A cold-sprayed cookware with bottom oil-collecting function and its preparation method
By forming an annular protrusion and arc-shaped structure at the bottom of the cookware, and combining cold spraying and arc spraying technologies, the problem of cracking caused by poor oil flow and material expansion coefficient differences at high temperatures is solved, achieving oil-gathering function and long-term high-efficiency electromagnetic heating effect.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- NINGBO GOLDEN ELEPHANT KITCHENWARE CO LTD
- Filing Date
- 2024-01-25
- Publication Date
- 2026-06-30
AI Technical Summary
Existing cookware has poor oil flow at the bottom during high-temperature heating, resulting in poor cooking results. Furthermore, due to differences in the coefficients of thermal expansion of the materials, defects such as cracking may occur after long-term use.
Cold spraying technology is used to form an annular protrusion and arc-shaped structure on the bottom of the cookware. Through internal spraying, external spraying and polishing, combined with magnetic powder and metal aluminum coating, a stable coating structure is formed to improve oil retention and magnetic conductivity.
It achieves effective oil retention in cookware under high-temperature conditions, extending its service life and improving cooking results, while avoiding cracking problems caused by differences in the coefficients of material expansion.
Smart Images
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Abstract
Description
Technical Field
[0001] This invention relates to the technical field of cookware, and more particularly to a cold-sprayed cookware with bottom oil-collecting function and its preparation method. Background Technology
[0002] Most household induction cookers, microwave ovens, and ceramic cooktops use flat control panels, and the bottoms of the cookware used are designed to bulge slightly inwards to prevent the cookware from being uneven or spinning on the cooktop. Additionally, a magnetic plate is usually located on the bottom of the cookware. This magnetic plate, responding to the high-frequency magnetic field of the induction cooker, transfers energy to the cookware, thus heating it.
[0003] Traditional magnetic sheets are integrally laminated to the bottom of an aluminum substrate. Due to the difference in thermal expansion coefficients between the magnetic sheet and the aluminum substrate, the bottom of the pot will bulge inward to varying degrees during heating. The bulge increases with temperature, causing cooking oil poured into the pot to flow to the edges of the bottom, resulting in a lack of oil in the center and affecting the cooking effect. In addition, the difference in expansion coefficients between the two materials makes it easy for defects such as localized cracking to occur between the film layers after long-term use.
[0004] Therefore, there is an urgent need to develop a cookware with a bottom oil-collecting function that can meet the requirements of long-term use. Summary of the Invention
[0005] In view of the shortcomings of the prior art, the present invention provides a method for preparing cold-sprayed cookware with bottom oil-gathering function, so as to solve the problem that the existing cookware preparation methods cannot produce cookware that has both bottom oil-gathering function and can be subjected to long-term and efficient electromagnetic heating and heat conduction under high temperature conditions.
[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:
[0007] A method for preparing a cold-sprayed cookware with bottom oil-collecting function, the method comprising the following steps:
[0008] S1 Pot body forming operation: A large-tonnage press is used to form aluminum alloy sheet into pot blank shape. The outer periphery of the bottom of the pot blank has an outward protrusion of an annular boss. The bottom center area of the pot blank is formed with an outward protrusion of an arc surface.
[0009] S2 Pretreatment operation: The pot blank obtained in step S1 is degreased and internally sandblasted to make the surface roughness of the pot blank reach Ra2.8~Ra4.5.
[0010] S3 Internal spraying operation: An internal spraying device is used to spray the non-stick coating onto the inner surface of the pot blank obtained in step S2 to obtain a non-stick coating. The internal spraying device and the non-stick coating are conventional technical means in this application, and will not be described in detail here. As an example, the non-stick coating of this application can be polytetrafluoroethylene coating. As an example, any prior art about non-stick coating materials disclosed in the following patent documents can also be cited, such as CN202110239015.3, CN201910589192.7, CN202110239029.5, CN202210256925.7.
[0011] S4 Outer Bottom Spraying Operation: First, a cold gas spraying device is used to cold spray magnetic powder onto the outer bottom of the pot blank obtained in step S3 to obtain a magnetic coating; then, an electric arc spraying device is used to arc spray metallic aluminum onto the magnetic coating to obtain a rust-proof coating.
[0012] S5 External polishing operation: Polish the outer wall of the pot blank obtained in step S4 on a polishing machine to remove defects such as scratches and indentations on the outer wall surface of the pot blank;
[0013] S6 External spraying operation: Using external spraying equipment, a high-temperature resistant protective outer layer is sprayed onto the overall outer surface of the pot blank obtained in step S5, and finally the cold-sprayed pot with bottom oil-gathering function is obtained.
[0014] As a preferred technical solution, the height H difference between the center point of the outermost surface of the arc surface and the outer peripheral edge of the annular boss is 1.0 to 1.5 mm.
[0015] As a preferred technical solution, the degreasing operation first uses sodium hydroxide solution to remove grease and oxides from the surface of the pot blank, then rinses it clean with water; then neutralizes it with dilute nitric acid at room temperature, and finally rinses it clean with water and blows it dry to obtain a clean pot blank.
[0016] As a preferred technical solution, the internal sandblasting operation uses a sandblasting machine to uniformly spray 60-mesh or 80-mesh brown corundum abrasive at an air pressure of 0.6-0.7 MPa onto the inner surface of the pot blank, so as to meet the roughness required when spraying the internal coating.
[0017] As a preferred technical solution, in step S4, the cold spraying operation specifically includes the following steps: On a cold gas spraying device, an inert compressed gas at a temperature of 800–900°C is used as the accelerating medium to accelerate the magnetically conductive metal particles (magnetic powder or 430 magnetic powder) to a critical velocity. This causes the metal particles to collide with the outer bottom surface of the pot blank at a supersonic speed of 800–1000 m / s in a solid state, causing the particles to undergo intense plastic deformation and deposit to form a magnetically conductive coating. The thickness of the magnetically conductive coating is controlled between 150 and 200 μm. Throughout the cold spraying process, the metal particles are not melted due to the low temperature. The accelerating medium uses an inert gas (nitrogen, temperature 800–900°C), ensuring that the metal particles do not melt or oxidize, thus preserving the original physical and chemical properties of the material. In this invention, the cold spraying process involves the deposition of magnetic powder or 430 magnetic powder (with a particle size of 15-45 μm) onto the outer bottom of the pot blank at extremely high speed. The particles are stacked together, unlike traditional cold-coated and hot-coated bottom sheets which are a single unit. The deformation during heating is minimal. Furthermore, because the magnetic metal particles are uniformly deposited on the outer bottom of the pot blank without the perforations that separate them like in traditional cold-coated bottom sheets, the magnetic power is close to that of hot-coated bottom products and far greater than that of traditional cold-coated bottom products when used on induction cookers and other stoves.
[0018] As a preferred technical solution, in step S4, the arc spraying operation specifically includes the following steps: using an arc generated between two continuously fed aluminum wires as a heat source, the aluminum wires are melted by an arc spraying device; compressed air at 0.6–0.7 MPa is used to atomize the molten aluminum wire, and the atomized aluminum droplets are accelerated to a speed of 120–180 m / s, spraying them onto the outer bottom of the pot blank to form an aluminum anti-rust coating. The thickness of the anti-rust coating is controlled between 5 and 10 μm. Since magnetic powder or 430 magnetic powder is prone to rusting when in contact with air, water, or salt, this application avoids the problem of rusting of magnetic powder or 430 magnetic powder by arc spraying an aluminum anti-rust coating after the magnetic powder coating is applied to the outer bottom of the pot blank with cold gas.
[0019] As a preferred technical solution, before the cold spraying operation in step S4, the outer bottom surface of the pot blank is first subjected to ion beam treatment (operating at 2500V). The gas used in the ion beam treatment is a mixture of 15 sccm argon and 5 sccm sulfur dioxide, forming a sulfur interface material layer no more than 5 atomic layers thick on the outer bottom surface of the pot blank. This application uses a high-energy ion beam to break and recombine chemical bonds, allowing sulfur atoms to combine with the aluminum atoms of the pot blank substrate. After the nucleation reaction, stable chemical bonds are formed and adhere to the surface of the pot blank. Furthermore, in the subsequent cold spraying operation, the magnetic powder metal particles react with the sulfur interface material layer no more than 5 atomic layers thick under the action of an inert compressed gas at 800-900℃, forming strongly chemically bonded iron sulfide. This improves the adhesion between the cold sprayed magnetic coating and the pot blank substrate, avoiding defects such as cracks or fine lines that may occur after long-term use due to the difference in expansion coefficients between the functional coating material and the aluminum alloy pot blank. This further extends the service life of the cold sprayed cookware of this application and improves its cooking effect.
[0020] As a preferred technical solution, after the cold spraying operation in step S4, the surface of the magnetic coating is then subjected to ion beam treatment (operating at 2500V). The gas used in the ion beam treatment is a mixture of 20 sccm argon and 10 sccm sulfur dioxide, forming a sulfur interface material layer 5-10 atomic layers thick on the surface of the magnetic coating of the pot blank. Similarly, this application uses a high-energy ion beam to break and recombine chemical bonds, allowing sulfur atoms to react with iron atoms in the magnetic powder metal particles to form stable chemical bonds that adhere to the surface of the magnetic coating. Furthermore, during the subsequent arc spraying operation, the atomized high-temperature aluminum droplets react with the 5-10 atomic layer thick sulfur interface material layer on the magnetic coating to form strongly chemically bonded aluminum sulfide. This improves the bonding force between the aluminum-protected anti-rust coating and the magnetic coating, avoiding defects such as cracks or fine lines that may occur after long-term use due to differences in the coefficients of thermal expansion between different material functional coatings. This further extends the service life of the cold-sprayed cookware of this application and improves its cooking effect.
[0021] As a preferred technical solution, in step S6, the protective outer layer can be selected from at least one of high-temperature paint, ceramic coating, or non-stick coating. For example, any of the prior art concerning coating materials disclosed in the following patent documents can be cited, such as CN201910589481.7, CN201910589193.1, CN202110239015.3, CN201910589192.7, CN202110239029.5, and CN202210256925.7.
[0022] Another aspect of the present invention is to provide a cold-sprayed cookware with bottom oil-gathering function, wherein the cookware is prepared by the cold-sprayed cookware preparation method with bottom oil-gathering function described above.
[0023] Compared with the prior art, the beneficial effects of the present invention are as follows:
[0024] This application presents a method for preparing cold-sprayed cookware with bottom oil-gathering function. The method involves shaping the pot blank into annular protrusions and an arc surface, followed by pretreatment and internal spraying to ensure excellent oil-gathering function at the bottom of the pot, thereby improving the cooking effect. Furthermore, by combining cold spraying and arc spraying operations with interface materials of different atomic layers, a cookware capable of long-term, efficient electromagnetic heating and heat conduction under high-temperature conditions is obtained, further ensuring the long service life and excellent cooking effect of the cookware. Attached Figure Description
[0025] Figure 1 This is a schematic diagram of the structure of the cold spraying cookware with bottom oil collection function of the present invention.
[0026] Figure 2 for Figure 1 A magnified view of a portion of point A in the middle.
[0027] Figure 3 for Figure 2 A magnified view of a section at point B in the middle.
[0028] Among them, 1 is the pot blank, 11 is the annular boss, 12 is the arc surface, 101 is the non-stick coating, 102 is the magnetic coating, 103 is the anti-rust coating, and 104 is the protective outer layer. Detailed Implementation
[0029] The following description is intended to disclose the invention and enable those skilled in the art to implement it. The preferred embodiments described below are merely examples, and other obvious variations will occur to those skilled in the art.
[0030] Example
[0031] like Figures 1 to 3 As shown, the method for preparing a cold-sprayed cookware with bottom oil-gathering function in this embodiment includes the following steps:
[0032] S1 Pot body forming operation: A large-tonnage press is used to form aluminum alloy sheet into the shape of pot blank 1. The outer peripheral edge of the bottom of the pot blank 1 has an outward protrusion of an annular boss 11. The bottom center area of the pot blank 1 is formed with an outward protrusion of an arc surface 12. The height H difference between the center point of the outermost surface of the arc surface 12 and the outer peripheral edge of the annular boss 11 is 1.0 to 1.5 mm.
[0033] S2 Pretreatment Operation: The pot blank 1 obtained in step S1 is subjected to degreasing and internal sandblasting operations. The degreasing operation first uses sodium hydroxide solution to remove grease and oxides from the surface of the pot blank 1, and then rinses it clean with water; then it is neutralized with dilute nitric acid at room temperature, and finally rinsed clean with water and dried to obtain a clean pot blank 1; the internal sandblasting operation uses a sandblasting machine to uniformly spray 60-mesh brown corundum abrasive at a pressure of 0.6 MPa onto the inner surface of the pot blank 1, so that the roughness of the inner surface of the pot blank 1 reaches Ra3.6±4, so as to meet the roughness required for internal coating.
[0034] S3 Internal spraying operation: Using an internal spraying device, non-stick coating is sprayed onto the inner surface of the pot blank 1 obtained in step S2 to obtain a non-stick coating 101; the non-stick coating is polytetrafluoroethylene coating with a thickness of 200um±5um.
[0035] S4 Outer Bottom Spraying Operation: First, a cold gas spraying device is used to cold spray magnetic powder onto the outer bottom of the pot blank 1 obtained in step S3 to obtain a magnetic coating 102; then, an arc spraying device is used to arc spray aluminum metal onto the magnetic coating 102 to obtain a rust-proof coating 103; the cold spraying operation specifically includes the following steps: on the cold gas spraying device, nitrogen inert compressed gas at a temperature of 850℃ is used as the accelerating medium to accelerate the magnetic powder metal particles (magnetic powder with an average particle size of 25um) to a critical speed, causing the metal particles to collide with the outer bottom surface of the pot blank 1 at a supersonic speed of 920m / s in the solid state, causing the particles to undergo strong plastic deformation and deposit to form the magnetic coating 102, and the film thickness of the magnetic coating 102 is controlled at 180um±5um. The arc spraying operation specifically includes the following steps: using an arc generated between two continuously fed aluminum wires (diameter ∮2mm) as a heat source, the aluminum wires are melted (flame temperature around 3000℃) through an arc spraying device. The molten aluminum wire is atomized with 0.7MPa compressed air, and the atomized aluminum droplets are accelerated and sprayed onto the outer bottom of the pot blank 1 at a speed of 160m / s to form an aluminum anti-rust coating 103. The film thickness of the anti-rust coating 103 is controlled at 10um±1um.
[0036] Before the cold spraying operation in step S4, the outer bottom surface of the pot blank 1 is first subjected to ion beam treatment (operated at 2500V). The gas used in the ion beam treatment is a mixture of 15 sccm argon and 5 sccm sulfur dioxide, forming a sulfur interface material layer (not shown) with a thickness of 2 atomic layers on the outer bottom surface of the pot blank 1. After the cold spraying operation in step S4, the surface of the magnetic coating 102 is then subjected to ion beam treatment (operated at 2500V). The gas used in the ion beam treatment is a mixture of 20 sccm argon and 10 sccm sulfur dioxide, forming a sulfur interface material layer (not shown) with a thickness of 8 atomic layers on the surface of the magnetic coating 102 of the pot blank 1.
[0037] S5 External polishing operation: Polish the outer wall of the pot blank 1 obtained in step S4 on a polishing machine to remove scratches, indentations and other defects on the outer wall surface of the pot blank 1.
[0038] S6 External Spraying Operation: Using external spraying equipment, a high-temperature resistant protective outer layer 104 is sprayed onto the overall outer surface of the pot blank 1 obtained in step S5, ultimately obtaining the cold-sprayed pot with bottom oil-collecting function, referred to as the oil-collecting pot. The protective outer layer 104 is prepared with reference to the prior art CN201910589481.7.
[0039] According to the above cookware preparation method, three different specifications of poly-oil pan samples of Examples 1 to 3 were prepared; then, under the same specifications and the same coating material, they were compared with traditional hot-coated flat-bottomed pans and traditional cold-coated flat-bottomed pans. The test results are shown in Table 1.
[0040] Table 1. Comparison data of tests between oil-concentrated woks and traditional multi-layered woks.
[0041]
[0042] Note: Repeating the above test process 10 times in the laboratory yielded similar test data and results.
[0043] Therefore, it is evident that this invention patent has significant advantages over currently used technologies. The basic principles, main features, and advantages of this invention have been shown and described above. Those skilled in the art should understand that this invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely principles of the invention. Various changes and modifications can be made to this invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.
Claims
1. A method for preparing a cold-sprayed cookware with bottom oil-collecting function, characterized in that, The preparation method includes the following steps: S1 Pot body forming operation: A large-tonnage press is used to form aluminum alloy sheet into pot blank shape. The outer periphery of the bottom of the pot blank has an outward protrusion of an annular boss. The bottom center area of the pot blank is formed with an outward protrusion of an arc surface. S2 Pretreatment operation: The pot blank obtained in step S1 is degreased and internally sandblasted to make the surface roughness of the pot blank reach Ra2.8~Ra4.
5. S3 Internal spraying operation: Using internal spraying equipment, non-stick coating is sprayed onto the inner surface of the pot blank obtained in step S2 to obtain a non-stick coating. S4 Outer Bottom Spraying Operation: First, a cold gas spraying device is used to cold spray magnetic powder onto the outer bottom of the pot blank obtained in step S3 to obtain a magnetic coating; then, an electric arc spraying device is used to arc spray metallic aluminum onto the magnetic coating to obtain a rust-proof coating. S5 External polishing operation: Polish the outer wall of the pot blank obtained in step S4 on a polishing machine. S6 External spraying operation: Using external spraying equipment, a high-temperature resistant protective outer layer is sprayed onto the overall outer surface of the pot blank obtained in step S5, and finally the cold sprayed pot with bottom oil collection function is obtained. Before performing the cold spraying operation in step S4, the outer bottom surface of the pot blank is first subjected to ion beam treatment. The gas used in the ion beam treatment is a mixture of 15 sccm argon and 5 sccm sulfur dioxide, forming a sulfur interface material layer with a thickness of no more than 5 atomic layers on the outer bottom surface of the pot blank. After the cold spraying operation in step S4, the surface of the magnetic coating is then subjected to ion beam treatment. The gas used in the ion beam treatment is a mixture of 20 sccm argon and 10 sccm sulfur dioxide, forming a sulfur interface material layer with a thickness of 5 to 10 atomic layers on the surface of the magnetic coating of the pot blank.
2. The method for preparing a cold-sprayed cookware with bottom oil-collecting function as described in claim 1, characterized in that, The height H between the center point of the outermost surface of the arc surface and the outer edge of the annular boss is 1.0 to 1.5 mm.
3. The method for preparing a cold-sprayed cookware with bottom oil-collecting function as described in claim 1, characterized in that, The degreasing process first uses sodium hydroxide solution to remove grease and oxides from the surface of the pot blank, then rinses it clean with water; then neutralizes it with dilute nitric acid at room temperature, and finally rinses it clean with water and blows it dry to obtain a clean pot blank.
4. The method for preparing a cold-sprayed cookware with bottom oil-collecting function as described in claim 1, characterized in that, The internal sandblasting operation uses a sandblasting machine to uniformly spray 60-mesh or 80-mesh brown corundum abrasive at an air pressure of 0.6-0.7 MPa onto the inner surface of the pot blank, so as to meet the roughness required when spraying the internal coating.
5. The method for preparing a cold-sprayed cookware with bottom oil-gathering function as described in claim 1, characterized in that, In step S4, the cold spraying operation specifically includes the following steps: on a cold gas spraying device, an inert compressed gas with a temperature of 800-900℃ is used as an acceleration medium to accelerate the magnetic powder metal particles to a critical speed, causing the metal particles to collide with the outer bottom surface of the pot blank at a supersonic speed of 800-1000m / s in the solid state, so that the particles undergo strong plastic deformation and deposition to form a magnetic coating.
6. The method for preparing a cold-sprayed cookware with bottom oil-collecting function as described in claim 1, characterized in that, In step S4, the arc spraying operation specifically includes the following steps: using an arc generated between two continuously fed aluminum wires as a heat source to melt the aluminum wires through an arc spraying device, atomizing the molten aluminum wires with compressed air at 0.6 to 0.7 MPa, and accelerating the atomized aluminum droplets to spray them onto the outer bottom of the pot blank at a speed of 120 to 180 m / s to form an aluminum anti-rust coating.
7. The method for preparing a cold-sprayed cookware with bottom oil-gathering function as described in claim 1, characterized in that, In step S6, the protective outer layer may be selected from at least one of high-temperature paint, ceramic coating or non-stick coating.
8. A cold-sprayed cookware with bottom oil-collecting function, characterized in that, The cookware is prepared using the cold spray cookware preparation method with bottom oil-gathering function as described in any one of claims 1 to 7.