Cooking appliance and its preparation method

Abstract

The present invention provides a cooking utensil and a method for manufacturing the same, relating to the technical field of cooking utensil technology. The cooking utensil comprises: a substrate; a transition layer formed on the inner surface of the substrate; and an anti-rust treatment layer formed on the surface of the transition layer. The transition layer is an iron-based transition layer having a porosity of ≤10%. The present invention can improve the poor anti-rust performance of existing cooking utensil designs.

Description

Technical Field

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

[0002] Iron pans are widely used due to their healthiness, especially in traditional Chinese culture. However, ordinary iron pans have disadvantages such as being easily oxidized and rusted.

[0003] Currently, the process for producing iron pans with a certain degree of rust resistance on the market mainly involves cleaning, nitriding, and oxidation of the pan body to achieve a certain level of pitting resistance and rust / corrosion resistance. However, for iron pans made of steel or composite steel plates, the rust-resistant structure created by these processes still has the disadvantage of being prone to pitting corrosion and having poor rust prevention.

[0004] In view of this, the present invention is proposed. Summary of the Invention

[0005] The first object of the present invention is to provide a cooking utensil having the advantages of good pitting and rust resistance and not prone to pitting, which can overcome the above problems or at least partially solve the above technical problems.

[0006] The second purpose of the present invention is to provide a method for preparing cooking utensils. The method is simple and easy to implement. The resulting cooking utensils have the advantages of good pitting and rust resistance and are not prone to pitting corrosion. It can overcome the above-mentioned problems or at least partially solve the above-mentioned technical problems.

[0007] According to one aspect of the present application, the present application provides a cooking appliance, comprising:

[0008] substrate;

[0009] forming a transition layer on the inner surface of the substrate; and

[0010] An anti-rust treatment layer is formed on the surface of the transition layer;

[0011] Wherein, the transition layer is an iron-based transition layer, and the porosity of the iron-based transition layer is ≤10%.

[0012] In one possible implementation, the material of the iron-based transition layer includes pure iron or an iron-based alloy or a mixture of pure iron and an iron-based alloy in any proportion; the porosity of the iron-based transition layer is 0.1 to 10%, preferably 0.5 to 8%, and more preferably 1 to 5%.

[0013] In a possible implementation, the material of the iron-based transition layer is powder or wire;

[0014] Preferably, the particle size of the powdered material is 30 to 1000 mesh, preferably 50 to 400 mesh, and more preferably 60 to 300 mesh;

[0015] Preferably, the diameter of the wire is 0.5-5 mm.

[0016] In one possible implementation, the material of the iron-based transition layer includes a first component and a second component, wherein the first component includes pure iron or an iron-based alloy or a mixture of pure iron and an iron-based alloy in any proportion, and the second component includes a carbon material, a silicon material, a silicate, or a mixture of any two or three of the carbon material, the silicon material, and the silicate in any proportion; the porosity of the iron-based transition layer is ≤10%, preferably 0.1 to 8%, and more preferably 1 to 5%;

[0017] Preferably, the weight content of the first component in the iron-based transition layer is greater than or equal to 70% and less than 100%, preferably 75-99%, and more preferably 80-95%.

[0018] In a possible implementation, the first component is in powder form or filament form, and / or the second component is in powder form;

[0019] Preferably, the particle size of the first component is 30 to 1000 mesh, preferably 50 to 400 mesh, and more preferably 60 to 300 mesh;

[0020] Preferably, the particle size of the second component is 30-1000 mesh, preferably 500-1000 mesh, and more preferably 800-1000 mesh.

[0021] In a possible implementation, the material of the iron-based transition layer is cast iron; the porosity of the iron-based transition layer is ≤10%, preferably 0.1 to 8%, and more preferably 1 to 5%.

[0022] In a possible implementation, the cast iron is in the form of powder or wire;

[0023] Preferably, the particle size of the powdered cast iron is 30 to 1000 mesh, preferably 60 to 300 mesh;

[0024] Preferably, the diameter of the wire-shaped cast iron is 0.5 to 5 mm.

[0025] In a possible implementation, the thickness of the iron-based transition layer is 10 to 500 μm, preferably 20 to 300 μm, preferably 25 to 350 μm, and further preferably 50 to 250 μm.

[0026] In a possible implementation, the thickness of the substrate is 0.5 to 5 mm, preferably 0.5 to 3 mm;

[0027] Preferably, the material of the substrate includes at least one of carbon steel, stainless steel, titanium, titanium alloy, aluminum, aluminum alloy, copper or copper alloy.

[0028] In a possible implementation, the thickness of the anti-rust treatment layer is 0.5 to 50 μm, preferably 5 to 40 μm;

[0029] Preferably, the anti-rust treatment layer is prepared by at least one of nitriding, phosphating, oxidation or spraying anti-rust paint.

[0030] According to another aspect of the present application, the present application provides a method for preparing a cooking utensil, comprising the following steps:

[0031] providing a substrate;

[0032] forming a transition layer on the inner surface of the substrate;

[0033] forming an anti-rust treatment layer on the surface of the transition layer;

[0034] Wherein, the transition layer is an iron-based transition layer, and the porosity of the iron-based transition layer is ≤10%.

[0035] In a possible implementation, a method of forming the iron-based transition layer includes: one or more of thermal spraying, cold spraying, powder metallurgy, or solid phase sintering (optional).

[0036] In a possible implementation, the iron-based transition layer is formed on the inner surface of the substrate by using a thermal spraying method; the thermal spraying method is preferably a plasma spraying method.

[0037] In a possible implementation, the material of the iron-based transition layer is at least one of pure iron or an iron-based alloy;

[0038] Alternatively, the material of the iron-based transition layer includes a first component and a second component, wherein the first component includes at least one of pure iron or an iron-based alloy, and the second component includes at least one of a carbon material, a silicon material or a silicate;

[0039] Alternatively, the material of the iron-based transition layer is cast iron.

[0040] Preferably, the material of the iron-based transition layer is at least one of pure iron or an iron-based alloy; or, the material of the iron-based transition layer includes a first component and a second component, wherein the first component includes at least one of pure iron or an iron-based alloy, and the second component includes at least one of a carbon material, a silicon material, or a silicate; and the operating conditions of the plasma spraying meet at least one of the following:

[0041] The current is 100-500A, preferably 300-400A;

[0042] The main gas flow rate is 100-5000 L / H, preferably 1500-4200 L / H;

[0043] The plasma gas flow rate is 10 to 200 L / H, preferably 50 to 100 L / H;

[0044] The particle size of the material of the iron-based transition layer is 30 to 1000 meshes.

[0045] Preferably, when the material of the iron-based transition layer is cast iron, the operating conditions of ion spraying meet at least one of the following:

[0046] The current is 100-500A, preferably 350-450A;

[0047] The main gas flow rate is 100-5000 L / H, preferably 3000-4200 L / H;

[0048] The plasma gas flow rate is 10 to 200 L / H, preferably 80 to 120 L / H;

[0049] The cast iron is in powder form, and the particle size of the powdered cast iron is 30 to 1000 meshes.

[0050] In a possible implementation, the thickness of the iron-based transition layer is 10 to 500 μm, preferably 20 to 300 μm, or preferably 25 to 350 μm.

[0051] In a possible implementation, the cooking utensil includes at least one of a stainless frying pan, a stainless frying pan, a stainless pan, a stainless pressure cooker, a stainless rice cooker, or a stainless electric pressure cooker.

[0052] Compared with the prior art, the technical solution provided by the present invention can achieve the following beneficial effects:

[0053] The cooking utensil provided by the present invention comprises a substrate, a transition layer disposed on the inner surface of the substrate, and an anti-rust treatment layer disposed on the surface of the transition layer. The transition layer is an iron-based transition layer having a porosity of ≤10%. On the one hand, the porosity of the transition layer allows the transition layer to form a surface staggered structure. Specifically, the surface pores or certain free elements form a staggered structure with the substrate material. This staggered structure prevents pitting corrosion caused by the large cathode and small anode during corrosion resistance, thereby improving the pitting resistance. In addition, the small gaps in the staggered structure can absorb grease, providing a secondary rust prevention effect, thereby achieving a pitting resistance effect. In other words, the iron-based transition layer can achieve the same or similar pitting resistance as existing cast iron true stainless steel, thereby improving the pitting resistance and rust prevention effect. On the other hand, setting the porosity of the iron-based transition layer to 10% or less can reduce the thickness of the film layer and improve the strength of the film layer, avoiding the problem that when the porosity is too high, the film layer thickness required is increased when the corrosion resistance requirement is certain.

[0054] Therefore, the cooking utensil produced by the present invention has excellent corrosion resistance and improves the pitting and rust resistance of the cooking utensil product.

[0055] It should be understood that the foregoing general description and the following detailed description are exemplary only and are not restrictive of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0057] Figure 1 This is a schematic structural diagram of a cooking utensil provided in an embodiment of the present invention.

[0058] icon:

[0059] 100-base material; 200-transition layer; 300-anti-rust treatment layer. DETAILED DESCRIPTION

[0060] In order to make the purpose, technical solutions and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below in conjunction with the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, rather than all the embodiments. Based on the technical solutions and embodiments provided in this application, all other embodiments obtained by those skilled in the art without making creative work are within the scope of protection of this application. If the specific conditions are not specified in the embodiments, they shall be carried out according to conventional conditions or the conditions recommended by the manufacturer.

[0061] The endpoints and any values of the ranges disclosed herein are not limited to the exact ranges or values, and these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, the endpoint values of each range, the endpoint values of each range or the individual point values, and the individual point values can be combined with each other to obtain one or more new numerical ranges.

[0062] In this article, unless otherwise specified, directional words such as "upper" and "lower" are generally used with reference to the upper and lower shown in the drawings; "inner" and "outer" can be understood as the inner and outer relative to the outline of each component itself.

[0063] It should be noted that the term "and / or" or " / " used in this article is merely a description of the association relationship between associated objects, indicating that three relationships may exist. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone.

[0064] Unless otherwise specified, all technical features and preferred features mentioned herein can be combined with each other to form new technical solutions. Unless otherwise defined or specified, the professional and scientific terms used herein have the same meanings as those familiar to those skilled in the art.

[0065] Please refer to Figure 1 As shown, in some embodiments, the present invention provides a cooking utensil comprising:

[0066] substrate 100;

[0067] A transition layer 200 formed on the inner surface of the substrate 100; and

[0068] An anti-rust treatment layer 300 formed on the upper surface of the transition layer 200;

[0069] The transition layer 200 is an iron-based transition layer, and the porosity of the iron-based transition layer is ≤10%.

[0070] In the aforementioned cooking utensils, the iron-based transition layer can be understood as a transition layer made primarily of iron. The porosity of the iron-based transition layer is ≤10%, i.e., the porosity of the iron-based transition layer is greater than 0 and less than or equal to 10%. Typical, but non-limiting, porosities include, for example, 0.1%, 0.2%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.3%, 4.5%, 5%, 5.5%, 6%, 6.8%, 7%, 7.6%, 7.8%, 8%, 8.6%, 9%, 9.5%, 10%, and any value within a range consisting of any two of these values.

[0071] Those skilled in the art understand that the porosity of a material refers to the percentage of the volume of pores in the material to the total volume of the material. In the present invention, the porosity of the iron-based transition layer refers to the ratio of the volume of all pores in the iron-based transition layer to the total volume of the iron-based transition layer, which can be expressed as volume %. By controlling the porosity of the iron-based transition layer, the corrosion resistance of the cooking utensil can be improved. In particular, when the porosity of the iron-based transition layer is preferably ≤10%, the resulting cooking utensil can achieve the advantages of both excellent corrosion resistance and light weight.

[0072] When the porosity of the membrane layer is greater than 10%, on the one hand, the strength of the membrane layer will be reduced, making it easy to be shoveled off by metal shovels such as iron shovels during use; on the other hand, the porosity is large, and when the corrosion resistance requirements are certain, the greater the porosity, the higher the thickness of the membrane layer, resulting in higher cost and heavier weight.

[0073] The cooking utensil of the present invention comprises a substrate, a transition layer, and an anti-rust treatment layer stacked in sequence. By providing an iron-based transition layer on the inner surface of the substrate and controlling the porosity of the iron-based transition layer, the structure and properties of the iron-based transition layer on the inner surface of the cooking utensil are similar to those of cast iron, achieving the same or similar pitting corrosion resistance as cast iron. Specifically, the pitting corrosion resistance of cast iron is based on the following principles: Cast iron contains a large amount of free carbon (carbon) and silicon (silicon) in its chemical composition; Furthermore, cast iron contains a large amount of cementite. During the nitriding and oxidation process (high temperature, above 580°C), the cementite in the cast iron also precipitates some free carbon (carbon). During the anti-rust treatment of the cast iron surface, the large amount of free carbon and silicon is chemically stable and does not chemically react even during subsequent anti-rust treatment. This creates a multi-point interlaced structure of carbon and silicon sites on the surface, which does not react with electrolytes to cause pitting corrosion. This is similar to the condition where numerous pores form on the surface, which does not react with electrolytes to cause pitting corrosion. For example, rust prevention uses nitriding or nitriding oxidation. During this process, a large amount of free carbon and silicon (C) do not react with nitrogen (N), instead forming a multi-point interlaced structure of C and Si on the surface. This prevents corrosion if it occurs, as the multi-point interlaced structure of C and Si on the surface will not react with the electrolyte, thus preventing the formation of a large cathode and a small anode that can lead to pitting. Furthermore, in household use, the interlaced structure of cast iron allows the tiny gaps between C, Si, and the iron-based alloy to absorb grease, providing a secondary rust prevention effect.

[0074] Based on this, the pore of the iron-based transition layer that the present invention arranges has the same characteristic of the staggered structure of C and Si positions formed on the cast iron surface, that is, the place where these pores exist will not react with the electrolyte, thereby will not have the phenomenon that large cathode and small anode cause pitting, and improve the anti-pitting effect. In addition, the pore of the iron-based transition layer can absorb grease, play a secondary rust-proof effect, and then achieve the anti-pitting effect. That is, this iron-based transition layer can reach the anti-pitting principle identical or similar to existing cast iron true stainless, and improves the anti-pitting rust-proof effect. In addition, the porosity of the iron-based transition layer is set to below 10%, the thickness of the film layer can be reduced and the strength of the film layer can be promoted, and it is avoided that because porosity is too large, when corrosion resistance requires certain, the larger the porosity, the higher the required film thickness is, causing the problem that cost is higher.

[0075] In some embodiments, the material of the iron-based transition layer includes at least one of pure iron or an iron-based alloy; that is, the material of the iron-based transition layer can be pure iron, an iron-based alloy, or a mixture of pure iron and an iron-based alloy in any proportion. It should be noted that when the material of the iron-based transition layer includes a mixture of pure iron and an iron-based alloy, the components can be mixed in any proportion; that is, when the material includes a mixture of pure iron and an iron-based alloy, the pure iron and the iron-based alloy can be mixed in any proportion without affecting the performance of the cooking appliance. The specific proportions or contents are not particularly limited and can be adjusted by those skilled in the art based on actual conditions.

[0076] It should be understood that an iron-based alloy, also known as a ferroalloy, generally refers to an intermediate alloy composed of iron and one or more elements. In the embodiments of the present application, the specific type or grade of the ferroalloy is not limited and can be set by those skilled in the art according to actual needs. For example, it can be carbon steel or other iron-based alloys.

[0077] When the material of the iron-based transition layer is pure iron and / or iron-based alloy, the transition layer can also be called an imitation cast iron layer. Its anti-pitting corrosion principle is similar to that of existing cast iron, except that the free C and Si in the existing cast iron are replaced with pores. The staggered structure of the surface pores and pure iron or iron-based alloy achieves an anti-pitting corrosion principle similar to that of existing cast iron, thereby improving corrosion resistance (its anti-pitting corrosion principle is similar to that of the aforementioned cast iron and will not be described in detail here).

[0078] Specifically, when the material of the iron-based transition layer is pure iron and / or iron-based alloy, the porosity of the iron-based transition layer can be 0.1-10%, preferably 0.5-8%, and further preferably 1-5%; typically but not limitatively, the porosity can be, for example, 0.1%, 0.2%, 0.5%, 0.8%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 7%, 8%, 9%, 10% and any value in the range formed by any two of these point values.

[0079] When the porosity of this iron-based transition layer is less than 0.1%, the intersecting area between the surface pores and the pure iron or iron-based alloy is small, which easily forms a large cathode and small anode corrosion structure, causing pitting corrosion. When the porosity of the transition layer exceeds 10%, the film strength decreases, making it easy for metal shovels such as iron to scrape it off during use, thus shortening the life of the rust prevention. In addition, when the porosity is high, when the corrosion resistance requirement is certain, the film layer with higher porosity increases in thickness, resulting in higher cost and heavier weight.

[0080] Preferably, the thickness of the iron-based transition layer may be 10 to 500 μm, preferably 50 to 450 μm, more preferably 50 to 250 μm, further preferably 50 to 180 μm, further preferably 180 to 250 μm. Specifically, the thickness of the iron-based transition layer may be 50 μm, 70 μm, 80 μm, 95 μm, 100 μm, 150 μm, 170 μm, 190 μm, 200 μm, 220 μm, 260 μm, 280 μm, 300 μm, 330 μm, 350 μm, 360 μm, 400 μm, 390 μm, 420 μm, 430 μm, 445 μm, and 450 μm.

[0081] Specifically, when the material of the iron-based transition layer is pure iron and / or iron-based alloy, the thickness of the iron-based transition layer can be 10 to 500 μm, preferably 20 to 300 μm, more preferably 50 to 250 μm, further preferably 50 to 180 μm, further preferably 180 to 250 μm; typically but not limitatively, the thickness of the iron-based transition layer can be, for example, 10 μm, 20 μm, 40 μm, 50 μm, 60 μm, 80 μm, 100 μm, 150 μm, 180 μm, 200 μm, 220 μm, 250 μm, 300 μm, 350 μm, 400 μm, 500 μm and any value in the range formed by any two of these point values.

[0082] When the thickness of the iron-based transition layer is less than 10 μm, the transition layer is too thin. When corrosion occurs, it is easy to penetrate into the substrate and cause pitting corrosion, which reduces the corrosion resistance. When the thickness is greater than 500 μm, the transition layer is too thick, the cost is high, and the performance is not significantly improved.

[0083] Specifically, the pure iron or iron-based alloy in the iron-based transition layer can be in the form of powder or wire, that is, the material of the iron-based transition layer can be either powder or wire according to different process requirements.

[0084] When pure iron or iron-based alloy is in powder form, the particle size of the powder can be 30-1000 mesh, preferably 50-400 mesh, more preferably 60-300 mesh, further preferably 40-280 mesh, further preferably 100-300 mesh, further preferably 60-120 mesh; typically but not limitatively, the particle size of the powder can be, for example, 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.

[0085] By using powdered pure iron and / or iron-based alloys with an appropriate particle size, costs can be reduced and the bonding strength between the transition layer and the substrate can be improved. On the one hand, if the powder size is less than 30 mesh, the larger the particles, the more demanding the process required to achieve the desired bonding strength between the film and the substrate, and the higher the process cost. If the powder size is greater than 1000 mesh, the smaller the particles, the higher the powder production cost. On the other hand, from a manufacturing process perspective, larger particles require greater heat to melt. With the same external heat, larger particles have a lower degree of melting. Under the same main gas conditions, the film porosity increases and the film strength decreases. When the particle size is less than 30 mesh, the larger the particle size, the higher the porosity, resulting in lower film strength. When the powder size is greater than 1000 mesh, the smaller the particle size, the higher the degree of melting, and the greater the stress in the resulting coating, which may cause the coating to spontaneously crack.

[0086] When pure iron or an iron-based alloy is used as the wire, the diameter of the wire can be 0.5-5 mm, further 1-4 mm, and further 2-3 mm. Typically, but not limiting, the diameter of the wire can be, for example, 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, and any value in the range formed by any two of these values.

[0087] It is understood that, similarly, by using pure iron and / or iron-based alloys in the form of wires of appropriate diameters, costs can be reduced and the bonding strength between the transition layer and the substrate can be improved. On the one hand, when the wire diameter is less than 0.5 mm, the wire-making cost is high; on the other hand, when the diameter is greater than 5.0 mm, the process required to achieve the required bonding strength between the film layer and the substrate becomes more demanding, resulting in higher process costs.

[0088] In other embodiments, the material of the iron-based transition layer may include a first component and a second component, wherein the first component includes at least one of pure iron or an iron-based alloy, and the second component includes at least one of a carbon material, a silicon material, or a silicate. In other words, the first component may be pure iron, an iron-based alloy, or a mixture of pure iron and an iron-based alloy in any proportion. The second component may be an inorganic material, specifically a carbon material (C), a silicon material (Si), a silicate, a mixture of C and Si in any proportion, or a mixture of C and a silicate in any proportion.

[0089] Preferably, the first component is pure iron powder, and the second component is C powder or Si powder.

[0090] It should be noted that when the first component comprises a mixture of pure iron and an iron-based alloy, the two can be mixed in any proportion without affecting the performance of the cooking utensil. The specific proportions or contents are not particularly limited and can be adjusted by those skilled in the art based on practical circumstances. As described above in terms of the anti-pitting corrosion mechanism, the carbon material, silicon material, silicate, or carbon material, silicon material, and silicate in the second component primarily increase free carbon (carbon) or silicon (silicon), thereby creating a uniformly interlaced structure of the iron-based alloy and free carbon and silicon, thereby achieving pitting corrosion and rust prevention. Therefore, the second component can increase free carbon (carbon) or silicon (silicon). Therefore, when the second component comprises a mixture of any combination of carbon, silicon, and silicate, the components can be mixed in any proportion. For example, when the second component is a mixture of carbon and silicon, the two can be mixed in any proportion without affecting the performance of the cooking utensil. The specific proportions or contents are not particularly limited and can be adjusted by those skilled in the art based on practical circumstances.

[0091] When the material of the iron-based transition layer includes the aforementioned first component and second component, the transition layer can also be called an imitation cast iron layer, and its anti-pitting corrosion principle is equivalent to that of existing cast iron true stainless steel, that is, pure iron and / or iron-based alloys are mixed with one or more of free C, Si or silicates to form a uniformly staggered structure of C, Si or silicates and pure iron or iron-based alloys, thereby reducing the surface structure of large cathode and small anode and improving corrosion resistance (its anti-pitting corrosion principle is similar to that of the aforementioned cast iron and will not be described in detail here).

[0092] Specifically, the weight content of the above-mentioned first component is 70-100% (excluding 100%), that is, the weight content of the first component is greater than or equal to 70% and less than 100%, preferably 75-99%, and more preferably 80-95%; typically but not limitatively, the weight content of the first component can be, for example, 70%, 72%, 75%, 78%, 80%, 82%, 85%, 88%, 90%, 92%, 95%, 96%, 97%, 98%, 99% and any value in the range formed by any two of these point values.

[0093] By controlling the ratio of the first component to the second component within a suitable range, it is helpful to control the porosity of the transition layer, so that the porosity is within a suitable range, and the cooking utensil has good film strength and corrosion resistance.

[0094] Specifically, when the iron-based transition layer comprises a first component and a second component, the porosity of the iron-based transition layer is ≤10%, preferably 0.1-8%, and more preferably 1-5%. Similarly, when the porosity of the transition layer exceeds 10%, the film strength decreases, making it easy for it to be scraped off with a metal shovel, such as an iron shovel, during use, thereby shortening the life of the rustproofing film. In addition, when the corrosion resistance requirement is certain, the higher the porosity, the thicker the film, resulting in higher cost and heavier weight.

[0095] Specifically, when the material of the iron-based transition layer includes a first component and a second component, the thickness of the iron-based transition layer can be 10 to 500 μm, preferably 20 to 300 μm, more preferably 50 to 250 μm, further preferably 50 to 180 μm, and further preferably 180 to 250 μm. Similarly, when the thickness of the iron-based transition layer is less than 10 μm, the transition layer is too thin and easily penetrates into the substrate when corrosion occurs, causing pitting corrosion and reducing corrosion resistance. When the thickness is greater than 500 μm, the transition layer is too thick, resulting in high cost and no significant performance improvement.

[0096] Specifically, when the material of the iron-based transition layer includes a first component and a second component, the first component may be in powder form or a wire material, and the second component may be in powder form;

[0097] Preferably, the first component and the second component are both in powder form.

[0098] Preferably, the particle size of the first component may be 30-1000 mesh, preferably 50-400 mesh, more preferably 60-300 mesh, further preferably 100-300 mesh, further preferably 60-120 mesh.

[0099] Preferably, the particle size of the second component is 30-1000 mesh, preferably 500-1000 mesh, and more preferably 800-1000 mesh.

[0100] Similarly, by using powdered pure iron and / or iron-based alloys of appropriate particle size, as well as powdered C, Si, or silicates of appropriate particle size, costs can be reduced and the bonding strength of the transition layer to the substrate can be improved. On the one hand, if the powder particle size is less than 30 mesh, the larger the particles, the more demanding the process required to achieve the desired bonding strength between the film and the substrate, resulting in higher process costs. If the powder particle size is greater than 1000 mesh, the smaller the particles, the higher the powder production cost. On the other hand, from a manufacturing process perspective, larger particles require greater heat to melt. With the same external heat, larger particles result in lower melting degree. Under the same main gas conditions, the film porosity increases and the film strength decreases. When the particle size is less than 30 mesh, the larger the particle size, the higher the porosity, resulting in lower film strength. When the powder particle size is greater than 1000 mesh, the smaller the particle size, the higher the melting degree, resulting in greater stress in the resulting coating, which may cause spontaneous cracking.

[0101] In other embodiments, the material of the iron-based transition layer may be cast iron.

[0102] When the iron-based transition layer is made of cast iron, it can also be referred to as a cast iron layer. Due to the material characteristics described above, cast iron has a uniformly staggered structure on its surface, which can achieve excellent pitting resistance and rust prevention. Therefore, the cast iron layer is provided on the surface of the substrate, and an anti-rust treatment layer is formed on the surface of the cast iron layer. The anti-pitting corrosion principle is similar to that of the aforementioned cast iron genuine stainless iron pan, which in turn makes the cooking utensil have excellent corrosion resistance and can effectively prevent metal products from oxidizing and rusting. At the same time, by replacing the existing cast iron substrate with a cast iron layer, the weight of the entire cooking utensil can be reduced.

[0103] Compared to existing cast iron true stainless pots, which are entirely made of cast iron, the cast iron layer on the base material reduces the weight of the entire cookware. Specifically, the cookware of this embodiment achieves comparable pitting-free performance (excellent corrosion resistance) compared to existing cast iron true stainless products, while being lighter than existing cast iron true stainless products, thereby reducing material weight and costs.

[0104] It can be understood that in the above cooking utensils, the base material may be a metal base material, and the material of the base material may not include cast iron.

[0105] To enhance the corrosion resistance of the cast iron layer, the specific type of cast iron can be optimized. In some embodiments, the cast iron can include at least one of gray cast iron, white cast iron, malleable cast iron, ductile iron, or vermicular cast iron. For example, the cast iron can be gray cast iron, white cast iron, ductile iron, or the like. Preferably, the cast iron is gray cast iron, which further enhances the corrosion resistance of the cooking utensil.

[0106] Specifically, when the iron-based transition layer is made of cast iron, the porosity of the iron-based transition layer is ≤10%, preferably 0.1-8%, and more preferably 1-5%. Similarly, when the porosity of the transition layer exceeds 10%, the film strength is reduced, making it easy for metal shovels such as iron shovels to scrape it off during use, thereby shortening the life of the rustproofing. In addition, when the corrosion resistance requirements are certain, the higher the porosity, the thicker the film layer, resulting in higher cost and heavier weight.

[0107] Specifically, when the material of the iron-based transition layer is cast iron, the thickness of the iron-based transition layer can be 10-500μm, preferably 50-450μm, 25-350μm, more preferably 50-250μm, further 50-180μm, further 180-250μm.

[0108] Specifically, when the material of the iron-based transition layer is cast iron, the cast iron may be in the form of powder or wire; that is, the cast iron may be in the form of powder or wire according to different process requirements.

[0109] When the cast iron is in powder form, the particle size of the powdered cast iron can be 30 to 1000 mesh, preferably 60 to 300 mesh, further 40 to 280 mesh, further 100 to 300 mesh, and further 60 to 120 mesh. Using powdered cast iron with an appropriate particle size can reduce costs and improve the bonding strength between the transition layer and the substrate. On the one hand, if the powder particle size is less than 30 mesh, the particles are larger, and the process required to meet the bonding strength between the film layer and the substrate is more demanding, resulting in higher process costs. If the powder particle size is greater than 1000 mesh, the particles are smaller, resulting in higher powder production costs. On the other hand, from the perspective of the preparation process, when the particles are larger, greater heat is required to melt the particles. When the external heat is the same, the larger the particles, the lower the degree of melting. Under the same main gas conditions, the greater the porosity of the membrane layer, the lower the membrane layer strength. When the particle size is less than 30 mesh, the particle size is larger and the membrane layer porosity is larger, resulting in lower membrane layer strength. When the powder particle size is greater than 1000 mesh, the particle size is smaller and the degree of particle melting is greater. The stress of the coating formed is greater, which may cause the coating to naturally crack.

[0110] When the cast iron is in the form of wire, the diameter of the wire-shaped cast iron can be 0.5-5 mm, further 1-4 mm, and further 2-3 mm. It is understood that, similarly, by using wire-shaped cast iron of an appropriate diameter, costs can be reduced and the bonding strength between the transition layer and the substrate can be improved. On the one hand, when the wire diameter is less than 0.5 mm, the wire-making cost is relatively high; on the other hand, when the diameter is greater than 5.0 mm, the process required to meet the bonding strength between the film layer and the substrate is more demanding, and the process cost is higher.

[0111] In some embodiments, the iron-based transition layer can be formed by spraying a spray material onto the substrate surface through a process such as thermal spraying, cold spraying, powder metallurgy, or solid-phase sintering. However, when the iron-based transition layer is made of cast iron, solid-phase sintering is not suitable.

[0112] In some embodiments, the transition layer formed on the substrate surface is then subjected to conventional rust-proofing treatment, such as conventional nitriding, phosphating, oxidation, or spraying with anti-rust paint, to form an anti-rust treatment layer. Its pitting resistance is comparable to that of conventional true stainless cast iron. It should be understood that the anti-rust treatment layer is disposed on the side of the transition layer away from the substrate.

[0113] It can be understood that the embodiments of the present application do not impose any special restrictions on the formation method of the anti-rust treatment layer. It can adopt the surface treatment methods commonly used in the field. For example, the anti-rust treatment layer can be prepared by at least one method including nitriding, phosphating, oxidation or spraying anti-rust paint.

[0114] Specifically, the thickness of the anti-rust treatment layer can be 0.5 to 50 μm, preferably 5 to 40 μm, further 5 to 20 μm, and further 10 to 40 μm; typically but not limitatively, the thickness of the anti-rust treatment layer can be, for example, 0.5 μm, 1 μm, 2 μm, 5 μm, 8 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm and any value in the range formed by any two of these point values.

[0115] By controlling the thickness of the anti-rust treatment layer within an appropriate range, it helps to better protect the transition layer and the substrate, helps to reduce costs and weight, and enables the cooking utensils to have good film strength and corrosion resistance.

[0116] Depending on the product requirements, the substrate can be a single-layer material or a multi-layer composite sheet structure. The specific number of layers of the substrate is not limited in the embodiments of this application. The specific material of the substrate can be selected from metal materials commonly used in the field. Of course, the substrate material does not need to include cast iron. Exemplary materials include at least one of carbon steel, stainless steel, titanium, titanium alloy, aluminum, aluminum alloy, copper, or copper alloy, with carbon steel preferably being low-carbon steel.

[0117] Specifically, when the substrate has a single-layer structure, its material can be low-carbon steel, stainless steel, titanium or titanium alloy, aluminum or aluminum alloy, copper or copper alloy, and of course, other similar materials. When the substrate has a multi-layer composite structure, its material can be a composite of any two or more of low-carbon steel, stainless steel, titanium, titanium alloy, aluminum, aluminum alloy, copper or copper alloy. For example, it can be low-carbon steel and stainless steel, low-carbon steel and titanium alloy, stainless steel, titanium alloy and aluminum alloy, low-carbon steel, aluminum and aluminum alloy, stainless steel, copper and copper alloy, etc.

[0118] Specifically, the thickness of the substrate can be 0.5 to 5 mm, preferably 0.5 to 3 mm, further 1 to 3 mm, and further 2 to 4 mm; typically but not limitatively, the thickness of the substrate can be, for example, 0.5 mm, 0.8 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm, 5 mm, and any value in the range formed by any two of these point values.

[0119] By controlling the base material thickness within an appropriate range, costs and weight can be reduced, ensuring that the cookware has good strength. For example, when the base material thickness is less than 0.5mm, the cookware (pot body) is weak and prone to deformation during use. When the base material thickness exceeds 5mm, the cookware is heavy and expensive, which does not meet the requirements of home consumers.

[0120] From the above description, it can be seen that no matter what base material is used for the pot body, in order to meet the consumer's consumption concept of using iron pots, the inner surface that comes into contact with food can be iron. And the above-mentioned anti-rust treatment method of the present invention forms the above-mentioned transition layer and anti-rust treatment layer on the inner surface of the base material in sequence, which can meet the anti-pitting and rust-proof functions during use. Its anti-pitting and rust-proofing principles and effects are as described above and will not be repeated here. It is particularly important to emphasize that the cooking utensil of the present invention forms an anti-cast iron structure on the inner surface by controlling the material and porosity of the transition layer to achieve the purpose of anti-pitting and rust-proofing. Therefore, the cooking utensil of the present invention does not need to limit the base material of the pot body; unlike existing cast iron rust-proof iron pots, there is no need to require that its base material must be cast iron material, which will make the pot body heavier. In other words, the cooking utensil of the present invention can not only achieve good anti-pitting and rust-proof performance, but also can reduce the weight of the pot body by changing the base material as needed, meeting the requirements of making the pot body lightweight and easy to move, flip the wok, etc. Unlike the existing cast iron rust-proof iron pot, which can only meet the rust-proof performance of anti-pitting corrosion but cannot reduce the weight of the pot body.

[0121] In a second aspect, the present invention further provides a method for preparing a cooking utensil, comprising:

[0122] providing a substrate;

[0123] forming a transition layer on the inner surface of the substrate;

[0124] forming an anti-rust treatment layer on the surface of the transition layer;

[0125] Wherein, the transition layer is an iron-based transition layer, and the porosity of the iron-based transition layer is ≤10%.

[0126] This preparation method is simple to operate, easy to implement, and readily achievable for large-scale production. Furthermore, the resulting cooking utensil comprises a substrate, an iron-based transition layer, and an anti-rust treatment layer stacked sequentially. The anti-rust treatment layer is disposed on a side of the iron-based transition layer away from the substrate. The porosity of the iron-based transition layer is ≤10%, thus possessing the advantages described above for the cooking utensil of the first aspect.

[0127] It should be understood that in the method for preparing the cooking utensil, the specific structure and components of the cooking utensil and the beneficial effects achieved can be referred to the description of the cooking utensil in the first aspect above, and will not be repeated here.

[0128] In some embodiments, the method for forming the iron-based transition layer includes, but is not limited to, one or more of thermal spraying, cold spraying, powder metallurgy, or solid-phase sintering. For example, the iron-based transition layer may be formed by thermal spraying, cold spraying, powder metallurgy, or solid-phase sintering.

[0129] Thermal spraying can be any conventional thermal spraying technique in the art, such as arc spraying, flame spraying, plasma spraying, or one or more of the following. Thermal spraying utilizes a heat source to heat a powdered or filamentary metal or non-metallic material to a molten or semi-molten state. The material is then sprayed onto a pre-treated substrate at a predetermined velocity using a flame or compressed air, depositing the material to form a surface coating with various functionalities. Thermal spraying offers advantages such as simplicity, ease of control, high feasibility, reliability, and high production efficiency.

[0130] In some specific embodiments, a thermal spraying method is used to form an iron-based transition layer on the inner surface of the substrate; further, a plasma spraying method is preferably used to form the iron-based transition layer on the inner surface of the substrate.

[0131] In this plasma spraying process, the coating material can be in the form of powder, wire, ribbon, rod, etc., preferably powder. For example, the material for the iron-based transition layer can be pure iron powder and C powder, pure iron powder and Si powder, or gray cast iron powder. When using plasma spraying to prepare the iron-based transition layer, the coating quality (including coating porosity and coating strength) is primarily affected by four factors: main gas flow rate, plasma gas flow rate, applied current, and particle size.

[0132] Specifically, according to embodiments of the present invention, the inventors have conducted a large number of thorough investigations and experimental verifications on the main gas flow rate of plasma spraying, and the inventors have found that the main gas flow rate of plasma spraying is 100-5000 L / H, more preferably, 550-1550 L / H. In some specific embodiments of the present invention, the main gas flow rate of plasma spraying can be, for example, 500 L / H, 550 L / H, 600 L / H, 650 L / H, 700 L / H, 750 L / H, 800 L / H, 900 L / H, 950 L / H, 1000 L / H, 1200 L / H, 1500 L / H, 2000 L / H, 2500 L / H, 3000 L / H, 3500 L / H, 3800 L / H, 4000 L / H, 4200 L / H, 4500 L / H, 5000 L / H, etc. The inventors discovered that a greater main air flow rate accelerates the molten iron particles, increasing the force exerted on the substrate surface, resulting in a denser transition layer and lower porosity. Therefore, when the main air flow rate is less than 100 L / H, the porosity is high, failing to meet the strength requirements for home use. When the main air flow rate exceeds 5000 L / H, the molten particles accelerate too quickly, resulting in a dense coating but high stress, which can cause the coating to spontaneously crack. Furthermore, within the aforementioned main air flow range, the method achieves high reliability and production efficiency, more complete coating material spraying, low energy consumption, and improved quality and performance of the resulting transition layer. The resulting cooking utensil offers excellent product performance and user experience.

[0133] It should be understood that in the plasma spraying process, the main gas may be a main gas commonly used in the art, such as argon.

[0134] Specifically, according to the embodiments of the present invention, the inventors have conducted a large number of careful investigations and experimental verifications on the plasma gas flow rate of plasma spraying, and the inventors have found that the plasma gas flow rate of plasma spraying is 10 to 200 L / H, preferably 30 to 50 L / H. In some specific embodiments of the present invention, the plasma gas flow rate of plasma spraying can be, for example, 10 L / H, 20 L / H, 30 L / H, 35 L / H, 40 L / H, 45 L / H, 50 L / H, 55 L / H, 60 L / H, 70 L / H, 80 L / H, 90 L / H, 100 L / H, 120 L / H, 150 L / H, 200 L / H, etc. The inventors discovered that the greater the plasma gas flow rate, the greater the external heat, and the greater the degree of melting of the iron material molten particles. Under the same main gas conditions, after impacting the substrate, the more molten particles form a coating with a lower porosity. Therefore, when the plasma gas flow rate is less than 10 L / H, the degree of melting of the material powder particles is low, and the poor film-forming performance of the coating leads to low coating strength. However, when the plasma gas flow rate is greater than 200 L / H, the degree of particle melting is greater, resulting in greater stress in the coating, which can cause the coating to naturally crack. Furthermore, within the aforementioned range, the plasma gas flow rate can make the method highly reliable and efficient, with more complete spraying of the coating material, low energy consumption, and better quality and performance of the resulting transition layer. The resulting cooking utensil product has excellent product performance and user experience.

[0135] It should be understood that in the plasma spraying process, the plasma gas may be any plasma gas commonly used in the art, such as hydrogen or helium, preferably hydrogen.

[0136] Specifically, according to embodiments of the present invention, the inventors have conducted extensive and thorough investigations and experimental verifications on the current of plasma spraying, and have found that the current of plasma spraying is 100 to 500 A, preferably 150 to 350 A. In some specific embodiments of the present invention, the current of plasma spraying can be, for example, 100 A, 150 A, 180 A, 200 A, 220 A, 250 A, 300 A, 320 A, 350 A, 380 A, 400 A, 450 A, 500 A, etc. The inventors found that the greater the current, the greater the degree of plasma gas plasmaization, the greater the external heat, and the greater the degree of melting of the iron material particles. Under the same plasma gas flow rate and main gas flow rate operating conditions, the greater the heat, the smaller the porosity of the coating accumulated by the particles with a greater degree of melting; therefore, when the current is less than 100A, the degree of melting of the material powder particles is low, and the low film-forming performance of the coating will lead to low coating strength. When the current is greater than 500A, the degree of melting of the particles is greater, and the stress of the coating formed is greater, which will cause the coating to naturally crack.

[0137] Specifically, according to the embodiments of the present invention, the inventors have conducted a large number of careful investigations and experimental verifications on the particle size of plasma sprayed powders, and the inventors have found that the particle size of plasma sprayed powders is 30 to 1000 mesh, preferably 200 to 550 mesh. In some specific embodiments of the present invention, the particle size of plasma sprayed powders can be, for example, 30 mesh, 50 mesh, 60 mesh, 80 mesh, 100 mesh, 120 mesh, 200 mesh, 300 mesh, 320 mesh, 400 mesh, 500 mesh, 600 mesh, 700 mesh, 800 mesh, 900 mesh, 1000 mesh, etc. The inventors found that when the particles are large, greater heat is required to melt the particles. When the external heat is the same, the larger the particles, the lower the degree of melting. Under the same main gas conditions, the greater the porosity of the membrane layer, the lower the membrane layer strength. When the particle size is less than 30 mesh, the particle size is larger and the membrane layer porosity is larger, resulting in lower membrane layer strength. When the particles are larger than 1000 mesh, the particle size is smaller and the degree of particle melting is greater. The stress of the coating formed is greater, which will cause the coating to naturally crack.

[0138] In addition, the inventors have also investigated and experimentally verified other operating conditions in plasma spraying. The preferred operating conditions for plasma spraying also include:

[0139] Powder feeding gas: argon, the powder feeding gas flow rate is 8-15 L / H, and can be further 10-12 L / H;

[0140] Spraying distance: The spraying distance is 15 to 25 cm, and can be further increased to 20 cm.

[0141] It should be noted that in the plasma spraying process, other operating conditions such as voltage, spray gun movement speed, etc. are not subject to special restrictions. As long as the requirements are met and the performance of the cooking appliance is not affected, they can be adjusted by technical personnel in this field according to actual conditions.

[0142] Thus, the thickness of the formed iron-based transition layer may be 10 to 500 μm, further 20 to 300 μm, further 25 to 300 μm, further 180 to 250 μm.

[0143] According to an embodiment of the present invention, in order to make the preparation method of the cooking utensil lower in cost, higher in production efficiency, better in reliability, and the quality and performance of the resulting coating better, the inventors comprehensively considered the current, main gas flow rate, plasma gas flow rate, and powder particle size used in plasma spraying. The inventors found that when the main gas flow rate is 100-5000 L / H, the plasma gas flow rate is 10-200 L / H, the current is 100-500 A, and the powder particle size is 30-1000 mesh, the various parameters influence each other and act synergistically with each other, so that the method can be made highly reliable, highly efficient, low in energy consumption, and low in cost, the quality and performance of the formed transition layer are better, and the resulting cooking utensil product performance and user experience are good.

[0144] In some specific embodiments, the method for preparing the cooking utensil may further include: pre-treating the substrate before forming the transition layer. The pre-treating method may be a conventional method in the art and will not be described in detail here.

[0145] In some specific embodiments, after the transition layer is formed on the surface of the substrate, it can undergo conventional anti-rust treatment, such as conventional nitriding, phosphating, oxidation or spraying of anti-rust paint, to form an anti-rust treatment layer, whose anti-pitting corrosion principle is equivalent to that of existing cast iron.

[0146] Specifically, after forming the transition layer on the surface of the substrate, the substrate may be sanded with 60-grit sandpaper until the surface becomes smooth, and then post-processing may be performed.

[0147] Specifically, the post-treatment scheme is preferably a nitriding oxidation method (a conventional nitriding oxidation process can be used).

[0148] Among them, the nitriding adopts gas nitriding, and the operating conditions of the nitriding include: temperature 560°C, time 6h, ammonia decomposition rate 50%;

[0149] The oxidation process adopts salt bath oxidation, the main components of which are sodium nitrite and sodium hydroxide, the temperature is 400-460°C, and the time is 2-4 hours.

[0150] As can be seen from the above, in the method for preparing the cooking utensil of the present invention, a transition layer is formed on the surface of the metal substrate by using methods such as thermal spraying or cold spraying. This transition layer can also be called an imitation cast iron layer or a cast iron layer. The imitation cast iron layer or the cast iron layer is polished to make the surface smooth, and then a subsequent rust-proof treatment is performed. In this way, the prepared cooking utensil can combine the advantages of cast iron and refined iron that are truly stainless.

[0151] The cooking utensil can be various commonly used cooking equipment, for example, a stainless rice cooker liner, a stainless pressure cooker liner, a stainless wok, a stainless frying pan, a stainless pan, a stainless baking tray, etc. Exemplarily, the cooking utensil is a stainless wok or a stainless frying pan.

[0152] To facilitate understanding of the present invention, the following description further illustrates the present invention with reference to specific examples and comparative examples. It should be noted that multiple samples were tested for each example, and the saltwater corrosion resistance and salt spray corrosion resistance values are the average values of the multiple samples tested in that example. Unless otherwise specified, all materials used in the following specific examples and comparative examples are commercially available. Furthermore, as described above in the anti-pitting corrosion mechanism, when the transition layer is a mixture of a first component and a second component, the carbon material, silicon material, silicate, or carbon material, silicon material, and silicate in the second component primarily increase free carbon (carbon) or silicon (silicon), thereby creating a uniformly interlaced structure of the iron-based alloy and free carbon and silicon, thereby achieving pitting corrosion and rust prevention. Therefore, either free carbon (carbon) or silicon (silicon) can be added. Therefore, in the following examples, the second component may also be referred to as an inorganic material. The specific content of the carbon material, silicon material, silicate, or carbon material, silicon material, and silicate in the inorganic material is no longer broken down, but rather randomly proportioned.

[0153] Example 1:

[0154] A transition layer is applied to the inner surface of the mild steel substrate using a thermal spray-plasma spray process.

[0155] The operating conditions of the plasma spray process include:

[0156] Main gas: argon, main gas flow rate is 1000L / H;

[0157] Plasma gas: hydrogen, plasma gas flow rate is 40L / H;

[0158] Current: 250A;

[0159] The particle size of cast iron powder is 400-500 mesh;

[0160] Powder feeding gas: argon, powder feeding gas flow rate is 12L / H;

[0161] Spraying distance: The spraying distance is 20cm.

[0162] The material of the transition layer is cast iron, the thickness of the transition layer is 50 μm, and the porosity is 3.0%.

[0163] Example 2:

[0164] The operating conditions of the plasma spraying process are: argon gas, main gas flow rate is 1000 L / H; hydrogen gas, plasma gas flow rate is 40 L / H.

[0165] The thickness of the transition layer is 280 μm.

[0166] Others are the same as in Example 1.

[0167] Example 3:

[0168] The operating conditions of the plasma spraying process are: the current is 220A.

[0169] The thickness of the transition layer is 200 μm.

[0170] Others are the same as in Example 1.

[0171] Example 4:

[0172] The operating conditions of the plasma spraying process are: argon gas, main gas flow rate is 1500 L / H; hydrogen gas, plasma gas flow rate is 50 L / H; current is 350A.

[0173] The porosity of the transition layer is 0.5% and the thickness is 350 μm.

[0174] Others are the same as in Example 1.

[0175] Example 5:

[0176] The operating conditions of the plasma spraying process are: argon gas, main gas flow rate is 800L / H; current is 350A; powder particle size is 200-320 mesh.

[0177] The porosity of the transition layer is 5.0% and the thickness is 350 μm.

[0178] Others are the same as in Example 1.

[0179] Example 6:

[0180] The operating conditions of the plasma spraying process are: hydrogen, plasma gas flow rate of 650L / H; current of 200A; powder particle size of 200-320 mesh.

[0181] The porosity of the transition layer is 7.6% and the thickness is 350 μm.

[0182] Others are the same as in Example 1.

[0183] Example 7:

[0184] The operating conditions of the plasma spraying process are: argon gas, main gas flow rate is 1200 L / H; hydrogen gas, plasma gas flow rate is 50 L / H; current is 350A.

[0185] The porosity of the transition layer is 1.0% and the thickness is 100 μm.

[0186] Others are the same as in Example 1.

[0187] Example 8:

[0188] The operating conditions of the plasma spraying process are: the current is 200A.

[0189] The porosity of the transition layer is 3.5% and the thickness is 150 μm.

[0190] Others are the same as in Example 1.

[0191] Example 9:

[0192] The operating conditions of the plasma spraying process are: argon gas, main gas flow rate is 650L / H; hydrogen gas, plasma gas flow rate is 35L / H; current is 200A; powder particle size is 200-320 mesh.

[0193] The porosity of the transition layer is 8.0% and the thickness is 420 μm.

[0194] Others are the same as in Example 1.

[0195] Example 10:

[0196] The operating conditions of the plasma spraying process are: hydrogen, plasma gas flow rate of 40L / H; current of 250A.

[0197] The porosity of the transition layer is 6.8% and the thickness is 360 μm.

[0198] Other details are the same as in Example 9.

[0199] Example 11:

[0200] The operating conditions of the plasma spraying process are: argon gas, main gas flow rate is 700 L / H; hydrogen gas, plasma gas flow rate is 35 L / H.

[0201] Other details are the same as in Example 10.

[0202] Example 12:

[0203] The operating conditions of the plasma spraying process are: the current is 300A.

[0204] Other details are the same as in Example 10.

[0205] Example 13:

[0206] The operating conditions of the plasma spraying process are: argon gas, main gas flow rate is 550L / H; hydrogen gas, plasma gas flow rate is 30L / H; current is 200A.

[0207] The porosity of the transition layer is 10.9% and the thickness is 100 μm.

[0208] Other details are the same as in Example 10.

[0209] Example 14:

[0210] The operating conditions of the plasma spraying process are: argon gas, main gas flow rate is 500L / H; current is 180A.

[0211] The porosity of the transition layer is 13% and the thickness is 150 μm.

[0212] Other details are the same as in Example 13.

[0213] Example 15:

[0214] A transition layer is applied to the inner surface of the mild steel substrate using a thermal spray-plasma spray process.

[0215] The material of the transition layer is pure iron powder, the porosity of the transition layer is 6.0%, and the thickness is 150 μm.

[0216] The operating conditions of the plasma spray process include:

[0217] Main gas: argon, main gas flow rate is 750L / H;

[0218] Plasma gas: hydrogen, plasma gas flow rate is 40L / H;

[0219] Current: 200A;

[0220] The particle size of pure iron powder is 200-320 mesh;

[0221] Powder feeding gas: argon, powder feeding gas flow rate is 12L / H;

[0222] Spraying distance: The spraying distance is 20cm.

[0223] Example 16:

[0224] The operating conditions of the plasma spraying process are: argon gas, main gas flow rate is 800 L / H; hydrogen gas, plasma gas flow rate is 30 L / H.

[0225] The thickness of the transition layer is 450 μm.

[0226] Other details are the same as in Example 15.

[0227] Example 17:

[0228] The operating conditions of the plasma spraying process are: argon gas, main gas flow rate is 1000 L / H; hydrogen gas, plasma gas flow rate is 45 L / H; current is 250 A; powder particle size is 400-500 mesh.

[0229] The porosity of the transition layer is 2.5% and the thickness is 200 μm.

[0230] Other details are the same as in Example 15.

[0231] Example 18:

[0232] The operating conditions of the plasma spraying process are: argon gas, main gas flow rate is 650L / H; hydrogen gas, plasma gas flow rate is 30L / H.

[0233] The porosity of the transition layer is 9.0% and the thickness is 300 μm.

[0234] Other details are the same as in Example 15.

[0235] Example 19:

[0236] The thickness of the transition layer is 300 μm.

[0237] Other details are the same as in Example 18.

[0238] Example 20:

[0239] The operating conditions of the plasma spraying process are: argon gas, main gas flow rate is 500L / H; current is 180A; powder particle size is 100-200 mesh.

[0240] The porosity of the transition layer is 15.0%.

[0241] Other details are the same as in Example 18.

[0242] Example 21:

[0243] A transition layer is applied to the inner surface of the mild steel substrate using a thermal spray-plasma spray process.

[0244] The material of the transition layer is iron alloy, the porosity of the transition layer is 6.0%, and the thickness is 150 μm.

[0245] The operating conditions of the plasma spray process include:

[0246] Main gas: argon, main gas flow rate is 750L / H;

[0247] Plasma gas: hydrogen, plasma gas flow rate is 40L / H;

[0248] Current: 200A;

[0249] The particle size of pure iron powder is 200-320 mesh;

[0250] Powder feeding gas: argon, powder feeding gas flow rate is 12L / H;

[0251] Spraying distance: The spraying distance is 20cm.

[0252] Example 22:

[0253] The operating conditions of the plasma spraying process are: argon gas, main gas flow rate is 750L / H; hydrogen gas, plasma gas flow rate is 40L / H.

[0254] The thickness of the transition layer is 450 μm.

[0255] Other details are the same as in Example 21.

[0256] Example 23:

[0257] The operating conditions of the plasma spraying process are: argon gas, main gas flow rate is 1000 L / H; hydrogen gas, plasma gas flow rate is 45 L / H; current is 250 A; powder particle size is 400-500 mesh.

[0258] The porosity of the transition layer is 2.5% and the thickness is 200 μm.

[0259] Other details are the same as in Example 21.

[0260] Example 24:

[0261] The operating conditions of the plasma spraying process are: argon gas, main gas flow rate is 650L / H; hydrogen gas, plasma gas flow rate is 30L / H.

[0262] The porosity of the transition layer is 9.0% and the thickness is 300 μm.

[0263] Other details are the same as in Example 21.

[0264] Example 25:

[0265] The thickness of the transition layer is 350 μm.

[0266] Other details are the same as in Example 24.

[0267] Example 26:

[0268] The porosity of the transition layer is 15%.

[0269] Other details are the same as in Example 24.

[0270] Example 27:

[0271] A transition layer is applied to the inner surface of the mild steel substrate using a thermal spray-plasma spray process.

[0272] The transition layer is made of a mixture of pure iron and iron alloy in a ratio of 1:1. The porosity of the transition layer is 6.0% and the thickness is 150 μm.

[0273] The operating conditions of the plasma spray process include:

[0274] Main gas: argon, main gas flow rate is 750L / H;

[0275] Plasma gas: hydrogen, plasma gas flow rate is 40L / H;

[0276] Current: 200A;

[0277] The particle size of pure iron powder is 200-320 mesh;

[0278] Powder feeding gas: argon, powder feeding gas flow rate is 12L / H;

[0279] Spraying distance: The spraying distance is 20cm.

[0280] Example 28:

[0281] The material of the transition layer is a mixture of pure iron and iron alloy in a ratio of 9:1.

[0282] The thickness of the transition layer is 450 μm.

[0283] Other details are the same as Example 27.

[0284] Example 29:

[0285] The material of the transition layer is a mixture of pure iron and iron alloy in a ratio of 3:7.

[0286] The operating conditions of the plasma spraying process are: argon gas, main gas flow rate is 1000 L / H; hydrogen gas, plasma gas flow rate is 45 L / H; current is 250 A; powder particle size is 400-500 mesh.

[0287] The porosity of the transition layer is 2.5% and the thickness is 200 μm.

[0288] Other details are the same as Example 27.

[0289] Example 30:

[0290] The material of the transition layer is a mixture of pure iron and iron alloy in a ratio of 4:1.

[0291] The porosity of the transition layer is 2.5% and the thickness is 200 μm.

[0292] Other details are the same as in Example 29.

[0293] Example 31:

[0294] The material of the transition layer is a mixture of pure iron and iron alloy in a ratio of 2.3:1.

[0295] The operating conditions of the plasma spraying process are: argon gas, main gas flow rate is 650L / H; hydrogen gas, plasma gas flow rate is 30L / H.

[0296] The porosity of the transition layer is 9.0% and the thickness is 300 μm.

[0297] Other details are the same as Example 27.

[0298] Example 32:

[0299] The thickness of the transition layer is 350 μm.

[0300] Other details are the same as Example 31.

[0301] Example 33:

[0302] The material of the transition layer is a mixture of pure iron and iron alloy in a ratio of 2:8.

[0303] The operating conditions of the plasma spraying process are: argon gas, main gas flow rate is 1000 L / H; hydrogen gas, plasma gas flow rate is 35 L / H; the particle size of the powder is 400-500 mesh.

[0304] The porosity of the transition layer is 4.0% and the thickness is 280 μm.

[0305] Other details are the same as Example 27.

[0306] Example 34:

[0307] The operating conditions of the plasma spraying process are: argon gas, main gas flow rate is 900 L / H; hydrogen gas, plasma gas flow rate is 40 L / H.

[0308] The thickness of the transition layer is 95 μm.

[0309] Other details are the same as in Example 33.

[0310] Example 35:

[0311] The porosity of the transition layer is 20.0%.

[0312] Other details are the same as in Example 34.

[0313] Example 36:

[0314] A transition layer is applied to the inner surface of the mild steel substrate using a thermal spray-plasma spray process.

[0315] The transition layer is made of pure iron and inorganic material in a ratio of 9.5:0.5. The porosity of the transition layer is 0.5% and the thickness is 280 μm.

[0316] The operating conditions of the plasma spray process include:

[0317] Main gas: argon, main gas flow rate is 1500L / H;

[0318] Plasma gas: hydrogen, plasma gas flow rate is 50L / H;

[0319] Current: 350A;

[0320] The particle size of pure iron powder is 400-500 mesh;

[0321] Powder feeding gas: argon, powder feeding gas flow rate is 12L / H;

[0322] Spraying distance: The spraying distance is 20cm.

[0323] Example 37:

[0324] The material of the transition layer is a mixture of pure iron and inorganic material in a ratio of 9:1.

[0325] The thickness of the transition layer is 280 μm.

[0326] The rest are the same as Example 36.

[0327] Example 38:

[0328] The operating conditions of the plasma spraying process are: argon gas, the main gas flow rate is 1200L / H.

[0329] The porosity of the transition layer is 1.0%.

[0330] Other details are the same as Example 37.

[0331] Example 39:

[0332] The material of the transition layer is a mixture of pure iron and inorganic material in a ratio of 8.5:1.5.

[0333] The thickness of the transition layer is 170 μm.

[0334] Other details are the same as Example 38.

[0335] Example 40:

[0336] The material of the transition layer is a mixture of pure iron and inorganic material in a ratio of 8:2.

[0337] The operating conditions of the plasma spraying process are: argon gas, main gas flow rate is 650L / H; hydrogen gas, plasma gas flow rate is 40L / H; current is 180A; powder particle size is 200-320 mesh.

[0338] The porosity of the transition layer is 7.8% and the thickness is 360 μm.

[0339] The rest are the same as Example 36.

[0340] Example 41:

[0341] The material of the transition layer is a mixture of pure iron and inorganic material in a ratio of 7.5:2.5.

[0342] The thickness of the transition layer is 450 μm.

[0343] Other details are the same as in Example 40.

[0344] Example 42:

[0345] The porosity of the transition layer is 9.5% and the thickness is 430 μm.

[0346] Other details are the same as Example 41.

[0347] Example 43:

[0348] The material of the transition layer is a mixture of pure iron and inorganic material in a ratio of 7:3.

[0349] The thickness of the transition layer is 390 μm.

[0350] Other details are the same as Example 42.

[0351] Example 44:

[0352] The porosity of the transition layer is 11%.

[0353] Other details are the same as Example 43.

[0354] Example 45:

[0355] A transition layer is applied to the inner surface of the mild steel substrate using a thermal spray-plasma spray process.

[0356] The transition layer is made of a mixture of ferroalloy and inorganic material in a ratio of 9.5:0.5. The porosity of the transition layer is 2.5% and the thickness is 190 μm.

[0357] The operating conditions of the plasma spray process include:

[0358] Main gas: argon, main gas flow rate is 1000L / H;

[0359] Plasma gas: hydrogen, plasma gas flow rate is 45L / H;

[0360] Current: 250A;

[0361] The particle size of pure iron powder is 400-500 mesh;

[0362] Powder feeding gas: argon, powder feeding gas flow rate is 12L / H;

[0363] Spraying distance: The spraying distance is 20cm.

[0364] Example 46:

[0365] The material of the transition layer is a mixture of ferroalloy and inorganic material in a ratio of 9:1.

[0366] The thickness of the transition layer is 220 μm.

[0367] Other details are the same as Example 45.

[0368] Example 47:

[0369] The operating conditions of the plasma spraying process are: argon gas, main gas flow rate is 950L / H; hydrogen gas, plasma gas flow rate is 35L / H; current is 200A.

[0370] The porosity of the transition layer is 4.3% and the thickness is 70 μm.

[0371] The rest is the same as Example 46.

[0372] Example 48:

[0373] The material of the transition layer is a mixture of ferroalloy and inorganic material in a ratio of 8.5:1.5.

[0374] The thickness of the transition layer is 400 μm.

[0375] Other details are the same as Example 47.

[0376] Example 49:

[0377] The material of the transition layer is a mixture of ferroalloy and inorganic material in a ratio of 8:2.

[0378] The operating conditions of the plasma spraying process are: argon gas, main gas flow rate is 800 L / H; hydrogen gas, plasma gas flow rate is 30 L / H; current is 200 A; powder particle size is 200-320 mesh.

[0379] The porosity of the transition layer is 6.0% and the thickness is 95 μm.

[0380] Other details are the same as Example 45.

[0381] Example 50:

[0382] The material of the transition layer is a mixture of ferroalloy and inorganic material in a ratio of 7.5:2.5.

[0383] The thickness of the transition layer is 445 μm.

[0384] Other details are the same as Example 49.

[0385] Example 51:

[0386] The operating conditions of the plasma spraying process are: argon gas, main gas flow rate is 650L / H; hydrogen gas, plasma gas flow rate is 40L / H; current is 150A.

[0387] The porosity of the transition layer is 8.6% and the thickness is 330 μm.

[0388] Other details are the same as in Example 50.

[0389] Example 52:

[0390] The material of the transition layer is a mixture of ferroalloy and inorganic material in a ratio of 7:3.

[0391] The thickness of the transition layer is 260 μm.

[0392] Other details are the same as Example 51.

[0393] Example 53:

[0394] The porosity of the transition layer is 10.3% μm.

[0395] The rest are the same as Example 52.

[0396] Example 54:

[0397] A transition layer is applied to the inner surface of the mild steel substrate using a thermal spray-plasma spray process.

[0398] The transition layer is made of a mixture of an iron-based alloy and an inorganic material in a ratio of 9.5:0.5. The porosity of the transition layer is 0.5% and the thickness is 200 μm.

[0399] The operating conditions of the plasma spray process include:

[0400] Main gas: argon, main gas flow rate is 1500L / H;

[0401] Plasma gas: hydrogen, plasma gas flow rate is 50L / H;

[0402] Current: 350A;

[0403] The particle size of pure iron powder is 400-500 mesh;

[0404] Powder feeding gas: argon, powder feeding gas flow rate is 12L / H;

[0405] Spraying distance: The spraying distance is 20cm.

[0406] Example 55:

[0407] The material of the transition layer is a mixture of iron-based alloy and inorganic material in a ratio of 9:1.

[0408] The operating conditions of the plasma spraying process are: argon gas, the main gas flow rate is 1200L / H.

[0409] The porosity of the transition layer is 1.0% and the thickness is 80 μm.

[0410] Other details are the same as Example 54.

[0411] Example 56:

[0412] The material of the transition layer is a mixture of iron-based alloy and inorganic material in a ratio of 8:2.

[0413] The operating conditions of the plasma spraying process are: argon gas, main gas flow rate is 650L / H; hydrogen gas, plasma gas flow rate is 40L / H; current is 180A; powder particle size is 200-320 mesh.

[0414] The porosity of the transition layer is 7.8% and the thickness is 360 μm.

[0415] Other details are the same as Example 54.

[0416] Example 57:

[0417] The material of the transition layer is a mixture of iron-based alloy and inorganic material in a ratio of 7.5:2.5.

[0418] The operating conditions of the plasma spraying process are: argon gas, main gas flow rate is 600 L / H; hydrogen gas, plasma gas flow rate is 30 L / H; current is 200 A; powder particle size is 200-320 mesh.

[0419] The porosity of the transition layer is 9.5% and the thickness is 430 μm.

[0420] Other details are the same as Example 54.

[0421] Example 58:

[0422] The operating conditions of the plasma spraying process are: argon gas, main gas flow rate is 1000 L / H; hydrogen gas, plasma gas flow rate is 45 L / H; current is 350A.

[0423] The porosity of the transition layer is 2.5% and the thickness is 190 μm.

[0424] Other details are the same as Example 54.

[0425] Example 59:

[0426] The operating conditions of the plasma spraying process are: argon gas, main gas flow rate is 950L / H; hydrogen gas, plasma gas flow rate is 35L / H; current is 200A.

[0427] The porosity of the transition layer is 4.3% and the thickness is 70 μm.

[0428] The rest is the same as Example 55.

[0429] Example 60:

[0430] The operating conditions of the plasma spraying process are: argon gas, the main gas flow rate is 800L / H.

[0431] The porosity of the transition layer is 6.0% and the thickness is 445 μm.

[0432] Other details are the same as Example 57.

[0433] Example 61:

[0434] The thickness of the transition layer is 165 μm.

[0435] The rest is the same as Example 60.

[0436] Example 62:

[0437] The material of the transition layer is a mixture of an iron-based alloy and an inorganic material in a ratio of 7:3.

[0438] The rest is the same as Example 61.

[0439] Example 63:

[0440] The porosity of the transition layer is 8.6% and the thickness is 260 μm.

[0441] The rest is the same as Example 62.

[0442] Example 64:

[0443] The porosity of the transition layer is 10.3% μm.

[0444] The rest is the same as Example 63.

[0445] Comparative Example 1

[0446] In this comparative example, the rust prevention treatment of the inner surface of a low-carbon steel base pot body is performed. Except for not providing a transition layer, the rust prevention treatment and post-treatment operation methods and conditions of this comparative example 1 are the same as those of the above-mentioned Examples 1-64.

[0447] Comparative Example 2

[0448] In this comparative example, the surface of the cast iron base pot is subjected to rust prevention treatment. Except for not providing a transition layer, the rust prevention treatment and post-treatment operation methods and conditions of this comparative example 2 are the same as those of the above-mentioned examples 1-64.

[0449] Performance Testing

[0450] The parameters and properties of the stainless cookware prepared in each embodiment and comparative example were tested according to the following method. The test results are shown in Table 1.

[0451] 1. Porosity: Porosity is tested by SEM imaging method.

[0452] 2. Salt spray resistance test: Refer to GB / T 10125 neutral salt spray test method and QB / T3822 simple 10-level method for judgment, and record the endpoint time.

[0453] 3. Salt water resistance test: Add 1 / 3 of the volume of 5% NaCl solution prepared with distilled water into the pot, add asbestos mesh on the gas stove and heat it until it boils and keeps boiling slightly. During the heating process, continuously add distilled water to maintain the original solution solubility, and record the time until rust occurs.

[0454] Table 1 Performance test results of various embodiments and comparative examples

[0455]

[0456]

[0457]

[0458]

[0459] As can be seen above, the cooking utensils provided by the embodiments of the present invention, compared to the cooking utensils of the comparative examples, have, overall, better corrosion resistance and superior pitting and rust resistance. Furthermore, looking at the embodiments of the present application as a whole, porosity has the greatest impact on pitting and rust resistance. Only when the porosity of the iron-based transition layer is controlled below 10% can the resulting cooking utensils exhibit superior pitting and rust resistance. Furthermore, under the same porosity conditions, a thicker transition layer increases corrosion resistance, while the material composition of the transition layer has little influence.

[0460] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

[0461] Note: A portion of this patent application contains material which is subject to copyright protection. The copyright owner reserves all rights reserved except for copies of the materials in the patent file or patent record in the Patent Office.

Claims

1. A cooking appliance comprising: substrate; forming a transition layer on the inner surface of the substrate; as well as, An anti-rust treatment layer is formed on the surface of the transition layer; It is characterized by: Among them, the transition layer is an imitation cast iron layer, the material of the imitation cast iron layer includes pure iron or iron-based alloy or a mixture of pure iron and iron-based alloy in any proportion, the porosity of the imitation cast iron layer is 0.1-10%, and the material of the imitation cast iron layer is powder or wire.

2. The cooking appliance according to claim 1, wherein The material of the imitation cast iron layer is powder with a particle size of 30 to 1000 meshes, or wire with a diameter of 0.5 to 5 mm.

3. The cooking appliance according to claim 1, wherein The material of the imitation cast iron layer includes a first component and a second component, wherein the first component includes pure iron or an iron-based alloy or a mixture of pure iron and an iron-based alloy in any proportion, and the second component includes a carbon material, a silicon material, a silicate or a mixture of any two or three of carbon materials, silicon materials and silicates in any proportion.

4. The cooking appliance according to claim 3, wherein: The weight content of the first component in the imitation cast iron layer is greater than or equal to 70% and less than 100%.

5. The cooking appliance according to claim 3, wherein: The first component is in the form of powder with a particle size of 30 to 1000 meshes or a wire with a diameter of 0.5 to 5 mm; the second component is in the form of powder with a particle size of 30 to 1000 meshes.

6. The cooking appliance according to claim 1, wherein The material of the imitation cast iron layer is cast iron.

7. The cooking appliance according to claim 6, characterized in that The cast iron is in the form of powder with a particle size of 30 to 1000 meshes, or in the form of wire with a diameter of 0.5 to 5 mm.

8. The cooking utensil according to any one of claims 1 to 7, characterized in that: The thickness of the imitation cast iron layer is 10 to 500 μm.

9. The cooking appliance according to any one of claims 1 to 7, characterized in that: The thickness of the anti-rust treatment layer is 0.5 to 50 μm.

10. A method for preparing a cooking utensil, characterized in that: The following steps are involved: providing a substrate; forming a transition layer on the inner surface of the substrate by one or more methods selected from the group consisting of thermal spraying, cold spraying, and solid-phase sintering; forming an anti-rust treatment layer on the surface of the transition layer; The transition layer is an imitation cast iron layer, the material of the imitation cast iron layer includes pure iron or iron-based alloy or a mixture of pure iron and iron-based alloy in any proportion, and the porosity of the imitation cast iron layer is 0.1-10%.

11. The method for preparing a cooking utensil according to claim 10, wherein: forming the imitation cast iron layer on the inner surface of the substrate by a plasma spraying method among thermal spraying methods; The operating conditions of the plasma spraying meet at least one of the following: Current is 100~500A; The main gas flow rate is 100~5000L / H; The plasma gas flow rate is 10-200L / H.

12. The method for preparing a cooking utensil according to claim 11, characterized in that: The particle size of the material of the imitation cast iron layer is 30 to 1000 meshes.

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