A coating process for a magnetic permeability layer

Abstract

The application discloses a kind of coating processes of magnetic conducting layer, it is characterized in that including the following steps: 1) ceramic green body high-temperature firing is formed ceramic body without glaze on inner surface;2) the inner surface of ceramic body is sandblasted, so that the inner surface of ceramic body cleanliness grade reaches Sa2.5 level, the inner surface roughness of ceramic body is between Ra2.5-Ra3.0;3) using air gun aims at the inner surface of ceramic body and carries out air cleaning;4) ceramic body is preheated after cleaning at 90-110 DEG C;5) magnetic conducting material is coated on the inner surface of ceramic body by hot melt processing mode, and magnetic conducting material at least covers the bottom of the inner surface of ceramic body, and the described magnetic conducting layer is prepared.This kind of coating process of magnetic conducting layer can enhance adhesion, improve the uniformity and consistency of magnetic conducting material.

Description

TECHNICAL FIELD

[0001] The present application relates to a cooking utensil, in particular to a coating process of a magnetic conductive layer. BACKGROUND

[0002] Ceramic material does not have the magnetic conductivity of metal, which limits the application of ceramic products on the induction cooker. The main process of the magnetic conductive ceramic cooking utensil is to directly bake a layer of magnetic conductive film on the bottom of the ceramic utensil, or to paste a layer of magnetic conductive film on the ceramic body, then enter the glazing process, and finally perform sintering to obtain a magnetic conductive ceramic utensil.

[0003] Patent applications with publication numbers CN105310460A and CN105310510A respectively disclose a manufacturing method of a ceramic pot, the features of which are that a magnetic conductive electric heating film is pasted on the inner bottom surface of the ceramic pot and is covered by a glaze layer. This method has two shortcomings: first, the magnetic induction efficiency and the heat conduction efficiency are low because the magnetic conductive electric heating film is pasted on the inner bottom surface of the ceramic pot; second, the magnetic conductive electric heating film is a shaped film layer, and after the shaped film layer is pasted on the inner bottom surface of the ceramic pot, the glaze is coated on the shaped film layer. However, the glaze and the shaped film layer cannot penetrate each other, which easily leads to cracks on the glaze surface, thereby causing the mechanical strength of the ceramic pot bottom and the pot body to be uneven. Once impacted, the ceramic pot bottom cracks first.

[0004] Application No. ZL200310103236.X discloses a ceramic pot for an induction cooker, the feature of which is that a layer of magnetic conductive electric heating film is laid on the outer bottom surface of the ceramic pot. This method has the disadvantage that the externally placed magnetic conductive electric heating film is not protected and is easily scratched, thereby having a short service life.

[0005] Some deficiencies of the magnetic conductive layer on the existing ceramic utensil include: 1) the adhesion of the magnetic conductive layer is not strong enough and is easily detached; 2) the uniformity and consistency of the magnetic conductive layer need to be improved; and 3) the magnetic conductive layer can have defects of not being firmly combined. SUMMARY

[0006] The problem to be solved by the present application is to provide a coating process of a magnetic conductive layer, which can enhance the adhesion and improve the uniformity and consistency of the magnetic conductive material.

[0007] In order to solve the above technical problems, the technical scheme adopted by the present application is as follows:

[0008] A coating process of a magnetic conductive layer, characterized in that it comprises the following steps:

[0009] 1) high-temperature sintering of a ceramic green body to form a ceramic body with an inner surface without glaze;

[0010] 2) Sandblast the inner surface of the ceramic blank to ensure that the cleanliness level of the inner surface of the ceramic blank reaches Sa2.5 and the roughness of the inner surface of the ceramic blank is between Ra2.5 and Ra3.0;

[0011] 3) Use an air gun to blow air to clean the inner surface of the ceramic blank;

[0012] 4) Preheating the cleaned ceramic blank at 90°C-110°C;

[0013] 5) The magnetic conductive material is coated on the inner surface of the ceramic blank by hot melting, and the magnetic conductive material at least covers the bottom of the inner surface of the ceramic blank to obtain the magnetic conductive layer.

[0014] In step 1), the inner surface of the ceramic blank is not covered with glaze, and the inner surface roughness of the ceramic blank is relatively high, which provides a better mechanical anchoring effect for the magnetic material, allowing the magnetic material to directly contact the ceramic blank, enhancing the adhesion of the magnetic material to the ceramic blank, providing a good foundation for subsequent magnetic material coating operations, and enhancing the bonding and stability between the magnetic material and the ceramic blank. Because the ceramic blank is fired at high temperature, its inner surface is unglazed, which can better withstand the preheating temperature before the magnetic material is sprayed, thereby increasing the heat resistance and stability of the magnetic layer.

[0015] In step 2), sandblasting uses compressed air as a power source to form a high-speed jet beam that sprays a material (copper ore sand, quartz sand, corundum, iron sand, or sea sand) onto the surface of the workpiece being treated, thereby changing the surface appearance or shape of the workpiece. The impact and cutting action of the material on the workpiece surface imparts a certain degree of cleanliness and varying degrees of roughness to the workpiece surface, improving the mechanical properties of the workpiece surface. This enhances the fatigue resistance of the workpiece, increases the adhesion between the workpiece surface and the coating, prolongs the durability of the coating, and facilitates the leveling and decorative properties of the coating. Sandblasting the inner surface of the ceramic blank removes impurities such as dirt and oxides from the inner surface of the ceramic blank, increases surface cleanliness and surface roughness, and enhances the adhesion of the magnetic material.

[0016] In the above step 3), using an air gun to blow air towards the inner surface of the ceramic blank to clean it can further remove impurities on the surface of the ceramic blank and ensure the quality of the magnetic conductive layer.

[0017] In the above step 4), the cleaned ceramic blank is preheated at 90°C-110°C. This preheating enables the molten magnetic conductive material in step 5) to react with the high-temperature surface of the ceramic blank to form a more stable chemical bond and crystal structure, thereby improving the thermal stability and heat resistance of the magnetic conductive layer.

[0018] In step 5), the hot-melt method allows the magnetic material to be applied in a molten state, resulting in a uniform coating of the magnetic material on the inner surface of the ceramic blank. This allows the magnetic material to better contact and adhere to the inner surface of the ceramic blank, improving the bonding strength between the magnetic material and the ceramic blank and reducing the possibility of the magnetic layer falling off. The magnetic layer prepared above can be roughened before subsequent processing to provide a clean surface for subsequent processing.

[0019] In a preferred embodiment, in step 5), the magnetic conductive layer comprises a top layer and a bottom layer, wherein the bottom layer is applied to the inner surface of the ceramic blank, and the top layer is applied to the upper surface of the bottom layer. The top layer is applied to the upper surface of the bottom layer, and the bottom layer serves as a foundation for the magnetic conductive layer, providing good support and load-bearing capacity for the top layer.

[0020] In a further preferred embodiment, in step 5), the base layer is first applied to the inner surface of the ceramic blank. After the base layer cools to a certain degree, the top layer is applied to the upper surface of the base layer. This arrangement allows the top layer and the base layer to fuse together, forming a mutually penetrating bonding layer, thereby enhancing the bonding between the top layer and the base layer.

[0021] In a further preferred embodiment, in step 5), when the surface temperature of the bottom layer is annealed to 500° C.-600° C., the top layer is coated on the upper surface of the bottom layer.

[0022] In a further preferred embodiment, in step 5), the magnetic conductive material is prepared by mixing the following raw materials in parts by weight: 10-20 parts silver powder, 20-30 parts aluminum powder, 10-15 parts titanium powder, 15-20 parts cobalt powder, and 10-20 parts nickel powder. The magnetic conductive material comprises silver powder, aluminum powder, titanium powder, cobalt powder, and nickel powder. These different metal powders play different roles in the magnetic conductive material: silver powder has high electrical and thermal conductivity; aluminum powder and titanium powder enhance the magnetic properties of silver powder; and cobalt powder and nickel powder further increase the magnetic permeability of the magnetic conductive material. The mixing of these various metal powders improves the uniformity and consistency of the magnetic conductive material, ensuring ideal magnetic properties during the coating and sintering processes.

[0023] In a further preferred embodiment, the top layer is made from a mixture of the following raw materials in parts by weight: 10-15 parts titanium powder and 5-10 parts silver powder; the bottom layer is made from a mixture of the following raw materials in parts by weight: 5-10 parts silver powder, 15-20 parts cobalt powder, 20-30 parts aluminum powder, and 10-20 parts nickel powder. The top layer, containing titanium and silver, and the bottom layer, containing silver, cobalt, aluminum, and nickel, both have high magnetic permeability and electrical conductivity, effectively distributing and conducting magnetic energy, improving magnetic conductivity, and enhancing the magnetic coupling efficiency between the electromagnetic coil and the ceramic pot body.

[0024] In a preferred embodiment, the magnetic conductive material in step 5) covers at least the entire inner surface of the ceramic blank from the bottom to the upper portion of the sidewalls. This arrangement increases the coverage of the magnetic conductive layer on the inner surface of the ceramic blank, completely covering areas that may come into contact with the induction cooker during cooking. This effectively enhances the magnetic conductive layer's magnetic conductivity in the induction cooker, improving cooking efficiency and uniformity.

[0025] In a further preferred embodiment, in step 5), the magnetic conductive layer extends from bottom to top to cover at least one quarter of the side wall of the inner surface of the ceramic blank.

[0026] In a preferred embodiment, in step 5), the thickness of the magnetic conductive layer is in the range of 0.05 mm to 1.00 mm. The thickness of the magnetic conductive layer is determined by the rated power, and the power is directly proportional to the thickness. The thickness range is approximately between 0.05 mm and 1.00 mm.

[0027] Compared with the prior art, the present invention has the following advantages:

[0028] 1) The unglazed inner surface of the ceramic blank of the present invention can enhance the adhesion of the magnetic conductive material, provide a good foundation for the subsequent coating operation of the magnetic conductive material, and enhance the bonding strength and stability between the magnetic conductive material and the ceramic blank.

[0029] 2) The present invention uses preheating to provide a prerequisite for subsequent hot-melt coating, so that the molten magnetic material reacts with the high-temperature surface of the ceramic blank to form a more stable chemical bond and crystal structure, thereby improving the thermal stability and heat resistance of the magnetic layer, improving the uniformity and consistency of the magnetic layer, and ensuring that the magnetic performance remains consistent across the entire surface of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 is a structural diagram of embodiment 1 of the present invention;

[0031] Figure 2 yes Figure 1 A is an enlarged schematic diagram. DETAILED DESCRIPTION

[0032] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0033] Example 1

[0034] like Figure 1-2 As shown, the coating process of the magnetic conductive layer in this embodiment includes the following steps:

[0035] 1) firing the ceramic green body at a high temperature to form a ceramic green body 1 with an unglazed inner surface;

[0036] 2) sandblasting the inner surface of the ceramic blank 1 to ensure that the cleanliness level of the inner surface of the ceramic blank 1 reaches Sa2.5 and the roughness of the inner surface of the ceramic blank 1 is between Ra2.5 and Ra3.0;

[0037] 3) Use an air gun to blow air to clean the inner surface of the ceramic blank 1;

[0038] 4) preheating the cleaned ceramic blank 1 at 90° C.-110° C.;

[0039] 5) The magnetic conductive material is coated on the inner surface of the ceramic blank 1 by hot melting, and the magnetic conductive material at least covers the bottom of the inner surface of the ceramic blank 1 to obtain the magnetic conductive layer 2.

[0040] In step 1) above, the inner surface of the ceramic blank 1 is not covered with glaze, and the inner surface roughness of the ceramic blank 1 is relatively high, which provides a better mechanical anchoring effect for the magnetic material, allowing the magnetic material to directly contact the ceramic blank 1, enhancing the adhesion of the magnetic material to the ceramic blank 1, providing a good foundation for subsequent magnetic material coating operations, and enhancing the bonding strength and stability between the magnetic material and the ceramic blank 1. Because the ceramic blank 1 is fired at a high temperature, its inner surface is unglazed, which can better withstand the preheating temperature before the magnetic material is sprayed, thereby increasing the heat resistance and stability of the magnetic layer 2.

[0041] In step 2), sandblasting utilizes compressed air as a power source to form a high-speed jet beam that sprays a material (copper ore sand, quartz sand, corundum, iron sand, or sea sand) onto the surface of the workpiece being treated, thereby changing the surface appearance or shape of the workpiece. The impact and cutting action of the material on the workpiece surface imparts a certain degree of cleanliness and varying degrees of roughness to the workpiece surface, improving the mechanical properties of the workpiece surface. This enhances the fatigue resistance of the workpiece, increases the adhesion between the workpiece surface and the coating, prolongs the durability of the coating, and facilitates the leveling and decorative properties of the coating. Sandblasting the inner surface of the ceramic blank 1 removes impurities such as dirt and oxides from the inner surface of the ceramic blank 1, increases surface cleanliness and surface roughness, and enhances the adhesion of the magnetically conductive material.

[0042] In the above step 3), an air gun is used to blow air towards the inner surface of the ceramic blank 1 to clean it, which can further remove impurities on the surface of the ceramic blank 1 and ensure the quality of the magnetic conductive layer 2 .

[0043] In the above step 4), the cleaned ceramic blank 1 is preheated at 90°C-110°C. This preheating enables the molten magnetic material in step 5) to react with the high-temperature surface of the ceramic blank 1 to form a more stable chemical bond and crystal structure, thereby improving the thermal stability and heat resistance of the magnetic layer 2.

[0044] In step 5), the magnetic conductive material is coated in a molten state to form a uniform coating on the inner surface of the ceramic body 1, so that the magnetic conductive material can better contact and adhere to the inner surface of the ceramic body 1, improve the bonding strength of the magnetic conductive material and the ceramic body 1, and reduce the possibility of the magnetic conductive layer 2 falling off. The prepared magnetic conductive layer 2 can be roughened for subsequent processing to provide a clean surface of the magnetic conductive layer 2 for subsequent processing.

[0045] In step 5), the magnetic conductive layer 2 includes a surface layer 21 and a base layer 22, the base layer 22 is coated on the inner surface of the ceramic body 1, and the surface layer 21 is coated on the upper surface of the base layer 22. The surface layer 21 is coated on the upper surface of the base layer 22, and the base layer 22 serves as the base layer of the magnetic conductive layer 2, which can provide good support and carrying capacity for the surface layer 21.

[0046] In step 5), the base layer 22 is first coated on the inner surface of the ceramic body 1, and then the surface layer 21 is coated on the upper surface of the base layer 22 after the base layer 22 cools to a certain extent. By this arrangement, the surface layer 21 and the base layer 22 can be melted to form a combined layer that penetrates each other, enhancing the bonding degree of the surface layer 21 and the base layer 22.

[0047] In step 5), the surface layer 21 is coated on the upper surface of the base layer 22 when the surface temperature of the base layer 22 is annealed to 500℃.

[0048] In step 5), the magnetic conductive material is prepared by mixing the following raw materials in the following proportions by weight: 10 parts of silver powder, 20 parts of aluminum powder, 10 parts of titanium powder, 15 parts of cobalt powder, and 10 parts of nickel powder. The above-mentioned magnetic conductive material is composed of silver powder, aluminum powder, titanium powder, cobalt powder and nickel powder, which play different roles in the magnetic conductive material: silver powder has high electrical conductivity and thermal conductivity; aluminum powder and titanium powder have the effect of enhancing the magnetic conductive performance of silver powder; cobalt powder and nickel powder can further increase the magnetic permeability of the magnetic conductive material. The mixing of the above-mentioned various metal powders can improve the uniformity and consistency of the magnetic conductive material, ensuring the ideal magnetic conductive performance in the coating and sintering process.

[0049] The surface layer 21 is prepared by mixing the following raw materials in the following proportions by weight: 10 parts of titanium powder and 5 parts of silver powder; the base layer 22 is prepared by mixing the following raw materials in the following proportions by weight: 5 parts of silver powder, 15 parts of cobalt powder, 20 parts of aluminum powder and 10 parts of nickel powder. The surface layer 21 containing titanium and silver, and the base layer 22 containing silver, cobalt, aluminum and nickel, both have high magnetic conductivity and electrical conductivity, which can effectively distribute and conduct magnetic energy, improve the magnetic effect, and enhance the magnetic coupling efficiency between the electromagnetic coil and the ceramic pot body.

[0050] Step 5) The magnetic conductive material is applied to at least the entire inner surface of the ceramic blank 1 from the bottom to the upper portion of the sidewalls. This arrangement increases the coverage of the magnetic conductive layer 2 on the inner surface of the ceramic blank 1, completely covering the area that may come into contact with the induction cooker during cooking. This effectively enhances the magnetic conductivity of the magnetic conductive layer 2 in the induction cooker, improving cooking efficiency and uniformity.

[0051] Step 5) The magnetic conductive layer 2 extends from bottom to top to cover at least one quarter of the side wall of the inner surface of the ceramic blank 1.

[0052] In step 5), the thickness of the magnetic conductive layer 2 is 0.10 mm.

[0053] Example 2

[0054] The coating process of the magnetic conductive layer in this embodiment differs from that in embodiment 1 in that:

[0055] In step 5), the magnetic conductive material is prepared by mixing the following raw materials in parts by weight: 15 parts of silver powder, 25 parts of aluminum powder, 12 parts of titanium powder, 17 parts of cobalt powder, and 15 parts of nickel powder.

[0056] The surface layer 21 is made by mixing the following raw materials in parts by weight: 12 parts titanium powder and 7 parts silver powder; the bottom layer 22 is made by mixing the following raw materials in parts by weight: 8 parts silver powder, 17 parts cobalt powder, 25 parts aluminum powder, and 15 parts nickel powder.

[0057] Example 3

[0058] The coating process of the magnetic conductive layer in this embodiment differs from that in embodiment 1 in that:

[0059] In the step 5), the magnetic conductive material is prepared by mixing the following raw materials in parts by weight: 20 parts of silver powder, 30 parts of aluminum powder, 15 parts of titanium powder, 20 parts of cobalt powder, and 20 parts of nickel powder.

[0060] The surface layer 21 is made by mixing the following raw materials in parts by weight: 15 parts of titanium powder and 10 parts of silver powder; the bottom layer 22 is made by mixing the following raw materials in parts by weight: 10 parts of silver powder, 20 parts of cobalt powder, 30 parts of aluminum powder, and 20 parts of nickel powder.

[0061] The following are the magnetic conductive layers of Examples 1-3, and their thermal efficiency data are tested based on a 4L capacity IH rice cooker with a power of 1100W, as shown in Table 1.

[0062] Table 1

[0063]

[0064] Comparative Example 1

[0065] A magnetic conductive film is attached to the bottom of the ceramic pot and covered with a glaze layer. The thermal efficiency data is tested based on a 4L capacity IH rice cooker with a power of 1100W, as shown in Table 2.

[0066] Table 2

[0067]

[0068] Comparative Example 2

[0069] The bottom of the ceramic pot is coated with a magnetic film and covered with a glaze layer. The thermal efficiency data is tested based on a 4L capacity IH rice cooker with a power of 1100W, as shown in Table 3.

[0070] Table 3

[0071]

[0072] According to the data in Tables 1-3, compared with the magnetic conductive film in Comparative Examples 1-2, the rice cooker with the magnetic conductive layer prepared in Examples 1-3 can greatly improve thermal efficiency and reduce power consumption.

[0073] In addition, it should be noted that the names of the various parts of the specific embodiments described in this specification may be different. Any equivalent or simple changes made based on the structure, features, and principles described in the patent concept of the present invention are included in the scope of protection of the patent of this invention. Those skilled in the art of the technical field to which the present invention relates may make various modifications, supplements, or replace the specific embodiments described in the description with similar methods. As long as they do not deviate from the structure of the present invention or exceed the scope defined by the claims, they shall fall within the scope of protection of the present invention.

Claims

1. A coating process for a magnetic conductive layer, characterized in that The steps include: 1) firing the ceramic green body at a high temperature to form a ceramic green body with an unglazed inner surface; 2) Sandblast the inner surface of the ceramic blank to ensure that the cleanliness level of the inner surface of the ceramic blank reaches Sa2.5 and the roughness of the inner surface of the ceramic blank is between Ra2.5 and Ra3.0; 3) Use an air gun to blow air to clean the inner surface of the ceramic blank; 4) Preheating the cleaned ceramic blank at 90°C-110°C; 5) coating the magnetic conductive material on the inner surface of the ceramic blank by hot-melt processing, and the magnetic conductive material at least covers the bottom of the inner surface of the ceramic blank to obtain the magnetic conductive layer; The magnetic conductive layer includes a surface layer and a bottom layer. The surface layer is made by mixing the following raw materials in parts by weight: 10-15 parts of titanium powder and 5-10 parts of silver powder; the bottom layer is made by mixing the following raw materials in parts by weight: 5-10 parts of silver powder, 15-20 parts of cobalt powder, 20-30 parts of aluminum powder, and 10-20 parts of nickel powder. First, the bottom layer is coated on the inner surface of the ceramic blank, and when the surface temperature of the bottom layer is annealed to 500-600° C., the surface layer is coated on the upper surface of the bottom layer.

2. The coating process for the magnetic conductive layer according to claim 1, wherein: In step 5), the magnetic conductive material is at least spread over the area from the bottom of the inner surface of the ceramic blank to the area above the side wall.

3. The coating process of the magnetic conductive layer according to claim 2, wherein: In step 5), the magnetic conductive layer extends from bottom to top to cover at least one quarter of the side wall of the inner surface of the ceramic blank.

4. The coating process for the magnetic conductive layer according to claim 1, wherein: In the step 5), the thickness of the magnetic conductive layer ranges from 0.05 mm to 1.00 mm.

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