Manganese gallium ferrite for high frequency as well as preparation method and application thereof

Abstract

The invention provides a high-frequency manganese gallium ferrite and a preparation method and application thereof, the high-frequency manganese gallium ferrite comprises a main component and an auxiliary component, the main component comprises 54.3-57.3 mol% of Fe2O3, greater than 0 and less than or equal to 3.0 mol% of Ga2O3, and the balance of MnO; the Ga2O3 with a specific content is added into the main component, so that on one hand, the defect that the magnetic property of the ferrite material is reduced due to excessive ZnO (ZnO is a non-magnetic component) is overcome, and the cost of the product is not favorably reduced due to relatively high price of ZnO; and on the other hand, the problem of high high-frequency loss of the Mn ferrite is solved (namely, the high-frequency low-power loss performance of the material is realized).

Description

Technical Field

[0001] The invention belongs to the technical field of soft ferrites and relates to a manganese gallium ferrite, and in particular to a manganese gallium ferrite for high frequency use and a preparation method and application thereof. Background Art

[0002] Soft ferrite materials and magnetic cores made from them are widely used in the field of high-frequency power electronics due to their high resistivity, high frequency and low power loss. Low-power-loss magnetic cores can reduce the temperature rise of electronic devices and improve the energy conversion efficiency of electronic devices. At the same time, in order to reduce the size of electronic devices, the operating frequency of ferrite cores is getting higher and higher, and the operating frequency of some cores has exceeded 1MHz. So far, in order to obtain high-frequency and low-power-loss soft ferrite cores, in-depth research has been conducted on the formulation design, preparation process optimization, and structural design of traditional MnZn or Mn ferrite materials.

[0003] The Chinese invention patent with the publication number CN115536379A discloses a high-frequency low-loss soft magnetic ferrite material and its preparation method and application, including a main material component and an auxiliary material component, wherein the main material component includes 58-62 mol% of ferric oxide and 38-42 mol% of manganese oxide in terms of molar percentage. The main component of the Mn-based ferrite is Fe 2 O 3 It is composed of ZnO and MnO. Although it overcomes the problem of lower material resonance frequency of MnZn ferrite due to the addition of ZnO, the high-frequency loss is still relatively high and there is a demand for further reduction. Summary of the invention

[0004] In order to solve the above technical problems, the purpose of the present invention is to provide a low-loss manganese gallium ferrite for high frequency use, so as to overcome the defect that the magnetic properties of the ferrite material are reduced due to the addition of excessive ZnO.

[0005] In order to achieve the above technical objectives, the present invention provides a high frequency manganese gallium ferrite, which includes a main component and a secondary component. In terms of molar percentage, the main component contains 54.3-57.3 mol% of Fe 2 O 3 、>0 and ≤3.0mol%Ga 2 O 3 , the balance is MnO.

[0006] Optimally, the main component Ga 2 O 3 The content is 0.5~1.5mol%.

[0007] Optimally, based on the total weight of the main component, the auxiliary component comprises 800-1600 ppm of CaO, 200-1200 ppm of V 2O 5 100~600ppm HfO 2 and 100-600ppm Ta 2 O 5 .

[0008] Another object of the present invention is to provide a method for preparing the above-mentioned high-frequency manganese gallium ferrite, comprising the following steps:

[0009] Step S1: mixing and pre-calcining the raw materials of the main component in proportion, adding the raw materials of the auxiliary components and grinding them, and then adding a binder to granulate them to obtain a molded body;

[0010] Step S2: After sintering the molded body, cool it to room temperature in an atmosphere of protective gas to obtain the high-frequency manganese gallium ferrite; during sintering, the oxygen partial pressure concentration between 700° C. and the sintering temperature is controlled to be ≤0.5%.

[0011] Optimally, in step S2, the sintering temperature is 1000-1200°C and the sintering time is 2-10h.

[0012] Furthermore, in step S1, the pre-sintering temperature is 750-1050°C and the sintering time is 1-6h.

[0013] Optimally, in step S1, the mixing is wet mixing, the mixing medium of the wet mixing is water, and the wet mixing time is 1 to 3 hours; in step S1, the grinding is wet grinding, the grinding medium of the wet grinding is water, and the wet grinding time is 1 to 3 hours.

[0014] Optimally, in step S1, the binder is a mixture of one or more selected from polyvinyl alcohol, carboxymethyl cellulose and polyvinyl acetate, and its usage mass is 0.5% to 1.5% in terms of dry powder.

[0015] Optimally, in step S1, the granulation is spray granulation; in step S2, the protective gas is nitrogen or argon.

[0016] Another object of the present invention is to provide an application of the above-mentioned manganese gallium ferrite for high frequency, wherein the manganese gallium ferrite for high frequency is used to make a toroidal magnetic core.

[0017] The high frequency manganese gallium ferrite of the present invention is prepared by adding a specific content of Ga to the main component. 2 O 3 On the one hand, it overcomes the defect that excessive ZnO (ZnO is a non-magnetic component) leads to reduced magnetic properties of ferrite materials, and the high price of ZnO is not conducive to reducing product costs; on the other hand, it overcomes the problem of high high-frequency loss of Mn-based ferrites (that is, achieving high-frequency and low power loss performance of the material).

[0018] The preparation method of high-frequency manganese gallium ferrite of the present invention is fully compatible with the existing preparation process of MnZn ferrite, and further controls the loss performance of the material by controlling the temperature and oxygen partial pressure during the sintering process. When the temperature is lower than 700°C, the oxygen partial pressure is low, which is not conducive to the discharge of the molding binder on the one hand, and on the other hand, the production cost is increased due to the premature injection of inert protective gas; when the temperature is above 700°C, the excessively high oxygen partial pressure is not conducive to the completion of the solid phase reaction of the sintered body, the degree of densification is low, the porosity is high, and the loss is deteriorated.

[0019] The present invention also strictly controls the content of the accessory components, because the accessory components will exist at the grain boundaries, increase the grain boundary resistivity, reduce the eddy current loss, and thus reduce the total loss. When the content of the above accessory components is lower than the lower limit, the grain boundary resistivity cannot be effectively increased, and the loss cannot be reduced; when the content of the above accessory components is higher than the upper limit, it is easy to cause abnormal growth of the grains, which worsens the loss.

[0020] The high frequency manganese gallium ferrite of the present invention is used to make a toroidal magnetic core. The power loss of the standard magnetic core of Φ12×7×5 prepared at 1MHz / 50mT and 100°C is 200kW / m 3 the following. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 The X-ray diffraction (XRD) spectrum of the high frequency manganese gallium ferrite of the present invention (x in the figure is Ga based on the main component) 2 O 3 mole percentage). DETAILED DESCRIPTION

[0022] The high frequency manganese gallium ferrite of the present invention comprises a main component and a secondary component. In terms of molar percentage, the main component comprises 54.3-57.3 mol% of Fe 2 O 3 、>0 and ≤3.0mol%Ga 2 O 3 , the balance is MnO. By adding a specific amount of Ga to the main component 2 O 3 On the one hand, it overcomes the defect that excessive ZnO (ZnO is a non-magnetic component) leads to reduced magnetic properties of ferrite materials, and the high price of ZnO is not conducive to reducing product costs; on the other hand, it overcomes the problem of high high-frequency loss of Mn-based ferrites (i.e., achieving high-frequency low power loss performance of the material). 2 O 3 The content of is preferably 0.5 to 1.5 mol%.

[0023] Based on the total weight of the main components, the auxiliary components include 800-1600 ppm of CaO, 200-1200 ppm of V 2 O 5 100~600ppm HfO 2 and 100-600ppm Ta 2 O 5 It is also preferred to strictly control the content of the accessory components, because the accessory components will exist at the grain boundaries, increase the grain boundary resistivity, reduce the eddy current loss, and thus reduce the total loss. When the above accessory component content is lower than the lower limit, the grain boundary resistivity cannot be effectively increased, and the effect of reducing the loss cannot be achieved; when the above accessory component content is higher than the upper limit, it is easy to cause abnormal growth of grains, which worsens the loss.

[0024] The method for preparing the manganese gallium ferrite for high frequency includes the following steps: step S1: mixing and pre-sintering the raw materials of the main component in proportion, adding the raw materials of the auxiliary component for grinding, and then adding the binder for granulation to obtain a molded body; step S2: sintering the molded body, cooling it to room temperature under a protective gas atmosphere to obtain the manganese gallium ferrite for high frequency; during sintering, the oxygen partial pressure concentration between 700°C and the sintering temperature is controlled to be ≤0.5%. This process is fully compatible with the existing preparation process of MnZn ferrite, and the loss performance of the material is further controlled by controlling the temperature and oxygen partial pressure during the sintering process. When the temperature is lower than 700°C, the oxygen partial pressure is low, which is not conducive to the discharge of the molding binder on the one hand, and on the other hand, the production cost is increased due to the premature injection of the inert protective gas; when the temperature is above 700°C, the excessively high oxygen partial pressure is not conducive to the completion of the solid phase reaction of the sintered body, the degree of densification is low, the porosity is high, and the loss is deteriorated.

[0025] In step S2, the sintering temperature is preferably 1000-1200°C, and the sintering time is preferably 2-10h. In step S1, the pre-calcining temperature is preferably 750-1050°C, and the sintering time is preferably 1-6h. In step S1, the mixing is wet mixing, the mixing medium of the wet mixing is water, and the wet mixing time is 1-3h; the grinding is wet grinding, the grinding medium of the wet grinding is water, and the wet grinding time is 1-3h. In step S1, the binder is a mixture of one or more selected from polyvinyl alcohol, carboxymethyl cellulose and polyvinyl acetate, and its usage mass is 0.5% to 1.5% in terms of dry powder. In step S1, the granulation is spray granulation; in step S2, the protective gas is nitrogen or argon.

[0026] The application of the above-mentioned high-frequency manganese gallium ferrite is to make a toroidal magnetic core. For example, a standard magnetic core of Φ12×7×5 is prepared, and the power loss at 1MHz / 50mT and 100°C is 200kW / m 3 the following.

[0027] The following will describe in detail the preferred embodiments of the present invention.

[0028] Example 1

[0029] This embodiment provides a high frequency manganese gallium ferrite and a preparation method thereof, which are specifically as follows:

[0030] Step S1: 55.8 mol% Fe 2 O 3 (Fe 2 O 3 Weigh 357.9 g), 1.5 mol% Ga 2 O 3 (With Ga 2 O 3 Weigh 11.3 g) and 42.7 mol% MnO (in terms of Mn 3 O 4 130.8 g of the raw material was weighed and wet-ground in a sand mill for 1 hour (grinding medium was water), and then pre-fired at 900°C for 3 hours. Based on the mass of the pre-fired powder (i.e., dry powder), the auxiliary components (1000 ppm CaO, 500 ppm V 2 O 5 、300ppm HfO 2 and 300ppm Ta 2 O 5 ), and then perform secondary sand grinding for 3 hours (wet grinding, the grinding medium is water); after adding polyvinyl alcohol (based on dry powder, the mass is 1.0% of the dry powder), spray granulation is performed (the inlet temperature is controlled at 300°C and the outlet temperature is controlled at 100°C) to obtain a molded body;

[0031] Step S2: sintering the molded body: During the sintering process, the first heating stage: in this stage, the temperature is first raised from room temperature to 700°C, the heating rate is 2.0°C / minute, and the heating is carried out in the atmospheric atmosphere; the second heating stage: from 700°C to 1150°C, the heating rate is 1.0°C / minute, and the oxygen partial pressure in this heating stage is maintained at 0.3%; then, it is kept at 1150°C for 5 hours, and the oxygen partial pressure is maintained at 2.0%; finally, it is cooled to room temperature under the protection of nitrogen while maintaining the equilibrium oxygen partial pressure to obtain manganese gallium ferrite for high frequency.

[0032] The high frequency manganese gallium ferrite prepared above was made into a standard magnetic core of Φ12×7×5, and then the power loss of the standard magnetic core was tested at 1MHz / 50mT and 100℃ using a SY8219 BH analyzer. The result was 153kW / m 3 .

[0033] Example 2

[0034] This embodiment provides a high frequency manganese gallium ferrite and a preparation method thereof, which are specifically as follows:

[0035] Step S1: 56 mol% Fe 2 O 3 (Fe 2 O 3 Weigh 360.2 g), 1 mol% Ga 2 O 3 (With Ga 2 O 3 Weigh 7.6 g) and 43 mol% MnO (in terms of Mn 3 O 4 132.2 g of the raw material was weighed and wet-ground for 1 hour (grinding medium was water), and then pre-calcined at 950°C for 2 hours. Based on the mass of the pre-calcined powder (i.e., dry powder), the auxiliary components (800 ppm CaO, 600 ppm V 2 O 5 、200ppm HfO 2 and 200ppm Ta 2 O 5 ), and then perform secondary sand grinding for 2 hours (wet grinding, the grinding medium is water); after adding polyvinyl alcohol (based on dry powder, the mass is 1.0% of the dry powder), spray granulation is performed (the inlet temperature is controlled at 300°C and the outlet temperature is controlled at 100°C) to obtain a molded body;

[0036] Step S2: sintering the molded body: During the sintering process, the first heating stage: in this stage, the temperature is first raised from room temperature to 700°C, the heating rate is 2.0°C / minute, and the heating is carried out in the atmospheric atmosphere; the second heating stage: from 700°C to 1130°C, the heating rate is 1.0°C / minute, and the oxygen partial pressure in this heating stage is maintained at 0.3%; then, it is kept at 1130°C for 6 hours, and the oxygen partial pressure is maintained at 1.5%; finally, it is cooled to room temperature under the protection of nitrogen while maintaining the equilibrium oxygen partial pressure to obtain the manganese gallium ferrite for high frequency.

[0037] The high-frequency low-loss soft ferrite material prepared above was made into a standard magnetic core of Ф12×7×5, and then the power loss of the standard magnetic core was tested at 1MHz / 50mT and 100℃ using a SY8219 BH analyzer. The result was 138kW / m3 .

[0038] Example 3

[0039] This embodiment provides a high frequency manganese gallium ferrite and a preparation method thereof, which are specifically as follows:

[0040] Step S1: 57 mol% Fe 2 O 3 (Fe 2 O 3 Weigh 365.9 g), 0.5 mol% Ga 2 O 3 (With Ga 2 O 3 Weigh 3.8 g) and 42.5 mol% MnO (in terms of Mn 3 O 4 130.3 g of the raw material was weighed and wet-ground for 1 hour (grinding medium was water), and then pre-fired at 900°C for 3 hours. Based on the mass of the pre-fired powder (i.e., dry powder), the auxiliary components (900 ppm CaO, 400 ppm V 2 O 5 、250ppm HfO 2 and 250ppm Ta 2 O 5 ), performing secondary sand grinding for 2 hours (wet grinding, the grinding medium is water), adding polyvinyl alcohol (based on dry powder, the mass is 1.0% of the dry powder), and then spray granulation (controlling the inlet temperature at 300°C and the outlet temperature at 100°C) to obtain a molded body;

[0041] Step S2: sintering the molded body: During the sintering process, the first heating stage: in this stage, the temperature is first raised from room temperature to 700°C, the heating rate is 2.0°C / minute, and the heating is carried out in the atmospheric atmosphere; the second heating stage: from 700°C to 1060°C, the heating rate is 1.0°C / minute, and the oxygen partial pressure in this heating stage is maintained at 0.3%; keep warm at 1060°C for 5 hours, and the oxygen partial pressure is maintained at 1.0%; finally, cool to room temperature under the protection of nitrogen while maintaining the equilibrium oxygen partial pressure to obtain the manganese gallium ferrite for high frequency.

[0042] The high-frequency low-loss soft ferrite material prepared above was made into a standard magnetic core of Ф12×7×5, and then the power loss of the standard magnetic core was tested at 1MHz / 50mT and 100℃ using a SY8219 BH analyzer. The result was 119kW / m 3 .

[0043] Comparative Example 1

[0044] This example provides a high frequency manganese gallium ferrite and a preparation method thereof, which is basically the same as Example 2, except that the secondary component only contains 1800 ppm CaO.

[0045] The prepared high-frequency low-loss soft ferrite material was made into a standard magnetic core of Ф12×7×5, and then the power loss of the standard magnetic core was tested at 1MHz / 50mT and 100℃ using a SY8219 BH analyzer. The result was 323kW / m 3 .

[0046] Comparative Example 2

[0047] This example provides a high frequency manganese gallium ferrite and a preparation method thereof, which is basically the same as Example 2, except that the secondary component contains only 1500ppm V 2 O 5 .

[0048] The prepared high-frequency low-loss soft ferrite material was made into a standard magnetic core of Ф12×7×5, and then the power loss of the standard magnetic core was tested at 1MHz / 50mT and 100℃ using a SY8219 BH analyzer. The result was 347kW / m 3 .

[0049] Comparative Example 3

[0050] This example provides a high frequency manganese gallium ferrite and a preparation method thereof, which is basically the same as Example 3, except that in the second heating stage: from 700°C to 1060°C, the heating rate is 1.0°C / minute, but the oxygen partial pressure in the heating stage is maintained at 2.0%.

[0051] The prepared high-frequency low-loss soft ferrite material was made into a standard magnetic core of Ф12×7×5, and then the power loss of the standard magnetic core was tested at 1MHz / 50mT and 100℃ using a SY8219 BH analyzer. The result was 463kW / m 3 .

[0052] Comparative Example 4

[0053] This example provides a high frequency manganese gallium ferrite and a preparation method thereof, which is basically the same as Example 3, except that: during the heat preservation, the temperature is kept at 1060° C. for 5 hours and the oxygen partial pressure is maintained at 9.0%.

[0054] The prepared high-frequency low-loss soft ferrite material was made into a standard magnetic core of Ф12×7×5, and then the power loss of the standard magnetic core was tested at 1MHz / 50mT and 100℃ using a SY8219 BH analyzer. The result was 519kW / m 3 .

[0055] Comparative Example 5

[0056] This example provides a high frequency manganese gallium ferrite and a preparation method thereof, which is basically the same as Example 1, except that: 55.8 mol% Fe 2 O 3 (Fe 2 O 3 Weigh 350g), 4mol%Ga 2 O 3 (With Ga 2 O 3 Weigh 29.5 g) and 40.2 mol% MnO (Mn 3 O 4 Weigh 120.5 g) as raw material. 2 O 3 excess.

[0057] The prepared high frequency manganese gallium ferrite material was made into a standard magnetic core of Ф12×7×5, and then the power loss of the standard magnetic core was tested at 1MHz / 50mT and 100℃ using a SY8219 BH analyzer. The result was 381kW / m 3 .

[0058] Comparative Example 6

[0059] This example provides a method for preparing high frequency manganese gallium ferrite, which is basically the same as that of Example 1, except that: 59 mol% Fe 2 O 3 (Fe 2 O 3 Weigh 365.7 g), 3 mol% Ga 2 O 3 (With Ga 2 O 3 Weigh 21.8 g) and 38 mol% MnO (in terms of Mn 3 O 4 Weigh 112.5 g) as raw material (at this time Fe 2 O 3 excess).

[0060] The prepared high frequency manganese gallium ferrite material was made into a standard magnetic core of Ф12×7×5, and then the power loss of the standard magnetic core was tested at 1MHz / 50mT and 100℃ using a SY8219 BH analyzer. The result was 523kW / m 3 .

[0061] Comparative Example 7

[0062] This example provides a method for preparing high frequency manganese gallium ferrite, which is basically the same as that of Example 1, except that 55.8 mol% of Fe2 O 3 (Fe 2 O 3 Weigh 362.7 g) and 44.2 mol% MnO (in terms of Mn 3 O 4 Weigh 137.3 g) as the raw material (Ga was not added at this time). 2 O 3 ).

[0063] The prepared high frequency manganese gallium ferrite material was made into a standard magnetic core of Ф12×7×5, and then the power loss of the standard magnetic core was tested at 1MHz / 50mT and 100℃ using a SY8219 BH analyzer. The result was 375kW / m 3 .

[0064] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with the technology to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A manganese gallium ferrite for high frequency use, comprising a main component and a subsidiary component, characterized in that: In terms of molar percentage, the main component comprises 54.3-57.3 mol% of Fe2O3, >0 and ≤3.0 mol% of Ga2O3, and the remainder is MnO.

2. The high frequency manganese gallium ferrite according to claim 1, characterized in that: The content of Ga2O3 in the main component is 0.5-1.5 mol%.

3. The high frequency manganese gallium ferrite according to claim 1, characterized in that: Based on the total weight of the main components, the auxiliary components include 800-1600 ppm of CaO, 200-1200 ppm of V2O5, 100-600 ppm of HfO2 and 100-600 ppm of Ta2O5.

4. The method for preparing high frequency manganese gallium ferrite according to any one of claims 1 to 3, characterized in that: The following steps are involved: Step S1: mixing and pre-calcining the raw materials of the main component in proportion, adding the raw materials of the auxiliary components and grinding them, and then adding a binder to granulate them to obtain a molded body; Step S2: After sintering the molded body, cool it to room temperature in an atmosphere of protective gas to obtain the high-frequency manganese gallium ferrite; during sintering, the oxygen partial pressure concentration between 700° C. and the sintering temperature is controlled to be ≤0.5%.

5. The method for preparing high frequency manganese gallium ferrite according to claim 4, characterized in that: In step S2, the sintering temperature is 1000-1200°C and the sintering time is 2-10 hours.

6. The method for preparing high frequency manganese gallium ferrite according to claim 5, characterized in that: In step S1, the pre-sintering temperature is 750-1050°C and the sintering time is 1-6h.

7. The method for preparing high frequency manganese gallium ferrite according to claim 4, characterized in that: In step S1, the mixing is wet mixing, the mixing medium of the wet mixing is water, and the wet mixing time is 1 to 3 hours; the grinding is wet grinding, the grinding medium of the wet grinding is water, and the wet grinding time is 1 to 3 hours.

8. The method for preparing high frequency manganese gallium ferrite according to claim 4, characterized in that: In step S1, the binder is a mixture of one or more selected from polyvinyl alcohol, carboxymethyl cellulose and polyvinyl acetate, and its usage mass is 0.5% to 1.5% in terms of dry powder.

9. The method for preparing high frequency manganese gallium ferrite according to claim 4, characterized in that: In step S1, the granulation is spray granulation; in step S2, the protective gas is nitrogen or argon.

10. The use of the high frequency manganese gallium ferrite according to any one of claims 1 to 3, characterized in that: The high frequency manganese gallium ferrite is used to make a toroidal magnetic core.

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