Cold spray cookware and cold spray treatment method thereof

Abstract

The present invention provides a cold spray treatment method for cold sprayed cookware, wherein a cold spray coating is provided in the brazing groove on the bottom surface of the bottom of the pot and on the bottom surface of the pot, and the cold spray coating is any one or more of Al-Cu-Mg aluminum alloy, iron-manganese alloy, constant elasticity alloy, amorphous soft magnetic alloy, and precision alloy, which are formed after cold spraying. The cold spray treatment method comprises the following steps: A. pre-treatment of the pot body, B. pre-treatment of cold spray powder, C. cold spraying, and D. after random inspection and testing, qualified products are shipped out of the factory. The present invention improves the structure of the cookware and cooperates with the improvement of the cold spraying process of the pot bottom to further optimize the performance of the cold spray coating of the pot bottom, enhance the mechanical interlocking between the deposited layer and the lower surface of the pot bottom, and improves the effective deposition rate through annealing treatment of the powder, thereby greatly improving the mechanical properties and corrosion resistance of the cold spray coating, and the Curie point temperature is 70-220 degrees Celsius, which has a constant temperature effect during use.

Description

Technical Field

[0001] The present invention relates to the technical field of cookware, in particular to a cold spray cookware and a cold spray processing method thereof. Background Art

[0002] There are many kinds of surface treatment for pots, such as compounding other metal alloys on the bottom of the pot by high pressure of hydraulic press, such as Figure 1 Figure 1 shows a schematic diagram of a conventional hydraulically laminated pot bottom. The bottom of the pot body 3 is hydraulically pressed together with an alloy metal layer 21 to provide magnetic conductivity. However, this structure presents the technical problem of the alloy metal layer 21 falling off during daily use. Other metal coatings are applied to the pot bottom using thermal spraying or cold spraying. Cold spraying offers significant advantages for pot bottom coatings. Cold spray coatings primarily rely on the kinetic energy of particle-substrate collisions. Cold spraying induces strong plastic deformation at the particle-substrate and particle-particle interfaces, forming metallurgical bonds and mechanical interlocking. These deposition characteristics of cold spray coatings effectively avoid the oxidation and phase change issues associated with high-temperature deposition during conventional thermal spraying. During cold spraying, effective deposition of raw material particles is only possible when the particle velocity exceeds the critical deposition velocity. When cold spraying a pot bottom, the raw material particles first deposit on the pot bottom, during which time the raw material particles and the substrate (i.e., the pot bottom) bond to form a deposited layer. Then comes the deposition of raw material particles on the surface of the deposition layer, which is the combination of each raw material particle on the deposition layer. There are corresponding critical deposition rates between raw material particles and the matrix, and between particles. In actual production, the structure of the pot bottom, the raw material of the particles and the process control will lead to problems with effective deposition between particles and the matrix, and between particles, resulting in unstable product quality, including unstable mechanical properties and corrosion resistance of the cold spray coating on the pot bottom. In view of this, it is necessary to provide a cold spray pot and its cold spray treatment method that improves the structure of the pot, and cooperates with the improvement of the cold spray process of the pot bottom to optimize the performance of the cold spray coating on the pot bottom. Summary of the Invention

[0003] In view of the shortcomings of the existing technology, the present invention provides a cold spray cookware and a cold spray treatment method thereof, which improves the structure of the cookware and cooperates with the improvement of the cold spray process of the bottom of the cookware to further optimize the performance of the cold spray coating of the bottom of the cookware.

[0004] To achieve the above objectives, the present invention is implemented through the following technical solutions: a cold spray cookware, including a pot body and a pot bottom, wherein a plurality of brazing grooves are opened on the bottom surface of the pot bottom, one of the brazing grooves is located at the center of the bottom surface of the pot bottom, and an alloy block is embedded in it. The alloy block pulls the pot bottom downward so that the upper surface of the pot bottom 1 is concave to form an oil collecting center, and cold spray coatings are provided in the remaining brazing grooves and on the bottom surface of the pot bottom.

[0005] Furthermore, a texture layer is pressed on the upper surface of the pot bottom, which is composed of several four-pointed stars in a row. The four-pointed stars are integrally formed with ridges and protrusions with a gradually gentle slope from the center to the four corners. The four four-pointed stars form an oil grid, and the connection between the heads and tails of two adjacent four-pointed stars forms an oil channel.

[0006] Furthermore, the cold spray coating is formed by cold spraying any one or more of Al-Cu-Mg aluminum alloy, iron-manganese alloy, constant elasticity alloy, amorphous soft magnetic alloy, and precision alloy.

[0007] Furthermore, the cross section of the brazing groove is open at the top and closed at the bottom. The cross section of the brazing groove is preferably an isosceles trapezoid.

[0008] Furthermore, the depth of the brazing groove is 0.2-0.8 mm.

[0009] In order to better achieve the purpose of the present invention, the present invention further discloses a cold spraying treatment method for cold spraying cookware, which comprises the following steps:

[0010] A. Pre-treatment of the pot body,

[0011] B. Pretreatment of cold spray powder,

[0012] C. Cold spraying,

[0013] D. After random inspection and testing, qualified products will be shipped out.

[0014] Furthermore, step A is specifically as follows: pre-treatment of the pot bottom by sandblasting, under inert gas protection conditions, to improve the surface roughness and enhance the mechanical interlocking between the deposited layer and the lower surface of the pot bottom, using glass beads or corundum powder for sandblasting at a sandblasting speed of 40-45 g / min, so that the roughness Ra of the lower surface of the pot bottom and the inner surface of the brazing tank is greater than 6 μm.

[0015] Furthermore, step B is specifically as follows: annealing the cold sprayed powder at 350 degrees Celsius, heating rate 12-18 degrees Celsius / minute, keeping warm at normal pressure for 1.5 hours, and cooling normally; drying the annealed powder in a drying oven at 100 degrees Celsius for 20 minutes before spraying, and then cold spraying the bottom of the pot after sandblasting.

[0016] Furthermore, step C is specifically as follows: cold spraying in a vacuum state, first spraying the brazing groove at a fixed point, and after the lower surface of the pot bottom forms a plane, spraying the entire pot bottom, forming a deposition layer between the pot bottom and the powder; continuing to spray at the same rate on the deposition layer to form a cold spray coating of the same material.

[0017] Furthermore, the random inspection test in step D includes mechanical property testing and corrosion resistance testing of the cold spray coating.

[0018] Furthermore, the pot bottom and the powder are made of the same material, and the deposited layer and the cold spray coating are made of the same material.

[0019] Furthermore, the pot bottom and the powder are made of different materials, and the deposited layer and the cold spray coating are made of the same material or different materials.

[0020] Furthermore, the Curie point temperature is between 70-220 degrees Celsius.

[0021] The present invention improves the structure of the cookware and cooperates with the improvement of the cold spraying process of the pot bottom to optimize the performance of the cold spraying coating on the pot bottom, enhances the mechanical interlocking between the deposited layer and the lower surface of the pot bottom, and increases the effective deposition rate through annealing treatment of the powder, thereby greatly improving the mechanical properties and corrosion resistance of the cold spraying coating, avoiding the oil-free pot sticking phenomenon caused by the inner bulge of the pot bottom. The Curie point temperature is between 70-220 degrees Celsius, and a constant temperature effect is achieved during use. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a structural schematic diagram of the hydraulic composite pot bottom in the prior art.

[0023] Figure 2 It is a structural schematic diagram of the present invention.

[0024] Figure 3 It is a partially enlarged cross-sectional view of the bottom of the pot of the present invention.

[0025] Figure 4 It is a structural schematic diagram of the inner surface of the pot bottom of the present invention.

[0026] Figure 5 BSE image of the cross section of the cold spray coating (10 μm)

[0027] Figure 6 Cross-sectional micrograph of the cold spray coating after etching (20 μm)

[0028] Figure 7 This is a local high-magnification mirror image (20μm) of the cold spray coating under corrosion experimental conditions.

[0029] Reference numerals

[0030] 1. Bottom of the pot 2. Cold spray coating 3. Pot body

[0031] 4. Brazing groove 5. Texture layer 51. Oil channel

[0032] 52, ridge 53, oil grid 11, oil center

[0033] 21. Alloy metal layer DETAILED DESCRIPTION

[0034] The present invention will be further described below with reference to the accompanying drawings and examples. Figure 1 The figure shows a schematic diagram of the structure of a hydraulically composite pot bottom in the prior art. In the figure, the bottom of the pot body 3 is hydraulically pressed with an alloy metal layer 21, the purpose of which is to make the pot magnetically conductive. However, this structure has the technical problem of the alloy metal layer 21 falling off during daily use. In addition, the pot body is easily bulged from the center of the pot bottom when heated, causing cooking oil to accumulate on the four edges of the pot. At the same time, the thermal conductivity, constant temperature and even Curie point temperature of the alloy metal layer 21 cannot meet the requirements. Therefore, the structure of the pot of the present invention is improved, and the cold spraying process of the pot bottom is improved to optimize the performance of the cold spraying coating on the pot bottom. Figure 2-Figure 4 As shown, Figure 2 It is a structural schematic diagram of the present invention. Figure 3 It is a partially enlarged cross-sectional view of the bottom of the pot of the present invention. Figure 4 The figure is a schematic diagram of the structure of the inner surface of the pot bottom of the present invention. The cold sprayed pot of the present invention includes a pot body 3 and a pot bottom 1, wherein the bottom surface of the pot bottom 1 is provided with a plurality of brazing grooves 4, one of which is located at the center of the bottom surface of the pot bottom 1 and has an alloy block embedded therein. The alloy block pulls the pot bottom 1 downward, causing the upper surface of the pot bottom 1 to be concave, thereby forming an oil collecting center 11. The remaining brazing grooves 4 and the bottom surface of the pot bottom 1 are provided with a cold spray coating 2. A texture layer 5 is pressed on the upper surface of the pot bottom 1. The texture layer 5 is composed of a plurality of four-pointed stars in a square pattern. The four-pointed stars are integrally formed from the center to the four corners with ridges 52 with a gradually decreasing slope. The four four-pointed stars form an oil grid 53, and the connection between the head and tail of two adjacent four-pointed stars forms an oil channel 51. The cold spray coating 2 is formed by cold spraying any one or more of Al-Cu-Mg aluminum alloy, iron-manganese alloy, constant elastic alloy, amorphous soft magnetic alloy, and precision alloy. The cross section of the soldering groove 4 is open at the top and closed at the bottom. The cross section of the soldering groove is preferably an isosceles trapezoid. The depth of the soldering groove is 0.2-0.8 mm.

[0035] The cold spraying treatment method of the cold spraying cookware of the present invention comprises the following steps:

[0036] A. Pre-treatment of the pot body,

[0037] B. Pretreatment of cold spray powder,

[0038] C. Cold spraying,

[0039] D. After random inspection and testing, qualified products will be shipped out.

[0040] Step A is specifically as follows: pre-treatment of the pot bottom by sandblasting, under inert gas protection conditions, to improve the surface roughness and enhance the mechanical interlocking between the deposited layer and the lower surface of the pot bottom. Glass beads or corundum powder are used for sandblasting at a sandblasting speed of 40-45g / min, so that the roughness Ra of the lower surface of the pot bottom and the inner surface of the brazing tank is greater than 6μm.

[0041] Step B specifically includes annealing the cold sprayed powder at 350 degrees Celsius, heating rate 12-18 degrees Celsius / minute, keeping warm at normal pressure for 1.5 hours, and cooling normally; drying the annealed powder in a drying oven at 100 degrees Celsius for 20 minutes before cold spraying the bottom of the pot after sandblasting.

[0042] Step C is specifically as follows: cold spraying in a vacuum state, first spraying the brazing groove at a fixed point, and after the lower surface of the pot bottom forms a plane, spraying the entire pot bottom to form a deposition layer between the pot bottom and the powder; continuing to spray at the same rate on the deposition layer to form a cold spray coating of the same material.

[0043] The random inspection test in step D includes the mechanical property test and corrosion resistance test of the cold spray coating.

[0044] The pot bottom and the powder are made of the same material, and the deposited layer and the cold spray coating are made of the same material.

[0045] The pot bottom and the powder are made of different materials, and the deposited layer and the cold spray coating are made of the same material or different materials.

[0046] Specific embodiment:

[0047] The bottom of the pot is made of 2024 aluminum alloy. After an alloy block (preferably 3J58 constant elastic alloy) is pressed and embedded in the brazing groove at the center of the bottom of the pot, the bottom of the pot is sandblasted with corundum powder. Under a pressure of 1MPa and nitrogen protection, the lower surface of the pot is sandblasted twice at a speed of 45g / min and a sweep speed of 25mm / s. The roughness Ra of the bottom is 6.5±0.3μm.

[0048] Preferred materials for the cold spray powder are Cu and its alloys, Al and its alloys, Zn or Zn-Al alloys. In this embodiment, the cold spray powder material is a 7075 Zn-Al alloy. 5.2 wt% Al₂O₃ is added to the powder and thoroughly mechanically mixed. The mixed cold spray powder is then annealed at 350°C at a heating rate of 12-18°C / minute, held at atmospheric pressure for 1.5 hours, and then cooled normally. Before spraying the pretreated pot bottom, the annealed mixed cold spray powder is dried in a drying oven at 100°C for 20 minutes. The sandblasted pot bottom is then cold sprayed (vacuum cold spraying). The brazing groove is initially sprayed. Once the lower surface of the pot bottom is flattened, the entire pot bottom is sprayed, forming a deposited layer between the pot bottom and the powder. Spraying is continued at the same rate to form a cold spray coating of the same material on top of the deposited layer. (The cold spraying process is conventional.)

[0049] Experimental data:

[0050] Mechanical properties testing:

[0051] like Figure 5As shown in FIG, the BSE image (10 μm) of the cross section of the cold spray coating shows that the coatings have a dense microstructure, no interconnected pores, and no obvious defects such as pores and cracks can be seen on the interface.

[0052] like Figure 6 As shown in the cross-sectional micrograph (20 μm) of the cold spray coating after etching, it can be observed that the particles are elongated to a certain extent in the direction perpendicular to the impact, the particle boundaries are almost perpendicular to the impact direction, plastic deformation occurs effectively during the deposition process, and the effective deposition rate is high.

[0053] The measured bonding strength of the cold spray coating is 54±8MPa, with high bonding strength and good mechanical properties.

[0054] Corrosion resistance test: 2cm square of cold spray coating was immersed in 5wt% NaCl solution for 12 hours.

[0055] like Figure 7 As shown, a local high-magnification mirror image (20μm) of the cold spray coating under corrosion experimental conditions.

[0056] There are some dark gray corrosion areas randomly distributed on the coating surface. Further magnification shows that these corrosion areas are mainly concentrated around the bright copper-rich precipitate phase, which indicates that there is galvanic corrosion between the cathode copper-rich precipitate phase and the adjacent anode aluminum substrate. However, the corrosion reaction produces some hydroxide deposits, which play a certain shielding role and hinder the further occurrence of the corrosion reaction, resulting in a good corrosion resistance effect.

[0057] The cold spray coating in this application is preferably any one of: Al-Cu-Mg aluminum alloy, iron-manganese alloy, constant elastic alloy, amorphous soft magnetic alloy, precision alloy, and the constant temperature effect temperature value (Curie point) thereof is as follows: (For cookware used with an induction cooker, excessively high temperature will cause the texture layer (destruction of the non-stick coating), and the temperature is generally required to be controlled within 260 degrees Celsius)

[0058] Alloy type Alloy grade Curie point Iron-manganese alloy 4J59 70 Constant elastic alloy 3J53 110 Amorphous soft magnetic alloy (FeNiCo)78(SiB)22 150 Precision Alloys 4J32 220 Zn-Al alloy (Example) <![CDATA[7075 (doped with 5.2 wt% of Al2O3)]]> 185

[0059] Comparative data:

[0060] The pot bottoms with the cold spray coating of this patent application are group A, the pot bottoms with the hydraulically pressed alloy metal layer of the prior art are group B, and the pot bottoms with the thermal spray coating of the prior art are group C. Comparative data:

[0061]

[0062] In summary, the present invention optimizes the performance of the cold spray coating on the bottom of the pot by improving the structure of the pot and coordinating the cold spray process of the pot bottom with improvements, enhances the mechanical interlocking between the deposited layer and the lower surface of the pot bottom, and improves the effective deposition rate through annealing treatment of the powder, thereby greatly improving the mechanical properties and corrosion resistance of the cold spray coating. The Curie point temperature is between 70 and 220 degrees Celsius, and a constant temperature effect is achieved during use.

Claims

1. A cold spray cookware, comprising a cookware body (3) and a cookware bottom (1), characterized in that: The bottom surface of the pot bottom (1) is provided with a plurality of brazing grooves (4), one of which is located at the center of the bottom surface of the pot bottom (1) and has an alloy block embedded therein. The alloy block pulls the pot bottom (1) downward, causing the upper surface of the pot bottom (1) to be concave, thereby forming an oil collecting center (11). Cold spray coatings (2) are provided in the remaining brazing grooves (4) and on the bottom surface of the pot bottom (1), wherein the cold spray coatings (2) in the brazing grooves (4) form a plane on the lower surface of the pot bottom (1).

2. The cold spray cookware according to claim 1, characterized in that: A texture layer (5) is pressed on the upper surface of the pot bottom (1), and the texture layer (5) is composed of a plurality of four-pointed stars in a row. The four-pointed stars are integrally formed with ridges (52) with a gradual slope from the center to the four corners. The four four-pointed stars form an oil grid (53), and the connection between the head and tail of two adjacent four-pointed stars forms an oil channel (51).

3. The cold spray cookware according to claim 1 or 2, characterized in that: The cold spray coating (2) is formed by cold spraying any one or more of Al-Cu-Mg aluminum alloy, iron-manganese alloy, constant elastic alloy, amorphous soft magnetic alloy, and precision alloy.

4. A cold spraying method for a cold sprayed cookware according to claim 2, characterized in that: The steps include: A. Pre-treatment of the pot body, B. Pretreatment of cold spray powder, C. Cold spraying: cold spraying in vacuum state, first spray the brazing groove at a fixed point, after the lower surface of the pot bottom forms a plane, spray the entire pot bottom, and form a deposition layer between the pot bottom and the powder; continue to spray at the same rate on the deposition layer to form a cold spray coating of the same material. D. After random inspection and testing, qualified products will be shipped out.

5. The cold spraying method for cold spraying cookware according to claim 4, characterized in that: Step A is specifically as follows: pre-treatment of the pot bottom by sandblasting, under inert gas protection conditions, to improve the surface roughness and enhance the mechanical interlocking between the deposited layer and the lower surface of the pot bottom. Glass beads or corundum powder are used for sandblasting at a sandblasting speed of 40-45g / min, so that the roughness Ra of the lower surface of the pot bottom and the inner surface of the brazing tank is greater than 6μm.

6. The cold spraying method for cold spraying cookware according to claim 4, characterized in that: Step B specifically includes annealing the cold sprayed powder at 350 degrees Celsius, heating rate 12-18 degrees Celsius / minute, keeping warm at normal pressure for 1.5 hours, and cooling normally; drying the annealed powder in a drying oven at 100 degrees Celsius for 20 minutes before cold spraying the bottom of the pot after sandblasting.

7. The cold spraying method for cold spraying cookware according to claim 4, characterized in that: The random inspection test in step D includes the mechanical property test and corrosion resistance test of the cold spray coating.

8. The cold spraying method for cold spraying cookware according to claim 4, characterized in that: The pot bottom and the powder are made of the same material, and the deposited layer and the cold spray coating are made of the same material.

9. The cold spraying method for cold spraying cookware according to claim 4, characterized in that: The pot bottom and the powder are made of different materials, while the deposited layer and the cold spray coating are made of the same material.

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