Wide-temperature low-medium-frequency low-loss MnZn ferrite and preparation method thereof

Abstract

The invention provides wide-temperature low-medium-frequency low-loss MnZn ferrite and a preparation method thereof.The ferrite is formed by secondary sintering of a main component and an auxiliary modifier, the auxiliary modifier is mainly composed of nanometer calcium oxide, nanometer silicon oxide, vanadium oxide, titanium oxide, niobium oxide and other oxides, the main component and the auxiliary modifier are compounded, and therefore the high-loss MnZn ferrite is obtained. The ferrite is prepared by adopting a secondary sintering mode, so that the crystal form and the particle size range of the ferrite can be controlled in the sintering process, the growth stability of ferrite crystals is ensured, the size of the formed crystals is reduced, the porosity in the ferrite is reduced, and the method has the advantages of effectively promoting the development of a transformer towards the miniaturization and light weight direction, improving the production efficiency and the like. The transformer has the advantages that the applicability of the transformer is improved, the use requirement for reducing iron core loss of the transformer under the conditions of medium-low frequency and high temperature can be met, the implementation and improvement cost is low, and popularization and implementation are convenient.

Description

Technical Field

[0001] The present application belongs to the technical field of ferrite material preparation, and specifically relates to a wide-temperature, medium-low-frequency, low-loss MnZn ferrite and a preparation method thereof. Background Art

[0002] In the prior art, with the development of generative artificial intelligence technology, the requirements for computer processing power are becoming increasingly higher. In order to ensure processing power, existing computers occupy a large area, consume high power and generate high heat during the operation of generative artificial intelligence, making them inconvenient to use.

[0003] In the prior art, as a core component of computer equipment, transformers have increasingly higher requirements for their performance, and need to be developed in the direction of miniaturization, thinness, and high conversion efficiency. During the operation of the transformer, its total input power is affected by the operating frequency, the operating magnetic field, and the effective core cross-sectional area. In the prior art, the total input power is often guaranteed by increasing the operating frequency or the operating magnetic field.

[0004] In the prior art, the total loss of the transformer core is affected by the hysteresis loss coefficient, eddy current loss coefficient, residual loss, working magnetic field, and working frequency. In order to promote the miniaturization of the transformer, reduce the volume of the transformer, and reduce the total loss of the transformer core while ensuring the input power and a wide range of working temperatures, it is necessary to adjust the working frequency, working magnetic field, and core material. The core materials currently developed for 300kHz / 120mT on the market have a narrow working temperature range. When the working temperature is high, the total core loss is significantly increased, and the loss can reach 400-800kW / m3. Therefore, it is urgently needed to improve the core material of small transformers so that they can maintain low core loss values ​​and input power under working conditions of medium and low working frequencies and medium and low working magnetic fields. Summary of the invention

[0005] In order to solve the technical problems in the prior art that the transformer is large in size, the operating temperature range of the transformer is narrow, the total loss of the ferrite is high under medium and low frequency and high temperature working conditions, and the service life of the transformer is short, the application proposes a wide temperature medium and low frequency low loss MnZn ferrite;

[0006] In order to solve the technical problem raised by the present application, the present application also provides a method for preparing a wide temperature, medium and low frequency low-loss MnZn ferrite.

[0007] The present application adopts the following scheme: a wide temperature, medium and low frequency, low loss MnZn ferrite is prepared by mixing the main components and the auxiliary modifier and then sintering them in two stages;

[0008] The main components are composed of the following components by weight: 60-72% iron oxide, 10-15% zinc oxide and the balance manganese oxide;

[0009] Relative to the main component, the auxiliary component is composed of the following components, calculated by weight fraction of the main component: 0.05-0.1% nano calcium oxide, 0.2-0.6% cobalt oxide, 0.2-0.8% nickel oxide, 0.005-0.03% nano silicon oxide, 0.001-0.05% vanadium oxide, 0.1-0.5% titanium oxide, 0.001-0.05% niobium oxide, 0.001-0.05% zirconium oxide, and 0.001-0.02% copper oxide.

[0010] By compounding a variety of oxides as auxiliary modifiers for ferrite, on the one hand, the difficulty of two-stage sintering can be reduced, and on the other hand, the nucleus formation and crystal growth of ferrite during the sintering process can be effectively controlled;.

[0011] During the sintering process, nano-calcium carbonate will decompose to generate calcium oxide, which can form a high-resistance layer on the grain boundary, thereby increasing the resistivity and effectively inhibiting grain growth, controlling the crystal particle size range, and making the grains smaller and more uniform, thereby effectively improving the magnetic permeability and mechanical properties of the ferrite. During the sintering process, the addition of titanium oxide can attach to the crystal nuclei generated in the first sintering stage in the second sintering stage, thereby promoting stable crystal growth and increasing the coercive force of the ferrite, making it more suitable for medium and low frequency application scenarios.

[0012] In order to solve the technical problem raised by the present application, the present application also provides a method for preparing a wide temperature, medium and low frequency low loss MnZn ferrite, comprising the following steps:

[0013] Step 101. Dry-mix the iron oxide, zinc oxide and manganese oxide and put them into a calcining furnace. After calcining at 700-900° C., a rough blank is obtained.

[0014] Step 102. The coarse stock and the auxiliary modifier prepared in step 101 are sequentially put into a ball mill, and ball-milled to a particle size range of 1-2 μm to obtain a coarse slurry;

[0015] Step 103. After the coarse slurry prepared in step 102 is sprayed and granulated, it is transferred to the corresponding station in the molding machine for compression molding to obtain a green blank;

[0016] Step 104. The green material prepared in step 103 is transferred to a bell-shaped sintering furnace for sintering to obtain a wide temperature, medium and low frequency, low-loss MnZn ferrite.

[0017] Furthermore, in step 102, the coarse stock and the auxiliary modifier are sequentially put into the ball mill, and then deionized water, polyvinyl alcohol and grinding steel balls are sequentially put into the ball mill.

[0018] Furthermore, the diameter specification of the grinding steel ball in step 102 is 3 / 8.

[0019] Furthermore, the density of the green material prepared in step 103 is 2.99-3.03 g / cm 3 .

[0020] Furthermore, in step 104, the green blank sintering process includes a first sintering stage, a cooling stage, and a second sintering stage, and the sintering end temperature of the first sintering stage is higher than the sintering end temperature of the second sintering stage.

[0021] Furthermore, the sintering end point temperature of the first sintering stage is 1300-1330°C, and the sintering end point temperature of the second sintering stage is 1240-1280°C.

[0022] Furthermore, the sintering duration of the first sintering stage is 1-4 hours, the sintering duration of the second sintering stage is 3-6 hours, and the temperature reduction stage is performed by atmosphere sintering.

[0023] Furthermore, the heating rate in the first sintering stage is 1.8-2.5°C / min, and the cooling rate in the cooling stage is 3.1-3.9°C / min.

[0024] Ferrite is prepared by a two-stage sintering process. With the help of an auxiliary modifier, the porosity of ferrite can be effectively reduced and the density of ferrite can be significantly improved. After high-temperature sintering in the first sintering stage, the auxiliary modifier can adsorb inorganic non-metallic impurities such as phosphorus and boron in ferrite, and remove inorganic non-metallic impurities such as phosphorus and boron in ferrite during high-temperature sintering to avoid inorganic non-metallic elements from reducing the magnetic permeability of ferrite. During the second sintering stage, the sintering temperature is uniformly reduced. At this time, ferrite crystals have been stably produced in the green embryo, and the air has been discharged. Lowering the temperature can avoid air flow disturbance inside the crystal, thereby hindering crystal growth. The crystal form and particle size range of the crystal can be effectively controlled to keep the particle size range of the ferrite crystal at the nanometer level. Under the premise of ensuring the magnetic permeability of ferrite, it can effectively promote the development of transformers in the direction of miniaturization and lightweight, improve the applicability of transformers, and meet the use requirements of transformers to reduce core loss under medium and low frequency and high temperature conditions.

[0025] Compared with the prior art, this application has the following beneficial effects:

[0026] The present application provides a wide-temperature, medium-low-frequency, low-loss MnZn ferrite and a preparation method thereof, wherein the ferrite is formed by secondary sintering of a main component and an auxiliary modifier, wherein the auxiliary modifier is mainly composed of oxides such as nano calcium oxide, nano silicon oxide, vanadium oxide, titanium oxide, and niobium oxide. By compounding the main component with the auxiliary modifier and preparing the ferrite by secondary sintering, the crystal form and particle size range of the ferrite can be controlled during the sintering process to ensure the stability of the ferrite crystal growth, reduce the size of the crystal after forming, and reduce the porosity in the ferrite. The ferrite has the advantages of effectively promoting the development of transformers in the direction of miniaturization and lightweight, improving the applicability of transformers, meeting the use requirements of transformers under medium-low frequency and high temperature conditions to reduce core loss, and having the advantages of low cost for implementation and easy promotion and implementation. DETAILED DESCRIPTION

[0027] Example 1

[0028] The preparation of wide temperature, medium and low frequency low loss MnZn ferrite is carried out according to the composition table shown in Table 1, including the following steps:

[0029] Step 101. Dry-mix iron oxide, zinc oxide and manganese oxide according to the component table shown in Table 1 and put them into a calcining furnace. After calcining at 800° C., a rough blank is obtained;

[0030] Step 102. The coarse stock, auxiliary modifier, ionized water, polyvinyl alcohol and grinding steel balls with a diameter of 3 / 8 prepared in step 101 are sequentially put into a ball mill, and ball-milled until the particle size range is 1.3 μm to obtain a coarse slurry;

[0031] Step 103: The coarse slurry prepared in step 102 is sprayed and granulated and transferred to the corresponding station in the molding machine, and pressed and molded until the density of the blank is 3.01 g / cm 3 After that, the raw material is obtained;

[0032] Step 104. The green material prepared in step 103 is transferred to a bell jar sintering furnace for sintering to obtain a wide temperature, medium and low frequency, low loss MnZn ferrite;

[0033] The green billet sintering process includes a first sintering stage, a cooling stage, and a second sintering stage. The sintering terminal temperature of the first sintering stage is 1300°C, and the sintering terminal temperature of the second sintering stage is 1280°C. The sintering duration of the first sintering stage is 2h, and the sintering duration of the second sintering stage is 4h. The cooling stage adopts atmosphere sintering for cooling. The heating rate of the first sintering stage is 1.9°C / min, and the cooling rate of the cooling stage is 3.3°C / min.

[0034] Example 2

[0035] The preparation of wide temperature, medium and low frequency low loss MnZn ferrite is carried out according to the composition table shown in Table 1, including the following steps:

[0036] Step 101. Dry-mix iron oxide, zinc oxide and manganese oxide according to the component table shown in Table 1 and put them into a calcining furnace. After calcining at 850° C., a rough blank is obtained;

[0037] Step 102. The coarse stock, auxiliary modifier, ionized water, polyvinyl alcohol and grinding steel balls with a diameter of 3 / 8 prepared in step 101 are sequentially put into a ball mill, and ball-milled to a particle size range of 1.5 μm to obtain a coarse slurry;

[0038] Step 103. The coarse slurry prepared in step 102 is sprayed and granulated and transferred to the corresponding station in the molding machine, and pressed to form the blank to a density of 3.02 g / cm 3 After that, the raw material is obtained;

[0039] Step 104. The green material prepared in step 103 is transferred to a bell jar sintering furnace for sintering to obtain a wide temperature, medium and low frequency, low loss MnZn ferrite;

[0040] The green billet sintering process includes a first sintering stage, a cooling stage, and a second sintering stage. The sintering terminal temperature of the first sintering stage is 1320°C, and the sintering terminal temperature of the second sintering stage is 1270°C. The sintering duration of the first sintering stage is 1h, and the sintering duration of the second sintering stage is 4h. The cooling stage adopts atmosphere sintering for cooling. The heating rate of the first sintering stage is 2.2°C / min, and the cooling rate of the cooling stage is 3.5°C / min.

[0041] Example 3

[0042] The preparation of wide temperature, medium and low frequency low loss MnZn ferrite is carried out according to the composition table shown in Table 1, including the following steps:

[0043] Step 101. Dry-mix iron oxide, zinc oxide and manganese oxide according to the component table shown in Table 1 and put them into a calcining furnace. After calcining at 880° C., a rough blank is obtained;

[0044] Step 102. The coarse stock, auxiliary modifier, ionized water, polyvinyl alcohol and grinding steel balls with a diameter of 3 / 8 prepared in step 101 are sequentially put into a ball mill, and ball-milled to a particle size range of 1.7 μm to obtain a coarse slurry;

[0045] Step 103: The coarse slurry prepared in step 102 is sprayed and granulated and transferred to the corresponding station in the molding machine, and pressed and molded until the density of the blank is 3.03 g / cm 3 After that, the raw material is obtained;

[0046] Step 104. The green material prepared in step 103 is transferred to a bell jar sintering furnace for sintering to obtain a wide temperature, medium and low frequency, low loss MnZn ferrite;

[0047] The sintering process of the green billet includes a first sintering stage, a cooling stage, and a second sintering stage. The sintering terminal temperature of the first sintering stage is 1325°C, and the sintering terminal temperature of the second sintering stage is 1277°C. The sintering duration of the first sintering stage is 4h, and the sintering duration of the second sintering stage is 6h. The cooling stage adopts atmosphere sintering for cooling. The heating rate of the first sintering stage is 2.5°C / min, and the cooling rate of the cooling stage is 3.9°C / min.

[0048] Comparative Example 1

[0049] The preparation of wide temperature, medium and low frequency low loss MnZn ferrite is carried out according to the composition table shown in Table 1, including the following steps:

[0050] Step 101. Dry-mix iron oxide, zinc oxide and manganese oxide according to the component table shown in Table 1 and put them into a calcining furnace. After calcining at 800° C., a rough blank is obtained;

[0051] Step 102. The coarse stock, auxiliary modifier, ionized water, polyvinyl alcohol and grinding steel balls with a diameter of 3 / 8 prepared in step 101 are sequentially put into a ball mill, and ball-milled to a particle size range of 1.3 μm to obtain a coarse slurry;

[0052] Step 103: The coarse slurry prepared in step 102 is sprayed and granulated and transferred to the corresponding station in the molding machine, and pressed and molded until the density of the blank is 3.01 g / cm 3 After that, the raw material is obtained;

[0053] Step 104. The green material prepared in step 103 is transferred to a bell jar sintering furnace for sintering to obtain a wide temperature, medium and low frequency, low loss MnZn ferrite;

[0054] The green material sintering process adopts one-stage sintering, the sintering end temperature is 1350°C, the sintering duration is 4h, and the heating rate in the sintering stage is 2.5°C / min.

[0055] Comparative Example 2

[0056] The preparation of wide temperature, medium and low frequency low loss MnZn ferrite is carried out according to the composition table shown in Table 1, including the following steps:

[0057] Step 101. Dry-mix iron oxide, zinc oxide and manganese oxide according to the component table shown in Table 1 and put them into a calcining furnace. After calcining at 800° C., a rough blank is obtained;

[0058] Step 102. The coarse stock, auxiliary modifier, ionized water, polyvinyl alcohol and grinding steel balls with a diameter of 3 / 8 prepared in step 101 are sequentially put into a ball mill, and ball-milled until the particle size range is 1.3 μm to obtain a coarse slurry;

[0059] Step 103. The coarse slurry prepared in step 102 is sprayed and granulated and transferred to the corresponding station in the molding machine, and pressed and molded until the density of the blank is 3.02g / cm 3 After that, the raw material is obtained;

[0060] Step 104. The green material prepared in step 103 is transferred to a bell jar sintering furnace for sintering to obtain a wide temperature, medium and low frequency, low loss MnZn ferrite;

[0061] The green billet sintering process includes a first sintering stage, a cooling stage, and a second sintering stage. The sintering terminal temperature of the first sintering stage is 1280°C, and the sintering terminal temperature of the second sintering stage is 1200°C. The sintering duration of the first sintering stage is 2h, and the sintering duration of the second sintering stage is 4h. The cooling stage adopts atmosphere sintering for cooling. The heating rate of the first sintering stage is 1.9°C / min, and the cooling rate of the cooling stage is 3.3°C / min.

[0062] Comparative Example 3

[0063] The preparation of wide temperature, medium and low frequency low loss MnZn ferrite is carried out according to the composition table shown in Table 1, including the following steps:

[0064] Step 101. Dry-mix iron oxide, zinc oxide and manganese oxide according to the component table shown in Table 1 and put them into a calcining furnace. After calcining at 800° C., a rough blank is obtained;

[0065] Step 102. The coarse stock, auxiliary modifier, ionized water, polyvinyl alcohol and grinding steel balls with a diameter of 3 / 8 prepared in step 101 are sequentially put into a ball mill, and ball-milled until the particle size range is 1.3 μm to obtain a coarse slurry;

[0066] Step 103: The coarse slurry prepared in step 102 is sprayed and granulated and transferred to the corresponding station in the molding machine, and pressed and molded until the density of the blank is 3.03 g / cm 3 After that, the raw material is obtained;

[0067] Step 104. The green material prepared in step 103 is transferred to a bell jar sintering furnace for sintering to obtain a wide temperature, medium and low frequency, low loss MnZn ferrite;

[0068] The green billet sintering process includes a first sintering stage, a cooling stage, and a second sintering stage. The sintering terminal temperature of the first sintering stage is 1300°C, and the sintering terminal temperature of the second sintering stage is 1280°C. The sintering duration of the first sintering stage is 2h, and the sintering duration of the second sintering stage is 4h. The cooling stage adopts atmosphere sintering for cooling. The heating rate of the first sintering stage is 1.9°C / min, and the cooling rate of the cooling stage is 3.3°C / min.

[0069] Table 1 Composition of components in Examples 1-3 and Comparative Examples 1-3

[0070]

[0071] The ferrites prepared in Examples 1-3 and Comparative Examples 1-3 were measured for tertiary oxide loss using an Iwatsu electronic measuring device according to the method of use of the device. The test results are shown in Table 2 below.

[0072] Table 2 Test results of Examples 1-3 and Comparative Examples 1-3

[0073]

[0074] As can be seen from Table 2, in Comparative Example 1, when the parameters such as the content of each component in Example 1 remain unchanged, the two-stage sintering in Example 1 is replaced by one-stage sintering. Due to the one-stage sintering and the excessively high sintering temperature, the pores inside the grains expand rapidly, the grain boundaries deform, and the sintering density is reduced. Under the action of the auxiliary modifier, the ferrite grains grow abnormally, the uniformity and magnetic properties of the ferrite are reduced, and the overall loss of the ferrite material is improved.

[0075] In Comparative Example 2, while keeping the parameters such as the content of each component in Example 1 unchanged, the terminal temperature of the first sintering stage and the terminal temperature of the second sintering stage are reduced. Since the sintering temperature is too low, the range of the grain size of the ferrite is increased, the air during the sintering process cannot be discharged from the inside of the grain, the pores are dispersed inside the grains and grain boundaries, the crystal porosity is significantly increased, and the magnetic permeability is reduced, the coercive force is increased, and the overall loss of the ferrite material is significantly improved;

[0076] In Comparative Example 3, while keeping the parameters such as the content of each component in Example 1 unchanged, reducing the input of the low-melting-point auxiliary modifier can effectively avoid the sintering temperature being too low, which in turn leads to the sintering temperature being too high, the pores inside the grains expanding rapidly, the grain boundaries deforming, and the sintering density being reduced. Under the action of the auxiliary modifier, the ferrite grains will grow abnormally, reducing the uniformity and magnetic properties of the ferrite, and increasing the overall loss of the ferrite material.

[0077] The present application provides a wide-temperature, medium-low-frequency, low-loss MnZn ferrite and a preparation method thereof, wherein the ferrite is formed by secondary sintering of a main component and an auxiliary modifier, wherein the auxiliary modifier is mainly composed of oxides such as nano calcium oxide, nano silicon oxide, vanadium oxide, titanium oxide, and niobium oxide. By compounding the main component with the auxiliary modifier and preparing the ferrite by secondary sintering, the crystal form and particle size range of the ferrite can be controlled during the sintering process to ensure the stability of the ferrite crystal growth, reduce the size of the crystal after forming, and reduce the porosity in the ferrite. The ferrite has the advantages of effectively promoting the development of transformers in the direction of miniaturization and lightweight, improving the applicability of transformers, meeting the use requirements of transformers under medium-low frequency and high temperature conditions to reduce core loss, and having the advantages of low cost for implementation and easy promotion and implementation.

[0078] The above are only embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A wide temperature, medium and low frequency, low loss MnZn ferrite, characterized in that: It is made by mixing the main components and auxiliary modifiers and then sintering them in two stages; The main components are composed of the following components by weight: 60-72% iron oxide, 10-15% zinc oxide and the balance manganese oxide; Relative to the main component, the auxiliary component is composed of the following components, calculated by weight fraction of the main component: 0.05-0.1% nano calcium oxide, 0.2-0.6% cobalt oxide, 0.2-0.8% nickel oxide, 0.005-0.03% nano silicon oxide, 0.001-0.05% vanadium oxide, 0.1-0.5% titanium oxide, 0.001-0.05% niobium oxide, 0.001-0.05% zirconium oxide, and 0.001-0.02% copper oxide.

2. A method for preparing a wide temperature, medium and low frequency low loss MnZn ferrite, characterized in that: The following steps are involved: Step 101. Dry-mix the iron oxide, zinc oxide and manganese oxide and put them into a calcining furnace. After calcining at 700-900° C., a rough blank is obtained. Step 102. The coarse stock and the auxiliary modifier prepared in step 101 are sequentially put into a ball mill, and ball-milled to a particle size range of 1-2 μm to obtain a coarse slurry; Step 103. After the coarse slurry prepared in step 102 is sprayed and granulated, it is transferred to the corresponding station in the molding machine for compression molding to obtain a green blank; Step 104. The green material prepared in step 103 is transferred to a bell-shaped sintering furnace for sintering to obtain a wide temperature, medium and low frequency, low-loss MnZn ferrite.

3. The method for preparing a wide temperature, medium and low frequency, low loss MnZn ferrite according to claim 2, characterized in that: In step 102, the coarse stock and the auxiliary modifier are sequentially put into a ball mill, and then deionized water, polyvinyl alcohol and grinding steel balls are sequentially put into the ball mill.

4. The method for preparing a wide temperature, medium and low frequency, low loss MnZn ferrite according to claim 3, characterized in that: The diameter specification of the grinding steel ball in step 102 is 3 / 8.

5. The method for preparing a wide temperature, medium and low frequency low loss MnZn ferrite according to claim 2, characterized in that: The density of the green material prepared in step 103 is 2.99-3.03 g / cm 3 .

6. The method for preparing a wide temperature, medium and low frequency, low loss MnZn ferrite according to claim 2, characterized in that: In step 104, the green material sintering process includes a first sintering stage, a cooling stage, and a second sintering stage. The sintering end temperature of the first sintering stage is higher than the sintering end temperature of the second sintering stage.

7. The method for preparing a wide temperature, medium and low frequency, low loss MnZn ferrite according to claim 6, characterized in that: The sintering end temperature of the first sintering stage is 1300-1330°C, and the sintering end temperature of the second sintering stage is 1240-1280°C.

8. The method for preparing a wide temperature, medium and low frequency, low loss MnZn ferrite according to claim 6, characterized in that: The sintering duration of the first sintering stage is 1-4 hours, the sintering duration of the second sintering stage is 3-6 hours, and the temperature reduction stage adopts atmosphere sintering method for temperature reduction.

9. The method for preparing a wide temperature, medium and low frequency, low loss MnZn ferrite according to claim 6, characterized in that: The heating rate in the first sintering stage is 1.8-2.5°C / min, and the cooling rate in the cooling stage is 3.1-3.9°C / min.

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