Cooking appliance and method of manufacturing the same

Abstract

The application provides a cooking utensil and a preparation method thereof, and relates to the technical field of cooking utensils. The cooking utensil comprises a base body, a material of the base body comprising aluminum, an aluminum alloy or an aluminum composite material, and an aluminum oxide layer arranged on a surface of the base body, wherein the aluminum oxide layer is a thermal spraying layer or a cold spraying layer, and the aluminum oxide layer comprises alpha-Al2O3. The cooking utensil has the advantages of high surface hardness, good corrosion resistance, good long-lasting wear resistance and non-stickness, and long service life.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of cooking utensils, in particular to a cooking utensil and a preparation method thereof. BACKGROUND

[0002] In the traditional cooking utensil and household appliance industry, in order to reduce the weight of the product, meet the needs of fast heating and uniform heat transfer, etc., the base of the cooking utensil is generally made of aluminum or aluminum alloy materials. However, aluminum or aluminum alloy materials are prone to defects such as low hardness, poor wear resistance or corrosion resistance during use, and need to be surface treated.

[0003] In the prior art, in order to improve the hardness and wear resistance of aluminum or aluminum alloy base materials, the base materials are generally subjected to oxidation treatment to form an aluminum oxide (Al2O3) film to achieve the purpose of surface strengthening. However, the aluminum oxide film formed at present still has more or less defects, such as the low-temperature sulfuric acid anodic oxidation technology commonly used at present, the hardness of the aluminum oxide film formed is generally 350-450HV, the film hardness is low, and the corrosion resistance and wear resistance also need to be improved. With the continuous development of science and technology or economy, users' requirements for cooking utensil products are continuously improving, and the aluminum oxide film formed by the existing low-temperature sulfuric acid anodic oxidation technology has been unable to meet market needs and customer expectations. Therefore, it has become a technical problem to be solved in the related industry to develop a surface strengthening technology that can achieve higher hardness and stronger corrosion resistance. SUMMARY

[0004] The purpose of the present application is to provide a cooking utensil and a preparation method thereof, which has the advantages of high surface hardness, good corrosion resistance and good wear resistance, and can overcome the above problems or at least partially solve the above technical problems.

[0005] To achieve the above-mentioned purposes, the technical solutions adopted by the present application are as follows:

[0006] According to one aspect of the present application, the present application provides a cooking utensil, which comprises:

[0007] a base, the material of the base comprising aluminum, aluminum alloy or aluminum composite material;

[0008] an aluminum oxide layer arranged on the surface of the base;

[0009] wherein the aluminum oxide layer is a thermal spray coating or a cold spray coating, and the aluminum oxide layer comprises α-Al2O3.

[0010] The cooking utensil forms the aluminum oxide layer on the surface of the different aluminum base material by cold spraying or hot spraying, and the formed aluminum oxide layer comprises alpha-Al2O3, thereby realizing the effects of high hardness, strong corrosion resistance, low investment, low processing cost, and high output. In detail, alpha-Al2O3 is the most stable phase among all aluminum oxides, and has the characteristics of good formability, stable crystal phase, high hardness, and good structural stability. Therefore, compared with the aluminum oxide film layer formed by ordinary sulfuric acid anodic oxidation, the alpha-Al2O3 film layer formed by the cooking utensil can significantly improve the hardness and corrosion resistance of the film layer, and the wear resistance of the alpha-Al2O3 film layer is also better, which is beneficial to prolong the service life of the coating. At the same time, the cooking utensil forms the aluminum oxide layer on the surface of the different aluminum base material by cold spraying or hot spraying, which can reduce the equipment investment cost, reduce the production cost, improve the efficiency, and reduce the noise compared with the existing micro-arc oxidation method. The method can avoid the limitation of the existing sulfuric acid anodic oxidation and micro-arc oxidation method on the silicon content in the base material, and can realize the surface strengthening and corrosion resistance enhancement effect on the base material including the base material with high silicon content, thereby improving the comprehensive performance of the product. In addition, compared with the existing method of spraying metal or titanium-containing ceramic powder by hot spraying, the alpha-Al2O3 film layer formed by the cooking utensil can avoid potential corrosion and chlorine corrosion, and improve the corrosion resistance.

[0011] In a possible implementation manner, the material of the base body comprises cast aluminum, and the mass content of silicon in the cast aluminum is less than 15%.

[0012] Alternatively, the mass content of silicon in the cast aluminum is 15% to 25%.

[0013] Compared with the existing sulfuric acid anodic oxidation and micro-arc oxidation method, the cast aluminum with high silicon content (the cast aluminum with a silicon content of more than 15%) cannot realize the purpose of surface strengthening and increasing corrosion resistance, which limits the popularization and application of the cast aluminum base material in the field of cookware. The cooking utensil provided by the present application forms an aluminum oxide layer by cold spraying or hot spraying, and the base material thereof can be cast aluminum with a silicon content of more than 15%, thereby avoiding the limitation on the base material and widening the further application of the cast aluminum base material in the field of cookware, which is good in flexibility and strong in practicality.

[0014] In a possible implementation manner, the raw material for forming the aluminum oxide layer comprises alpha-Al2O3 powder or alpha-Al2O3 coated with aluminum.

[0015] When forming the aluminum oxide layer on the surface of the substrate, the utilization rate of the spraying raw material of the aluminum-coated α-Al2O3 powder filament is higher than that of the powder spraying raw material, and the aluminum-coated α-Al2O3 powder filament contains aluminum with a lower melting point, so that the melting point of the filament is relatively low (generally about 640°C), and the melting state can be reached in a short time during the spraying process, thereby improving the production efficiency. Moreover, due to the lower melting point of the aluminum-coated α-Al2O3 powder filament, the adhesion can be improved without the need for heating gas (such as hydrogen, propane, etc.) to assist melting during the processing, so that the aluminum-coated α-Al2O3 powder filament can be used to achieve a more close combination with the aluminum-based substrate under lower process operation requirements or lower process cost.

[0016] In a possible implementation, the thickness of the aluminum oxide layer is 30 μm to 120 μm. In this thickness range, the cost is reduced, and the mechanical properties and corrosion resistance of the aluminum oxide layer are ensured.

[0017] In a possible implementation, the cooking utensil further comprises an atomized spraying layer, and a material of the atomized spraying layer comprises at least one of a fluorine-containing coating, a silicone coating, or a ceramic coating.

[0018] According to another aspect of the present application, the present application provides a preparation method of a cooking utensil, comprising the following steps:

[0019] providing a substrate, and a material of the substrate comprises aluminum, an aluminum alloy, or an aluminum composite material;

[0020] performing thermal spraying or cold spraying treatment on an aluminum oxide raw material to form an aluminum oxide layer on a surface of the substrate, and the aluminum oxide layer comprises α-Al2O3.

[0021] The preparation method of the cooking utensil is based on the same inventive concept as the aforementioned cooking utensil, and thus at least has the advantages of the aforementioned first aspect cooking utensil, which will not be described herein again.

[0022] In a possible implementation, the thermal spraying comprises at least one of plasma spraying, electric arc spraying, or high-velocity oxygen fuel spraying.

[0023] In a possible implementation, the operating condition of the electric arc spraying comprises:

[0024] a voltage of 20 V to 40 V (volts);

[0025] a current of 100 A to 380 A (amperes);

[0026] a time of 0.2 min to 2 min (minutes).

[0027] In a possible implementation, the operating condition of the plasma spraying comprises:

[0028] The voltage is 20-40 V;

[0029] The power is 30-45 kW (kilowatt) ;

[0030] The time is 0.2-2 min.

[0031] In a possible implementation, the alumina raw material comprises α-Al2O3 powder or an aluminum-coated α-Al2O3 wire;

[0032] And / or, the material of the substrate comprises cast aluminum, the mass content of silicon in the cast aluminum is less than 15%; or, the mass content of silicon in the cast aluminum is 15%-25%.

[0033] In a possible implementation, the thickness of the alumina layer is 30 μm-120 μm.

[0034] In a possible implementation, after the alumina layer is formed, the preparation method further comprises:

[0035] At least one of the fluorine-containing coating, the silicone coating or the ceramic coating is subjected to an atomization spraying treatment to form an atomization spraying layer on the surface of the alumina layer.

[0036] It should be noted that the above numerical ranges all include the endpoints.

[0037] It should be understood that the foregoing general description and the following detailed description are only examples and are not limiting the present application. DETAILED DESCRIPTION

[0038] For the purpose of making the objects, technical solutions and advantages of the present application more clear, the technical solutions of the present application will be described clearly and completely below in conjunction with the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments of the present application. Based on the technical solutions provided by the present application and the embodiments given, all the other embodiments obtained by those skilled in the art without making any creative efforts fall within the scope of protection of the present application. The specific conditions are not specified in the embodiments, and the conventional conditions or the conditions suggested by the manufacturers are adopted. The reagents or instruments used are not specified by the manufacturers, and are all the conventional products that can be purchased in the market.

[0039] The endpoints of the ranges and any values disclosed herein are not limited to the precise values stated. The ranges or values should be construed to include values adjacent and approximating such ranges or values. For values whose endpoints are not antecedent basis, combinations of the values in the range are not original and anticipated to be a subset of the disclosed ranges value.

[0040] The term "and / or" or " / " used in this document only describes an association relationship of associated objects, and means that three relationships can exist, for example, A and / or B can mean that A exists alone, A and B exist together, and B exists alone. The singular forms "a", "said" and "the" used in the embodiments of the present application and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise.

[0041] In this document, "inner" and "outer" can be understood as inner and outer relative to the outline of each component itself.

[0042] As described in the background, the existing sulfuric acid anodizing technology cannot meet the requirements. In order to overcome the shortcomings of the traditional sulfuric acid anodizing technology, relevant personnel in the field have researched some new technologies, such as weak alkaline anodizing technology, i.e. micro-arc oxidation. The film layer structure formed on the surface of aluminum or aluminum alloy substrate material by micro-arc oxidation can include α-aluminum oxide (i.e. α-Al2O3), and the hardness is also high, for example, it can reach 1000-1700 HV, and the corrosion resistance is also improved compared with sulfuric acid anodizing. However, the micro-arc oxidation method also has some shortcomings, for example, this technology has the disadvantages of high energy consumption (about 10 times of sulfuric acid anodizing), high equipment investment cost, and high noise, which limits the popularization and use of this technology in the cookware industry. In addition, the above-mentioned sulfuric acid anodizing and micro-arc oxidation also have high requirements for the substrate. For aluminum alloy substrates containing more than 15% silicon, it is impossible to achieve surface strengthening by these two technologies. This is because the surface of aluminum alloy (such as cast aluminum) contains a large amount of primary and eutectic silicon, and silicon cannot be anodized. A large proportion of silicon content, such as more than 15% silicon content, will destroy the surface continuous distribution of the aluminum alloy structure, thereby affecting the current distribution and heat dissipation of anodizing. Therefore, anodizing of high-silicon aluminum alloy (such as cast aluminum) often has defects such as easy ablation, low hardness, thin film thickness, and large color difference, which cannot meet the hard anodizing quality standard, which also limits the popularization and use of the above two technologies.

[0043] In addition, in order to overcome the shortcomings of the above two technologies, relevant personnel in the field have developed a method of surface strengthening by thermal spraying of metal wires (or metal powder) or ceramic powder and other materials. However, due to the potential difference between the melted metal or ceramic and the aluminum substrate material, the product has poor corrosion resistance, which cannot meet the requirements. The ceramic powder commonly used at present, such as AT40 or AT13, contains titanium elements. Due to the sensitivity of titanium elements to chlorine elements, there is a strong chlorine affinity, so the salt water corrosion resistance cannot meet the expected effect of product development.

[0044] In general, the existing sulfuric acid anodizing method mainly has the problems of low hardness and poor corrosion resistance; the existing micro-arc oxidation method mainly has the problems of high cost, high noise and high equipment investment; the existing sulfuric acid anodizing and micro-arc oxidation methods also have the problem that they cannot achieve the purpose of surface strengthening for substrates with high silicon content; and the existing thermal spraying metal or titanium-containing ceramic powder can achieve the effect of surface strengthening, but cannot solve the problem of corrosion resistance.

[0045] Therefore, in order to overcome the imperfections of the prior art and alleviate the problems that the existing surface strengthening schemes for aluminum or aluminum alloy substrates cannot balance material quality, performance, cost, equipment investment, etc., the technical scheme of the embodiments of the present application provides a cooking utensil and a preparation method thereof, so as to significantly improve the hardness, corrosion resistance and wear resistance of the film layer formed on the surface of the substrate, and reduce equipment investment cost, processing cost and the limitation on the substrate material.

[0046] In some embodiments, a cooking utensil is provided, which can be various commonly used cooking equipment, such as a non-stick pan, a frying pan, a griddle, a flat-bottomed pan, an electric rice cooker, a pressure cooker, an electric pressure cooker, a baking tray, etc. The specific type of the cooking utensil is not limited in the embodiments of the present application.

[0047] Specifically, in some embodiments, the cooking utensil of the embodiments of the present application comprises:

[0048] a substrate, the material of the substrate comprising aluminum, aluminum alloy or aluminum composite material;

[0049] an aluminum oxide layer arranged on the surface of the substrate;

[0050] The aluminum oxide layer is a thermal spraying layer or a cold spraying layer, and the aluminum oxide layer comprises α-Al2O3.

[0051] The α-Al2O3 refers to Al2O3 with an α-type crystal form. α-Al2O3 is the most stable phase among all aluminum oxides, has good formability, stable crystal phase, high hardness, good dimensional stability, etc., and also has high-temperature resistance and good stability in a high-temperature environment.

[0052] The aluminum oxide layer is a thermal spraying layer or a cold spraying layer, which means that the aluminum oxide layer can be formed by a thermal spraying method or a cold spraying method.

[0053] The material of the substrate can be aluminum (i.e., pure aluminum) or an aluminum alloy, and can also be an aluminum composite material. The material of the substrate at least includes aluminum, and thus can be referred to as an aluminum-based substrate. The aluminum composite material, also referred to as an aluminum-based composite material, refers to an aluminum-based composite material containing other non-metallic materials and aluminum, i.e., an aluminum-based composite material formed by combining aluminum and other non-metallic materials. For example, the other non-metallic materials can be graphite, carbon fiber, or some ceramic materials, etc.

[0054] The cooking utensil of the embodiments of the present application forms an aluminum oxide layer on the surface of different aluminum-based substrates by cold spraying or thermal spraying, and the formed aluminum oxide layer includes α-Al2O3, thereby achieving the effects of high hardness, strong corrosion resistance, low investment, low processing cost, and high output. In detail, α-Al2O3 is the most stable phase among all aluminum oxides, and has the characteristics of good formability, stable crystal phase, high hardness, and good structural stability. Therefore, compared with the aluminum oxide film layer formed by ordinary sulfuric acid anodic oxidation, the α-Al2O3 film layer formed by the present application can significantly improve the hardness and corrosion resistance of the film layer, and the wear resistance of the α-Al2O3 film layer is also better, which is beneficial to prolonging the service life of the coating. At the same time, the present application forms an aluminum oxide layer on the surface of different aluminum-based substrates by cold spraying or thermal spraying, which can reduce the equipment investment cost, reduce the production cost, improve the efficiency, and reduce the noise compared with the existing micro-arc oxidation method. The cold spraying or thermal spraying method can avoid the limitation of the existing sulfuric acid anodic oxidation and micro-arc oxidation method on the silicon content in the substrate material, and can achieve the effects of surface strengthening and corrosion resistance enhancement of the substrate material including a high silicon content, thereby improving the comprehensive performance of the product. In addition, compared with the existing method of using thermal sprayed metal or titanium-containing ceramic powder, the α-Al2O3 film layer formed by the present application can avoid potential corrosion and chlorine corrosion, thereby improving the corrosion resistance.

[0055] Experiments show that the hardness of the aluminum oxide layer in the cooking utensil of the embodiments of the present application can reach 1000-2000 HV, the wear and non-stick performance can reach no less than 30,000 times, and the corrosion resistance can be improved by at least 2-5 times or more.

[0056] In addition, the substrate material in the cooking utensil of the embodiments of the present application is not suitable for using steel materials such as carbon steel and stainless steel, or glass materials, etc. For example, when the material of the substrate is a steel material, a special pretreatment process needs to be used before spraying the aluminum oxide layer, and the pretreatment requirements are very high, otherwise the effects of improving the corrosion resistance cannot be achieved. Or the α-Al2O3 film layer provided by the embodiments of the present application is directly covered on the surface of the substrate of the steel material, and the corrosion resistance cannot meet the requirements.

[0057] In some embodiments, the material of the substrate includes cast aluminum, and the mass content of silicon in the cast aluminum is less than 15%.

[0058] Alternatively, the mass content of silicon in the cast aluminum is 15% to 25%.

[0059] The forming process or processing process of cast aluminum is different from that of ordinary drawn aluminum. Generally speaking, cast aluminum needs to be extrusion molded at high temperature and high pressure in a molten state, for example, aluminum in a molten state is poured into a mold to form an aluminum part of a required shape after cooling. Ordinary drawn aluminum can be deep drawn in a normal state. In comparison, the product structure of cast aluminum is more diversified, and the casting performance and mechanical properties of cast aluminum are more excellent. In order to meet the forming process or processing process of cast aluminum, it is necessary to ensure that the cast aluminum contains a certain proportion of silicon elements, which can improve the flowability of the alloy in a molten state, thereby meeting the special forming requirements. Cast aluminum belongs to aluminum alloy, and cast aluminum can be cast aluminum alloy such as die-cast aluminum alloy.

[0060] The silicon element in the cast aluminum is one of the elements for strengthening the matrix structure. The role of silicon can increase the hardness, and the content of silicon can improve the flowability of casting, but the content of silicon should not be too high, which will affect the heat resistance of the casting.

[0061] According to an embodiment of the present application, on the one hand, the material of the substrate is cast aluminum, which has the advantages of more diversified product structure, more excellent casting performance and mechanical properties, etc. On the other hand, the mass content of silicon in the cast aluminum can be less than 15%, or greater than or equal to 15%, for example, it can be 15% to 25%, further, it can be 16% to 24%, further, it can be 18% to 22%, for example, it can be 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, etc. It can be seen that, compared with the existing sulfuric acid anodic oxidation and micro-arc oxidation method, the cast aluminum with high silicon content (the silicon content of the cast aluminum is more than 15%) cannot achieve the purpose of increasing the surface strengthening and corrosion resistance, which limits the popularization and application of the cast aluminum substrate in the cookware field. The cooking utensil provided by the embodiment of the present application adopts the cold spraying or hot spraying method to form an aluminum oxide layer, and the substrate material can adopt cast aluminum with a silicon content of more than 15%, thereby avoiding the limitation of the substrate material, widening the further application of the cast aluminum substrate in the cookware field, and having good flexibility and strong practicality.

[0062] In order to adapt to different product requirements or process requirements, the specific content of silicon in the above-mentioned cast aluminum can be selectively adjusted according to actual conditions, for example, the mass content of silicon can be less than 15%, or it can be 15% to 25%. Alternatively, in other embodiments, the mass content of silicon in the cast aluminum can also be greater than 25%.

[0063] It should be understood that the material of the base in the embodiments of the present application can be cast aluminum, but is not limited thereto, for example, in other embodiments, the material of the base can also be selected from aluminum, other types of aluminum alloy or aluminum matrix composite, etc. In addition, according to product requirements, the base can adopt a single layer material or a multi-layer composite sheet structure, and the specific number of layers of the base is not limited in the embodiments of the present application.

[0064] The thickness of the base in the embodiments of the present application is not specially limited, and the thickness of the base can be within a conventional thickness range. Preferably, the thickness of the base can be 0.5-5 mm, further can be 0.5-3 mm, further can be 1-3 mm, further can be 2-4 mm, etc.

[0065] By controlling the thickness of the base within a suitable range, the cost and weight can be reduced, and the cooking utensil can have good strength. For example, when the thickness of the base is less than 0.5 mm, the strength of the cooking utensil (pot body) is low, and the cooking utensil is easy to deform during use; and when the thickness of the base is greater than 5 mm, the weight of the cooking utensil is heavy, and the cost is high, which cannot well meet the requirements of family consumers.

[0066] In some embodiments, the raw material for forming the alumina layer includes α-Al2O3 powder or aluminum-coated α-Al2O3 wire.

[0067] Specifically, the form of the raw material for forming the alumina layer can be powder or wire, or the raw material for forming the alumina layer can be in other forms such as strip or rod according to different process requirements. Preferably, the raw material for forming the alumina layer in the embodiments of the present application can be selected from two types of raw materials, i.e. powder or wire.

[0068] In particular, the wire-shaped raw material used in the present application is aluminum-coated α-Al2O3 wire, also referred to as aluminum-coated α-Al2O3 powder wire. That is, the wire-shaped raw material can be in a core-shell structure, including a core and a shell, wherein the shell is coated on the outside of the core, the core can include α-Al2O3 powder (ceramic powder), and the shell can include aluminum. During preparation, the α-Al2O3 powder can be filled into an empty tubular aluminum material, and after processing, the aluminum-coated α-Al2O3 powder wire is formed.

[0069] When forming the aluminum oxide layer on the surface of the substrate, the utilization rate of the aluminum-coated a-Al2O3 powder wire as the spraying raw material is higher than that of the powder spraying raw material. Moreover, the aluminum-coated a-Al2O3 powder wire contains aluminum with a low melting point, and thus the melting point of the wire is low (generally about 640°C), so that the melting state can be reached in a short time during the spraying process, and the production efficiency can be improved. Moreover, because the aluminum-coated a-Al2O3 powder wire has a low melting point, the adhesion can be improved without the need for heating the gas source (such as hydrogen, propane, etc.) to assist melting during the processing, so that the aluminum-coated a-Al2O3 powder wire can be used to achieve a more close combination with the aluminum-based substrate under lower process operation requirements or lower process cost.

[0070] Therefore, the aluminum-coated a-Al2O3 wire provided by the embodiment of the present application has a higher combination firmness with the aluminum-based substrate than the ordinary wire or powder raw material, and can reduce the spraying time, improve the production efficiency, reduce the processing cost, and improve the utilization rate of the raw material. In addition, the aluminum-coated a-Al2O3 powder wire has better safety and less dust pollution than the powder, and is safe and environmentally friendly.

[0071] When the aluminum oxide raw material is a-Al2O3 powder, the particle size of the powder can be micron level. For example, the particle size of the powder can be 30-1000 mesh, 50-800 mesh, 60-500 mesh, 40-480 mesh, 80-400 mesh, 100-300 mesh; typically but not limited to, the particle size of the powder can be 30 mesh, 40 mesh, 50 mesh, 60 mesh, 80 mesh, 100 mesh, 120 mesh, 150 mesh, 180 mesh, 200 mesh, 250 mesh, 280 mesh, 300 mesh, 500 mesh, 600 mesh, 800 mesh, 1000 mesh, and any value in the range formed by any two of these point values.

[0072] By using a-Al2O3 powder with a suitable particle size, the cost can be reduced, and the bonding force between the aluminum oxide layer and the substrate can be improved. If the particle size of the powder is too small, the particle is large, and in order to meet the bonding force between the film layer and the substrate, the process required is more harsh, and the process cost is higher; on the contrary, if the particle size of the powder is too large, the particle is small, and the cost of powder preparation is higher. In addition, from the perspective of the preparation process, a suitable particle size of the powder helps to ensure the strength of the film layer, and the stress of the formed coating is moderate.

[0073] When the aluminum oxide raw material used is an aluminum-coated a- AI2O3 powder filament, the diameter (outer diameter) of the filament can be 0.2-8 mm, can be 0.5-5 mm, further can be 1-4 mm, further can be 2-3 mm; typically but not limitedly, the diameter of the filament can be, for example, 0.2 mm, 0.5 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.2 mm, 3.8 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, and any value in the range constituted by any two of these point values. It can be understood that, similarly, by using an aluminum-coated a- AI2O3 powder filament with a suitable diameter, the cost can be reduced, and the adhesion of the aluminum oxide layer to the substrate can be improved. On the one hand, when the diameter of the filament is too small, the cost of filament production is high; on the other hand, when the diameter is too large, in order to meet the adhesion of the film layer to the substrate, the process required is more demanding, and the process cost is higher.

[0074] In some embodiments, in the aluminum-coated a- AI2O3 powder filament, the content of aluminum can be 10%-20%, and the content of a- AI2O3 powder can be 10%-80%.

[0075] In some embodiments, the thickness of the aluminum oxide layer is 30-120 μm, preferably 35-100 μm, further preferably 40-80 μm, further can be 40-60 μm; typically but not limitedly, the thickness of the aluminum oxide layer can be, for example, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, 55 μm, 60 μm, 65 μm, 70 μm, 80 μm, 90 μm, 100 μm, 110 μm, 120 μm, and any value in the range constituted by any two of these point values.

[0076] The thickness of the aluminum oxide layer is in the range of 30-120 μm, especially in the range of 40-60 μm, which helps to reduce the cost and ensure the mechanical properties, corrosion resistance, etc. of the aluminum oxide layer. For example, when the thickness is less than 30 μm, the aluminum oxide layer is too thin, and when corrosion occurs, it is easy to penetrate into the substrate and cause corrosion, reducing the corrosion resistance. In addition, the thickness of the aluminum oxide layer is too thin and is difficult to achieve in the process. When the thickness is greater than 120 μm, the aluminum oxide layer is too thick, increasing the cost, and the performance is not significantly improved.

[0077] The porosity of the alumina layer is not specially limited in the embodiments of the present application. For example, the porosity of the alumina layer can be 0.5% to 30%, further 1% to 30%, further 1% to 15%, further 5% to 15%, and the like. The appropriate porosity of the alumina layer helps to ensure certain hardness and corrosion resistance, etc. For example, when the porosity of the alumina layer is too small, the effective oil film area formed is relatively small, which is easy to cause sticking or poor corrosion resistance; when the porosity of the alumina layer is too large, the effective support area of the alumina layer is reduced, which is easy to cause the hardness or strength to be reduced or the wear resistance to be weakened.

[0078] In some embodiments, the cooking utensil further comprises an atomized spray coating layer, and a material of the atomized spray coating layer comprises at least one of a fluorine-containing coating, a silicone coating or a ceramic coating. The atomized spray coating layer is located on the alumina layer and away from the base.

[0079] According to the embodiments of the present application, after the alumina layer is formed by spraying the α-Al2O3 powder or the aluminum-coated α-Al2O3 wire on the surface of the base by cold spraying or thermal spraying, the fluorine-containing coating, the silicone coating or the ceramic coating, etc. can be atomized and sprayed on the alumina layer to form an atomized spray coating layer on the surface of the alumina layer.

[0080] It should be noted that the alumina layer can be formed on the inner surface of the base, or can be formed on the outer surface of the base, or can be provided on both the inner surface and the outer surface of the base.

[0081] The raw material of the atomized spray coating layer can be a fluorine-containing coating (such as fluorocarbon coating, PTFE), a silicone coating, a ceramic coating, or any combination of the above. The ceramic coating is different from the ceramic powder used to form the alumina layer, and the ceramic powder can be of a type other than the ceramic powder used to form the alumina layer. Preferably, the raw material of the atomized spray coating layer is a fluorine-containing coating or a silicone coating.

[0082] By covering the alumina layer with an atomized spray coating layer, the alumina layer is protected, and the wear resistance and corrosion resistance of the cooking utensil are further improved, so that the cooking utensil has good long-lasting non-stick service life, the service life of the cooking utensil is prolonged, and the user's experience is improved.

[0083] As can be seen from the above, the cooking utensil of the embodiment of the present application adopts cold spraying or thermal spraying on the roughened aluminum material matrix surface (both the inner and outer surfaces can be used) to spray α-Al2O3 raw material similar to the chemical composition of the matrix material to form an aluminum oxide layer on the surface of the matrix, and then carries out atomized spraying treatment of fluorine-containing paint or silicone paint on the surface of the aluminum oxide layer, so that a composite functional film with high hardness, high corrosion resistance and strong wear resistance can be obtained. In particular, the aluminum oxide layer containing α-Al2O3 can be used to improve the wear resistance, corrosion resistance and hardness.

[0084] In a second aspect, in some embodiments, a preparation method of a cooking utensil is provided, which comprises the following steps:

[0085] providing a matrix, the material of the matrix comprising aluminum, aluminum alloy or aluminum composite material;

[0086] carrying out thermal spraying or cold spraying treatment on the aluminum oxide raw material to form an aluminum oxide layer on the surface of the matrix, the aluminum oxide layer comprising α-Al2O3.

[0087] The preparation method is simple to operate, easy to implement and easy to realize large-scale production. At the same time, the cooking utensil prepared comprises a matrix and an aluminum oxide layer which are sequentially stacked, and in particular, the aluminum oxide layer is formed on the surface of different aluminum matrix by cold spraying or thermal spraying, and the formed aluminum oxide layer comprises α-Al2O3, so that the effects of high hardness, strong corrosion resistance, low investment, low processing cost and high output can be achieved. The preparation method of the cooking utensil has the advantages of the cooking utensil of the first aspect.

[0088] It should be understood that in the preparation method of the cooking utensil, the specific structure and composition of the cooking utensil and the achieved beneficial effects can refer to the description of the cooking utensil in the first aspect. The preparation method of the cooking utensil and the aforementioned cooking utensil are based on the same inventive concept. In the description of the preparation method of the cooking utensil, the parts corresponding to the aforementioned cooking utensil can refer to the related description in the aforementioned cooking utensil, which will not be repeated here.

[0089] In the embodiments of the present application, the method for forming the aluminum oxide layer includes thermal spraying or cold spraying. Among them, thermal spraying is a technology that uses a certain heat source to heat the powder or wire-shaped metal or non-metallic material to a molten or semi-molten state, and then sprays it to the pretreated substrate surface at a certain speed by means of flame itself or compressed air, etc. to form a surface coating with various functions. It has the advantages of simple method, easy to control, high feasibility, good reliability and high production efficiency. The thermal spraying method can be, for example, flame spraying, oxy-ethane flame powder spraying, oxy-ethane flame wire spraying, oxy-ethane flame spraying, high-velocity oxygen flame spraying (HVOF), arc spraying, plasma spraying, atmospheric plasma spraying, low-pressure plasma spraying.

[0090] Specifically, in some embodiments, the thermal spraying includes plasma spraying, arc spraying or high-velocity oxy-fuel spraying.

[0091] The thermal spraying can adopt various ways such as plasma spraying, arc spraying, high-velocity oxy-fuel spraying, etc., wherein the arc spraying has the advantages of low equipment investment, high material utilization rate and good safety; while the plasma spraying and the high-velocity oxy-fuel spraying need to use flammable gas as a melting medium. In addition, the plasma spraying and the high-velocity oxy-fuel spraying generally use powdery α-Al2O3 powder, and the formed coating is hard and brittle, while the arc spraying can use wire material coated with α-Al2O3, and due to the aluminum component, the formed coating has higher toughness and impact strength. Therefore, relatively, the wire material coated with α-Al2O3 is sprayed by the arc spraying, which has the characteristics of good safety, high efficiency, and more excellent coating performance.

[0092] Specifically, in some embodiments, the preparation method of the cooking utensil can include:

[0093] The machined aluminum-based substrate is subjected to certain mechanical and chemical pretreatment, which can include oil removal, mechanical sanding, shot blasting, sand blasting, chemical etching, etc.

[0094] Then, the surface of the aluminum-based material substrate is subjected to α-Al2O3 powder or aluminum-coated α-Al2O3 powder wire thermal spraying or cold spraying treatment to form an aluminum oxide layer with high hardness and corrosion resistance on the surface of the substrate.

[0095] Then, the surface of the aluminum oxide layer can be subjected to atomization spraying treatment, such as PTFE or silicone paint, to form an atomization spraying layer on the surface of the aluminum oxide layer.

[0096] In some specific embodiments, the arc spraying method is used to form an aluminum oxide layer containing α-Al2O3 on the inner surface of the substrate. Specifically, the preparation method of the cooking utensil includes the following steps:

[0097] (a) forming: the aluminum or aluminum alloy workpiece can be machined into a substrate by deep drawing, spinning, extrusion, cutting, etc.

[0098] The specific forming method of the substrate can adopt various methods known to those skilled in the art, and the specific operation method can also be known in the art, which is not limited by the present application and will not be described in detail.

[0099] (b) pretreatment: the machined aluminum-based substrate is subjected to certain mechanical and chemical pretreatment, which can include oil removal, mechanical sanding, shot blasting, sand blasting, chemical etching, etc.

[0100] The pre-treatment method can adopt various methods known to those skilled in the art, and the specific operation method can be known in the art, and the present application does not limit this and will not be described in detail.

[0101] (c) Preparation of the aluminum oxide layer: arc spraying is performed on the substrate to form an aluminum oxide layer containing α-Al2O3 on the surface of the substrate.

[0102] Specifically, the operation conditions of the arc spraying include:

[0103] Equipment: metal arc spraying equipment.

[0104] Substrate: The material of the substrate is cast aluminum, and the mass content of silicon in the cast aluminum is less than 15%, or the mass content of silicon in the cast aluminum is 15% to 25%.

[0105] Aluminum oxide raw material: α-Al2O3 coated aluminum wire;

[0106] Voltage: 20-40V; in some embodiments of the present application, the voltage may, for example, be 20V, 25V, 30V, 35V, 40V, etc.

[0107] Current: 100-380A; in some embodiments of the present application, the current may, for example, be 100A, 120A, 150A, 180A, 200A, 250A, 280A, 300A, 350A, 380A, etc.

[0108] Time: 0.2-2min; in some embodiments of the present application, the time may, for example, be 0.2min, 0.5min, 0.8min, 1min, 1.5min, 1.8min, 2min, etc.

[0109] The thickness of the formed aluminum oxide layer is 30-120μm, and in some embodiments of the present application, the thickness of the aluminum oxide layer may, for example, be 30μm, 35μm, 40μm, 45μm, 50μm, 55μm, 60μm, 65μm, 70μm, 80μm, 90μm, 100μm, 110μm, 120μm, etc. By controlling the thickness of the aluminum oxide layer within an appropriate range, the substrate can be better protected, the cost can be reduced and the weight can be reduced, and the cooking utensil can have good film layer strength, wear resistance and corrosion resistance, etc. For example, when the thickness of the aluminum oxide layer is too small, the aluminum oxide layer is too thin, and when corrosion occurs, it is easy to penetrate into the substrate and cause corrosion, reducing the corrosion resistance; when the thickness of the aluminum oxide layer is too large, the aluminum oxide layer is too thick, the product is thick and heavy, and the cost is also high.

[0110] The aluminum-coated a-Al2O3 wire is sprayed by arc spraying to form an alumina layer on the surface of the substrate, which has the characteristics of good safety, high efficiency, and more excellent performance of the obtained coating, such as higher toughness and impact strength of the coating. Moreover, under the arc spraying operation conditions in the above operation range, the method has high reliability, the coating material is sprayed more fully, the energy consumption is low, the aluminum-coated a-Al2O3 wire can be more fully attached to the surface of the substrate, the quality and performance of the formed alumina layer are better, and the performance of the final obtained cooking utensil product and the user experience are good.

[0111] In the aluminum-coated a-Al2O3 powder wire, the content of aluminum can be 10% to 20%, and the content of a-Al2O3 powder can be 10% to 80%. Within this range, the cost can be reduced, and the adhesion of the coating to the substrate can be improved, and the wear resistance, corrosion resistance, and film forming property of the obtained coating are all excellent.

[0112] (d) Preparation of the atomized spray layer: the surface of the alumina layer is subjected to atomized spray treatment to form an atomized spray layer on the surface of the alumina layer.

[0113] The atomized spray material can be fluorine-containing paint, silicone paint, etc., which is not limited in the embodiments of the present application.

[0114] In addition, the specific treatment method of the atomized spray is a common parameter or conventional operation method easily thought of by those skilled in the art, which can be referred to the prior art or adjusted by those skilled in the art according to the actual situation, so the detailed description thereof can be omitted.

[0115] In some specific embodiments, a plasma spraying method is used to form an alumina layer containing a-Al2O3 on the inner surface of the substrate. Specifically, the preparation method of the cooking utensil comprises the following steps:

[0116] (a) forming.

[0117] (b) pretreatment.

[0118] The steps (a) and (b) thereof are the same as the steps (a) and (b) in the foregoing arc spraying method, which will not be described in detail here.

[0119] (c) Preparation of the alumina layer: the substrate is subjected to plasma spraying to form an alumina layer containing a-Al2O3 on the surface of the substrate.

[0120] Specifically, the operation conditions of the plasma spraying include:

[0121] Equipment: metal plasma spraying equipment.

[0122] The material of the base body is cast aluminum, the mass content of silicon in the cast aluminum is less than 15%, or the mass content of silicon in the cast aluminum is 15%-25%.

[0123] The aluminum oxide raw material is α-Al2O3 powder.

[0124] The voltage is 20-40V; in some specific embodiments of the present application, the voltage may, for example, be 20V, 25V, 30V, 35V, 40V, etc.

[0125] The power is 30-45kW; in some specific embodiments of the present application, the power may, for example, be 30kW, 32kW, 35kW, 38kW, 40kW, 42kW, 45kW, etc.

[0126] The time is 0.2-2min; in some specific embodiments of the present application, the time may, for example, be 0.2min, 0.5min, 0.8min, 1min, 1.5min, 1.8min, 2min, etc.

[0127] The thickness of the formed aluminum oxide layer is 30-70μm, in some specific embodiments of the present application, the thickness of the aluminum oxide layer may, for example, be 30μm, 35μm, 40μm, 45μm, 50μm, 55μm, 60μm, 65μm, 70μm, etc. By controlling the thickness of the aluminum oxide layer within a suitable range, the base body is better protected, the cost is reduced and the weight is lightened, and the cooking appliance has good film layer strength, wear resistance and corrosion resistance, etc. For example, when the thickness of the aluminum oxide layer is too small, the aluminum oxide layer is too thin, when corrosion occurs, it is easy to penetrate into the base body and corrosion occurs, reducing the corrosion resistance; when the thickness of the aluminum oxide layer is too large, the aluminum oxide layer is too thick, the product is thick and heavy, and the cost is also high.

[0128] Under the plasma spraying operation conditions within the above operation range, the method has high reliability, the coating material is sprayed more fully, the energy consumption is low, the α-Al2O3 powder can be more fully attached to the surface of the base body, the quality and performance of the formed aluminum oxide layer are better, and the performance of the final obtained cooking appliance product and the user experience are good.

[0129] In the plasma spraying process, the coating material can be in the form of powder, wire, strip, rod, etc., and is preferably in the form of powder.

[0130] The particle size of the powder can be microns. For example, the particle size of the powder can be 30-1000 mesh, 50-800 mesh, further 60-500 mesh, further 40-480 mesh, further 80-400 mesh, further 100-300 mesh.

[0131] By using the powder α-Al2O3 with appropriate particle size, the cost can be reduced, and the adhesion between the alumina layer and the substrate can be improved. Specifically, if the particle size of the powder is too small, the particles are large, and in order to meet the adhesion between the film layer and the substrate, the process required is more harsh, and the process cost is higher; on the contrary, if the particle size of the powder is too large, the particles are small, and the cost of powder preparation is higher. The particle size of the powder also has a certain influence on wear resistance, corrosion resistance, film forming property or adhesion, etc. Within the above range, the particle size can reduce the cost, improve the adhesion between the coating and the substrate, and the wear resistance, corrosion resistance, compactness, etc. of the obtained coating are all excellent. In addition, from the perspective of preparation process, appropriate powder particle size helps to ensure the strength of the film layer, and the stress of the formed coating is moderate, which will not cause the natural cracking of the coating.

[0132] (d) Preparation of the atomized sprayed layer: the surface of the alumina layer is subjected to atomized spraying treatment to form an atomized sprayed layer on the surface of the alumina layer.

[0133] The atomized sprayed material can be a fluorine-containing coating, a silicone coating, etc., which is not limited in the embodiments of the present application.

[0134] In addition, the specific treatment method of the atomized spraying is a common parameter or a conventional operation method easily thought by those skilled in the art, which can be referred to the prior art or adjusted by those skilled in the art according to the actual situation, so the detailed description thereof can be omitted.

[0135] It should be noted that in the above arc spraying and plasma spraying processes, other operating conditions such as spraying distance, spraying gun moving speed, etc. are not specially limited, as long as the requirements are met, and the performance of the cooking utensil is not affected, which can be adjusted by those skilled in the art according to the actual situation, so the detailed description thereof can be omitted.

[0136] In order to facilitate the understanding of the present application, the present application will be further described below in combination with specific examples, comparative examples and test examples.

[0137] Example 1

[0138] An alumina layer containing α-Al2O3 is formed on the surface of the substrate by arc spraying method.

[0139] The operating conditions of the arc spraying process include:

[0140] Equipment: metal arc spraying equipment;

[0141] Substrate: the material of the substrate is cast aluminum, and the mass content of silicon in the cast aluminum is 15% to 25%;

[0142] Alumina raw material: α-Al2O3 wire coated with aluminum;

[0143] Voltage: 25 V;

[0144] Current: 100 A.

[0145] Time: 1 min.

[0146] The thickness of the formed alumina layer was 40 μm to 80 μm.

[0147] A mist spray treatment of PTFE was performed on the surface of the formed alumina layer to form a mist spray layer on the surface of the alumina layer.

[0148] Example 2

[0149] An alumina layer containing α-Al2O3was formed on the surface of the substrate by a plasma spraying method.

[0150] The operating conditions of the plasma spraying process included:

[0151] Apparatus: Plasma spraying apparatus;

[0152] Substrate: The material of the substrate was cast aluminum, and the mass content of silicon in the cast aluminum was 15% to 25%;

[0153] Alumina raw material: α-Al2O3powder;

[0154] Voltage: 25 V;

[0155] Power: 45 kW.

[0156] Time: 1 min.

[0157] The thickness of the formed alumina layer was 30 μm to 60 μm.

[0158] A mist spray treatment of PTFE was performed on the surface of the formed alumina layer to form a mist spray layer on the surface of the alumina layer.

[0159] Example 3

[0160] The operating conditions of the plasma spraying process included:

[0161] Voltage: 40 V;

[0162] The thickness of the formed alumina layer was 40 μm to 50 μm.

[0163] The others were the same as in Example 2.

[0164] Example 4

[0165] The operating conditions of the plasma spraying process included:

[0166] Power: 30 kW;

[0167] Time: 2 min.

[0168] The other is the same as Example 2.

[0169] Example 5

[0170] In the operating conditions of the arc spraying process:

[0171] Voltage: 40 V;

[0172] The thickness of the formed aluminum oxide layer is 40 μm to 50 μm.

[0173] The other is the same as Example 1.

[0174] Example 6

[0175] In the operating conditions of the arc spraying process:

[0176] Current: 380 A;

[0177] Time: 0.5 min.

[0178] The thickness of the formed aluminum oxide layer is 50 μm to 60 μm.

[0179] The other is the same as Example 1.

[0180] Comparative Example 1

[0181] In this comparative example, the material of the substrate used is ordinary 3003 aluminum. The surface of the substrate is subjected to atomized spraying of PTFE to form an atomized sprayed layer on the surface of the substrate.

[0182] Comparative Example 2

[0183] In this comparative example, the material of the substrate used is cast aluminum with a silicon content of 15% to 25%. The surface of the substrate is subjected to atomized spraying of PTFE to form an atomized sprayed layer on the surface of the substrate.

[0184] Comparative Example 3

[0185] In this comparative example, the material of the substrate used is ordinary 3003 aluminum. An aluminum oxide layer is formed on the surface of the substrate using a conventional low-temperature sulfuric acid anodization method. The surface of the formed aluminum oxide layer is subjected to atomized spraying of PTFE to form an atomized sprayed layer on the surface of the aluminum oxide layer.

[0186] Comparative Example 4

[0187] In this comparative example, a coating layer is formed on the surface of the substrate by melting titanium wire using a conventional thermal spraying metal wire (powder) or ceramic powder method. The surface of the formed coating layer is subjected to atomized spraying of PTFE to form an atomized sprayed layer on the surface of the coating layer.

[0188] Comparative Example 5

[0189] In the present comparative example, a coating layer was formed on the surface of the substrate by using the existing method of plasma spraying a titanium-containing ceramic powder (AT40). A mist spray coating process was performed on the surface of the formed coating layer to form a mist spray coating layer on the surface of the coating layer.

[0190] Test Example

[0191] The respective parameters and performances of the cooking utensils prepared according to the various examples and comparative examples were tested according to the following method. The test results are shown in Table 1.

[0192] The specific test methods or standards are shown as follows:

[0193] 1. Film thickness (alumina layer thickness in Examples 1-6 and Comparative Example 3, and coating layer thickness in Comparative Examples 4-5): The cross section of the product was placed under a microscopic magnifying glass to measure the relevant thickness.

[0194] 2. Abrasion and non-stick test: After 1000 times of use of the direct insertion type abrasion tester, the product was subjected to a milk non-stick test until the milk adhered to the pot, and the relevant experimental data were recorded.

[0195] 3. Bonding strength test: The bonding strength was measured according to the bonding strength method of the national standard GB / T 32388.

[0196] 4. Hardness test: The product was placed under a Vickers hardness tester to measure the hardness.

[0197] 5. Salt water corrosion resistance test: The corrosion test was performed according to the national standard GB / T 32388 for cookware products.

[0198] Table 1: Performance test results of the various examples and comparative examples

[0199]

[0200] As can be seen from the above experimental data, the cooking utensils provided by the examples of the present application have better corrosion resistance and abrasion resistance, and higher hardness as a whole, compared to the cooking utensils of the comparative examples.

[0201] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

[0202] It should be noted that part of the patent application file contains copyrighted material. Except for making copies of the patent document content of the patent file or record of the patent office, the copyright owner reserves the copyright.

Claims

1. A method of preparing a cooking appliance, characterized in that, The method comprises the following steps: providing a base body, a material of the base body comprising aluminum, aluminum alloy or aluminum composite material; applying an aluminum-coated alpha-Al2O3 wire as an alumina raw material to a thermal spraying or cold spraying process to form an alumina layer on a surface of the base body, the alumina layer comprising alpha-Al2O3.

2. The preparation method of a cooking appliance according to claim 1, characterized in that, The thermal spraying comprises at least one of plasma spraying, arc spraying or high-velocity oxygen fuel spraying.

3. The method of claim 2, wherein the cooking appliance is a microwave oven. The operating conditions of the arc spraying comprise: a voltage of 20-40 V; a current of 100-380 A; a time of 0.2-2 min.

4. The method of claim 2, wherein the cooking appliance is a microwave oven. The operating conditions of the plasma spraying comprise: a voltage of 20-40 V; a power of 30-45 kW; a time of 0.2-2 min.

5. The method of claim 1-4, wherein, The material of the base body comprises cast aluminum, a mass content of silicon in the cast aluminum being less than 15%; or, a mass content of silicon in the cast aluminum being 15%-25%.

6. The method of claim 1-4, wherein, The thickness of the alumina layer is 30-120 μm.

7. The method of claim 1-4, wherein, After the alumina layer is formed, the preparation method further comprises: applying at least one of a fluorine-containing coating, a silicone coating or a ceramic coating to an atomized spraying process to form an atomized spraying layer on a surface of the alumina layer.

8. A cooking appliance characterized by, The cooking appliance is made by the preparation method according to any one of claims 1-7.

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