Magnetic conductive material for cookware and preparation method thereof

Abstract

The present invention provides a magnetic conductive material for a cookware and a preparation method thereof. The magnetic conductive material comprises high entropy alloy powder and ferromagnetic material, and the weight ratio of the high entropy alloy powder to the ferromagnetic material is 1:2-1:3. The magnetic conductive material according to the present invention has the advantages of high strength, high hardness, good toughness, high magnetic permeability and corrosion resistance; in addition, the magnetic conductive material also has good processing performance, is easy to form a magnetic conductive layer, and the formed magnetic conductive layer has the advantages of uniform heating, corrosion resistance and high bonding strength when used in the cookware.

Description

Technical Field

[0001] The present invention relates to the technical field of household appliances, and more particularly to a magnetic conductive material for cookware and a preparation method thereof. Background Art

[0002] At present, the use of induction cookers is becoming more and more common. Due to the working characteristics of induction cookers, only iron pots can be used to cook food on induction cookers, and pots of other materials cannot be used on induction cookers. In order to allow pots of other materials to be used normally on induction cookers, it is necessary to improve the pots of other materials. The existing modified magnetic conductive appliances have the following problems: the cold-riveted stainless steel composite bottom sheet has the disadvantages of not being tightly bonded and easy to fall off, which will cause the product to deform and concave, and the pot needs to have a flat bottom surface with a certain diameter; the iron and stainless steel composite pot body has the disadvantages of high cost, complex process, and easy delamination at high temperature; the outer bottom is hot-sprayed with iron and stainless steel, which is easy to rust and corrode, and requires additional protective coating; the existing magnetic conductive appliances have high electromagnetic noise and slow heat transfer when used on induction cookers. Summary of the invention

[0003] The present invention aims to solve at least one of the technical problems existing in the above-mentioned prior art or related technology.

[0004] To this end, a first aspect of the present invention is to provide a magnetic conductive material for a cooker.

[0005] A second aspect of the present invention is to provide a method for preparing a magnetic conductive material for a cooker.

[0006] To achieve the above object, the first embodiment of the present invention provides a magnetic conductive material for a cooker, wherein the magnetic conductive material comprises a high entropy alloy powder and a ferromagnetic material, wherein the weight ratio of the high entropy alloy powder to the ferromagnetic material is 1:1-1:3, and the ferromagnetic material has ferromagnetism and an amorphous structure. The magnetic conductive material according to the present invention has the advantages of high strength, high hardness, good toughness, high magnetic permeability and corrosion resistance.

[0007] According to an embodiment of the present invention, the ferromagnetic material may include at least one of Fe, Co and Ni and at least one of Zr, Cu, Al, Mg, Ti, Sn, Ni, Pb, Zn, Nd, Ga, Mo, Hf, Cr, Ca, Y, Si, P, B and C. The high entropy alloy powder includes at least four of Mg, Al, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Zr, Nb, Mo, Sn, Hf, Ta, W, Pb, Si and B. The ferromagnetic material and the high entropy alloy powder are formed of the above elements to better ensure the magnetic permeability of the formed magnetic conductive material.

[0008] According to an embodiment of the present invention, the particle sizes of the high entropy alloy powder and the ferromagnetic material are both 500-2000 meshes; the particle size of the magnetic conductive material is 200-1500 meshes. Controlling the particle sizes of the high entropy alloy powder and the ferromagnetic material within this range can better mix them, and the prepared magnetic conductive material can be better used in cookware.

[0009] According to another aspect of the present invention, a method for preparing a magnetic conductive material for a cookware is provided, the method comprising the following steps: mixing a high entropy alloy powder with a ferromagnetic material having ferromagnetism and an amorphous structure to obtain a mixed material, wherein the weight ratio of the high entropy alloy powder to the ferromagnetic material is 1:1-1:3; and preparing the mixed material into a magnetic conductive material having a predetermined particle size. The magnetic conductive material prepared by the method has good processing performance, is easy to form a magnetic conductive layer, and the formed magnetic conductive layer has the advantages of uniform heating, corrosion resistance, and high bonding strength when used in a cookware.

[0010] According to an embodiment of the present invention, the preparation method may further include: before the step of preparing the mixed material into a magnetic conductive material having a predetermined particle size, mixing the mixed material with a binder, a filler, an auxiliary agent and a solvent to obtain a slurry; wherein the slurry is spray-dried to obtain a magnetic conductive material having a predetermined particle size. This step can facilitate the formation of the magnetic conductive material by spray drying.

[0011] According to an embodiment of the present invention, the binder may include at least one of polyvinyl alcohol, polyvinyl pyrrolidone and sodium carboxymethyl cellulose; the filler may include at least one of graphite and carbon black; and the solvent may include water. Selecting the binder, filler and solvent from the above substances can better form the magnetic conductive material through spray drying.

[0012] According to an embodiment of the present invention, the auxiliary agent may include at least one of a dispersant and a defoamer, the dispersant may include at least one of stearic acid monoglyceride and tristearic acid glyceride, and the defoamer may include at least one of polydimethylsiloxane, trialkyl melamine, cyanuric chloride melamine and fatty amine. The addition of the auxiliary agent can improve the dispersibility of each substance and eliminate bubbles in the slurry.

[0013] According to an embodiment of the present invention, the slurry may include, by weight percentage: 30wt%-60wt% of ferromagnetic material, 15wt%-30wt% of high entropy alloy powder, 5wt%-10wt% of binder, 5wt%-20wt% of filler, 0.2wt%-5wt% of auxiliary agent and 10wt%-40wt% of solvent. Controlling the content of each component of the slurry within the above range can better form a magnetic conductive material.

[0014] According to the embodiment of the present invention, when the atomization pressure is 0.3-0.6 MPa and the atomization air flow rate is 0.5-5 m3 / h, inlet temperature of 200-600° C., and outlet temperature of 50-200° C. Spray drying can improve production efficiency under these conditions.

[0015] According to an embodiment of the present invention, the step of preparing the mixed material into a magnetic conductive material with a predetermined particle size can be performed by a sintering process. In addition to the spray drying process, the magnetic conductive material can be formed by a sintering process, thereby providing another way to prepare the magnetic conductive material.

[0016] The present invention has the following beneficial effects:

[0017] (1) Compared with the prior art, the present invention uses a spray drying process or a sintering process to make a magnetic conductive material with a particle size of 200-1500 meshes from a high entropy alloy powder and a ferromagnetic material, thereby compensating for the problem of high material brittleness caused by structural defects such as the lack of dislocation slip paths in the ferromagnetic material, and the magnetic conductive layer formed on the surface of the cookware substrate using the magnetic conductive material has the advantages of high strength, high hardness, good toughness, high magnetic permeability, and good corrosion resistance;

[0018] (2) Compared with the prior art, the magnetic coating formed by the magnetic material in the present invention has a high bonding strength with the pot body substrate, thereby extending the service life of the magnetic cookware prepared using the magnetic material in the present invention. DETAILED DESCRIPTION

[0019] The following describes the magnetic conductive materials for cookware and the preparation methods thereof according to some embodiments of the present invention.

[0020] However, the present invention may be embodied in many different forms and should not be construed as limited to the specific embodiments set forth herein. Rather, these embodiments are provided so that this invention will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

[0021] In the art, a ferromagnetic material with magnetic conductivity and amorphous structure (such as ferromagnetic liquid metal) can be selected to form a magnetic conductive layer and used to improve cookware of other materials. The magnetic conductive sheet or magnetic conductive layer made of ferromagnetic material with magnetic conductivity and amorphous structure has the advantages of good bonding with the base of cookware of other materials and simple improvement process. However, since the magnetic conductive layer formed by the ferromagnetic material with amorphous structure has no structural defects such as dislocation and stacking fault, the formed magnetic conductive layer has problems such as high brittleness.

[0022] Therefore, the present invention provides a magnetic conductive material for cookware, wherein the magnetic conductive material comprises a high entropy alloy powder and a ferromagnetic material having a ferromagnetic and amorphous structure, or is composed of a high entropy alloy powder and a ferromagnetic material having a ferromagnetic and amorphous structure, and the weight ratio of the high entropy alloy powder to the ferromagnetic material having a ferromagnetic and amorphous structure is 1:1-1:3, preferably 1:2. In the present invention, the weight ratio of the high entropy alloy powder to the ferromagnetic material is controlled to be 1:1-1:3, which can not only ensure that the magnetic conductive properties of the magnetic conductive layer formed by the obtained magnetic conductive material will not be affected; and the formed magnetic conductive material can have the advantages of reducing magnetic loss, improving toughness, reducing magnetostriction characteristics, and improving the rust resistance of the cookware.

[0023] In some embodiments, the ferromagnetic material having ferromagnetism and an amorphous structure may include ferromagnetic liquid metal powder, specifically, may include a combination of at least one of Fe, Co and Ni and at least one of Zr, Cu, Al, Mg, Ti, Mn, Sn, Ni, Pb, Zn, Nd, Ga, Mo, Hf, Cr, Ca, Y, Si, P, B and C. For example, the ferromagnetic material may include FeCoNiMnZn or Fe 80 Si5B5Nb7Cu3, etc. In addition, in the ferromagnetic material, Fe, Co and / or Ni as main magnetic conductive elements account for no less than 60%, for example, no less than 80%.

[0024] In some embodiments, with the development of the technology in this field, high entropy alloy powder may refer to an alloy formed by four or more equal or approximately equal amounts of metals (or may be formed by five or more equal or approximately equal amounts of metals), for example, the high entropy alloy powder may include at least four of Mg, Al, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Zr, Nb, Mo, Sn, Hf, Ta, W, Pb, Si and B. Preferably, the high entropy alloy powder may include an alloy composed of at least one of Fe, Co and Ni and an element other than Fe, Co and Ni in the above to ensure that the magnetic conductive material formed by the ferromagnetic material and the high entropy alloy powder has good magnetic conductivity. For example, the high entropy alloy powder may include (or may be) CuTiVFeNiZr, AlCoCrCuNi, CoCrFeNi, AlMoNbV, MoNbTiV or FeCoNiCu.

[0025] In some embodiments, the particle size of the high entropy alloy powder and the ferromagnetic material can be 500 mesh to 2000 mesh. Ferromagnetic materials and high entropy alloy powders with a particle size of 500 mesh to 2000 mesh are conducive to uniform mixing when preparing magnetic conductive materials, and ensure that the magnetic conductive properties of the magnetic conductive layer formed by the magnetic conductive material are uniform, avoiding problems such as uneven heating and deformation when the magnetic conductive material is used as the magnetic conductive layer of the cookware.

[0026] In addition, the particle size of the prepared magnetic conductive material can be 200 mesh to 1500 mesh, thereby meeting the use environment.

[0027] In the present invention, the high entropy alloy can make up for the problem that the ferromagnetic material with an amorphous structure has a large brittle magnetic layer due to the absence of structural defects such as dislocations. In addition, the magnetic material formed by the ferromagnetic material and the high entropy alloy has the characteristics of high strength, high hardness, good toughness, high magnetic permeability, low magnetic loss and low magnetic expansion. In addition, when the obtained magnetic material is used as the magnetic layer of the cookware, the formed magnetic cookware has the advantages of uniform heating, deformation resistance, constant temperature and corrosion resistance during use.

[0028] The preparation method of the magnetic conductive material for cookware according to the present invention will be described in detail below.

[0029] The method for preparing the magnetic conductive material for cookware according to the present invention comprises: mixing high entropy alloy powder with ferromagnetic material to obtain a mixed material; and making the mixed material into a magnetic conductive material with a predetermined particle size.

[0030] In this embodiment, ferromagnetic material and high entropy alloy powder with particle sizes of 500-2000 mesh are selected to obtain a mixed material. In the present invention, the selection of ferromagnetic material and high entropy alloy powder with particle sizes of 500-2000 mesh is conducive to the high mixing of the two materials, ensuring that the magnetic conductivity of the magnetic layer formed by the magnetic material is uniform, and avoiding problems such as uneven heating and deformation when the magnetic material is used as the magnetic layer of the cookware.

[0031] As an example, the ferromagnetic material and high entropy alloy powder in this embodiment are mixed by ball milling to obtain a mixed material. For example, a planetary ball mill is used to mix the material under the conditions of a ball-to-material ratio of 10:1, a grinding ball diameter of 10 mm, a ball mill speed of 400 r / min, and a ball milling time of 2 h. In the present invention, ball milling is used for mixing, which can ensure that the two materials are fully mixed on the one hand, and on the other hand, the particle size of the raw materials can be reduced during ball milling, further promoting a high degree of mixing of the two materials.

[0032] In this embodiment, a spray drying process or a sintering process may be used to perform the step of preparing the mixed material into a magnetic conductive material having a predetermined particle size.

[0033] When a spray drying process is used to perform the step of making the mixed material into a magnetic conductive material with a predetermined particle size, the mixed material is first mixed with a binder, a filler, an additive and a solvent to obtain a slurry, and then the slurry is spray dried to obtain a magnetic conductive material with a predetermined particle size.

[0034] In the step of mixing the mixed material with the binder, filler, auxiliary agent and solvent, the mixed material may be first mixed with a portion of the solvent, and the binder may be mixed with another portion of the solvent, and then they may be mixed together, and the filler and auxiliary agent may be added to obtain a slurry. Specifically, the mixed material is dispersed in a solvent to obtain a mixed material solution; the binder is mixed with another portion of the solvent at a weight ratio of 1:2 to 1:3, and a binder solution is obtained after impurities are removed; and then the mixed material solution, the binder solution, the auxiliary agent and the filler are stirred and mixed for 30 to 50 minutes to obtain a slurry.

[0035] In the present invention, controlling the weight ratio of the binder to the solvent to be 1:2 to 1:3 can ensure that the formed binder solution has a certain viscosity, thereby avoiding the stratification phenomenon in the binder solution due to the different densities of the components in the mixed material when the binder solution is mixed with the mixed material, thereby preventing the uneven distribution of the mixed material in the slurry from causing the magnetic properties of the magnetic layer formed by the magnetic material to be inconsistent, and ultimately causing the problem of uneven heating when the magnetic material is used as the magnetic layer of the cookware. In this embodiment, if the weight ratio of the binder to the solvent is higher than 1:2, the viscosity of the binder solution is large, making it difficult to disperse the mixed material; if the weight ratio of the binder to the solvent is lower than 1:3, the binder solution is too dilute and the bonding effect is poor.

[0036] In addition, in order to allow the binder to be completely dissolved in the solvent, the solvent can be heated when the solvent dissolves the binder. For example, taking the binder as polyvinyl alcohol and the solvent as water, when the polyvinyl alcohol is completely dissolved in water, it is heated to above 95°C, at which time the polyvinyl alcohol is completely dissolved in water, and the binder solution finally obtained has a certain viscosity and is transparent. In addition, the obtained binder solution needs to be further impurity-removed to finally obtain a binder solvent that can be used in the spray drying process.

[0037] In this embodiment, the binder may include at least one of polyvinyl alcohol, polyvinyl pyrrolidone and sodium carboxymethyl cellulose.

[0038] In this embodiment, the filler is used to adjust the viscosity of the slurry and prevent the mixed material from settling. For example, the filler may include at least one of graphite and carbon black.

[0039] In this embodiment, the solvent may include water.

[0040] In this embodiment, the auxiliary agent may include at least one of a dispersant and a defoamer, so as to facilitate better dispersion of the mixed material and the binder, or eliminate bubbles in the slurry. The dispersant may include at least one of stearic acid monoglyceride and tristearic acid glyceride; the defoamer may include at least one of polydimethylsiloxane, trialkyl melamine, cyanuric chloride melamine and fatty amine (e.g., C8 to C10 fatty amine).

[0041] In this embodiment, the mass fraction of each component in the slurry is described to ensure that the magnetic layer formed by the magnetic material prepared by the slurry of each component at this mass fraction through a spray drying process has the characteristics of high strength, high hardness, good toughness, high magnetic permeability, low magnetic loss and low degree of magnetostriction.

[0042] As an example, the slurry may include by weight percentage: 30wt%-60wt% of ferromagnetic material, 15wt%-30wt% of high entropy alloy powder, 5wt%-10wt% of binder, 5wt%-20wt% of filler, 0.2wt%-5wt% of auxiliary agent and 10wt%-40wt% of solvent. Preferably, the slurry may include by weight percentage: 40wt%-50wt% of ferromagnetic material, 15wt%-30wt% of high entropy alloy powder, 6wt%-8wt% of binder, 8wt%-15wt% of filler, 0.2wt%-1wt% of auxiliary agent and 30wt%-40wt% of solvent.

[0043] The ferromagnetic material is controlled within the range of 30wt%-60wt%, mainly to make the granulated powder have good ferromagnetism. If it is less than 30wt%, the ferromagnetic effect is not good. If it is more than 60wt%, the granulated composite powder is too brittle and the subsequent spray deposition rate is poor. The high entropy alloy powder is controlled within the range of 15wt%-30wt% to reduce the brittleness of the composite powder. The binder is controlled within the range of 5wt%-10wt% to better combine the two powders required for granulation. If it is less than 5wt%, the bonding strength is poor, and if it is more than 10wt%, it is easy to agglomerate. The filler is controlled within the range of 5wt%-30wt% to prevent material sedimentation and adjust the slurry viscosity. The content of the additive can be added according to the actual situation. The solvent is used for powder dispersion and slurrying.

[0044] In the step of spray drying the slurry, a magnetic conductive material with a particle size of 200-1500 mesh can be obtained by spraying cleanly. Specifically, the slurry is fluidized by mechanical action, so that the slurry is dispersed into fine particles like mist, which increases the evaporation area of ​​the solvent in the slurry, and can quickly remove the solvent in the particles during drying, so that the solid matter in the particles is dried into a magnetic conductive material with a regular shape and a particle size of 200-1500 mesh.

[0045] In order to ensure that the particle size distribution of the magnetic conductive material is uniform and there is no uneven distribution of ferromagnetic material and high entropy alloy powder in the magnetic conductive material, and the particle size of the magnetic conductive material is 200-1500 mesh, this embodiment is used as an example to illustrate the spray drying conditions. Specifically, the spray drying conditions are: the atomization pressure is 0.3-0.6Mpa, the atomization air flow rate is 0.5-5m 3 / h, inlet temperature is 200~600℃, outlet temperature is 50~200℃; preferably, atomization pressure is 0.4~0.5Mpa, atomization air flow rate is 1~3m 3 / h, inlet temperature is 300-400℃, outlet temperature is 80-160℃. In the spray drying process, if the atomization pressure is too large, the particle size of the particles formed by the slurry atomization will be small, resulting in a small particle size of the obtained magnetic conductive material. If the atomization airflow is too small, the movement of the particles is not sufficient, and the temperature and humidity distribution in different areas are obviously uneven, which is easy to form large-size particles; when the atomization airflow is too large, there will be collisions between particles and between particles and the dryer wall, which is easy to produce relatively fine magnetic conductive materials, and relatively fine magnetic conductive materials are easy to escape from the atomization dryer.

[0046] In this embodiment, spray drying can avoid the agglomeration and sedimentation separation of ferromagnetic materials and high entropy alloy powders in the slurry, maintain the original uniformity of the slurry, and avoid the uneven distribution of metal powders in the obtained magnetic conductive material; at the same time, spray drying also has the characteristics of fast drying speed and uniform slurry atomization, ensuring that the particle size distribution of the obtained magnetic conductive material is uniform.

[0047] According to another embodiment of the present invention, a magnetic conductive material with a predetermined particle size can be formed by a sintering process. Specifically, under the protection of an inert gas (for example, argon), the temperature is raised to 1200°C at a heating rate of 2 to 5°C / min, and the temperature is kept at this temperature for 15 to 20 hours. After sintering, the obtained magnetic conductive material is cooled, crushed and sieved in sequence, and finally a magnetic conductive material for cookware with a particle size of 200 to 1500 is obtained. During sintering, the use of an inert gas for protection is to avoid oxidation of the ferromagnetic material in the ferromagnetic material. The temperature is gradually raised to 1200°C and kept at this temperature for 15 to 20 hours. The purpose is to allow the surface of the granular metal powder in the mixed material to melt at high temperature, thereby melting the ferromagnetic material and the high entropy alloy powder together to form a magnetic conductive material. The sintering process can also avoid the problem of segregation of the obtained magnetic conductive material. Since the surface of the ferromagnetic material melts and combines with the high entropy alloy powder to form a larger magnetic conductive material, the magnetic conductive material after sintering and cooling needs to be crushed to finally obtain a magnetic conductive material for cookware with a particle size of 200 to 1500 meshes.

[0048] The prepared magnetic conductive material with a particle size of 200 to 1500 mesh has good processing performance. Therefore, when used as a magnetic conductive material for cookware, it is easy to spray on the surface of the cookware or easily processed into a magnetic conductive sheet, which reduces the processing difficulty of the magnetic conductive material in the later use and is conducive to the promotion and use of the magnetic conductive material.

[0049] The magnetic conductive material in this embodiment can form a magnetic conductive coating on the surface of the cookware base by spraying, such as plasma spraying; in addition, the magnetic conductive material can also be directly made into a magnetic conductive sheet, and then directly pressed together with the cookware base.

[0050] The magnetic conductive material and the preparation method thereof according to the present invention will be described in detail below with reference to the embodiments and comparative examples.

[0051] Example 1

[0052] The method for preparing a magnetic conductive material for a cooker comprises the following steps:

[0053] Preparation of mixed materials:

[0054] The mixed material is obtained by mixing the high entropy alloy powder with a particle size of about 550 mesh and the ferromagnetic material at a mass ratio of about 1:2 through ball milling. The mass fraction of each component in the mixed material is shown in Table 1 below:

[0055] Table 1

[0056]

[0057] Preparation of magnetic conductive materials:

[0058] The binder polyvinyl alcohol and solvent water were mixed in a weight ratio of 1:2, heated to 95°C during mixing to completely dissolve the polyvinyl alcohol in the solvent water, and then cooled and impurities were removed to obtain a binder solution; the mixed material was dispersed in the solvent water, and then stirred and mixed with the binder solution, additives and fillers for 50 minutes to obtain a slurry. The mass fractions of the components in the slurry are shown in Table 2 below; the slurry was atomized at an atomization pressure of 0.3 MPa and an atomization air flow rate of 0.5 m 3 / h, an inlet temperature of 200°C, and an outlet temperature of 50°C, and spray drying was performed to prepare a magnetic conductive material for cookware with a particle size of about 200 meshes.

[0059] Finally, the magnetic conductive material prepared in this embodiment is sprayed onto the outer surface of the pot body substrate by a plasma spraying process, forming a magnetic conductive layer with a thickness of 500 μm on the surface of the pot body substrate, and finally obtaining a magnetic conductive cookware.

[0060] Table 2

[0061] Components Mass fraction (wt%) Ferromagnetic materials 40 High Entropy Alloy Powder 20 Binder 6 filler 10 Additives 1 Solvent water 23

[0062] Example 2

[0063] In addition to the method in Table 3, the weight ratio of high entropy alloy powder to ferromagnetic material is 1:1, and the particle size of high entropy alloy powder and ferromagnetic material is about 1000 mesh; and the atomization pressure is 0.6Mpa, the atomization air flow rate is 5m 3 / h, an inlet temperature of 600°C and an outlet temperature of 200°C, and spray-drying the magnetic conductive material with a particle size of 450-600 mesh for cookware. The magnetic conductive material is prepared by the same method as in Example 1.

[0064] Finally, the magnetic conductive material prepared in this embodiment is sprayed onto the outer surface of the pot body substrate by a plasma spraying process, forming a magnetic conductive layer with a thickness of 500 μm on the surface of the pot body substrate, and finally obtaining a magnetic conductive cookware.

[0065] Table 3

[0066] Components Mass fraction (wt%) Ferromagnetic materials 30 High Entropy Alloy Powder 30 Binder 6 filler 10 Additives 1 Solvent water 23

[0067] Example 3

[0068] In addition to the weight ratio of high entropy alloy powder to ferromagnetic material being 1:3 according to Table 4, the particle sizes of high entropy alloy powder and ferromagnetic material are both about 2000 mesh; and the atomization pressure is 0.4 MPa, the atomization air flow rate is 3 m 3 / h, an inlet temperature of 400°C and an outlet temperature of 140°C, spray drying to obtain a magnetic conductive material with a particle size of about 1000 mesh for cookware, the magnetic conductive material is prepared in the same manner as in Example 1.

[0069] Finally, the magnetic conductive material prepared in this embodiment is sprayed onto the outer surface of the pot body substrate by a plasma spraying process, forming a magnetic conductive layer with a thickness of 500 μm on the surface of the pot body substrate, and finally obtaining a magnetic conductive cookware.

[0070] Table 4

[0071]

[0072]

[0073] Example 4

[0074] In addition to the weight ratio of high entropy alloy powder to ferromagnetic material being 1:2 according to Table 5, and the particle size of high entropy alloy powder and ferromagnetic material being about 1500 mesh; and the atomization pressure being 0.5 MPa, and the atomization air flow rate being 3 m 3 / h, an inlet temperature of 400°C and an outlet temperature of 160°C, in addition to preparing a magnetic conductive material with a particle size of about 900 mesh for cookware, the magnetic conductive material is prepared in the same manner as in Example 1.

[0075] Finally, the magnetic conductive material prepared in this embodiment is sprayed onto the outer surface of the pot body substrate by a plasma spraying process, forming a magnetic conductive layer with a thickness of 500 μm on the surface of the pot body substrate, and finally obtaining a magnetic conductive cookware.

[0076] Table 5

[0077] Components Mass fraction (wt%) Ferromagnetic materials 40 High Entropy Alloy Powder 20 Binder 6 filler 10 Additives 1 Solvent water 23

[0078] Comparative Example 1

[0079] After mixing FeCoNiMnZn ferromagnetic material and FeCoNiCu high entropy alloy powder, the mixture is directly sprayed on the outer surface of the pot body substrate by plasma spraying process, so as to form a magnetic conductive layer with a thickness of 500 μm on the surface of the pot body substrate, and finally obtain a magnetic conductive cookware.

[0080] Comparative Example 2

[0081] The FeCoNiMnZn ferromagnetic material is sprayed on the outer surface of the pot body substrate by a plasma spraying process, a magnetic conductive layer with a thickness of 500 μm is formed on the surface of the pot body substrate, and finally a magnetic conductive cookware is obtained.

[0082] Performance index test

[0083] The performance of the magnetic cookware prepared in the above-mentioned Examples 1 to 4 and Comparative Example 1 was tested, and the test results are recorded in the following Table 6.

[0084] (1) Hardness testing method

[0085] The present invention adopts the following method to test the hardness of the magnetic cookware prepared in the above embodiments and comparative examples:

[0086] Sample preparation: Cut the cookware coating sample, inlay, grind and polish the sample section. The hardness is measured by "HVS-1000" digital microhardness tester. The specific steps include: set the test load to 300g, the pressure holding time to 15s; select 10 points on different layers of the metallographic sample along the cross direction; record the coordinate values ​​of the four vertices on the tetrahedral pyramid impression; calculate the diagonal length from the values ​​recorded in the previous step, and calculate the mean of the diagonal; find the hardness of each point by looking up the table from the average value, select the value, and finally calculate the microhardness based on the valid data.

[0087] (2) Toughness test method

[0088] The present invention adopts the following method to test the crack toughness of the magnetic cookware prepared in the above embodiment and comparative example:

[0089] The sample preparation is consistent with the requirements for measuring microhardness. The test platform is a Huayin HV5 small-load Vickers hardness tester. Under a load of 5kg, an indentation is made at a certain distance on the cross section, for a total of 10 indentations. The indentation diagonal must be parallel to the bonding surface of the coating substrate. There must be enough distance between the cracks generated by the two indentations and they cannot interfere with each other. Finally, half of the length of the indentation diagonal a and the length of the indentation crack c are read under a metallographic microscope. Finally, the crack toughness of the coating is calculated according to the Wilshaw formula, and the final result is the average of the calculation results of 10 indentations.

[0090] (3) Corrosion resistance test

[0091] The magnetic cookware prepared in the above-mentioned embodiments and comparative examples was subjected to corrosion resistance test using the neutral salt spray test method of GB / T10125, and the time when corrosion occurred was recorded.

[0092] (4) Bonding strength

[0093] The present invention adopts the method of hot and cold shock to analyze the bonding strength of the magnetic conductive layer in the magnetic conductive cookware prepared in the above embodiment and comparative example. The specific test method is: firstly, the magnetic conductive cookware is heated to 260°C, kept warm for 30 minutes, and then immediately placed in 20°C cold water, and the heating, keeping warm and cooling are regarded as a cycle. The enterprise cookware standard is that the cookware is qualified if there is no damage after 50 cycles of hot and cold shock, and it is unqualified if it is less than 50 times.

[0094] (5) Magnetic permeability measurement

[0095] High magnetic permeability corresponds to high heating efficiency. The heating efficiency is measured to reflect the magnetic permeability. The heating efficiency is the time required for the bottom of the pot to heat up to 200°C.

[0096] Table 6

[0097]

[0098] According to Table 6, the present invention combines high entropy alloy powder and ferromagnetic material together through a spray granulation process or a sintering process, which changes the problem of high material brittleness caused by the lack of structural defects such as dislocation slip paths in the amorphous ferromagnetic material, thereby obtaining a magnetic material with high strength, high hardness, good toughness, high magnetic permeability, low magnetic loss and low magnetostriction. From Examples 1 to 4 and Comparative Example 1, it can be concluded that the magnetic layer formed by the magnetic material prepared from high entropy alloy powder and ferromagnetic material has better hardness and toughness than the magnetic layer formed only by ferromagnetic material; the magnetic pots prepared in Examples 1 to 4 are heated more evenly than the magnetic pots prepared in Comparative Example 1, because the high magnetic permeability is conducive to the uniform distribution of eddy current heat in the magnetic pots, thereby improving the uniform heating of the magnetic pots. In addition, the magnetic layer in the magnetic pots prepared in Examples 1 to 4 has better bonding strength with the pot substrate and better corrosion resistance.

[0099] In summary, the present invention has the following beneficial effects:

[0100] (1) Compared with the prior art, the present invention uses a spray drying process or a sintering process to make a magnetic conductive material with a particle size of 200 to 1500 meshes from a high entropy alloy powder and a ferromagnetic material, thereby compensating for the problem of high material brittleness caused by structural defects such as the lack of dislocation slip paths in the ferromagnetic material, and the magnetic conductive layer formed on the surface of the cookware substrate using the magnetic conductive material has the advantages of high strength, high hardness, good toughness, high magnetic permeability, and good corrosion resistance;

[0101] (2) Compared with the prior art, the magnetic coating formed by the magnetic material in the present invention has a high bonding strength with the pot body substrate, thereby extending the service life of the magnetic cookware prepared using the magnetic material in the present invention.

[0102] The specific implementation methods of the present invention are described in detail above. Although some embodiments have been shown and described, those skilled in the art should understand that these embodiments may be modified and improved (for example, different features described in different embodiments may be combined) without departing from the principles and spirit of the present invention, the scope of which is defined by the claims and their equivalents. These modifications and improvements should also be within the scope of protection of the present invention.

Claims

1. A magnetic conductive material for a cooker, the magnetic conductive material comprising high entropy alloy powder and ferromagnetic material, The weight ratio of the high entropy alloy powder to the ferromagnetic material is 1:1-1:3, The ferromagnetic material has ferromagnetism and an amorphous structure, wherein: The ferromagnetic material includes a combination of at least one of Fe, Co and Ni and at least one of Zr, Cu, Al, Mg, Ti, Mn, Sn, Ni, Pb, Zn, Nd, Ga, Mo, Hf, Cr, Ca, Y, Si, P, B and C; The high entropy alloy powder includes at least four of Mg, Al, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Zr, Nb, Mo, Sn, Hf, Ta, W, Pb, Si and B.

2. The magnetic conductive material according to claim 1, wherein: The weight ratio of the high entropy alloy powder to the ferromagnetic material is 1:

2.

3. The magnetic conductive material according to claim 1, wherein: The particle sizes of the high entropy alloy powder and the ferromagnetic material are both 500 mesh to 2000 mesh; and / or The particle size of the magnetic conductive material is 200 meshes to 1500 meshes.

4. A method for preparing a magnetic conductive material for a cooker, wherein: The preparation method comprises the following steps: Mixing a high entropy alloy powder with a ferromagnetic material having ferromagnetism and an amorphous structure to obtain a mixed material, wherein a weight ratio of the high entropy alloy powder to the ferromagnetic material is 1:1-1:3; and The mixed material is made into a magnetic conductive material with a predetermined particle size; Wherein, the ferromagnetic material comprises a combination of at least one of Fe, Co and Ni and at least one of Zr, Cu, Al, Mg, Ti, Mn, Sn, Ni, Pb, Zn, Nd, Ga, Mo, Hf, Cr, Ca, Y, Si, P, B and C; The high entropy alloy powder includes at least four of Mg, Al, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Zr, Nb, Mo, Sn, Hf, Ta, W, Pb, Si and B.

5. The preparation method according to claim 4, wherein: The preparation method further comprises: before the step of preparing the mixed material into a magnetic conductive material with a predetermined particle size, mixing the mixed material with a binder, a filler, an auxiliary agent and a solvent to obtain a slurry; The slurry is spray-dried to obtain a magnetic conductive material with a predetermined particle size.

6. The preparation method according to claim 5, wherein: The binder comprises at least one of polyvinyl alcohol, polyvinyl pyrrolidone and sodium carboxymethyl cellulose; The filler includes at least one of graphite and carbon black; The solvent includes water.

7. The preparation method according to claim 5, wherein: The auxiliary agent includes at least one of a dispersant and a defoamer, The dispersant comprises at least one of stearic acid monoglyceride and tristearic acid glyceride, The defoaming agent includes at least one of polydimethylsiloxane, trialkyl melamine, melamine cyanurate chloride and fatty amine.

8. The preparation method according to claim 5, wherein: The slurry comprises, by weight percentage, 30wt%-60wt% of ferromagnetic material, 15wt%-30wt% of high entropy alloy powder, 5wt%-10wt% of binder, 5wt%-20wt% of filler, 0.2wt%-5wt% of additive and 10wt%-40wt% of solvent.

9. The preparation method according to claim 5, wherein: When the atomizing pressure is 0.3~0.6Mpa and the atomizing air flow rate is 0.5~5m 3 / h, inlet temperature of 200~600℃, and outlet temperature of 50~200℃ for spray drying.

10. The preparation method according to claim 4, wherein: The step of manufacturing the mixed material into a magnetic conductive material having a predetermined particle size is performed through a sintering process.

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