Electromagnetic ceramic casserole

Abstract

The invention discloses an electromagnetic ceramic casserole, comprising a casserole body, a casserole glaze layer, a magnetic conductive layer and a protective layer; the preparation steps are as follows: S1. uniformly mixing the raw materials for the casserole glaze layer to prepare a glaze slurry; S2. polishing the bottom of the casserole body to be smooth, pouring the prepared glaze slurry onto the surface of the casserole body, naturally air-drying and then firing to form a glaze layer; S3. spraying the raw materials for the magnetic conductive layer on the surface of the glaze layer by a cold spraying method to form a magnetic conductive layer; S4. uniformly mixing the raw materials for the protective layer to prepare a glaze slurry, coating the glaze slurry on the surface of the magnetic conductive layer, and then firing. The invention provides a casserole glaze layer, a magnetic conductive layer and a protective layer at the bottom of the casserole, and the ceramic casserole can be directly placed on an induction cooker and directly heated for use without any auxiliary tools. The design of the three-layer structure makes the magnetic conductive layer structure dense and has good magnetic conductive properties. High-purity silver is also added to the glaze layer and the protective layer, which can significantly improve the heating efficiency of the casserole and at the same time stabilize the power used.

Description

Technical Field

[0001] The invention belongs to the technical field of ceramic products, and particularly relates to an electromagnetic ceramic casserole and a preparation method thereof. Background Art

[0002] An induction cooker is a common type of cooking appliance that uses the principle of electromagnetic induction to heat food. Typically, an induction cooker's surface is a heat-resistant ceramic plate. Under the action of an alternating current, a coil located beneath the ceramic plate generates a magnetic field. The magnetic lines of force within this field, when passing through the ferromagnetic bottom of the pot, generate eddy currents, causing the pot bottom to rapidly heat up, thereby heating the food. Therefore, the pots currently used in induction cookers are all made of ferromagnetic materials, such as iron and stainless steel. Ceramic pots, as environmentally friendly products, are chemically stable and less susceptible to chemical reactions. They also conduct heat quickly and dissipate heat slowly, effectively reducing heat dissipation and allowing cooking with minimal heat. However, because ceramic materials lack ferromagnetic properties, they are difficult to use in induction cookers. Currently, ceramic casseroles and kettles cannot be placed directly on induction cookers. Instead, they require a magnetic film applied to the bottom of the casserole, or a stainless steel sheet placed inside. This is very inconvenient, and the production process for magnetic film is complex. Using a patch-type method can lead to low heating efficiency and unstable bonding, resulting in low heating power and unstable power during use.

[0003] Cold spraying is a surface spraying process. The metal particles are not melted during the whole process. Compressed air is used to accelerate the metal particles to a critical speed (supersonic). The metal particles are flattened on the surface of the substrate and firmly attached. Cold spraying is a metal and ceramic spraying process, but it is different from traditional thermal spraying (super-velocity flame spraying, plasma spraying, explosion spraying and other traditional thermal spraying). It does not need to melt the sprayed metal particles, so the temperature generated on the surface of the sprayed substrate will not exceed 150 degrees Celsius. At the same time, the sintering temperature of ceramics is above 1500 degrees Celsius, so cold spraying can spray ceramic coatings (such as alumina) on almost all substrates, but if the metal particles do not reach supersonic speed, they cannot adhere. The bonding force of cold-sprayed magnetic films on the surface of ceramic casseroles should be better, which has certain research significance.

[0004] Therefore, researching an electromagnetic ceramic casserole with high heating efficiency and stable use has great practical significance and broad market prospects. Summary of the Invention

[0005] The purpose of the present invention is to provide an electromagnetic ceramic casserole, at the bottom of which a casserole glaze layer, a magnetic conductive layer and a protective layer are arranged. The ceramic casserole can be directly placed on an induction cooker and heated directly without any auxiliary tools, and has high heating efficiency and stable use.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] An electromagnetic ceramic casserole, comprising a casserole body, a casserole glaze layer, a magnetic conductive layer and a protective layer; the thickness ratio of the casserole glaze layer, the magnetic conductive layer and the protective layer is 2-5:1-3:1-2; the raw materials of the casserole glaze layer include, by weight, 30-33 parts of kaolin, 20-25 parts of spodumene, 1-10 parts of lithium feldspar, 3-5 parts of quartz, 8-10 parts of volcanic rock, 1-3 parts of high-purity silver and 1-3 parts of zirconium oxide; the material of the magnetic conductive layer includes Fe, Ni, Co, ferroalloy and stainless steel; the raw materials of the protective layer include, by weight: 15-20 parts of kaolin, 10-15 parts of dolomite, 5-10 parts of wollastonite, 5-10 parts of sodium silicate water glass, 5-10 parts of bentonite, 3-5 parts of feldspar, 3-5 parts of calcium stearate, 1-3 parts of high-purity silver, 0.1-0.5 parts of zinc oxide, 0.1-0.5 parts of zirconium oxide, 0.05-1 parts of strontium oxide, and 0.01-0.03 parts of cerium oxide;

[0008] The preparation of the electromagnetic ceramic casserole comprises the following steps:

[0009] S1. The raw materials for the casserole glaze layer are mixed evenly to prepare a glaze slurry;

[0010] S2. After polishing the bottom of the casserole body, apply the glaze slurry prepared in S1 to its surface, let it air dry and then fire it at a temperature of 1270-1350°C for 10-20h.

[0011] S3 the raw material of the magnetic layer by cold spraying method on the surface of the glaze layer to form a magnetic layer;

[0012] S4. The raw materials for the protective layer are mixed uniformly to prepare a glaze slurry, the glaze slurry is coated on the surface of the magnetic conductive layer, and then fired at a temperature of 800 to 1000° C. for 2 to 5 hours.

[0013] The present invention arranges a casserole glaze layer, a magnetic conductive layer and a protective layer at the bottom of the casserole. The raw materials of the casserole glaze layer are adjusted so that the glaze layer is firmly bonded to the casserole body, and the casserole glaze layer is tightly bonded to the casserole body after firing. At the same time, high-purity silver is added to the casserole glaze layer, and the magnetic conductive layer is formed by cold spraying. Due to the physical properties of silver, the erosion effect is strong, and it is easier to form a dense magnetic conductive layer on the surface of the glaze layer, which can improve the bonding strength between the casserole and the magnetic conductive layer. The raw materials of the protective layer are selected with high hardness, which can protect the magnetic conductive layer and prolong the service life of the magnetic conductive layer. At the same time, high-purity silver is also added. With the design of the three-layer structure, the magnetic conductive layer has a dense structure and good magnetic conductivity. High-purity silver is also added to the glaze layer and the protective layer, which can significantly improve the heating efficiency of the casserole and at the same time stabilize the power used.

[0014] The high-purity silver described in the present invention is 98 silver or 99 silver.

[0015] In the present invention, preferably, the cold spraying is to cold spray the metal powder on the surface of the glaze layer by the working gas to form a magnetic conductive layer, and the process parameters of the cold spraying include a spray pressure of 3 to 5 MPa, a spray temperature of 300 to 500 ° C, and a gas velocity of 2 to 3 m 3 / min, the spraying distance is 20-30mm.

[0016] The above-mentioned process parameters of cold spraying are summarized by the inventor after long-term and extensive experiments and practices: if the spray pressure is too high, the sprayed powder will be difficult to deposit in the later stage; if the spray pressure is too low, it will be difficult to reach the deposition rate (critical deposition speed), and it will not be easy to form a film; if the spray temperature is too high, it will affect the service life of the spray gun; if the spray temperature is too low, the bonding force with the interface will be low; if the gas velocity is too high, the particle flight speed will be too high, which will easily erode the original magnetic coating and make it difficult to deposit in the later stage; if the gas velocity is too low, the powder particle flight speed will be low, which will make it difficult for the powder to deposit on the surface of the pot body; if the spray distance is too high, the particle velocity will be too low when reaching the interface, making it difficult to deposit; if the spray distance is too low, the particle velocity will be too high when reaching the interface, which will easily erode the original magnetic coating and make it difficult to deposit in the later stage.

[0017] After the magnetic conductive layer is cold-sprayed, the porosity is tested and found to be 0.10-0.25%. Therefore, the structure of the magnetic conductive layer is relatively dense. The design of the process parameters achieves a good deposition rate and density.

[0018] In the present invention, preferably, the particle size of the metal powder is 100 to 1000 nm, and the thickness of the magnetic conductive layer is 0.1 to 0.3 mm. The particle size selection of the metal powder is conducive to the formation of a dense film structure by the cold spraying process, and the thickness of the magnetic conductive layer can form good magnetic conductivity. During the electromagnetic induction heating process, the better the density of the magnetic conductive layer, the higher the density of the magnetic flux lines cut by it, the higher the eddy current effect of the electromagnetic heating, and the corresponding increase in the heating power.

[0019] In the present invention, preferably, the mass ratio of Fe, Ni, Co, iron alloy and stainless steel in the magnetic conductive layer is 7-10: 3-5: 1-2: 1-3: 3-5. The mass ratio of the above metal materials achieves better magnetic conductivity without significantly increasing the cost.

[0020] In the present invention, preferably, the thickness of the casserole glaze layer is 0.2 to 0.5 mm, the thickness of the magnetic conductive layer is 0.1 to 0.3 mm, and the thickness of the protective layer is 0.1 to 0.2 mm. The thickness design of the glaze layer, the magnetic conductive layer and the protective layer comprehensively considers the cost and thermal conductivity efficiency, can form a good circulation, and has high thermal efficiency.

[0021] In the present invention, preferably, the raw materials of the casserole glaze layer include, by weight: 32 parts of kaolin, 23 parts of spodumene, 7 parts of lithium feldspar, 4 parts of quartz, 8 parts of volcanic stone, 1 part of high-purity silver, and 1 part of zirconium oxide. The raw materials of the casserole glaze layer are selected to be similar in composition to the casserole body and have a similar thermal expansion coefficient. After firing, it fits tightly to the casserole body and provides a smooth surface for the cold-sprayed magnetic conductive layer.

[0022] In the present invention, preferably, the raw materials of the protective layer include, by weight: 16 parts of kaolin, 12 parts of dolomite, 7 parts of wollastonite, 8 parts of sodium silicate water glass, 6 parts of bentonite, 3 parts of feldspar, 4 parts of calcium stearate, 2 parts of high-purity silver, 0.3 parts of zinc oxide, 0.2 parts of zirconium oxide, 0.07 parts of strontium oxide, and 0.02 parts of cerium oxide. The raw materials of the protective layer are selected so that the overall hardness is high after firing, which can protect the magnetic conductive layer and be bonded to the magnetic conductive layer.

[0023] In the present invention, preferably, S1. The raw materials for the glaze layer of the casserole are mixed and ground for 20-30 hours until the particle size is 30-50 μm, and then an appropriate amount of water is added and mixed evenly to obtain a glaze slurry, and the glaze slurry is vacuum-defoamed and set aside; the solid content of the glaze slurry is 58-62%, and when the glaze slurry is poured on the bottom of the casserole body, the glaze slurry flow rate is 38-40 seconds, and the glaze amount is 700-800 g / m 2 .

[0024] In the present invention, the firing temperature in S2 is preferably increased gradually: in the first stage, the temperature is 450°C to 600°C for 1-2 hours; then the temperature is increased to 900°C to 1000°C for 2-3 hours; and finally the temperature is increased to 1270-1350°C for 7-15 hours. This gradual increase in temperature can reduce obvious firing defects and ensure a tight bond between the glaze layer and the casserole body.

[0025] In the present invention, preferably, S4. The raw materials of the protective layer are mixed and ground for 10-18 hours until the particle size is 60-80 μm, and then an appropriate amount of water is added and mixed evenly to obtain a glaze slurry, and the glaze slurry is vacuum defoamed and set aside. The solid content of the glaze slurry is 63-65%; the surface of the magnetic conductive layer is dipped in the above-mentioned glaze slurry for 3-5 minutes; after natural drying, it is fired at a firing temperature of 850°C and a firing time of 4 hours.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] (1) The present invention provides a casserole glaze layer, a magnetic conductive layer and a protective layer at the bottom of the casserole. The ceramic casserole can be directly placed on an induction cooker and heated directly without any auxiliary tools. The design of the three-layer structure makes the magnetic conductive layer dense and has good magnetic conductivity. The glaze layer and the protective layer are also added with high-purity silver, which can significantly improve the heating efficiency of the casserole and at the same time stabilize the power used.

[0028] (2) In the present invention, the raw material selection of the glaze layer of the casserole is adjusted so that the glaze layer is firmly bonded to the casserole body. After firing, the glaze layer and the casserole body are tightly bonded. At the same time, high-purity silver is added to the glaze layer of the casserole. The magnetic conductive layer is cold-sprayed to form a dense magnetic conductive layer on the surface of the glaze layer, which can improve the bonding strength between the casserole and the magnetic conductive layer. The raw material selection of the protective layer has high hardness, which can protect the magnetic conductive layer and prolong the service life of the magnetic conductive layer.

[0029] (3) The present invention optimizes the cold spraying process parameters. After the magnetic layer is cold sprayed, the porosity of the magnetic layer is tested and found to be 0.10-0.25%. Therefore, the design of the process parameters of the present invention achieves a good deposition rate and a dense magnetic layer. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments, but the scope of protection claimed by the present invention is not limited to the embodiments.

[0031] Unless otherwise specified, the experimental methods or test methods described in the following examples are all conventional methods; the reagents and materials described are all obtained from conventional commercial channels or prepared by conventional methods unless otherwise specified.

[0032] Embodiment 1:

[0033] An electromagnetic ceramic casserole comprises a casserole body, a casserole glaze layer, a magnetic conductive layer and a protective layer; the casserole glaze layer is 0.2 mm thick, the magnetic conductive layer is 0.1 mm thick, and the protective layer is 0.1 mm thick.

[0034] The raw materials of the casserole glaze layer are as follows in parts by weight: 30 parts of kaolin, 20 parts of spodumene, 1 part of lithium feldspar, 3 parts of quartz, 8 parts of volcanic rock, 1 part of high-purity silver, and 1 part of zirconium oxide; the material of the magnetic conductive layer is metal powder composed of Fe, Ni, Co, iron alloy and stainless steel, the particle size of the metal powder is 300-500 nm, and the mass ratio of Fe, Ni, Co, iron alloy and stainless steel is 7:3:1:1:3; the raw materials of the protective layer are as follows in parts by weight: 15 parts of kaolin, 10 parts of dolomite, 5 parts of wollastonite, 5 parts of sodium silicate water glass, 5 parts of bentonite, 3 parts of feldspar, 3 parts of calcium stearate, 1 part of high-purity silver, 0.1 part of zinc oxide, 0.1 part of zirconium oxide, 0.05 part of strontium oxide, and 0.01 part of cerium oxide.

[0035] The preparation of the electromagnetic ceramic casserole comprises the following steps:

[0036] S1. The raw materials for the casserole glaze are mixed and ground for 20-30 hours until the particle size is 30-50 μm. An appropriate amount of water is then added and mixed evenly to obtain a glaze slurry. The glaze slurry is vacuum-defoamed and set aside. The glaze slurry has a solid content of approximately 60%. When pouring the glaze slurry on the bottom of the casserole body, the glaze slurry flow rate is 38.5 seconds and the glaze weight is 751 g / m 2 .

[0037] S2. After polishing the bottom of the casserole body smoothly, pour the glaze slurry prepared in S1 on its surface. After natural air drying, it is fired at a temperature of 1270°C and a firing time of 18 hours.

[0038] S3. The raw material of the magnetic layer is sprayed on the surface of the glaze layer by cold spraying to form a magnetic layer; the cold spraying method uses a working gas to cold spray the metal powder on the surface of the glaze layer to form a magnetic layer. The process parameters of the cold spraying include a spray pressure of 3 MPa, a spray temperature of 500 ° C, and a gas velocity of 2 m 3 / min, the spray distance is 20mm.

[0039] S4. Mix the raw materials for the protective layer and grind them for 10-18 hours until the particle size is 60-80μm. Then add an appropriate amount of water and mix them evenly to obtain a glaze slurry. The glaze slurry is vacuum-defoamed and set aside. The solid content of the glaze slurry is about 63%. The surface of the magnetic conductive layer is dipped with the above glaze slurry for 3-5 minutes. After natural drying, it is fired at a temperature of 800℃ for 5 hours.

[0040] In this embodiment, after the magnetic conductive layer is cold-sprayed, its porosity is tested and found to be 0.15-0.18%. The maximum heating power of the prepared electromagnetic ceramic casserole is as high as 1680W.

[0041] Example 2:

[0042] An electromagnetic ceramic casserole comprises a casserole body, a casserole glaze layer, a magnetic conductive layer and a protective layer; the casserole glaze layer is 0.5 mm thick, the magnetic conductive layer is 0.3 mm thick, and the protective layer is 0.2 mm thick.

[0043] The raw materials of the casserole glaze layer are as follows by weight: 33 parts of kaolin, 25 parts of spodumene, 10 parts of lithium feldspar, 5 parts of quartz, 10 parts of volcanic rock, 3 parts of high-purity silver, and 3 parts of zirconium oxide; the material of the magnetic conductive layer is a metal powder composed of Fe, Ni, Co, iron alloy and stainless steel, the particle size of the metal powder is 500-600 nm, and the mass ratio of Fe, Ni, Co, iron alloy and stainless steel is 10:5:2:3:5; the raw materials of the protective layer are as follows by weight: 20 parts of kaolin, 15 parts of dolomite, 10 parts of wollastonite, 10 parts of sodium silicate water glass, 10 parts of bentonite, 5 parts of feldspar, 5 parts of calcium stearate, 3 parts of high-purity silver, 0.5 parts of zinc oxide, 0.5 parts of zirconium oxide, 1 part of strontium oxide, and 0.03 parts of cerium oxide.

[0044] The preparation of the electromagnetic ceramic casserole comprises the following steps:

[0045] S1. The raw materials for the casserole glaze are mixed and ground for 20-30 hours until the particle size is 30-50 μm. Then, an appropriate amount of water is added and mixed evenly to obtain a glaze slurry. The glaze slurry is vacuum-defoamed and set aside. The solid content of the glaze slurry is about 58%. When pouring the glaze slurry on the bottom of the casserole body, the glaze slurry flow rate is 40 seconds and the glaze amount is 730g / m 2 .

[0046] S2. After polishing the bottom of the casserole, apply the glaze slurry prepared in S1. After air-drying, fire the casserole in a gradual temperature increase: first, at 450°C for 2 hours; then to 900°C for 3 hours; and finally to 1300°C for 10 hours. This gradual temperature increase reduces noticeable firing defects and ensures a tight bond between the glaze and the casserole.

[0047] S3. The raw material of the magnetic layer is sprayed on the surface of the glaze layer by cold spraying to form a magnetic layer; the cold spraying method uses a working gas to cold spray the metal powder on the surface of the glaze layer to form a magnetic layer. The process parameters of the cold spraying include a spray pressure of 5 MPa, a spray temperature of 300 ° C, and a gas velocity of 3 m 3 / min, the spray distance is 30mm.

[0048] S4. Mix the raw materials for the protective layer and grind them for 10-18 hours until the particle size is 60-80μm. Then add an appropriate amount of water and mix them evenly to obtain a glaze slurry. The glaze slurry is vacuum-defoamed and set aside. The solid content of the glaze slurry is about 65%. The surface of the magnetic conductive layer is dipped with the above glaze slurry for 3-5 minutes. After natural drying, it is fired at a firing temperature of 1000℃ for 2 hours.

[0049] In this embodiment, after the magnetic conductive layer is cold-sprayed, its porosity is tested and found to be 0.13-0.15%. The maximum electromagnetic heating power of the prepared electromagnetic ceramic casserole is as high as 1860W.

[0050] Example 3:

[0051] An electromagnetic ceramic casserole comprises a casserole body, a casserole glaze layer, a magnetic conductive layer and a protective layer; the thickness of the casserole glaze layer is 0.3 mm, the thickness of the magnetic conductive layer is 0.15 mm, and the thickness of the protective layer is 0.2 mm.

[0052] The raw materials of the casserole glaze layer are as follows by weight: 32 parts of kaolin, 23 parts of spodumene, 7 parts of lithium feldspar, 4 parts of quartz, 8 parts of volcanic rock, 1 part of high-purity silver, and 1 part of zirconium oxide; the material of the magnetic conductive layer is a metal powder composed of Fe, Ni, Co, iron alloy and stainless steel, the particle size of the metal powder is 200-300 nm, and the mass ratio of Fe, Ni, Co, iron alloy and stainless steel is 8:4:2:2:3; the raw materials of the protective layer are as follows by weight: 16 parts of kaolin, 12 parts of dolomite, 7 parts of wollastonite, 8 parts of sodium silicate water glass, 6 parts of bentonite, 3 parts of feldspar, 4 parts of calcium stearate, 2 parts of high-purity silver, 0.3 parts of zinc oxide, 0.2 parts of zirconium oxide, 0.07 parts of strontium oxide, and 0.02 parts of cerium oxide.

[0053] The preparation of the electromagnetic ceramic casserole comprises the following steps:

[0054] S1. The raw materials for the casserole glaze are mixed and ground for 25-30 hours until the particle size is 30-40 μm. Then, an appropriate amount of water is added and mixed evenly to obtain a glaze slurry. The glaze slurry is vacuum-defoamed and set aside. The solid content of the glaze slurry is about 60%. When pouring the glaze slurry on the bottom of the casserole body, the glaze slurry flow rate is 39 seconds and the glaze weight is 728g / m 2 .

[0055] S2. After polishing the bottom of the casserole body smoothly, pour the glaze slurry prepared in S1 on its surface. After natural air drying, it is fired. The firing temperature is gradually increased; the first stage temperature is 500℃, and the firing is carried out for 1 hour; then the temperature is raised to 950℃ and fired for 2 hours; finally, the temperature is raised to 1330℃ and fired for 9 hours. The gradual increase in temperature can reduce obvious firing defects and ensure a close bond between the glaze layer and the casserole body.

[0056] S3. The raw material of the magnetic layer is sprayed on the surface of the glaze layer by cold spraying to form a magnetic layer; the cold spraying method uses a working gas to cold spray the metal powder on the surface of the glaze layer to form a magnetic layer. The process parameters of the cold spraying include a spray pressure of 4 MPa, a spray temperature of 400°C, and a gas velocity of 2.5 m 3 / min, the spray distance is 25mm.

[0057] S4. Mix the raw materials for the protective layer and grind them for 14-18 hours until the particle size is 60-70μm. Then add an appropriate amount of water and mix evenly to obtain a glaze slurry. The glaze slurry is vacuum-defoamed and set aside. The solid content of the glaze slurry is 65%. The surface of the magnetic conductive layer is dipped with the above glaze slurry for 3-5 minutes. After natural drying, it is fired at a temperature of 900°C for 3 hours.

[0058] In this embodiment, after the magnetic conductive layer is cold-sprayed, its porosity is tested and found to be 0.12-0.13%. The maximum electromagnetic heating power of the prepared electromagnetic ceramic casserole is as high as 1880W.

[0059] Embodiment 4:

[0060] An electromagnetic ceramic casserole comprises a casserole body, a casserole glaze layer, a magnetic conductive layer and a protective layer; the thickness of the casserole glaze layer is 0.4 mm, the thickness of the magnetic conductive layer is 0.15 mm, and the thickness of the protective layer is 0.2 mm.

[0061] The raw materials of the casserole glaze layer are as follows by weight: 32 parts of kaolin, 22 parts of spodumene, 5 parts of lithium feldspar, 4 parts of quartz, 9 parts of volcanic rock, 1.5 parts of high-purity silver, and 2 parts of zirconium oxide; the material of the magnetic conductive layer is a metal powder composed of Fe, Ni, Co, iron alloy and stainless steel, the particle size of the metal powder is 100-300 nm, and the mass ratio of Fe, Ni, Co, iron alloy and stainless steel is 9:4:2:2:4; the raw materials of the protective layer are as follows by weight: 18 parts of kaolin, 14 parts of dolomite, 7 parts of wollastonite, 8 parts of sodium silicate water glass, 6 parts of bentonite, 4 parts of feldspar, 4 parts of calcium stearate, 1.5 parts of high-purity silver, 0.3 parts of zinc oxide, 0.2 parts of zirconium oxide, 0.08 parts of strontium oxide, and 0.02 parts of cerium oxide.

[0062] The preparation of the electromagnetic ceramic casserole comprises the following steps:

[0063] S1. The raw materials for the casserole glaze are mixed and ground for 30 hours until the particle size is 30-32 μm. Then, an appropriate amount of water is added and mixed evenly to obtain a glaze slurry. The glaze slurry is vacuum-defoamed and set aside. The solid content of the glaze slurry is 61%. When pouring the glaze slurry on the bottom of the casserole body, the glaze slurry flow rate is 38.5 seconds and the glaze weight is 745g / m 2 .

[0064] S2. After polishing the bottom of the casserole body, pour the glaze prepared in S1 on its surface. After natural air drying, it is fired. The firing temperature is gradually increased; the first stage temperature is 550°C, and the firing time is 1 hour; then the temperature is raised to 960°C and fired for 2 hours; finally, the temperature is raised to 1310°C and fired for 12 hours.

[0065] S3. The raw material of the magnetic layer is sprayed on the surface of the glaze layer by cold spraying to form a magnetic layer; the cold spraying method uses a working gas to cold spray the metal powder on the surface of the glaze layer to form a magnetic layer. The process parameters of the cold spraying include a spray pressure of 4.5 MPa, a spray temperature of 350°C, and a gas velocity of 2.4 m 3 / min, the spray distance is 23mm.

[0066] S4. Mix the raw materials for the protective layer and grind them for 10-15 hours until the particle size is 70-80μm. Then add an appropriate amount of water and mix them evenly to obtain a glaze slurry. The glaze slurry is vacuum-defoamed and set aside. The solid content of the glaze slurry is 64%. The surface of the magnetic conductive layer is dipped with the above glaze slurry for 3-5 minutes. After natural drying, it is fired at a temperature of 850°C for 4 hours.

[0067] In this embodiment, after the magnetic conductive layer is cold-sprayed, its porosity is tested and found to be 0.16-0.18%. The maximum electromagnetic heating power of the prepared electromagnetic ceramic casserole is as high as 1740W.

[0068] Example 5:

[0069] An electromagnetic ceramic casserole comprises a casserole body, a casserole glaze layer, a magnetic conductive layer and a protective layer; the casserole glaze layer is 0.35 mm thick, the magnetic conductive layer is 0.15 mm thick, and the protective layer is 0.2 mm thick.

[0070] The raw materials of the casserole glaze layer are as follows by weight: 33 parts of kaolin, 22 parts of spodumene, 5 parts of lithium feldspar, 3 parts of quartz, 9 parts of volcanic rock, 2 parts of high-purity silver, and 3 parts of zirconium oxide; the material of the magnetic conductive layer is a metal powder composed of Fe, Ni, Co, iron alloy and stainless steel, the particle size of the metal powder is 800-900 nm, and the mass ratio of Fe, Ni, Co, iron alloy and stainless steel is 7:3:2:3:4; the raw materials of the protective layer are as follows by weight: 18 parts of kaolin, 14 parts of dolomite, 7 parts of wollastonite, 9 parts of sodium silicate water glass, 7 parts of bentonite, 4 parts of feldspar, 3 parts of calcium stearate, 1.5 parts of high-purity silver, 0.4 parts of zinc oxide, 0.3 parts of zirconium oxide, 0.07 parts of strontium oxide, and 0.03 parts of cerium oxide.

[0071] The preparation of the electromagnetic ceramic casserole comprises the following steps:

[0072] S1. The raw materials for the casserole glaze are mixed and ground to a particle size of 35-40 μm. An appropriate amount of water is then added and mixed to obtain a glaze slurry. The glaze slurry is vacuum-defoamed and set aside. The glaze slurry has a solid content of 62%. When pouring the glaze slurry on the bottom of the casserole body, the glaze slurry flow rate is 40 seconds and the glaze weight is 768g / m 2.

[0073] S2. After polishing the bottom of the casserole body smoothly, pour the glaze slurry prepared in S1 on its surface. After natural air drying, it is fired at a temperature of 1290°C and a firing time of 16 hours.

[0074] S3. The raw material of the magnetic layer is sprayed on the surface of the glaze layer by cold spraying to form a magnetic layer; the cold spraying method uses a working gas to cold spray the metal powder on the surface of the glaze layer to form a magnetic layer. The process parameters of the cold spraying include a spray pressure of 4.5 MPa, a spray temperature of 380°C, and a gas velocity of 2.7 m 3 / min, the spray distance is 28mm.

[0075] S4. Mix the raw materials for the protective layer and grind them to a particle size of 75-80μm. Then add an appropriate amount of water and mix them evenly to obtain a glaze slurry. The glaze slurry is vacuum-defoamed and set aside. The solid content of the glaze slurry is 65%. The surface of the magnetic conductive layer is dipped with the above glaze slurry for 5 minutes. After natural drying, it is fired at a temperature of 950℃ for 3 hours.

[0076] In this embodiment, after the magnetic conductive layer is cold-sprayed, its porosity is tested and found to be 0.18-0.20%. The maximum electromagnetic heating power of the prepared electromagnetic ceramic casserole is as high as 1710W.

[0077] According to the disclosure and teachings of the above description, those skilled in the art to which the present invention belongs may also change and modify the above-mentioned embodiments. Therefore, the present invention is not limited to the specific embodiments disclosed and described above, and some modifications and changes to the invention should also fall within the scope of protection of the claims of the present invention. In addition, although some specific terms are used in this description, these terms are only for convenience of explanation and do not constitute any limitation to the present invention.

Claims

1. An electromagnetic ceramic casserole, characterized in that: The invention comprises a casserole body, a casserole glaze layer, a magnetic conductive layer and a protective layer; the thickness ratio of the casserole glaze layer, the magnetic conductive layer and the protective layer is 2-5:1-3:1-2; the raw materials of the casserole glaze layer include, by weight, 30-33 parts of kaolin, 20-25 parts of spodumene, 1-10 parts of lithium feldspar, 3-5 parts of quartz, 8-10 parts of volcanic stone, 1-3 parts of high-purity silver and 1-3 parts of zirconium oxide; the material of the magnetic conductive layer includes Fe, Ni, Co, , ferroalloy and stainless steel; the raw materials of the protective layer include, by weight: 15-20 parts of kaolin, 10-15 parts of dolomite, 5-10 parts of wollastonite, 5-10 parts of sodium silicate water glass, 5-10 parts of bentonite, 3-5 parts of feldspar, 3-5 parts of calcium stearate, 1-3 parts of high-purity silver, 0.1-0.5 parts of zinc oxide, 0.1-0.5 parts of zirconium oxide, 0.05-1 parts of strontium oxide, and 0.01-0.03 parts of cerium oxide; The preparation of the electromagnetic ceramic casserole comprises the following steps: S1. The raw materials for the casserole glaze layer are mixed evenly to prepare a glaze slurry; S2. After polishing the bottom of the casserole body, apply the glaze slurry prepared in S1 to its surface, let it air dry and then fire it at a temperature of 1270-1350°C for 10-20h. S3 the raw material of the magnetic layer by cold spraying method on the surface of the glaze layer to form a magnetic layer; S4. The raw materials for the protective layer are mixed uniformly to prepare a glaze slurry, the glaze slurry is coated on the surface of the magnetic conductive layer, and then fired at a temperature of 800 to 1000° C. for 2 to 5 hours.

2. The electromagnetic ceramic casserole according to claim 1, characterized in that: The cold spraying process uses working gas to cold spray metal powder on the surface of the glaze layer to form a magnetic conductive layer. The process parameters of the cold spraying process include a spray pressure of 3 to 5 MPa, a spray temperature of 300 to 500°C, and a gas velocity of 2 to 3 m 3 / min, the spraying distance is 20-30mm.

3. The electromagnetic ceramic casserole according to claim 2, characterized in that: The particle size of the metal powder is 100-1000 nm, and the thickness of the magnetic conductive layer is 0.1-0.3 mm.

4. The electromagnetic ceramic casserole according to claim 1, characterized in that: The mass ratio of Fe, Ni, Co, iron alloy and stainless steel in the magnetic conductive layer is 7-10:3-5:1-2:1-3:3-5.

5. The electromagnetic ceramic casserole according to claim 1, characterized in that: The thickness of the casserole glaze layer is 0.2-0.5 mm, the thickness of the magnetic conductive layer is 0.1-0.3 mm, and the thickness of the protective layer is 0.1-0.2 mm.

6. The electromagnetic ceramic casserole according to claim 1, characterized in that: The raw materials of the casserole glaze layer include, by weight, 32 parts of kaolin, 23 parts of spodumene, 7 parts of lithium feldspar, 4 parts of quartz, 8 parts of volcanic stone, 1 part of high-purity silver, and 1 part of zirconium oxide.

7. The electromagnetic ceramic casserole according to claim 1, characterized in that: The raw materials of the protective layer include, by weight, 16 parts of kaolin, 12 parts of dolomite, 7 parts of wollastonite, 8 parts of sodium silicate water glass, 6 parts of bentonite, 3 parts of feldspar, 4 parts of calcium stearate, 2 parts of high-purity silver, 0.3 parts of zinc oxide, 0.2 parts of zirconium oxide, 0.07 parts of strontium oxide, and 0.02 parts of cerium oxide.

8. The electromagnetic ceramic casserole according to claim 1, characterized in that: S1. Mix the raw materials for the casserole glaze and grind them for 20-30 hours until the particle size is 30-50 μm. Then, add an appropriate amount of water and mix evenly to obtain a glaze slurry. Vacuum the glaze slurry to remove bubbles and set aside. The glaze slurry has a solid content of 58-62%. When pouring the glaze slurry on the bottom of the casserole body, the glaze slurry flow rate is 38-40 seconds and the glaze weight is 700-800 g / m 2 .

9. The electromagnetic ceramic casserole according to claim 1, characterized in that: S4. Mix the raw materials for the protective layer and grind them for 10-18 hours until the particle size is 60-80μm. Then add an appropriate amount of water and mix them evenly to obtain a glaze slurry. The glaze slurry is vacuum-defoamed and set aside. The solid content of the glaze slurry is 63-65%. The surface of the magnetic conductive layer is dipped with the above glaze slurry for 3-5 minutes. After natural drying, it is fired at a temperature of 850°C for 4 hours.

10. The electromagnetic ceramic casserole according to claim 1, characterized in that: The firing temperature in S2 is gradually increased; the first stage temperature is 450℃~600℃, and the firing is carried out for 1-2 hours; then the temperature is increased to 900℃~1000℃, and the firing is carried out for 2-3 hours; finally the temperature is increased to 1270~1350℃, and the firing is carried out for 7-15 hours.

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