Non-stick pan without coating and preparation method

Abstract

The invention discloses a non-stick pan without a coating. Micro-nano concave-convex structures are uniformly distributed on the surface of a pan body; the micro-nano concave-convex structure comprises micro-nano bulges or micro-nano recesses, the micro-nano bulges are particle films formed by particles, the thickness of the particle films is 0.1-0.98 [mu] m, and the particle size of the formed particle films is 0.02-0.3 [mu] m; the diameter of the size of the micro-nano recesses comprises densely distributed recesses of 0.1-0.98 [mu] m. Micro-nano concave-convex structures with multi-stage diameter sizes are arranged; the diameters of the sizes of the micro-nano recesses also include 40 + / -20 microns and 5 + / -2 microns; the micro-nano recess is processed by adopting a pressing and corrosion method; and the depth of the micro-nano recess is 20 to 1500 nm.

Description

Technical Field

[0001] The invention relates to the preparation of a cooking utensil, namely a pot, and in particular to a method for preparing a non-coating non-stick pot. Background Art

[0002] The prior art non-stick pans have a honeycomb mesh structure on the surface, and the honeycomb holes are relatively large, with a hole size of more than 3 mm. The bottom surface of the honeycomb holes is also coated, and the coating area is generally relatively large, reaching about 80-90% of the surface area of ​​the substrate. Therefore, the contact area between the coating and the food is also large, resulting in a larger friction surface with the food, which also limits the use of the spatula.

[0003] The prior art also has cookware with nano-scale pores. The nano-scale pores will absorb air and grease during actual use, and will generate hot air and oil mist during the heating process, while holding up the food. Combined with the fluff effect achieved by the aforementioned nipple structure, the friction between the food and the inner surface of the pot body is reduced. Without adding chemical coatings, the non-stick effect is achieved by physical means, making it healthier for consumers to cook food. If the plate forming the pot body is titanium metal, a titanium dioxide hardening layer with a Vickers hardness of not less than HV600 will be generated on its surface after micro-arc oxidation; if the plate forming the pot body is an aluminum alloy, a aluminum oxide hardening layer with a Vickers hardness of not less than HV1000 will be generated on its surface after micro-arc oxidation. The plate is an aluminum plate, a titanium plate or a magnesium plate; the surface of the plate with shallow pits etched or punched is aluminum, magnesium or titanium. However, this material has no advantages in application.

[0004] The applicant has applied for a non-stick pan, including a non-coated pan body, including a pan body (thickness of more than 1mmc), and a metal (thickness of more than 1mmc) pan body and food contact surface is provided with uniformly distributed concave holes; the concave hole diameter is 0.1-0.5mm, especially 0.3-0.5mm, the hole edge spacing is 0.3-2mm, the hole depth is 0.1-0.3mm, especially 0.1-0.15mm, the hole area accounts for 15-40% of the entire pan body area, the concave hole is circular or polygonal; the concave hole is gradually concave from a plane. The metal is iron, stainless steel, etc.

[0005] The inner wall of the existing pot body is provided with an anti-stick structure, which is a periodically distributed protrusion or / and concave portion on the inner wall, and the size of the protrusion and concave portion is between a few microns and tens of microns, but the size is too small. The above existing technologies cannot well achieve the functions of non-toxicity and non-stick. If a physical non-stick layer is provided on the surface of the pot body, it is not enough to achieve long-term non-stick, because each time the spatula is operated, it needs to rub against the pot surface repeatedly, and the long-term friction will wear the physical non-stick layer, and thus the long-term non-stick effect cannot be achieved. This problem also needs to be solved urgently.

[0006] CN2024101740492 A coating-free non-stick pan and a preparation method are the prior art of the applicant. The pan body has a concave hole structure and adopts a plasma carburizing process. The carburizing temperature of stainless steel, titanium or iron usually needs to be 350-900°C. Argon and carbon source gas, argon and methane gas are introduced in a volume ratio of 50-95%:50-5%; the processing time is more than 2-10h.

[0007] However, the non-stick property of the pot body requires not only macroscopic concave holes (aperture of 1 mm or larger), but also nanoscale micro-nano holes. How to process micro-nano holes is a problem that is not clearly stated in the existing technology.

[0008] CN2018218068341 discloses a pot and a cooking utensil, comprising: a pot body; a quasi-crystal coating, wherein the quasi-crystal coating is arranged on the inner surface of the pot body, wherein the quasi-crystal coating is prepared by magnetron sputtering or multi-arc ion plating, and further, the quasi-crystal coating is prepared by bias magnetron sputtering or bias multi-arc ion plating. Thus, the quasi-crystal coating has high density, and has good thermal conductivity while meeting the non-stick performance; as the inner surface coating of the pot, heat can be transferred to the conditioned object (food in contact with the pot), so that the pot has good non-stick properties, hardness and corrosion resistance, and the surface of the quasi-crystal coating is relatively smooth, which can further improve the non-stick properties of the pot and is also easy to clean. In addition, the quasi-crystal coating is relatively dense and can be strongly attached to the surface of the pot body.

[0009] Magnetron sputtering coating refers to filling a vacuum chamber with argon gas and applying a negative bias voltage to the magnetron sputtering target. Argon ions bombard the target surface under the action of the electric field. The sputtered film material atoms are partially ionized during the migration to the workpiece, and are accelerated under the negative bias voltage of the substrate, and finally deposited on the workpiece to form a film. Cathodic arc ion plating and multi-arc ion plating are also common surface treatment technologies. They use the high-temperature and high-energy ion beam generated by arc discharge to deposit metal ions on the surface of the workpiece, thereby changing the physical and chemical properties of the workpiece. Multi-arc ion plating, also known as the multi-arc method, is based on the theory of cold cathode discharge. Under vacuum conditions, gas discharge is used to evaporate and ionize the target material to form a plasma, and finally a film is deposited on the substrate surface.

[0010] The formation of a dense metal coating is not advocated by the present invention, but multi-arc ion plating can also produce a granular film coating, the surface of the coating is tiny particles, called "droplets", which currently require subsequent treatment. The present invention uses this granular film to form a direct pot surface layer. Summary of the invention

[0011] In order to solve the above problems, the object of the present invention is to provide a non-stick pan without coating and a preparation method thereof, in particular, a pressed non-stick pan prepared at low cost.

[0012] In order to achieve the above-mentioned purpose, the technical solution of the present invention is a coating-free non-stick pan, characterized in that a micro-nano concave-convex structure is evenly distributed on the surface of the pan body; the micro-nano concave-convex structure includes micro-nano protrusions or micro-nano depressions, the micro-nano protrusions are particle films formed by particles, the thickness of the particle film is 0.1-0.98μm, and the size of the particles forming the particle film is 0.02-0.3μm; the diameter of the size of the micro-nano depressions includes densely distributed 0.1-0.98μm depressions.

[0013] A micro-nano concave-convex structure with multiple (multiple) diameter sizes is provided; the diameter of the micro-nano concave size also includes 40±20μm and 5±2μm; the micro-nano concave is processed by pressing, corrosion and other methods; the depth of the micro-nano concave is 20-1500nm.

[0014] When the micro-nano protrusions are coated with a particle film, the diameter of the micro-nano particles forming the micro-nano particle film is particularly 20-300 nm.

[0015] The distribution of the pore size of the micro-nano depressions is the following three types: 40±20μm, 5±2μm, 5±2μm, and 0.2±0.1μm (including at least 0.2±0.1μm particle size).

[0016] The pot body includes stainless steel, titanium or iron, and the contact surface between the pot body and food is provided with evenly distributed composite multi-size concave holes; the concave hole diameter is 0.1-0.8mm, especially 0.3-0.5mm, the hole edge spacing is 0.3-2mm, the hole depth is 0.05-0.3mm, the hole area accounts for 15-40% of the entire pot body area, the concave holes are circular or polygonal; the concave holes are gradually concave from a plane.

[0017] The surface of the pot body that contacts the food is provided with two or more concave holes of uniformly distributed apertures; the aperture of the first concave hole is 0.3-0.8mm, and the aperture of the second concave hole is 0.05-0.29mm; the spacing between the centers of the first concave holes is 0.6-8mm, and the spacing between the centers of the second concave holes is 0.1-0.9mm; the hole depth is 0.05-0.3mm;

[0018] The preparation method of the uncoated non-stick pan is that the micro-nano depressions are formed by mechanical rolling wheel pressing or plane pressing, the mechanical rolling wheel (mechanical rolling can also be a mechanical pressing plate), the mechanical rolling or pressing is combined with multi-sized hard fine particles (such as corundum): the hard fine particles have a particle size distribution of at least the following two particle sizes of hard particles (D50) 50±20μm, 5±2μm, 0.2±0.1μm (at least 0.2±0.1μm particle size) are made into a mixed slurry in proportion, the rolling wheel pressure is applied, the metal plate surface is rolled, and the metal plate is prepared into a pan body (blank plane) after the rolling is completed; the micro-hard fine particles are corundum, boron carbide, silicon carbide, silicon nitride, boron nitride, and various corundums.

[0019] A mechanical rolling or pressing method is adopted, especially a mechanical rolling wheel (mechanical rolling can also be a mechanical pressing plate), and mechanical rolling or pressing is combined with multi-size fine hard particles (such as corundum): particles with a particle size distribution of at least two particle sizes (D50) 50±20μm, 5±2μm, 0.2±0.1μm (at least 0.2±0.1μm particle size) are made into a mixed slurry in a certain proportion, and the rolling wheel pressure is adjusted appropriately to roll the surface of the metal plate, and the metal plate is prepared into a pot body after rolling;

[0020] Each mechanical rolling wheel is a narrow wheel (e.g., 10-30 cm) applied to the metal surface to be pressed, and each mechanical rolling wheel presses an indentation with a width of 10-30 cm; a plurality of mechanical rolling wheels arranged in sequence press the metal plate of the entire width;

[0021] The rolling can be done more than once (it is better to use fine sand in the latter step), that is, rolling or pressing can be done multiple times; the concave holes on the pot body are pressed separately.

[0022] It can form a multi-size composite distributed micro-nano concave-convex (depression) structure on the metal surface, that is, millimeter-level concave holes are superimposed on the micron-level concave-convex surface, the micron-level is distributed from 0.2μm to 0.1mm, and the nano-level is distributed from 10nm to 150nm.

[0023] Mechanical rolling or pressing with multi-sized hard fine particles (such as corundum): corundum, boron carbide, silicon carbide, silicon nitride, boron nitride, various corundum. Multi-sized hard fine particles (such as corundum) with particle paste or water (oil) as the carrier of the particle suspension. The volume ratio of hard fine particles can be 8%-30%.

[0024] The micro-nano protrusions adopt a structure of a particle film coating; the particle diameter size forming the particle film is preferably obtained by multi-arc ion plating.

[0025] When the micro-nano protrusions are coated with a particle film, the diameter of the micro-nano particles forming the micro-nano particle film is 20-300 nm. A smooth film structure without particles is not required by the present invention.

[0026] The processing and construction of multi-level micro-nanostructure depressions on the surface of the pan body with uniformly distributed micro-nano concave-convex structures → achieving the non-stick performance of the metal pan body without chemical organic coating or modification; the preparation of the non-coated non-stick pan of the present application is mainly to prepare the pan body through concave holes or particle film protrusions on the metal surface with uniform micro-nano structures. When preparing the concave holes of the non-coated pressed non-stick pan: the uniform round protrusions of the alloy mold (which can match the size of the pan body and the concave shape of the pan) are used to press the titanium plate-shaped pan body on the inner surface of the pan body. The non-coated pressed non-stick pan is formed by austenitic titanium or martensitic stainless steel or titanium plate to obtain a concave pan body, or iron pans can be pressed.

[0027] Even when stir-frying at high temperature or the pan is burned empty, the uncoated non-stick pan will not release any toxic substances or gases, will not contaminate the food being cooked or the kitchen environment, and will make cooking safer.

[0028] Beneficial effects: The micro-nano surface treated by the present invention has good hardness and toughness. The retained oil and liquid of the surface micro-nano structure evaporate when heated to lift the food to be heated. The concave-convex metal particles have good non-stickiness and good bonding strength with the pot surface by ion plating and other methods; the micro-nano structure can improve the slipperiness of the inner surface of the pot body, reduce the friction between the food and the inner surface of the pot body, and make the shovel (a shovel of a certain hardness can be used) smoother when frying dishes. The non-stick effect basically reaches the level of the new PTFE Teflon coating application; the manufacturing cost is low. Through the uniform spacing of one or two superimposed millimeter or micron-level concave holes, when frying general non-noodle food, the distribution of the concave holes makes it easier for the gas evaporated when the food is heated to expand, making the physical anti-sticking function better (better effect when the pot or shovel is moved), and the concave hole area accounts for 15% to 40% of the pot body area. These characteristics and advantages of the present invention will be disclosed in detail in the following specific embodiments and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The present invention will be further described below in conjunction with the accompanying drawings:

[0030] Figure 1 This is a schematic diagram of the distribution of concave holes in a pot body according to an embodiment of the present invention;

[0031] Figure 2 This is a microscope photo of the concave hole after preparation in the present invention, which is a schematic diagram of the composite multi-scale micro-nano processing. DETAILED DESCRIPTION

[0032] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals refer to the same objects throughout.

[0033] The micro-nano raised structure on the pot surface will adopt the structure of particle film, and the particles will be plated on the surface of the pot body. In particular, multi-arc ion plating is adopted: by passing a large current to the arc target, the arc is struck by the arc-starting needle, and an arc is generated on the target surface. The arc temperature is very high, melting the target material, and by applying bias voltage to the product, the melted target material is deposited on the product.

[0034] The thickness of the micro-nano particle film is 100-980nm, especially 150-700nm. The diameter of the micro-nano particles forming the micro-nano particle film is 20-300nm. The multi-arc ion plating method is better: by passing a large current to the arc target, the arc is struck by an arc needle, and an arc is generated on the target surface. The arc temperature is very high, melting the target material. By applying a bias voltage to the product, the melted target material is deposited on the product. In the embodiment, the target material is easy to produce particles with a diameter of about 100nm and form a film on the surface of the plated material; particles with a diameter of about 100nm are the main distribution, and large particles can reach more than 200nm, which is related to the target material, current size, temperature, atmosphere control, etc.

[0035] The metals of the micro-nano particle film plated by multi-arc ion plating are especially chromium, nickel, titanium, zirconium or their alloys or CrN and TiN, etc., which can be plated into a film layer by selecting the target material or adding a working atmosphere. Micro-nano particle film can also be produced under extreme conditions by magnetron plating or cathode plating. Magnetron sputtering: Argon gas is filled into the vacuum chamber, and a negative bias is applied to the magnetron sputtering target. Argon ions bombard the target surface under the action of the electric field. The sputtered film material atoms are partially ionized during the migration process to the workpiece, and are accelerated under the negative bias of the substrate, and finally deposited on the workpiece to form a film. Relatively extreme conditions are required to achieve the particle film coating of multi-arc ion plating.

[0036] Processing method of the concave distribution micro-nano concave-convex structure on the body of an uncoated non-stick pan: adopt a mechanical rolling or pressing method, especially a mechanical rolling wheel or a metal plate is coated with a hard particle paste: the distribution of particle size is at least two or three particle sizes (D50) 50±20μm, 5±2μm, 0.2±0.1μm (at least 0.2±0.1μm particle size) are made into a mixed slurry in a certain proportion, the mass of the two or three particle sizes is basically the same, or the mass of the small-sized particles can be 100-200% of the mass of the large-sized particles, adjust the appropriate rolling wheel pressure, roll the metal plate surface, and prepare after the metal plate is rolled The pot body is formed; each mechanical rolling wheel uses a narrow wheel (for example, 10-30cm) to be applied to the metal surface to be pressed, and each mechanical rolling wheel presses a 10-30cm wide indentation; the rollers are arranged in sequence: if the rollers are staggered or arranged in sequence, each roller can apply a relatively high pressure, which is provided to each pressing wheel shaft and applied to the pressing wheel through hydraulic pressure or other means. The width of several mechanical rolling wheels can cover the metal plate of the entire width, and the width of the metal plate is 1 meter to 2.4 meters; if each pressing wheel is 30cm wide, 8 can be used to continuously press a 2.4-meter wide plate. After the pressing is completed, the mixed slurry is collected (flattened) and then the metal plate is cleaned. The metal plate presses the pot body again. The layer on the pot body that contacts the food is iron, stainless steel, etc., and the back of the stainless steel can be composited with an aluminum layer.

[0037] Mechanical rolling or pressing with multi-size fine particles of hard particles (such as corundum, corundum, boron carbide, silicon carbide, silicon nitride, boron nitride, various corundum, cerium salts containing tetravalent cerium ions and oxidants): particle size distribution is at least two particle sizes (D50) 50±20μm, 5±2μm, 0.2±0.1μm (at least 0.2±0.1μm particle size) in a certain proportion to make a mixed slurry. In addition to hard particles, the mixed slurry also needs to add a variety of aminocarboxylic acids, PEG (or polyvinyl alcohol), and more than 40wt% of water to stir into a paste for use.

[0038] The rolling process may be more than one time, that is, multiple rolling or pressing. The micro-nano depressions may also be formed by etching, by screen printing photoresist, cleaning and etching with an etching solution to form the above-mentioned uniform micro-nano depressions.

[0039] The concave holes on the pot body can be pressed on the pot body. Static pressure processing is also possible, using a mixed slurry of particles with at least two particle sizes. The press pressure must be large, such as more than 6,000 tons, and the pressing area is a metal surface of about one square meter. This hard particle paste is used for direct static pressure pressing of metal flat-plate presses to form a concave distribution of micro-nano concave-convex structures, and the effect of roller pressing is better. High efficiency and low equipment cost. It can cause the metal surface to form a multi-size composite distribution of micro-nano concave-convex (concave) structure, that is, nano-concave-convex is superimposed on the micron-level concave-convex surface, the micron-level is distributed from 0.2μm to 0.1mm, and the nano-level is distributed from 10nm to 200nm.

[0040] Figure 1 The surface of the pot body has a millimeter-level concave hole 1; this embodiment relates to a non-coated pressed non-stick pot, and the evenly distributed concave holes with the same depth are better, and the distribution of the concave holes can also be denser at the bottom of the pot than at the edge of the pot; the pan body plane 1 is between two adjacent concave holes. The black spots are micro-nano concave-convex (depression or protrusion) structures.

[0041] The surface of the pot body in contact with the food may also be provided with one, two or more evenly distributed concave holes with millimeter-level apertures; the first concave hole 3 has an aperture of 0.3-0.8mm, and the concave hole aperture is especially 0.3-0.5mm. The second concave hole 2 has an aperture of 0.05-0.29mm; the spacing between the centers of the first concave holes is 0.6-8mm, and the spacing between the centers of the second concave holes is 0.1-0.9mm; the depth of the concave holes is 0.05-0.3mm. The hole area of ​​the two concave holes accounts for 15-40% of the area of ​​the entire pot body. The concave holes are circular or polygonal; the concave holes are gradually concave from a plane. The total area of ​​the concave holes accounts for 15% to 40% of the area of ​​the entire region: 15%, 20%, 35%, and 40% are all embodiments of the present invention. It can not only ensure the physical non-stick performance of the entire non-stick pan, but also ensure the service life of the pan.

[0042] The pot body may have a macroscopic concave hole structure, wherein the two types of concave holes are circular or polygonal; and the concave holes are gradually concave from a plane.

[0043] The layer on the pot body that contacts with food is made of iron, titanium, stainless steel, etc., such as a composite aluminum layer on the back of titanium or stainless steel.

[0044] The roughness of the metal surface affects its non-stick performance, and surface modification can be performed to improve its non-stick performance.

[0045] First, micro-nano processing is performed on the metal surface, and then, the metal surface is processed again to form a concave-convex composite multi-size micro-nano structure. After the two-step processing, the non-stick performance of the pot surface is improved, reaching the first-level standard according to the national standard for non-stick properties of cookware GB / T32095.2-2015.

[0046] The method for preparing the non-coated pressed non-stick pan of the present application is to prepare the millimeter-level concave holes by pressing the titanium plate-shaped pan body with a press through a uniform round convex head of an alloy mold (which can match the size of the pan body and the concave shape of the pan). The non-coated pressed non-stick pan is formed by austenitic titanium or martensitic titanium plate to obtain a concave pan body.

[0047] Even if you stir-fry at high temperature or the pan is empty, the uncoated pressed non-stick pan will not release any toxic substances or gases, will not contaminate the food being cooked or the kitchen environment, and will make cooking safer.

[0048] The surface micro-nano processing forms a composite multi-size micro-nano structure on the metal surface. On the basis of the above micro-nano processing on the metal surface, the concave holes are prepared.

[0049] The diameter of the concave holes is 200, 300, 400, or 500 microns, and the surface width between the concave holes is 100 to 400 microns. The concave holes are pressed or etched by a mold made of hard alloy by a pressure device, so that both the concave holes and the pot body are hardened layer structures; the spacing between the centers of the concave holes is 0.6 to 2 mm, and the spacing between the edges of adjacent concave holes is controlled to be 0.3 to 1.8 mm; the depth of the concave holes is especially 0.05 to 0.18 mm.

[0050] The concave hole is circular or polygonal, and a uniform polygonal convex head is prepared on the mold corresponding to the polygonal concave hole; the concave hole is gradually concave from a plane.

[0051] The pot body is in a concave pot shape, which is formed by pressing a flat plate with a hydraulic press. A pot handle can be welded to the pot body.

[0052] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention without departing from the principles and intent of the present invention.

Claims

1. A non-stick pan without coating, characterized in that: The surface of the pot body is evenly distributed with micro-nano concave-convex structures; the micro-nano concave-convex structures include micro-nano protrusions or micro-nano depressions, the micro-nano protrusions are particle films formed by particles, the thickness of the particle film is 0.1-0.98μm, and the size of the particles forming the particle film is 0.02-0.3μm; the diameter of the size of the micro-nano depressions includes densely distributed 0.1-0.98μm depressions.

2. The uncoated non-stick pan according to claim 1, characterized in that: A micro-nano concave-convex structure with multi-level diameter sizes is provided; the diameters of the micro-nano concave sizes also include 40±20μm and 5±2μm; the micro-nano concave is processed by pressing and etching methods; the depth of the micro-nano concave is 20-1500nm.

3. The uncoated non-stick pan according to claim 1, characterized in that: When the micro-nano protrusion structure is coated with a particle film, the diameter of the micro-nano particles forming the micro-nano particle film is 20-300nm.

4. The uncoated non-stick pan according to claim 1, characterized in that: The pore size distribution of the micro-nano recessed structure is the following three types: 40±20μm, 5±2μm, 5±2μm, and 0.2±0.1μm.

5. The non-stick pan without coating according to claim 1-4, characterized in that the pan The pot body comprises a stainless steel, titanium or iron pot body, and the contact surface between the pot body and the food is also provided with evenly distributed composite multi-size concave holes; the diameter of the concave holes is 0.1-0.8mm, especially 0.3-0.5mm, the hole edge spacing is 0.1-2mm, the hole depth is 0.01-0.3mm, the hole area accounts for 15-40% of the entire pot body area, and the concave holes are circular or polygonal; the concave holes are gradually concave from a plane.

6. The non-stick pan without coating according to claim 5, characterized in that: The surface of the pot body in contact with food is provided with two or more concave holes with evenly distributed apertures; the aperture of the first concave holes is 0.3-0.8mm, and the aperture of the second concave holes is 0.05-0.29mm; the spacing between the centers of the first concave holes is 0.6-8mm, and the spacing between the centers of the second concave holes is 0.1-0.9mm; the hole depth is 0.01-0.3mm.

7. The method for preparing the uncoated non-stick pan according to any one of claims 1 to 8, characterized in that: The micro-nano depressions are made by mechanical rolling wheel pressing or plane pressing, mechanical rolling wheel, mechanical rolling or pressing with multi-sized hard fine particles: the particle size distribution of the hard fine particles is at least the following two particle sizes of hard particles (D50) 50±20μm, 5±2μm, 0.2±0.1μm are made into a mixed slurry in proportion, and rolling wheel pressure is applied to roll the surface of the metal plate. After the metal plate is rolled, it is prepared into a pot body; the micro-hard fine particles are corundum, boron carbide, silicon carbide, silicon nitride, boron nitride, and various corundum.

8. The method for preparing the uncoated non-stick pan according to claim 7, characterized in that: The method of mechanical rolling or pressing is adopted, especially a mechanical rolling wheel, and the mechanical rolling or pressing is combined with multi-sized hard fine particles: the particle size distribution is at least two particle sizes (D50) of 50±20μm, 5±2μm, 0.2±0.1μm; at least 0.2±0.1μm particle size is contained; a mixed slurry is made according to a certain proportion, and the appropriate rolling wheel pressure is adjusted to roll the surface of the metal plate. After the metal plate is rolled, it is prepared into a pot body.

9. The method for preparing a non-stick pan without coating according to claim 7, characterized in that: Each mechanical rolling wheel is applied to the metal surface to be pressed with a narrow wheel, and each mechanical rolling wheel presses an indentation with a width of 10-30cm; several mechanical rolling wheels arranged in sequence press the metal plate with the entire width of the format.

10. The method for preparing a non-stick pan without coating according to claim 7, characterized in that: A multi-size composite distributed micro-nano concave-convex (depression) structure is formed on the metal surface. The micron-sized concave-convex surface is superimposed with nano-sized concave-convex. The micron-sized ones are distributed from 0.2μm to 0.1mm, and the nano-sized ones are distributed from 10nm to 200nm.

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