non-stick coating and the base. BRIEF DESCRIPTION OF DRAWINGS

[0022] The above and / or other features and aspects of the present inventive concept will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings.

[0023] Figure 1 is a schematic diagram of a cross-sectional structure of a cookware along a thickness direction according to an embodiment of the present application;

[0024] Figure 2 is Figure 1 is a schematic diagram of an enlarged structure at I in FIG. 1.

[0025] SYMBOL EXPLANATION

[0026] 100, non-stick cookware; 110, base; 120, non-stick coating; 121, initial non-stick layer without modification; 122, modified layer; 130, primer layer. DETAILED DESCRIPTION

[0027] Example embodiments of the present inventive concept will be described below in greater detail. Although example embodiments of the present inventive concept are described below, it should be understood that the present inventive concept can be implemented in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided so that the present inventive concept can be more thoroughly understood and so that the scope of the present inventive concept can be conveyed to those skilled in the art.

[0028] In the art, fluorine coating or ceramic coating is a common non-stick material. Although the non-stick coating made of fluorine coating has excellent initial non-stick property, it is easily damaged by a spatula and easily aged or decomposed at high temperature during use. The silicon oil of the fluorine coating is quickly consumed at high temperature and thus the non-stick effect is quickly lost. Therefore, the durable non-stick property of the ceramic coating cannot meet the demand of cookware for non-stick property.

[0029] In order to ensure scratch resistance and high temperature resistance, in some pots, a coating layer formed of plasma sprayed inorganic ceramic is used. However, the initial non-stick property of such a coating layer is poor and thus a material with good non-stick property (e.g., fluorinated material) is usually used to modify the coating layer to meet the initial non-stick property required by the national standard.

[0030] As can be seen from the above, the existing non-stick coating is difficult to have excellent properties in multiple aspects such as initial non-stick property, durable non-stick property, hardness, corrosion resistance, and actual use test. Therefore, there is still an urgent need in the cookware manufacturing field to develop a new non-stick coating having excellent properties in multiple aspects such as initial non-stick property, durable non-stick property, hardness, corrosion resistance, and actual use test.

[0031] According to a first aspect of the present application, a method for preparing a non-stick coating for a cooking utensil is provided, wherein the method comprises thermal spraying of raw magnetite to form an initial non-stick layer with an amorphous structure; modifying the initial non-stick layer with an organosilicon modifier to obtain the non-stick coating; wherein the main components of the raw magnetite include 90%-95% of ferroferric oxide, 0.1%-1% of silicate minerals and the rest of harmless metal ions, based on the total weight of the raw magnetite being 100%.

[0032] According to the method for preparing a non-stick coating of the present application, the raw magnetite has low surface energy, certain wear resistance and hardness, so that the initial non-stick layer with excellent properties and an amorphous structure can be formed by thermal spraying of the raw magnetite. Although the initial non-stick layer has good initial non-stickness, generally grade II, it may still not be able to obtain higher user experience and improve the competitiveness of the product. The inventors found that the surface of the formed initial non-stick layer has hydroxyl groups, and the initial non-stick layer can be modified with an organosilicon modifier to obtain a non-stick coating for a cooking utensil. Specifically, the siloxy groups in the organosilicon modifier will form silicon hydroxyl groups after hydrolysis, and then undergo dehydration condensation reaction with the hydroxyl groups on the surface of the initial non-stick layer to form relatively firm bonds, thereby grafting a very thin layer of organic groups on the surface of the initial non-stick layer, which can improve the performance of the initial non-stick layer. For example, the initial non-stickness, corrosion resistance and hardness of the initial non-stick layer can be improved, and the affinity effect of the non-stick layer to cooking oil can be improved, so that the non-stick effect of the coating is more durable and stable.

[0033] Preparing raw magnetite

[0034] Hereinafter, the raw magnetite according to the present application will be specifically described as a non-stick material for a cooking utensil.

[0035] Providing raw magnetite

[0036] As a cooking tool, the inner surface of the pot will be in direct contact with the cooked food, so the coating material is required to be non-toxic and harmless, and to meet the food safety standards. However, the natural magnetite contains many impurities that cannot be used for cookware. For example, the main components of natural magnetite include triiron tetroxide, harmful metal ions (chromium ions, manganese ions, nickel ions, cobalt ions, copper ions, mercury ions and lead ions), harmless metal ions (such as iron ions, aluminum ions, titanium ions, vanadium ions, magnesium ions, zinc ions and calcium ions), and silicate minerals (quartz, calcium silicate and sodium silicate, etc.). Among them, the weight percentage of triiron tetroxide is 50%-70%, the weight percentage of silicate minerals is 10%-20%, the weight percentage of harmful metal ion compounds is 0.1%-1%, and the rest is harmless metal ion compounds, based on the total weight of natural magnetite being 100%. The excessive amount of harmful heavy metal components makes the material not meet the food safety standards.

[0037] Therefore, according to the present application, it is necessary to pretreat the natural magnetite to remove the harmful impurities therein and obtain a raw material magnetite that is safe and non-toxic and can meet the food safety standards and is suitable as a raw material part of the non-stick coating of cookware.

[0038] Specifically, the natural magnetite can be subjected to impurity removal treatment to obtain a raw material magnetite, which includes:

[0039] Primary grinding: the natural magnetite is crushed by a crushing and coarse grinding device to make the particles smaller to a particle size of 100-300 μm, facilitating subsequent processing.

[0040] Primary magnetic separation: a magnetic separation device is used to perform magnetic separation treatment on the magnetite after crushing and coarse grinding. The magnetic separation device separates magnetic minerals from non-magnetic minerals by utilizing the difference in magnetism, and extracts the magnetic minerals.

[0041] Secondary grinding: the magnetite particles after the primary magnetic separation are ground by a grinding device to a particle size of 25-48 μm.

[0042] Secondary magnetic separation: a magnetic separation device is used to perform magnetic separation treatment on the magnetite after crushing and coarse grinding. The magnetic separation can remove silicate minerals (quartz, sodium silicate, calcium silicate) therein.

[0043] Third grinding: the magnetite after impurity removal is subjected to grinding treatment to make the particles smaller to 10-25 μm.

[0044] Flotation: the powder after the two magnetic separations is subjected to impurity removal treatment by flotation. Flotation is a process that separates silicate particles from magnetic magnetite particles by injecting bubbles into a flotation tank, so that the silicate particles combine with the bubbles and float up, while the magnetic magnetite particles sink to the bottom.

[0045] Acid washing: the natural magnetite after flotation is washed with a hydrochloric acid solution, the mass concentration of the hydrochloric acid solution is 8%-20%, so that the target metal ions (e.g., chromium ions, nickel ions, cobalt ions, copper ions) in the natural magnetite are dissolved out, and then most of the harmful metal ions are removed through multiple water washing, filtering, and drying to separate the high-purity magnetite.

[0046] High-temperature roasting: the high-purity magnetite obtained by acid washing is heated until melting, and kept for 1-2h, so that the harmful metal ions such as mercuric chloride and lead chloride are volatilized to obtain the final raw material magnetite.

[0047] In these embodiments, in the steps of acid washing and high-temperature roasting, the harmful metal ions in the natural magnetite are removed as much as possible to obtain the raw material magnetite which can meet the food hygiene requirements and is suitable for being used as the non-stick material of the cookware according to the present application.

[0048] In the exemplary embodiments, the raw material magnetite is black, and the main chemical components include: triiron tetroxide, harmless metal ions (e.g., iron, aluminum), and silicate minerals (quartz, calcium silicate, sodium silicate, etc.), wherein, based on the total weight of the raw material magnetite being 100%, the raw material magnetite includes 90%-95% triiron tetroxide, 0.1%-1% silicate minerals, and the balance of harmless metal ions (e.g., iron ions, aluminum ions, titanium ions, vanadium ions, magnesium ions, zinc ions, and calcium ions). Among them, the triiron tetroxide is used to present a black appearance and good wear resistance, the harmless metal cations provide the effect of lattice distortion of the triiron tetroxide, improve the amorphous characteristics, and the silicates provide more surface hydroxyl groups to improve the surface modification effect.

[0049] It should be noted that the "chemical composition" described according to the present application can be understood based on the general understanding of those skilled in the art, which is different from "chemical substance". Specifically, the chemical composition describes the elements or compounds contained inside the substance, while the chemical substance is the actual substance composed of these elements or compounds. In simple terms, the chemical substance is the actually existing substance, while the chemical composition is the basis of these substances. As an example, in the present application, the raw material magnetite is a mineral material formed by mixing the above-mentioned components, rather than a crystalline or trace amorphous mixture formed by directly mixing the above-mentioned substances.

[0050] In the preferred embodiments, the more the components of the material, to a certain extent, the more the types of metal cations, in which case the degree of crystal distortion will also be greater, so it is more conducive to forming an initial non-stick coating with a higher degree of amorphization.

[0051] According to the present application, the raw magnetite is an amorphous material. For example, the volume fraction of the amorphous phase in the raw magnetite can be 60%-80%. Compared with a material with a crystalline structure or a trace of amorphous phase, the raw magnetite with a volume fraction of 60%-80% can form an initial non-stick layer with a higher degree of amorphization. Compared with a coating with a crystalline structure, the initial non-stick layer can exhibit lower surface energy and excellent non-stick properties due to the amorphous characteristics. In addition, compared with a crystalline raw magnetite, the amorphous raw magnetite has improved hardness and wear resistance, which can further improve the hardness of the initial non-stick layer formed by the raw magnetite.

[0052] In the present application, the raw magnetite with an amorphous phase can be obtained by the above method. For example, the volume fraction of the amorphous phase is generally in the range of 60%-80%. In some embodiments, the raw magnetite obtained by the above method can be directly used as a material for forming an initial non-stick layer. Of course, the present application is not limited thereto, and in other embodiments, the raw magnetite obtained by the above method can be sintered and quenched to obtain a raw magnetite with a higher volume fraction of amorphous phase.

[0053] Specifically, the sintering and quenching treatment of the raw magnetite obtained by the above method includes: placing the raw magnetite obtained by the above method in a sintering furnace at a temperature of 1200-1400°C for 2-5 hours, and then cooling at a preset cooling rate to obtain a raw magnetite with a preset volume fraction of amorphous phase. The preset cooling rate can be achieved by cooling the raw magnetite obtained by the above method in a cold gas, for example, the preset cooling rate can be 100-150°C / s. According to the present application, the raw magnetite obtained by the above method can be sintered and quenched to obtain a raw magnetite with a higher volume fraction of amorphous phase. For example, the volume fraction of the amorphous phase in the raw magnetite can be in the range of 68%-83%.

[0054] In some embodiments, the raw magnetite is black, and the color does not change after spraying, so that a black non-stick coating can be formed. On the one hand, the black initial non-stick layer can weaken the contrast of the blackening discoloration, has good hiding power, can cover some small defects or flaws on the surface of the coating, and improves the visual experience during use; on the other hand, the color change is relatively small with the passage of time, which can ensure that the appearance of the cookware is relatively uniform during use, reduces the visual difference caused by color change, and thus enhances the overall aesthetics of the product.

[0055] In some embodiments, the raw magnetite is in a granular form, and the particle size can reach the micron level. For example, the average particle size of the raw magnetite can be in the range of 300-500 mesh (converted to microns, 25-48 μm). If the average particle size of the raw magnetite is greater than 300 mesh, the particles of the raw magnetite are too large, which can easily block the powder feeding pipe, and the powder is not sufficiently melted, the initial non-stick layer has a low bonding force, the coating quality is reduced, and the final coating obtained has a large roughness and an uneven appearance. If the average particle size of the raw magnetite is less than 500 mesh, the particles of the raw magnetite are too small, the powder has poor flowability, and the flight speed is not sufficient during spraying, which can easily cause over-melting, produce particles, and reduce the deposition efficiency and coating quality.

[0056] In some embodiments, the raw magnetite has a spherical or spheroidal shape. The spherical or spheroidal raw magnetite can have good flowability during spraying, which can make the powder feeding in the plasma spraying process more smooth and uniform, and can improve the workability. It should be noted that the shape of the raw magnetite is not limited in the present application, and those skilled in the art can select other suitable shapes under the guidance of the present application, for example, an ellipsoidal shape.

[0057] Forming an initial non-stick layer

[0058] According to the present application, the initial non-stick layer can at least partially cover the inner surface of the substrate, which means that the non-stick coating 120 can cover the bottom surface or the entire inner surface of the substrate 110. The initial non-stick layer is formed by the raw magnetite provided by the embodiments of the present application, and has improved non-stickiness and hardness.

[0059] According to some embodiments of the present application, the volume fraction of the amorphous phase of the raw magnetite can be 60%-83%. The raw magnetite can retain the amorphous phase therein to form an initial non-stick layer having a certain volume fraction of amorphous phase. Specifically, during spraying, only the surface of the raw magnetite is slightly melted and the particles are connected to each other, thereby forming an initial non-stick layer having a volume fraction of amorphous phase of 60%-80%.

[0060] In an exemplary embodiment, the thermal spraying is specifically plasma spraying. The process parameters of the plasma spraying can be as follows: powder feeding speed 20-50 g / min; spraying distance 80-100 mm; arc current 450-650 A; hydrogen pressure 0.2-0.4 MPa; voltage 50-70 V; hydrogen flow 6-15 L / min, argon pressure 2.5-4.0 MPa, argon flow 1000-1500 L / min, spraying angle 45-80°; and workpiece temperature is room temperature.

[0061] According to the present application, by controlling the particle size of the raw magnetite and the spraying parameters, an initial non-stick layer with a preset pore structure can be formed. The surface layer of the initial non-stick layer is relatively dense. The raw magnetite is subjected to the thermal spraying process within the above-mentioned process parameter range. The raw magnetite powder can be fully melted and an initial non-stick layer with a suitable thickness, amorphous characteristics and pores is formed on the surface of the substrate. For example, the thickness of the formed initial non-stick layer can be 20-80 μm. For example, the formed initial non-stick layer has a surface pore structure suitable for reacting with fluorosilane or silane coupling agent. As an example, the coating has a high density, small and few pores invisible to the naked eye. Specifically, the porosity of the pore structure can be 10-15%, and the pore size is 3-5 μm. Under certain spraying parameters, the initial non-stick layer formed by the raw magnetite has similar characteristics to the raw magnetite, for example, similar amorphous characteristics, certain non-stickiness and hardness.

[0062] According to some embodiments of the present application, the raw magnetite powder itself has certain amorphousness, for example, 60-83%. The raw magnetite powder is used and the surface temperature of the cookware substrate is controlled during the spraying process to form an initial non-stick layer with an amorphous phase volume ratio in the range of 65-85%, which can be increased by 5-25% compared to the previous embodiments. This is determined by the chemical composition / content of the raw magnetite of the present application and the cooling speed of the coating during the spraying process, so that an initial non-stick layer with higher amorphous degree can be formed after spraying.

[0063] According to the present application, the substrate includes a first surface and a second surface opposite to each other. The step of controlling the surface temperature of the substrate during the spraying process includes cooling the second surface of the substrate and spraying the raw magnetite on the first surface of the substrate to form an initial non-stick layer with a preset amorphous phase volume ratio on the first surface of the substrate. Specifically, the step of cooling the second surface of the substrate includes applying cold gas to the second surface of the substrate, and the temperature of the cold gas is controlled at -15-0°C. Then, the raw magnetite is sprayed on the first surface of the substrate, and the initial non-stick layer thus formed has a relatively improved amorphous phase volume ratio. In an exemplary embodiment, the amorphous phase volume ratio in the initial non-stick layer is 65-85%, which can be increased by 5-25%. In this way, the surface of the cookware in contact with food materials has low surface energy, thereby having better non-stickiness. It should be noted that the first surface can be an inner surface and the second surface can be an outer surface. Of course, the present application does not make too many limitations on this. It can be understood that those skilled in the art can make the first surface an outer surface and the second surface an inner surface according to the actual use requirements under the teaching of the present application.

[0064] In an exemplary embodiment, cooling the second surface of the substrate includes placing the second surface of the substrate in an environment of a cooling gas. As an example, the cooling gas has a temperature of -15°C to 0°C and a flow rate of 2000 L / h to 4000 L / h.

[0065] The initial non-stick layer with amorphous structure according to the present application can retain the various properties of the raw magnetite described above, and can exhibit properties superior to the raw magnetite under the control of the surface temperature of the cookware during the spraying process, such as, but not limited to, non-stickiness and hardness.

[0066] According to the present application, the initial non-stick layer is an inorganic titanate-based coating with high hardness and high-temperature resistance, and can resist scratching and high-temperature deformation. At the same time, it also has good corrosion resistance.

[0067] Activating the surface of the initial non-stick layer

[0068] According to the present application, after the step of spraying the raw magnetite to form the initial non-stick layer, the step of surface modification treatment can be directly performed, or the surface of the initial non-stick layer can be activated before the step of surface modification treatment.

[0069] According to the present application, before the step of modifying the initial non-stick layer with a fluorosilane material, the method for preparing a non-stick coating further includes activating the surface of the initial non-stick layer. The step of activating the surface of the initial non-stick layer includes treating the initial non-stick layer with an acid solution to activate the surface of the initial non-stick layer to generate at least silicon hydroxyl groups and / or form a plurality of etching grooves, thereby providing more reactive groups (e.g., hydroxyl groups) and / or specific surface area for the subsequent modification treatment step. Specifically, the surface of the initial non-stick layer is activated by the acid solution, on the one hand, the hydroxyl groups on the surface of the initial non-stick layer can be increased to facilitate the subsequent modification treatment reaction step. On the other hand, the metal cations on the surface of the initial non-stick layer can be replaced and dissolved out (e.g., iron ions, aluminum ions, magnesium ions, and calcium ions) by the acid treatment, causing the surface of the initial non-stick layer to be etched to form a plurality of etching grooves, thereby increasing the micro-roughness of the surface of the initial non-stick layer and increasing the specific surface area of the subsequent modification treatment, thereby optimizing the non-stickiness. In addition, the size of the surface layer pores of the initial non-stick layer can also be increased by the acid treatment. +

[0070] In an exemplary embodiment, the step of treating the initial non-stick layer with an acid solution includes providing an acid solution including hydrogen peroxide and hydrochloric acid, placing the initial non-stick layer in the acid solution, and maintaining at a predetermined temperature for a predetermined time, thereby activating the surface of the initial non-stick layer to generate at least hydroxyl groups. The surface activation region covers all surfaces that can be contacted by the acid solution, specifically, including the inner surface of the surface layer pores and the outer surface of the initial non-stick layer. ​

[0071] In the acid solution, concentrated hydrochloric acid and hydrogen peroxide are used in a volume ratio of 5:2-4:1. Specifically, concentrated hydrochloric acid and hydrogen peroxide are mixed in a volume ratio of 5:2-4:1 to form a mixed acid, the raw magnetite is soaked in the mixed acid, and is kept at 60-100°C for 30-60 min, so that the surface of the raw magnetite is activated and hydroxyl groups are generated and / or a plurality of etching grooves are formed.

[0072] In some embodiments, after the step of treating the initial non-stick layer with the acid solution, and before the step of modifying the initial non-stick layer with the fluoro-silane material, the method of preparing the non-stick coating further comprises: placing the initial non-stick layer with the acid solution attached into an alkaline solution to remove the acid solution from the surface of the initial non-stick layer, and then cleaning the initial non-stick layer for use. Illustratively, the alkaline solution comprises a sodium hydroxide solution, a sodium bicarbonate solution.

[0073] Modifying the initial non-stick layer with an organosilicon modifier

[0074] According to the present application, the organic silicon modifier comprises a fluoro-silane material or a silane coupling agent, and the step of modifying the initial non-stick layer with the organic silicon modifier comprises: contacting and reacting a modification solution comprising the organic silicon modifier and an aqueous solvent with the surface of the initial non-stick layer, thereby obtaining the initial non-stick layer modified by the organic silicon modifier as the non-stick coating.

[0075] According to the present application, the initial non-stick layer modified by the organic silicon modifier has extremely strong hydrophobicity, low surface energy, and a large contact angle, so that the initial non-stick property of the non-stick coating is better.

[0076] Specifically, the organic silicon modifier is a silane coupling agent and a fluoro-silane material, and the fluoro-silane material or the silane coupling agent itself has a lower surface energy than the raw magnetite. By using the fluoro-silane material or the silane coupling agent to perform surface modification treatment on the initial non-stick layer, the fluoro-silane material or the silane coupling agent is grafted on the surface of the initial non-stick layer, which can further optimize the initial non-stick property of the entire coating. The method of preparing the non-stick coating not only utilizes the excellent performance of the raw magnetite, but also further optimizes the non-stick property of the non-stick coating by introducing a material with lower surface energy, so that the cookware with the coating can meet the requirements of long-lasting non-stick property, hardness, corrosion resistance, and actual use tests, etc.

[0077] In some embodiments, the organosilicon modifier is a silane coupling agent and a fluorosilane material, the modification solution includes the fluorosilane material and an aqueous solvent, or includes the silane coupling agent and an aqueous solvent, and correspondingly, the surface layer of the initial non-stick layer modified by the organosilicon modifier is a product after the fluorosilane material reacts with the initial non-stick layer; or is a product after the silane coupling agent reacts with the initial non-stick layer. In the case where the organosilicon modifier is a silane coupling agent, the molecule usually contains a silicon atom, and the functional group silicon hydroxyl formed by the silicon atom can be chemically bonded to the surface of the initial non-stick layer to form a stable siloxane network structure, so that not only the wear resistance and durability of the coating are improved, but also the adhesion between the coating and the substrate is enhanced. In the case where the organosilicon modifier is a fluorosilane material, in addition to the above-mentioned silicon atom, it also includes a fluorine atom, and the fluorine atom has a very high electronegativity, so that the initial non-stick layer (non-stick coating) modified by the fluorosilane material has low surface energy. Therefore, when the food contacts the cookware with the non-stick coating, the moisture and fat in the food are not easy to stay on the surface of the coating, thereby reducing the adhesion between the food and the coating. In addition, the organosilicon modifier can also form an ordered nanostructure on the outer surface of the initial non-stick layer by self-assembly or the like, and the nanostructure can further reduce the surface energy of the coating and increase its hydrophobicity, thereby further improving the non-stick performance.

[0078] According to some embodiments of the present application, the organosilicon modifier is a fluorosilane material, and the initial non-stick layer is modified by the fluorosilane material, specifically including the step of providing a modification solution including the fluorosilane material and an aqueous solvent. As an example, providing a modification solution including the fluorosilane material and an aqueous solvent includes providing the fluorosilane material, providing the aqueous solvent, mixing the fluorosilane material with the aqueous solvent, thereby obtaining the modification solution including the fluorosilane material and the aqueous solvent. Wherein, the volume ratio of the fluorosilane material to the aqueous solvent is 1:25-1:60. As an example, the fluorosilane material can include at least one of perfluorodecyltrimethoxysilane, perfluorooctyltriethoxysilane, perfluorododecyltrimethoxysilane, and trifluoropropylmethylsilane. As an example, the aqueous solvent is an ester solvent and / or an alcohol solvent, specifically, the ester solvent includes ethyl acetate, and the alcohol solvent includes ethanol, ethyl alcohol, and butanediol, etc. Since the solubility of the fluorosilane material in water is not high, the ester solvent and / or the alcohol solvent can increase the solubility of the fluorosilane material, and can inhibit the hydrolysis speed of the modification solution to a certain extent.

[0079] As some examples, modifying the initial non-stick layer with a fluorosilane material

[0080] According to the present application, the method for preparing a non-stick coating further includes the step of placing the obtained initial non-stick layer in acetone for multiple ultrasonic washing to remove dirt and dust on the surface, then drying again, and then performing the modification treatment.

[0081] According to the present application, the surface of the initial non-stick layer has silicon hydroxyl groups, modifying the initial non-stick layer with fluoro-silane type material includes impregnating the initial non-stick layer with a modifying solution, in this case, the surface of the initial non-stick layer and the surface layer pores can be impregnated with the modifying solution, then, the impregnated initial non-stick layer is taken out, and a heat treatment is performed, under the action of the heat treatment, the fluoro-silane type material can hydrolyze to form a siloxane type material, then the generated siloxane type material and the silicon hydroxyl groups on the surface layer of the initial non-stick layer undergo dehydration reaction to form a modified layer, thereby obtaining the initial non-stick layer modified by the fluoro-silane type material. The modified layer not only retains the excellent properties of the initial non-stick layer, but also adds new functional characteristics, such as improved non-stick performance, increased wear resistance, etc. And because the modified layer is obtained by removing water molecules between the silicon hydroxyl groups on the initial non-stick layer and the siloxane type material, a tight bond is formed between the two, which can avoid falling off during use and ensure the overall bonding force of the coating. In some embodiments, the impregnation is carried out at room temperature, and the impregnation time can be 30 min-1 h, and the heat treatment can be carried out at a predetermined temperature for a predetermined time to ensure the stable hydrolysis of the fluoro-silane type material and the dehydration reaction of the siloxane type material and the silicon hydroxyl groups on the surface layer of the initial non-stick layer. As some examples, the heat treatment is performed by using a heating furnace or hot air, etc., and the temperature of the heat treatment can be 50°C-100°C, and the time can be 15 min-30 min. As another example, the heat treatment can be performed by microwave heating, specifically, the initial non-stick layer can be contacted with the modifying solution under heating conditions by using ultrasonic method, for example, by using ultrasonic vibration, and the vibration frequency is set to 20 KHz-50 KHz, and heated to 50°C-80°C for 5 min-8 min.

[0082] According to the present application, the initial non-stick layer modified by the fluoro-silane type material serves as the non-stick coating of the cookware, and the formed non-stick coating includes the initial non-stick layer which is not modified by the fluoro-silane type material and the modified layer which is stacked on the initial non-stick layer which is not modified by the fluoro-silane type material. Among them, the modified layer is the surface layer part of the initial non-stick layer modified by the fluoro-silane type material, which is the product obtained by the reaction of the hydrolysis product of the fluoro-silane type material and the initial non-stick layer, and serves as the surface layer of the cookware, and the initial non-stick layer which is not modified by the fluoro-silane type material is the unreacted initial non-stick layer, which belongs to the internal part of the initial non-stick layer modified by the fluoro-silane type material (non-stick coating).

[0083] According to the present application, since the modified solution has fluidity, the modified solution not only acts on the surface of the initial non-stick layer, but also can act on the surface layer pores of the initial non-stick layer, so that a first modified region is formed on the outer surface of the initial non-stick layer, and a second modified region is formed on the inner wall surface of the surface layer pores of the initial non-stick layer. Among them, the first modified region and the second modified region are modified layers of the non-stick coating. It should be noted that the surface layer pores refer to the pores / holes existing in the region of a certain depth from the outer surface of the initial non-stick layer.

[0084] According to the present application, the fluorosilane material in the modified solution can be stably hydrolyzed in an acidic environment. In an acidic condition, the hydrolysis process of the fluorosilane material can be more controllable and uniform, which is helpful to form a uniform and dense modified layer on the surface of the initial non-stick layer. In an exemplary embodiment, the pH value of the modified solution is not greater than 7. As an example, a predetermined amount of dilute hydrochloric acid can be included in the modified solution to obtain a modified solution with a desired pH value. It should be noted that in the method of preparing the non-stick coating, a preset amount of dilute hydrochloric acid can be added regularly to ensure the stability of the pH value of the modified solution system.

[0085] According to the present application, after the modification treatment, the method of preparing the non-stick coating further comprises ultrasonic washing the initial non-stick layer (non-stick coating) modified by the silane coupling agent in acetone or anhydrous ethanol, so as to hydrolyze the unreacted silane coupling agent on the initial non-stick layer modified by the silane coupling agent, thereby removing the ungrafted silane coupling agent.

[0086] According to the present application, the volume fraction of amorphous phase of the initial non-stick layer obtained by spraying the raw material magnetite can be in the range of 60%-85%. Since the subsequent modification process involves the surface layer of the initial non-stick layer rather than the whole, the surface layer modification will not greatly affect the amorphization degree of the coating. In this case, the volume fraction of amorphous phase of the initial non-stick layer modified by the fluorosilane material or the initial non-stick layer modified by the silane coupling agent is also approximately in the range of 60%-85%.

[0087] As some other examples, modifying the initial non-stick layer with a silane coupling agent

[0088] For the convenience of description, only the differences between the ways of modifying the initial non-stick layer by the fluorosilane material will be specifically described in the present application below, and the other parts are the same as the way of modifying the initial non-stick layer by the fluorosilane material.

[0089] According to the present application, the surface of the initial non-stick layer has silicon hydroxyl groups, and modifying the initial non-stick layer with a silane coupling agent includes impregnating the initial non-stick layer with a modifying solution, wherein the modifying solution includes a silane coupling agent and an aqueous solvent, and the silane coupling agent can include at least one of vinyltriethoxysilane, vinyltrimethoxysilane, vinyltri(β-methoxyethoxy)silane, and γ-aminopropyltriethoxysilane. The volume ratio of the silane coupling agent to the aqueous solvent is 1:15-1:45, and the type of the aqueous solvent is the same as described above.

[0090] According to the present application, the silane coupling agent in the modifying solution can be stably hydrolyzed in an acidic environment, and the hydrolysis process of the silane coupling agent can be more controllable and uniform in the acidic conditions, which helps to form a uniform and dense modified layer on the surface of the initial non-stick layer. In an exemplary embodiment, the pH of the modifying solution is 4-6. As an example, a predetermined amount of at least one of dilute hydrochloric acid, formic acid, and acetic acid can be included in the modifying solution to obtain a modifying solution with a desired pH value. It should be noted that in the method of forming the non-stick coating, a predetermined amount of dilute hydrochloric acid can be added periodically to ensure the stability of the pH value of the modifying solution system.

[0091] According to a second aspect of the present application, a non-stick coating for a cookware is provided, wherein the non-stick coating is prepared by the method of preparing a non-stick coating provided in the above embodiments.

[0092] In an embodiment, the surface energy of the non-stick coating is 18 dynes to 40 dynes, so as to have excellent hydrophobicity and anti-sticking property.

[0093] In an embodiment, the surface layer structure of the non-stick coating is relatively dense, as an example, the porosity of the non-stick coating is in the range of 1% to 3%; and / or the pore size is 0.1 μm to 1 μm. Such a pore structure can effectively prevent external substances (such as moisture, oil, gas, etc.) from penetrating into the coating, and can protect the substrate from erosion and contamination, thereby ensuring the corrosion resistance of the cookware. In addition, the dense coating surface is not easy to be adhered by food or other substances, so that cooking and cleaning are more convenient.

[0094] In an embodiment, the non-stick coating has a suitable hardness, as an example, the hardness of the non-stick coating is 400 HV to 800 HV, and such a hardness can resist scratching and wear of the surface by external objects, thereby prolonging the service life. In addition, the coating with such a hardness is not easy to deform or damage when subjected to external force, thereby being able to maintain the stability of its shape and function.

[0095] In embodiments, the non-crystalline phase volume fraction of the non-stick coating is high, for example, the non-crystalline phase volume fraction of the non-stick coating is 65%-90%, the high non-crystalline phase volume fraction enables the non-stick coating to have a low surface energy. In addition, the high non-crystalline phase volume fraction makes the structure of the coating more uniform, and there is no clear grain boundary, which can improve the stability and reliability of the coating and reduce the risk of performance degradation or failure of the coating during use. In addition, the non-stick coating has better wear resistance, scratch resistance and impact resistance, and can better resist external forces to prolong the service life.

[0096] In embodiments, the modification layer has a suitable surface roughness, for example, the surface roughness of the modification layer is 20 μm-40 μm. The suitable surface roughness can make the coating surface more uniform and smooth, reduce the micro concave-convex and defects, so that the cookware can be cooked non-stick. The suitable surface roughness can reduce the wear or scratch of the coating, thereby prolonging the service life of the coating.

[0097] In embodiments, the color of the modification layer is black, and the color change is relatively small over time, which can ensure that the cookware with the modification layer has a uniform appearance during use, reduces the visual difference caused by color change, and enhances the overall aesthetics of the product. In addition, the use of a black modification layer can give the product a modern and textured look, better attract the attention of consumers, and improve the user experience. In addition, black also has good hiding power, which can cover up some small defects or flaws on the surface of the coating, further improving the appearance quality of the product.

[0098] In embodiments, the modification layer exists on the outer surface of the unreacted initial non-stick layer, which can effectively enhance the non-stick performance. The modification layer exists on the inner wall of the surface layer pores of the initial non-stick layer, which can make the pores of the initial non-stick layer more dense, and can fill part of the small defects and pores, making the coating surface more uniform and smooth, which helps to reduce the adhesion of food and dirt, and further improves the cleaning performance. In addition, it can effectively seal the pores to prevent harmful substances such as water and grease from penetrating into the coating, ensuring the corrosion resistance of the coating.

[0099] In exemplary embodiments, the thickness of the modification layer is a molecular level thickness, for example, the thickness is in the range of 0.3 nm-0.5 nm.

[0100] According to a third aspect of the present application, a cookware is provided, in particular a non-stick cookware. The cookware comprises a base body and a non-stick coating, the non-stick coating is formed on the base body, and the non-stick coating comprises the non-stick coating provided in the above embodiments.

[0101] Figure 1is a cross-sectional structure of the cookware after being cut along the thickness direction according to an embodiment of the present application, which comprises a base 110 and a non-stick coating 120. The non-stick coating 120 can at least partially cover the inner surface of the base 110, in other words, the non-stick coating can cover part or all of the inner surface of the base 110.

[0102] Figure 2 is Figure 1 is an enlarged structure diagram of I in FIG. 6. As shown in Figure 1 and Figure 2 The non-stick coating 120 comprises an unmodified initial non-stick layer 121 and a modified layer 122 stacked on the unmodified initial non-stick layer 121, the unmodified initial non-stick layer 121 as the inner part of the non-stick coating, and the modified layer 122 as the surface layer of the non-stick coating 120, and the surface layer of the non-stick coating is also the surface layer of the cookware, as the functional surface of the cookware during use. The modified layer 122 is a reaction product formed by chemical reaction between the product formed by hydrolysis of the modified solution and the silicon hydroxyl on the surface of the initial non-stick layer.

[0103] The raw magnetite belongs to ceramic materials, and has poor bonding force with the metal base. Even if the roughness of the metal base after general sand blasting treatment is small, in order to increase the bonding force between the non-stick coating and the base, in some embodiments, the cookware further comprises a primer layer 130, wherein the primer layer 130 is arranged between the base 110 and the non-stick coating 120, and the primer layer 130 is formed of a metal material.

[0104] In an exemplary embodiment, the primer layer can be prepared by thermal spraying or cold spraying method, and the primer layer material is selected from common metal powder materials, such as titanium and titanium alloy, iron and iron alloy, aluminum and aluminum alloy, zinc and zinc alloy, copper and copper alloy, zirconium and zirconium alloy, etc.

[0105] In an exemplary embodiment, the thickness of the primer layer is in the range of 8 μm-20 μm, and the surface roughness of the formed primer layer is in the range of 10 μm-20 μm.

[0106] According to a fourth aspect of the present application, a method for manufacturing a non-stick cookware is provided, wherein the method for manufacturing the non-stick cookware comprises:

[0107] Step S101, providing a base.

[0108] Step S102, providing raw magnetite.

[0109] Step S103, spraying the raw magnetite on the surface of the base to form an initial non-stick layer on the surface of the base.

[0110] In step S104, a modification solution is provided, and the modification solution is brought into contact with the surface of the initial non-stick layer and reacts, so that a non-stick coating layer including a modification layer is obtained. The modification solution is a modification solution including a fluorosilane material and an aqueous solvent or a modification solution including a silane coupling agent and an aqueous solvent.

[0111] Providing a substrate

[0112] According to the present application, the base body 110 can be made of a commonly used material. For example, the material can be stainless steel, titanium, aluminum, their corresponding alloys, and composite materials. The base body 110 can have a shape corresponding to the function. For example, as shown in FIG. 1, when the non-stick cookware 100 is a non-stick pot, the base body 110 can have a conventional pot body shape. It should be understood that, Figure 1 Figure 1 For example, only the main body part of the non-stick pot is shown in FIG. 1, and other parts are not shown, but the non-stick pot according to the present application can also include a handle (for example, a pot handle) and other common cookware structures / components.

[0113] According to the present application, the base body 110 can be a base body after surface alkali washing, drying, and sand blasting treatment, and the surface of the base body has a certain roughness. In an exemplary embodiment, the roughness of the surface of the base body is in the range of 4 μm-6 μm in terms of Ra value.

[0114] Providing raw magnetite

[0115] In the embodiments of the present application, the raw magnetite is the raw magnetite according to the above-mentioned various embodiments.

[0116] The method for preparing a non-stick coating layer provided in the above-mentioned embodiments forms a non-stick coating layer on a base body.

[0117] The present application will be described in detail below with reference to specific embodiments, but the scope of protection of the present application is not limited to the embodiments.

[0118] Example 1

[0119] The pot according to Embodiment 1 is manufactured by the following method.

[0120] In step S10, a pot base body is prepared. Specifically, a composite titanium sheet is drawn and formed, and the surface is alkali washed to remove oil, dried, and sand blasted, so that a pot base body with a thickness of 1.5 cm is obtained.

[0121] ​Step S20, preparing raw magnetite having an average particle size of 400 mesh, wherein the chemical composition of the raw magnetite includes 90% of Fe3O4, 0.1-1% of silicate minerals (quartz, calcium silicate, sodium silicate) and the balance of harmless metal ions (iron, magnesium, aluminum) based on 100% of the total weight of the raw magnetite.

[0122] Step S30, spraying the non-stick material on the pot base. Specifically, the outer surface of the pot base is placed in a circulating cooling air gas environment, wherein the temperature of the cooling gas is minus 15°C. The powder of the raw magnetite of 400 mesh is then loaded into the powder feeder, and the parameters are set as follows: powder feeding speed 30 g / min; spraying distance 90 mm; arc current 550 A; hydrogen pressure 0.3 MPa, hydrogen flow 8 L / min, argon pressure 3 MPa, argon flow 1200 L / min. The non-stick material powder is sprayed on the inner surface of the base material to obtain an initial non-stick layer with a thickness of 65 μm.

[0123] Step S40, forming a modified layer on the initial non-stick layer by treating the initial non-stick layer with a modified solution of perfluorodecyltrimethoxysilane: ethyl acetate mixed at a volume ratio of 1:40 at a pH of 6 and under microwave conditions (microwave vibration frequency 30 KHz, heated to 65°C for 6 min), and the initial non-stick layer with the modified layer is used as a coating of the pot of the present embodiment, thereby completing the manufacture of the pot of Example 1.

[0124] Example 2

[0125] Except that in Step S40, the modified solution of perfluorodecyltrimethoxysilane: ethyl acetate mixed at a volume ratio of 1:40 is used instead of the modified solution of Example 1, the pot of Example 2 is manufactured by the same method as Example 1.

[0126] Example 3

[0127] Except that in Step S40, the modified solution of perfluorodecyltrimethoxysilane: ethyl acetate mixed at a volume ratio of 1:40 is used instead of the modified solution of Example 1, the pot of Example 2 is manufactured by the same method as Example 1.

[0128] Example 4

[0129] Except that in Step S40, the modified solution of perfluorodecyltrimethoxysilane: ethyl acetate mixed at a volume ratio of 1:40 is used instead of the modified solution of Example 1, the pot of Example 2 is manufactured by the same method as Example 1.

[0130] Example 5

[0131] Example 5 was manufactured by the same method as Example 1, except that the modified solution of Example 1 was replaced with a modified solution prepared by mixing vinyltrimethoxysilane: ethyl acetate at a volume ratio of 1:40 in Step S40.

[0132] Example 6

[0133] Example 6 was manufactured by the same method as Example 1, except that the modified solution of Example 1 was replaced with a modified solution prepared by mixing γ-aminopropyltriethoxysilane: ethyl acetate at a volume ratio of 1:40 in Step S40.

[0134] Example 7

[0135] Example 7 was manufactured by the same method as Example 1, except that the raw material magnetite of Example 1 was replaced with 500 mesh raw material magnetite in Step S20.

[0136] Example 8

[0137] Example 8 was manufactured by the same method as Example 1, except that the raw material magnetite of Example 1 was replaced with 300 mesh raw material magnetite in Step S20.

[0138] Example 9

[0139] Example 9 was manufactured by the same method as Example 1, except that the outer surface of the pot base was not placed in a circulating cooling air gas environment in Step S30.

[0140] Example 10

[0141] Example 10 was manufactured by the same method as Example 1, except that a 40 μm thick primer layer was formed on the pot base by plasma spraying using a titanium alloy prior to Step S20 (spraying parameters: powder feed rate 40 g / min, spraying distance 120 mm, arc current 350 A, hydrogen pressure 0.7 MPa, flow rate 30 L / h, argon pressure 1.6 MPa, flow rate 2000 L / h).

[0142] Example 11

[0143] Example 11 A cookware was manufactured in the same manner as in Example 1, except that in Step S10, the raw magnetite was previously sintered (sintering temperature of 1400°C, sintering time of 4h), then cooled at a cooling rate of 80°C / s, and the sintered material was used to replace the raw magnetite of Example 1.

[0144] Example 12

[0145] Example 12 A cookware was manufactured in the same manner as in Example 1, except that between Step S30 and Step S40, a step of activating the surface of the initial non-stick layer was added (the initial non-stick layer was soaked in a mixed acid of hydrogen peroxide and concentrated hydrochloric acid at a volume ratio of 2:5, so that the initial non-stick layer was kept at a temperature of 90°C for 20 min).

[0146] Example 13

[0147] Example 13 A cookware was manufactured in the same manner as in Example 4, except that between Step S30 and Step S40, a step of activating the surface of the initial non-stick layer was added (the initial non-stick layer was soaked in a mixed acid of hydrogen peroxide and concentrated hydrochloric acid at a volume ratio of 1:4, so that the initial non-stick layer was kept at a temperature of 60°C for 30 min).

[0148] Comparative Example 1

[0149] Example 1, except that in Step S20, the raw magnetite of Example 1 was replaced with a different material (the material of the present comparative example was natural magnetite, with the total weight of the natural magnetite being 100%, the weight percentage of magnetite being 60%, the weight percentage of silicate minerals being 15%, the weight percentage of compounds of harmful metal ions being 0.1-1%, and the balance being compounds of non-harmful metal ions. The harmful metal ions included chromium ions, manganese ions, nickel ions, cobalt ions, copper ions, mercury ions and lead ions, the non-harmful metal ions included iron ions, aluminum ions, titanium ions, vanadium ions, magnesium ions, zinc ions and calcium ions, and the silicate minerals included quartz, calcium silicate and sodium silicate.), and Step S40 was not performed.

[0150] Comparative Example 2

[0151] The pot of Comparative Example 2 was manufactured by the same method as in Example 1 except that a different material (the material of this comparative example was natural magnetite, and the weight ratio of the magnetite was 60%, the weight ratio of silicate minerals was 15%, the weight ratio of compounds of harmful metal ions was 0.1-1%, and the remainder was compounds of non-harmful metal ions, based on the total weight of the natural magnetite) was used instead of the raw material magnetite of Example 1 in step S20.

[0152] Comparative Example 3

[0153] The pot of Comparative Example 3 was manufactured by the same method as in Example 1 except that a different material (the material of this comparative example was ferrous magnesium titanate) was used instead of the raw material magnetite of Example 1 in step S20 and step S40 was not performed.

[0154] Comparative Example 4

[0155] The pot of Comparative Example 4 was manufactured by the same method as in Example 1 except that a different material (the material of this comparative example was ferrous magnesium titanate) was used instead of the raw material magnetite of Example 1 in step S20.

[0156] Comparative Example 5

[0157] The pot of Comparative Example 5 was manufactured by the same method as in Example 1 except that a different material (the material of this comparative example was ferrous magnesium aluminum titanate) was used instead of the raw material magnetite of Example 1 in step S20 and step S40 was not performed.

[0158] Comparative Example 6

[0159] The pot of Comparative Example 6 was manufactured by the same method as in Example 1 except that a different material (the material of this comparative example was ferrous magnesium aluminum titanate) was used instead of the raw material magnetite of Example 1 in step S20.

[0160] Comparative Example 7

[0161] The pot of Comparative Example 7 was manufactured by the same method as in Example 1 except that a different material (the material of this comparative example was ferrous magnesium aluminum copper titanate) was used instead of the raw material magnetite of Example 1 in step S20 and step S40 was not performed.

[0162] Comparative Example 8

[0163] In addition to step S20, except that a different material (the material of the present comparative example is magnesium copper titanate) is used instead of the raw material magnetite of Example 1, the same method as Example 1 is used to manufacture the pot of Comparative Example 8.

[0164] Test Methods and Evaluation Criteria, Test Results

[0165] The coating of the pot obtained in Examples 1 to 13 and Comparative Examples 1 to 8 is tested for performance, and the results are recorded in Table 1 below. The specific performance test methods are as follows:

[0166] I. Test methods and evaluation criteria

[0167] 1. Amorphous degree test method: XRD test and analysis calculation by conventional full spectrum fitting method are used to obtain the amorphization degree of the coating. The steps of the conventional full spectrum fitting method are as follows: first, find a crystal phase with the same chemical structure as the amorphous phase, and assume that the amorphous phase is a small crystal grain of this crystal phase, which can be used to establish a model of the peak position and intensity of the amorphous phase; second, fit the spectrum of pure amorphous phase first to determine the grain size and microstrain; finally, fix the grain size and microstrain, and include this phase in the traditional Rietveld quantitative calculation, and the volume fraction of the amorphous phase of the coating (i.e. the amorphization degree) can be obtained.

[0168] 2. Initial non-stick test method: The frying egg non-stick test method in GB / T32095.2-2015 is used for initial non-stick test, which is divided into I, II and III levels, with I level being the best and III level being the worst.

[0169] 3. Long-term non-stick test method: The long-term non-stick test method in GB / T32388-2015 is used, with the unit being times, and the higher the number of times, the longer the service life. The non-stick result is evaluated every 500 times, and the number of times until level III is recorded.

[0170] 4. Hardness test and evaluation criteria: Vickers hardness test method is used to test the Vickers hardness of the coating of the pot, and the hardness value unit is HV. For hardness testing, the larger the hardness value, the harder the sample. When the sample is a non-stick coating, the greater the hardness, the harder the non-stick coating, the stronger the ability of the non-stick coating to resist the grinding of the spatula and food, and the less likely it is to be worn out, thus the longer the service life of the non-stick coating. In general, the hardness of the non-stick coating is expected to be no less than 200 HV.

[0171] 5. Surface energy test and evaluation standard: At a temperature of 20°C, using a SINDIN SDC-200SH contact angle measuring instrument, the contact angles of water and ethylene glycol on the surface of the sample are measured according to the goniometry method, and the surface energy of the sample is calculated using the OWRK method. Here, the sample refers to the coating of the pot obtained in the examples and comparative examples. For the surface energy test, the measured surface energy value of the sample is expected to be no more than 100 dynes.

[0172] 6. Corrosion resistance test method: Add 1 / 3 of the pot volume and 5% by mass of brine (prepared with distilled water) to the pot, keep boiling, continuously supplement distilled water to maintain the concentration, observe every half hour, and record the time of rust corrosion.

[0173] 7. Dish test method, i.e. actual use test method, the following 6 dishes are sequentially performed as one cycle.

[0174] First, fried potato chips

[0175] Pour 500g of room temperature oil into the pot, heat to 180±10°C on high heat, add 200g of freshly cut potato chips, heat on high heat to maintain the oil temperature at 130-150°C, and fry until golden brown (reference time: 2-3 min) and remove.

[0176] (Directly test the next dish without washing the pot)

[0177] Second, stir-fried snails

[0178] Put 20g of oil in the pot and add 400g of snails after heating. Add a small amount of vinegar, soy sauce, cooking wine, water, and salt, and continuously stir-fry for 200 times (reference time: total time about 2-3 min, reference method: about the first 100 times of stir-frying on high heat, and the last 100 times of stir-frying on medium heat, to ensure that the inner surface does not appear similar to dry burning or smoke phenomenon, if similar to dry burning or smoke phenomenon appears, a small amount of water can be added as needed).

[0179] After completion, use sponge + detergent to clean the inner surface of the pot, and replace the snails every 10 cycles.

[0180] Third, fried tofu

[0181] Put 20g of oil in the pot, heat on medium heat, add about 150g of tofu cubes (about 10-12 pieces), and heat on medium heat, fry until both sides are golden brown (reference time: 3-4 min).

[0182] After completion, use sponge + detergent to clean the inner surface of the pot.

[0183] Fourth, stir-fried potato strips

[0184] Put 20g oil in the pot, after heating, add 200g potato silk, add appropriate amount of salt, 5g cooking wine, 15g vinegar, appropriate fire stir-fry soft (reference time: 4min, about 1min before high heat, 3min after medium heat, to ensure that the inner surface does not appear similar to dry burning or oil smoke phenomenon, if similar to dry or oil smoke burning phenomenon, can be appropriate to add a small amount of water).

[0185] After the end, use sponge + detergent to clean the inner surface of the pot.

[0186] Fifth, tomato egg soup

[0187] Put 20g oil in the pot, after heating, add 1-2 tomatoes (reference weight: 200g), medium heat stir-fry about 1min; add 300g water, high heat until boiling, add 1 beaten egg liquid, keep simmering 1min out of the pot.

[0188] After the end, use sponge + detergent to clean the inner surface of the pot.

[0189] Sixth, national standard fried egg

[0190] According to GB / T32095.2-2015 test method, fry an egg, observe the non-stickiness.

[0191] After the end, use sponge + detergent to clean the inner surface of the pot.

[0192] It should be noted that in the process of circulating, when cooking the sixth kind of dishes, it is necessary to detect whether the non-stickiness of the inner surface of the pot can still be above level III, if so, continue the cooking of the next cycle of dishes, if not, the current cycle number is the actual cycle number of the pot.

[0193] II. Test results

[0194] Table 1 test results

[0195]

[0196]

[0197] As can be seen from Table 1, the non-stick coating on the surface of the pot has a good amorphous degree, the higher the amorphous degree, the higher the hardness, the better the wear resistance, and the stronger the persistent non-stickiness. Because the surface layer of the non-stick coating is an organic modified layer, on the one hand, it can improve the initial non-stickiness of the non-stick coating, and on the other hand, it can further seal the pores and improve the corrosion resistance of the pot.

[0198] As can be seen from Examples 1, 7 and 8, the larger the particle size of the non-stick material, the better the persistent non-stickiness, because the larger particle size can form a suitable surface rough structure, and these surface rough structures can protect the modified layer of the surface layer, ensuring that the non-stickiness is more persistent.

[0199] As can be seen from Example 1 and Example 9, by controlling the spraying process (i.e. placing the outer surface of the pot in a cooling gas environment in the process of plasma spraying), the amorphous degree of the non-stick coating can be improved to a certain extent, so that the surface energy is relatively low, thereby ensuring good and durable non-stick performance.

[0200] In summary, according to the present application, the non-stick coating of the pot is excellent in initial non-stickness, durable non-stickness, hardness, corrosion resistance, and actual use test, and the like, so that the pot is more durable.

[0201] The coating of the pot of the comparative example obviously cannot have the properties of initial non-stickness, durable non-stickness, hardness, and resistance to external force impact, and the like, and therefore, the durability of the pot is poor.

[0202] Although the present application has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those skilled in the art that various changes in form and details can be made therein without departing from the spirit and scope of the application as defined by the appended claims and their equivalents. The examples should be considered in a descriptive sense only and not for purposes of limitation. Therefore, the scope of the present application is defined not by the foregoing description of embodiments but by the following claims, and all differences within the scope of equivalents thereof are to be interpreted as being included in the present application.

[0203] Although the embodiments of the present application have been described in detail above, those skilled in the art will understand that various modifications and variations can be made to the embodiments of the present application without departing from the spirit and scope of the present application. However, it should be understood that these modifications and variations will still fall within the spirit and scope of the embodiments of the present application as defined by the claims.

Claims

1. A method for producing a non-stick coating for cookware, characterized in that, The method comprises: hot spraying raw magnetite to form an initial non-stick layer with an amorphous structure; modifying the initial non-stick layer with an organosilicon modifier to obtain the non-stick coating, wherein the organosilicon modifier comprises a fluorosilane material or at least one of vinyltriethoxysilane, vinyltrimethoxysilane, vinyltri(β-methoxyethoxy)silane and γ-aminopropyltriethoxysilane, and the main components of the raw magnetite include 90-95% of Fe3O4, 0.1-1% of silicate minerals and the balance of metal ions, wherein the metal ions include iron ions, aluminum ions, titanium ions, vanadium ions, magnesium ions, zinc ions and calcium ions, based on 100% of the total weight of the raw magnetite.

2. The method of claim 1, wherein, The step of modifying the initial non-stick layer with the organosilicon modifier comprises: contacting and reacting a modification solution comprising the organosilicon modifier and a solvent with the initial non-stick layer to obtain the organosilicon modifier-modified initial non-stick layer as the non-stick coating, wherein the solvent is an ester solvent and / or an alcohol solvent.

3. The method of claim 2, wherein, The surface layer of the organosilicon modifier-modified initial non-stick layer is the product after the hydrolysis product of the organosilicon modifier reacts with the initial non-stick layer.

4. The method of claim 2, wherein, The fluorosilane material comprises at least one of perfluorodecyltrimethoxysilane, perfluorooctyltriethoxysilane, perfluorododecyltrimethoxysilane and trifluoropropylmethylsilane.

5. The method of claim 1, wherein, The method for preparing the non-stick coating further comprises: subjecting natural magnetite powder to at least pickling and roasting to obtain the raw magnetite.

6. The method of claim 1, wherein, The hot spraying of the raw magnetite comprises: controlling the particle size of the raw magnetite and spraying parameters to form the initial non-stick layer with a predetermined pore structure.

7. The method of claim 6, wherein, The particle size of the raw magnetite is 300-500 mesh, and the spraying parameters are: a powder feeding speed of 20-50 g / min, a spraying distance of 80-100 mm, an arc current of 450-650 A, a hydrogen pressure of 0.2-0.4 MPa, a voltage of 50-70 V, a hydrogen flow of 6-15 L / min, an argon pressure of 2.5-4.0 MPa, an argon flow of 1000-1500 L / min, a spraying angle of 45-80°, and a workpiece temperature of normal temperature or -15-0°C.

8. A non-stick coating characterized in that, The non-stick coating comprises a non-stick coating prepared by the method for preparing a non-stick coating according to any one of claims 1-7.

9. The non-stick coating according to claim 8, characterized in that, The non-stick coating comprises at least one of the following characteristics: The surface energy of the non-stick coating is 18-40 dynes; The porosity of the non-stick coating is 1-3%; The pore size of the non-stick coating is 0.1-1 μm; The hardness of the non-stick coating is 400-800 HV; The volume fraction of the amorphous phase in the non-stick coating is 60-90%; The color of the non-stick coating is black.

10. A non-stick cookware characterized by, The non-stick cookware comprises a base and a non-stick coating formed on the base, and the non-stick coating comprises the non-stick coating according to claim 8 or 9.

11. The non-stick cookware of claim 10, wherein, The base is a metal base, and the non-stick cookware further comprises: a metal strike layer formed between the substrate and the non-stick coating.

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