Iron-silicon magnetic core with high magnetic saturation intensity and preparation method of iron-silicon magnetic core

Abstract

The invention relates to a high magnetic saturation intensity iron-silicon magnetic core and a preparation method thereof, the adopted raw material powder comprises, by weight, amorphous nanocrystalline atomized FeSi powder, 12%-18% of NiZn-ferrite powder and 1.0%-1.8% of non-magnetic additive powder, the non-magnetic additive powder is analytically pure MnO2 and V2O5 mixed powder, the NiZn-ferrite powder is (Ni < 0.35 > Zn < 0.65 >) Fe2O4 nano powder, the NiZn < 0.65 > Fe < 2 > O < 4 > nano powder is added into the non-magnetic additive powder, the NiZn < 0.65 > Zn < 0.65 > Fe < 2 > O < 4 > nano powder is added into the non-magnetic additive powder, and the non-magnetic additive powder is added into the non-magnetic additive powder. The amorphous nanocrystalline atomized FeSi powder is composed of 80.7 parts of Fe, 7.5 parts of Si, 5parts of B, 1parts of C, 2parts of Cr, 2.5 parts of Ti, 0.5 part of P and 0.8 part of Co. The saturation flux density of the obtained high-magnetic saturation iron-silicon magnetic core can reach 1.8 T, and meanwhile, the loss of the magnetic core can be as low as 53 W / kg (0.1 T / 100 KHz). The composite soft magnetic core is low in loss, high in saturation flux density and excellent in soft magnetic performance.

Description

Technical Field

[0001] This invention belongs to the field of magnetic materials technology, and particularly relates to a high magnetic saturation strength iron-silicon magnetic core and its preparation method. Background Technology

[0002] In recent years, the demand for metal magnetic cores has grown rapidly due to the development of new energy vehicles, charging piles, photovoltaic energy storage, and other fields. Furthermore, the penetration rate of magnetic cores in data centers, power quality improvement, consumer electronics, and servers is also gradually increasing. With continuous breakthroughs in magnetic core technology, application scenarios across different frequency bands are expanding, indicating significant market potential. The continuous development of new energy vehicle technology is placing increasingly higher demands on the performance of boost inductor magnetic assemblies. As the power density and operating frequency of new energy vehicles increase, higher requirements are being placed on the magnetic properties, voltage withstand performance, and temperature rise performance of boost inductor magnetic assemblies.

[0003] Gas-atomized iron-silicon materials possess advantages such as high saturation magnetic induction, low loss, and excellent high-frequency magnetic properties, meeting the high magnetic performance requirements of boost inductor magnetic assemblies used in new energy vehicles. Gas-atomized iron-silicon boost inductor magnetic assemblies for new energy vehicles have broad application prospects in the new energy vehicle field. With the continuous expansion of the new energy vehicle market and technological advancements, the demand for boost inductor magnetic assemblies will continue to increase. With the continuous development of magnetic material technology, the performance of gas-atomized iron-silicon materials has been further improved. By optimizing the preparation process and adding trace elements, the magnetic properties and pressure resistance of gas-atomized iron-silicon materials can be significantly improved.

[0004] Domestic companies have developed iron-silicon-aluminum composite magnetic cores using gas-atomized iron-silicon-aluminum magnetic powders with particle sizes of 75–48 μm, 48–37.4 μm, and less than 37.4 μm, graded at specific mass ratios and manufactured through a phosphate / silicone resin composite insulation process. With the development of new energy vehicle technology, the requirements for miniaturization and integration of boost inductor magnetic assemblies are becoming increasingly stringent; therefore, magnetic rings must meet the design requirements for miniaturization and integration. To improve the performance and efficiency of new energy vehicles, boost inductor magnetic assemblies need to have higher power density, and magnetic rings must be able to operate stably under high power density conditions. In the complex electromagnetic environment of new energy vehicles, magnetic rings need to have higher core saturation magnetic induction intensity and lower core loss to meet market demands and drive industry development. Summary of the Invention

[0005] This invention provides a high magnetic saturation strength iron-silicon magnetic core and its preparation method, solving the problems of low saturation magnetic induction and high core loss in current FeSi soft magnetic material cores. The high magnetic saturation strength iron-silicon magnetic core achieves a saturation magnetic induction of up to 1.8T, while the core loss at 0.1T and 100 kHz is as low as 53W / kg. The composite soft magnetic core exhibits low loss and high saturation magnetic induction, demonstrating excellent soft magnetic properties.

[0006] In a first aspect, the present invention relates to a high magnetic saturation strength iron-silicon magnetic core, comprising, by weight percentage, amorphous nanocrystalline atomized FeSi powder, 12%–18% NiZn-ferrite powder, and 1.0%–1.8% non-magnetic additive powder, wherein the non-magnetic additive powder is a mixture of analytically pure MnO2 and V2O5 powder, with a mass ratio of MnO2 to V2O5 of 1:2–4.

[0007] The NiZn-ferrite powder is (Ni 0.35 Zn 0.65 Fe2O4 nanopowder,

[0008] Amorphous nanocrystalline atomized FeSi powder, with a mass composition of Fe 80.7 Si 7.5 B5C1Cr2Ti 2.5 P 0.5 Co 0.8 .

[0009] Preferably, the mass ratio of MnO2 to V2O5 is 1:3.

[0010] Preferably, the amorphous nanocrystalline atomized FeSi powder has a particle size of 20–30 μm.

[0011] Secondly, the present invention relates to a method for preparing a high magnetic saturation strength iron-silicon magnetic core, comprising the following steps:

[0012] (1) Powder pretreatment: Amorphous nanocrystalline atomized FeSi powder was pre-calcined at 370 ℃~420 ℃ in a hydrogen atmosphere to obtain pre-calcined FeSi powder.

[0013] (2) Analytical pure MnO2 and V2O5 powders were ball-milled to nanoscale in a stainless steel ball mill at a speed of 400-500 r / min to obtain non-magnetic additive powder;

[0014] (3) The non-magnetic additive powder obtained in step (2) is ball-milled and mixed with NiZn-ferrite powder to obtain coated powder;

[0015] (4) The coated powder obtained in step (3) and the pre-calcined FeSi powder obtained in step (1) are ball-milled in a ball mill jar for insulating coating.

[0016] (5) After pressing the powder obtained in step (4) into shape, heat-treat it at 600 ℃~730 ℃ for 30~60 min to obtain a high magnetic saturation strength iron-silicon magnetic core;

[0017] The amorphous nanocrystalline atomized FeSi powder is composed of Fe 80.7 Si 7.5 B5C1Cr2Ti2.5 P 0.5 Co 0.8 .

[0018] Preferably, the (Ni) 0.35 Zn 0.65 The preparation method of Fe2O4 nanopowder is as follows:

[0019] An aqueous solution was obtained by mixing Zn(NO3)2·6H2O, Ni(NO3)2·6H2O and Fe(NO3)3·9H2O according to the stoichiometric ratio of the target components. Citric acid solution was added according to the molar ratio of metal ions to citric acid of 1:1.2. The mixture was stirred evenly, then heated at a constant temperature to evaporate into a gel. The gel was then dried by heating and finally calcined in a high-temperature furnace.

[0020] Preferably, the ball-to-material ratio in step (2) is 10-14:1.

[0021] Preferably, in step (3), the ball-to-material ratio is 1 to 3:1, and the rotation speed is 160 to 180 r / min.

[0022] Preferably, in step (4), the ball-to-material ratio is 1 to 3:1 and the rotation speed is 210 to 280 r / min.

[0023] Preferably, in step (5), the powder obtained in step (4) is pressed into shape and then heat-treated at 650 °C for 40 min to obtain a high magnetic saturation strength iron-silicon magnetic core.

[0024] The beneficial effects of this invention are as follows:

[0025] This invention uses a composite powder primarily composed of amorphous nanocrystalline atomized FeSi powder. Preferably, the amorphous nanocrystalline atomized FeSi powder has a Fe content... 80.7 Si 7.5 B5C1Cr2Ti 2.5 P 0.5 Co 0.8 The adjusted composition can better obtain amorphous nanocrystalline structures, as well as excellent saturation magnetic induction and low iron loss.

[0026] Choose NiZn-ferrite (Ni 0.35 Zn 0.65 Fe₂O₄ with a Ni / Zn ratio of 0.35:0.65 can optimize the spinel structure, balance magnetocrystalline anisotropy and saturation magnetization, and achieve broadband permeability with high saturation magnetization. Selecting a specific Zn-Ni-ferrite with Ni... 0.35 Zn 0.65 Fe2O4 nanopowder, used as an insulating coating layer, has high resistivity that can block the eddy current path between FeSi particles, thus more effectively suppressing eddy current loss.

[0027] Non-magnetic additive powders V2O5, MnO2 and (Ni 0.35 Zn 0.65 Fe2O4 combines to form an insulating layer, enhancing its mechanical strength. MnO2 and V2O5, as non-magnetic additives, play a synergistic role through electron transfer, interface optimization, and enhanced structural stability, further improving resistivity and reducing eddy current losses while ensuring high magnetic saturation strength.

[0028] Non-magnetic additives and specific NiZn-ferrites (Ni 0.35 Zn 0.65 Fe2O4 nanoparticles together form an insulating coating layer. During heat treatment, a series of complex chemical reactions and atomic diffusions occur, leading to changes in the ion concentration in the interface layer. Non-magnetic additives MnO2 and V2O5 further hinder electron transitions during the reaction, thereby increasing the resistivity of the interface layer. Through the effective combination of specific Zn-Ni ferrites and non-magnetic additives, eddy current losses are reduced.

[0029] Stepwise ball milling mixing achieves uniform and complete surface coating of NiZn-ferrite nanoparticles, non-magnetic powders, and FeSi powders. After heat treatment, the FeSi powder particles are completely separated by the insulating coating layer, which is uniform, complete, and void-free, ensuring high saturation magnetic induction and permeability while reducing eddy current losses. The fabricated high-saturation-strength iron-silicon magnetic core achieves a saturation magnetic induction of up to 1.8 T, with a core loss as low as 53 W / kg (0.1 T / 100 kHz). The composite soft magnetic core exhibits low loss and high saturation magnetic induction, demonstrating excellent soft magnetic properties. Attached Figure Description

[0030] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This is a schematic diagram of a process for preparing a high magnetic saturation strength iron-silicon magnetic core according to an embodiment of the present invention. Detailed Implementation

[0032] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] Existing FeSi soft magnetic material cores have low saturation magnetic induction and high core loss, making it urgent to develop a high magnetic saturation strength iron-silicon core to meet market demands and promote industry development.

[0034] To address the aforementioned technical problems, this invention provides a high magnetic saturation strength iron-silicon magnetic core, comprising, by weight percentage: amorphous nanocrystalline atomized FeSi powder, 12%–18% NiZn-ferrite powder, and 1.0%–1.8% non-magnetic additive powder. The non-magnetic additive powder is a mixture of analytically pure MnO2 and V2O5 powders, with a mass ratio of MnO2 to V2O5 of 1:2–4.

[0035] The NiZn-ferrite powder is (Ni 0.35 Zn 0.65 Fe2O4 nanopowder,

[0036] Amorphous nanocrystalline atomized FeSi powder is composed of Fe 80.7 Si 7.5 B5C1Cr2Ti 2.5 P 0.5 Co 0.8 .

[0037] In one embodiment, the mass ratio of MnO2 to V2O5 is 1:3.

[0038] In one embodiment, the amorphous nanocrystalline atomized FeSi powder has a particle size of 20–30 μm.

[0039] The composite powder is mainly composed of amorphous nanocrystalline atomized FeSi powder, and the amorphous nanocrystalline atomized FeSi powder is composed of Fe 80.7 Si 7.5 B5C1Cr2Ti 2.5 P 0.5 Co 0.8 Si, B, and P are metalloid elements that enhance amorphous formation ability and thermal stability, and suppress α-Fe phase coarsening during crystallization. C forms Fe3C nanoprecipitates with Fe, refining the grains. Cr and Ti, as high-melting-point elements, inhibit grain growth; Cr also improves oxidation resistance. Co partially replacing Fe increases the atomic magnetic moment of the alloy, raises the Curie temperature, and improves high-temperature magnetic properties. The optimized amorphous nanocrystalline atomized FeSi powder composition is Fe... 80.7 Si 7.5 B5C1Cr2Ti 2.5 P 0.5 Co 0.8 This allows for better acquisition of amorphous and nanocrystalline structures, as well as excellent saturation magnetic induction and low iron loss.

[0040] (Ni)0.35 Zn 0.65 Fe₂O₄ exhibits a spinel structure, belonging to the cubic crystal system. A Ni / Zn ratio of 0.35:0.65 can optimize the spinel structure, balance magnetocrystalline anisotropy and saturation magnetization, and achieve broadband permeability with high saturation magnetization. Selecting a specific Zn-Ni ferrite with Ni... 0.35 Zn 0.65 Fe2O4 nanopowder, used as an insulating coating layer, has high resistivity that can block the eddy current path between FeSi particles, thus more effectively suppressing eddy current loss.

[0041] The non-magnetic additive powder is composed of MnO2 and V2O5 in a mass ratio of 1:2 to 4. The non-magnetic additive powder consists of V2O5, MnO2, and (Ni) 0.35 Zn 0.65 Fe2O4 combines to form an insulating layer, enhancing its mechanical strength. MnO2 and V2O5, in a mass ratio of 1:2 to 4, act as non-magnetic additives, synergistically improving resistivity and reducing eddy current losses while maintaining high magnetic saturation strength. If the content is too low, it is insufficient to further increase resistivity and enhance the mechanical strength of the insulating layer; however, if the content is too high, it will decrease conductivity, further increasing eddy current losses. A more preferred mass ratio of MnO2 to V2O5 is 1:3.

[0042] In addition, non-magnetic additives and specific NiZn-ferrites (Ni 0.35 Zn 0.65 Fe2O4 nanoparticles together form an insulating coating layer. During heat treatment, a series of complex chemical reactions and atomic diffusions occur, leading to changes in the ion concentration in the interface layer. Non-magnetic additives MnO2 and V2O5 further hinder electron transitions during the reaction, thereby increasing the resistivity of the interface layer. Through the effective combination of specific Zn-Ni ferrites and non-magnetic additives, eddy current losses are reduced.

[0043] The amorphous nanocrystalline atomized FeSi powder has a particle size of 20–30 μm, which allows for better integration with nanoscale nonmagnetic additives and (Ni) 0.35 Zn 0.65 The use of Fe2O4 nanoparticles ensures efficient filling by maintaining powder flowability, increases density to improve core density and optimize magnetic properties, while avoiding the deterioration of eddy current losses.

[0044] like Figure 1 As shown, a method for preparing a high magnetic saturation strength iron-silicon magnetic core according to an embodiment of the present invention includes the following steps:

[0045] (1) Powder pretreatment: Amorphous nanocrystalline atomized FeSi powder was pre-calcined at 370 ℃~420 ℃ in a hydrogen atmosphere to obtain pre-calcined FeSi powder.

[0046] (2) Analytical pure MnO2 and V2O5 powders were ball-milled to nanoscale in a stainless steel ball mill at a speed of 400-500 r / min to obtain non-magnetic additive powder;

[0047] (3) The non-magnetic additive powder obtained in step (2) is ball-milled and mixed with NiZn-ferrite powder to obtain coated powder;

[0048] (4) The coating powder obtained in step (3) and the pre-calcined FeSi powder obtained in step (1) are ball-milled in a ball mill jar for insulating coating.

[0049] (5) After pressing the powder obtained in step (4) into shape, heat-treat it at 600 ℃~730 ℃ for 30~60 min to obtain a high magnetic saturation strength iron-silicon magnetic core.

[0050] The raw material powder used, by weight percentage, contains amorphous nanocrystalline atomized FeSi powder, 12%–18% NiZn-ferrite powder, and 1.0%–1.8% non-magnetic additive powder. The non-magnetic additive powder is a mixture of analytically pure MnO2 and V2O5 powders, with a mass ratio of MnO2 to V2O5 of 1:2–4.

[0051] The NiZn-ferrite powder is (Ni 0.35 Zn 0.65 Fe2O4 nanopowder,

[0052] Amorphous nanocrystalline atomized FeSi powder is composed of Fe 80.7 Si 7.5 B5C1Cr2Ti 2.5 P 0.5 Co 0.8 .

[0053] In one embodiment, the mass ratio of MnO2 to V2O5 is 1:3.

[0054] In one embodiment, the amorphous nanocrystalline atomized FeSi powder has a particle size of 20–30 μm.

[0055] The amorphous nanocrystalline atomized FeSi powder is composed of Fe 80.7 Si 7.5 B5C1Cr2Ti 2.5 P 0.5 Co 0.8 .

[0056] Preferably, the (Ni)0.35 Zn 0.65 The preparation method of Fe2O4 nanopowder is as follows:

[0057] An aqueous solution was obtained by mixing Zn(NO3)2·6H2O, Ni(NO3)2·6H2O and Fe(NO3)3·9H2O according to the stoichiometric ratio of the target components. Citric acid solution was added at a molar ratio of metal ions to citric acid of 1:1.2. The mixture was stirred evenly, then heated at a constant temperature to evaporate into a gel. The gel was then dried by heating and finally calcined in a high-temperature furnace.

[0058] Ni was obtained using a wet chemical method. 0.35 Zn 0.65 Fe2O4 nanoparticles are finer, reaching the nanoscale, and the powder composition can be more precisely controlled. The resulting composite material has better magnetic properties and ensures better magnetic permeability.

[0059] Amorphous nanocrystalline atomized FeSi powder is obtained through ultra-rapid condensation and atomization. However, some residual stress still exists inside. Pre-treating the powder at 370 ℃~420 ℃ can effectively eliminate the residual stress during the atomization process, improve the powder performance, enhance thermal stability, optimize the internal structure of the particles, eliminate magnetic domain walls of amorphous particles, thereby improving the DC bias performance of the iron-silicon magnetic ring and reducing magnetic loss.

[0060] Preferably, the ball-to-material ratio in step (2) is 10 to 14:1.

[0061] Preferably, in step (3), the ball-to-material ratio is 1 to 3:1 and the rotation speed is 160 to 180 r / min.

[0062] Preferably, in step (4), the ball-to-material ratio is 1 to 3:1 and the rotation speed is 210 to 280 r / min.

[0063] Preferably, in step (5), the powder obtained in step (4) is pressed into shape and then heat-treated at 650 °C for 40 min to obtain a high magnetic saturation strength iron-silicon magnetic core.

[0064] Stepwise ball milling mixing achieves uniform and complete surface coating of Ni-Zn ferrite nanoparticles, non-magnetic powders, and FeSi powders. After heat treatment, the FeSi powder particles are completely separated by an insulating coating layer, which is uniform, complete, and void-free, ensuring high saturation magnetic induction and permeability while reducing eddy current losses. The prepared high-saturation-strength iron-silicon magnetic core achieves a saturation magnetic induction of up to 1.8 T, while the core loss is as low as 53 W / kg (0.1 T / 100 kHz). The composite soft magnetic core exhibits low loss and high saturation magnetic induction, demonstrating excellent soft magnetic properties.

[0065] Example 1:

[0066] A method for preparing a high magnetic saturation strength iron-silicon magnetic core, wherein the raw material powder, by weight percentage, contains amorphous nanocrystalline atomized FeSi powder, 12% NiZn-ferrite powder, and 1.0% non-magnetic additive powder, wherein the non-magnetic additive powder is a mixture of analytically pure MnO2 and V2O5 powder, with a mass ratio of MnO2 to V2O5 of 1:2.

[0067] The NiZn-ferrite powder is (Ni 0.35 Zn 0.65 Fe2O4 nanopowder,

[0068] Amorphous nanocrystalline atomized FeSi powder is composed of Fe 80.7 Si 7.5 B5C1Cr2Ti 2.5 P 0.5 Co 0.8 The particle size is 20 μm.

[0069] Includes the following steps:

[0070] (1) Powder pretreatment: Amorphous nanocrystalline atomized FeSi powder was pre-calcined at 370 °C in a hydrogen atmosphere to obtain pre-calcined FeSi powder.

[0071] (2) Analytical pure MnO2 and V2O5 powders were ball-milled to nanoscale in a stainless steel ball mill at a speed of 450 r / min with a ball-to-material ratio of 10:1 to obtain non-magnetic additive powder.

[0072] (3) The non-magnetic additive powder obtained in step (2) is ball-milled with NiZn-ferrite powder at a ball-to-material ratio of 1:1 and a rotation speed of 165 r / min to obtain coated powder.

[0073] (4) The coated powder obtained in step (3) and the pre-calcined FeSi powder obtained in step (1) are ball-milled in a ball mill jar for insulating coating. The ball-to-material ratio is 2:1 and the rotation speed is 210 r / min.

[0074] (5) After pressing the powder obtained in step (4) into shape, heat-treat it at 600 °C for 60 min to obtain a high magnetic saturation strength iron-silicon magnetic core.

[0075] The (Ni) 0.35 Zn 0.65The preparation method of Fe2O4 nanopowder is as follows: Zn(NO3)2·6H2O, Ni(NO3)2·6H2O and Fe(NO3)3·9H2O are mixed according to the stoichiometric ratio of the nominal components to obtain an aqueous solution. Citric acid solution is added according to the molar ratio of metal ions to citric acid of 1:1.2. The mixture is stirred evenly, then heated at 85 °C to evaporate into a gel. The gel is then dried at 190 °C and finally calcined in a high-temperature furnace at 810 °C.

[0076] Example 2:

[0077] A method for preparing a high magnetic saturation strength iron-silicon magnetic core, comprising, by weight percentage, raw material powder containing, in addition to amorphous nanocrystalline atomized FeSi powder, 14% NiZn-ferrite powder and 1.5% non-magnetic additive powder, wherein the non-magnetic additive powder is a mixture of analytically pure MnO2 and V2O5 powder, with a mass ratio of MnO2 to V2O5 of 1:3.

[0078] The NiZn-ferrite powder is (Ni 0.35 Zn 0.65 Fe2O4 nanopowder,

[0079] Amorphous nanocrystalline atomized FeSi powder is composed of Fe 80.7 Si 7.5 B5C1Cr2Ti 2.5 P 0.5 Co 0.8 The particle size is 23 μm.

[0080] Includes the following steps:

[0081] (1) Powder pretreatment: Amorphous nanocrystalline atomized FeSi powder was pre-calcined at 380 °C in a hydrogen atmosphere to obtain pre-calcined FeSi powder;

[0082] (2) Analytical pure MnO2 and V2O5 powders were ball-milled to nanoscale in a stainless steel ball mill at a speed of 410 r / min with a ball-to-material ratio of 11:1 to obtain non-magnetic additive powder.

[0083] (3) The non-magnetic additive powder obtained in step (2) is ball-milled with NiZn-ferrite powder at a ball-to-material ratio of 2:1 and a rotation speed of 160 r / min to obtain coated powder.

[0084] (4) The coated powder obtained in step (3) and the pre-calcined FeSi powder obtained in step (1) are ball-milled in a ball mill jar for insulating coating. The ball-to-material ratio is 1:1 and the rotation speed is 230 r / min.

[0085] (5) After pressing the powder obtained in step (4) into shape, heat-treat it at 650 °C for 40 min to obtain a high magnetic saturation strength iron-silicon magnetic core.

[0086] The (Ni) 0.35 Zn 0.65 The preparation method of Fe2O4 nanopowder is as follows: Zn(NO3)2·6H2O, Ni(NO3)2·6H2O and Fe(NO3)3·9H2O are mixed according to the stoichiometric ratio of the nominal components to obtain an aqueous solution. Citric acid solution is added according to the molar ratio of metal ions to citric acid of 1:1.2. The mixture is stirred evenly, then heated at 85 °C to evaporate into a gel. The gel is then dried at 190 °C and finally calcined in a high-temperature furnace at 810 °C.

[0087] Example 3:

[0088] A method for preparing a high magnetic saturation strength iron-silicon magnetic core, comprising, by weight percentage, raw material powder containing, in addition to amorphous nanocrystalline atomized FeSi powder, 16% NiZn-ferrite powder and 1.8% non-magnetic additive powder, wherein the non-magnetic additive powder is a mixture of analytically pure MnO2 and V2O5 powder, with a mass ratio of MnO2 to V2O5 of 1:4.

[0089] The NiZn-ferrite powder is (Ni 0.35 Zn 0.65 Fe2O4 nanopowder,

[0090] Amorphous nanocrystalline atomized FeSi powder is composed of Fe 80.7 Si 7.5 B5C1Cr2Ti 2.5 P 0.5 Co 0.8 The particle size is 30μm.

[0091] Includes the following steps:

[0092] (1) Powder pretreatment: Amorphous nanocrystalline atomized FeSi powder was pre-calcined at 420 °C in a hydrogen atmosphere to obtain pre-calcined FeSi powder;

[0093] (2) Analytical pure MnO2 and V2O5 powders were ball-milled to nanoscale in a stainless steel ball mill at 400 r / min with a ball-to-material ratio of 12:1 to obtain non-magnetic additive powder.

[0094] (3) The non-magnetic additive powder obtained in step (2) is ball-milled with NiZn-ferrite powder at a ball-to-material ratio of 3:1 and a rotation speed of 170 r / min to obtain coated powder.

[0095] (4) The coated powder obtained in step (3) and the pre-calcined FeSi powder obtained in step (1) are ball-milled in a ball mill jar for insulating coating. The ball-to-material ratio is 3:1 and the rotation speed is 280 r / min.

[0096] (5) After pressing the powder obtained in step (4) into shape, heat-treat it at 730 °C for 30 min to obtain a high magnetic saturation strength iron-silicon magnetic core.

[0097] The (Ni) 0.35 Zn 0.65 The preparation method of Fe2O4 nanopowder is as follows: Zn(NO3)2·6H2O, Ni(NO3)2·6H2O and Fe(NO3)3·9H2O are mixed according to the stoichiometric ratio of the nominal components to obtain an aqueous solution. Citric acid solution is added according to the molar ratio of metal ions to citric acid of 1:1.2. The mixture is stirred evenly, then heated at 85 °C to evaporate into a gel. The gel is then dried at 190 °C and finally calcined in a high-temperature furnace at 810 °C.

[0098] Example 4:

[0099] A method for preparing a high magnetic saturation strength iron-silicon magnetic core, comprising, by weight percentage, 18% NiZn-ferrite powder and 1.3% non-magnetic additive powder, in addition to amorphous nanocrystalline atomized FeSi powder, the raw material powder, wherein the non-magnetic additive powder is a mixture of analytically pure MnO2 and V2O5 powder, with a mass ratio of MnO2 to V2O5 of 1:3.

[0100] The NiZn-ferrite powder is (Ni 0.35 Zn 0.65 Fe2O4 nanopowder,

[0101] Amorphous nanocrystalline atomized FeSi powder is composed of Fe 80.7 Si 7.5 B5C1Cr2Ti 2.5 P 0.5 Co 0.8 The particle size is 25 μm.

[0102] Includes the following steps:

[0103] (1) Powder pretreatment: Amorphous nanocrystalline atomized FeSi powder was pre-calcined at 390 °C in a hydrogen atmosphere to obtain pre-calcined FeSi powder;

[0104] (2) Analytical pure MnO2 and V2O5 powders were ball-milled to nanoscale in a stainless steel ball mill jar at a speed of 500 r / min. The ball-to-material ratio was 14:1 to obtain non-magnetic additive powder.

[0105] (3) The non-magnetic additive powder obtained in step (2) is ball-milled with NiZn-ferrite powder at a ball-to-material ratio of 2:1 and a rotation speed of 180 r / min to obtain coated powder.

[0106] (4) The coated powder obtained in step (3) and the pre-calcined FeSi powder obtained in step (1) are ball-milled in a ball mill jar for insulating coating. The ball-to-material ratio is 2:1 and the rotation speed is 240 r / min.

[0107] (5) After pressing the powder obtained in step (4) into shape, heat-treat it at 680°C for 45 min to obtain a high magnetic saturation strength iron-silicon magnetic core.

[0108] The (Ni) 0.35 Zn 0.65 The preparation method of Fe2O4 nanopowder is as follows: Zn(NO3)2·6H2O, Ni(NO3)2·6H2O and Fe(NO3)3·9H2O are mixed according to the stoichiometric ratio of the nominal components to obtain an aqueous solution. Citric acid solution is added according to the molar ratio of metal ions to citric acid of 1:1.2. The mixture is stirred evenly, then heated at 85 °C to evaporate into a gel. The gel is then dried at 190 °C and finally calcined in a high-temperature furnace at 810 °C.

[0109] Comparative Example 1

[0110] The difference between the preparation method of the high magnetic saturation strength iron-silicon magnetic core in Comparative Example 1 and Example 2 lies only in that: amorphous nanocrystalline atomized FeSi powder is used... 80.7 Si 7.5 B5C1Cr2Ti 2.5 P 0.5 Co 0.8 Replace it with atomized FeSi6.5 spherical powder of the same size.

[0111] Comparative Example 2

[0112] The preparation method of the high magnetic saturation strength iron-silicon magnetic core in Comparative Example 2 differs from that in Example 2 only in that: 10% NiZn-ferrite powder and 0.8% non-magnetic additive powder are used.

[0113] Comparative Example 3

[0114] The preparation method of the high magnetic saturation strength iron-silicon magnetic core in Comparative Example 3 differs from that in Example 2 only in that: 20% NiZn-ferrite powder and 2% non-magnetic additive powder are used.

[0115] Comparative Example 4

[0116] The only difference between the preparation method of the high magnetic saturation strength iron-silicon magnetic core in Comparative Example 4 and Example 2 is that the mass ratio of MnO2 to V2O5 is 1:6.

[0117] Comparative Example 5

[0118] The difference between the preparation method of the high magnetic saturation strength iron-silicon magnetic core in Comparative Example 5 and Example 2 is that the amorphous nanocrystalline atomized FeSi powder was not pre-fired and was directly used for insulation coating in step (4).

[0119] Comparative Example 6

[0120] The difference between the preparation method of the high magnetic saturation strength iron-silicon magnetic core in Comparative Example 6 and Example 2 is that: (5) the powder obtained in step (4) is pressed into shape and then heat-treated at 500°C for 40 min to obtain the high magnetic saturation strength iron-silicon magnetic core.

[0121] High magnetic saturation strength iron-silicon magnetic core wound coils were prepared in Examples 1-4 and Comparative Examples 1-6. The saturation magnetic induction intensity of the magnetic ring was measured using a magnetic saturation measuring device, and the power loss of the magnetic ring at 0.1T and 100KHz was tested. The results are shown in Table 1.

[0122] Table 1: Performance data of soft magnetic cores prepared in the examples and comparative examples

[0123] Saturation magnetic flux density (T) Core loss (W / kg) Example 1 1.7 57 Example 2 1.8 53 Example 3 1.7 58 Example 4 1.6 56 Comparative Example 1 1.2 85 Comparative Example 2 1.4 70 Comparative Example 3 1.5 69 Comparative Example 4 1.4 72 Comparative Example 5 1.3 98 Comparative Example 6 1.4 86

[0124] Table 1 shows that the high magnetic saturation strength iron-silicon magnetic core prepared by this invention can reach a saturation magnetic induction intensity of 1.8T, while the core loss at 0.1T and 100KHz is as low as 53W / kg. The prepared composite soft magnetic core has low loss and high saturation magnetic induction intensity, exhibiting excellent soft magnetic properties. In Example 2, the preferred mass ratio of MnO2 to V2O5 is 1:3, resulting in the lowest core loss and the highest saturation magnetic induction intensity, demonstrating relatively superior performance.

[0125] As can be seen from Comparative Examples 1 to 4, after adjusting the FeSi powder to conventional FeSi6.5 spherical powder and adjusting the ratio of raw material coating powder and non-magnetic powder, the amorphous nanocrystalline atomized FeSi powder, NiZn-ferrite powder, and non-magnetic additive powders MnO2 and V2O5 cannot achieve synergistic cooperation, thus failing to improve the saturation magnetic induction intensity of the iron-silicon magnetic core and increasing the core loss.

[0126] Comparative Example 5 was not pre-sintered, which resulted in the inability to eliminate residual stress in the amorphous nanocrystalline atomized FeSi powder. Optimizing the internal structure of the particles eliminated the magnetic domain walls of the amorphous particles, leading to a decrease in the saturation magnetic induction intensity of the iron-silicon magnetic core and an increase in core loss.

[0127] Comparative Example 6 reduced the heat treatment temperature, which may have resulted in the inability to eliminate pressing stress, insufficient diffusion at the powder interface, and failure to form effective chemical bonds, leading to a decrease in the saturation magnetic induction intensity of the iron-silicon magnetic core and an increase in core loss.

[0128] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

Claims

1. A high magnetic saturation strength iron-silicon magnetic core, characterized in that, The raw material powder, by weight percentage, contains amorphous nanocrystalline atomized FeSi powder, 12%–18% NiZn-ferrite powder, and 1.0%–1.8% non-magnetic additive powder. The non-magnetic additive powder is a mixture of analytical grade MnO2 and V2O5, with a mass ratio of MnO2 to V2O5 of 1:2–4. The NiZn-ferrite powder is (Ni 0.35 Zn 0.65 Fe2O4 nanopowder; The amorphous nanocrystalline atomized FeSi powder has a mass composition of Fe. 80.7 Si 7.5 B5C1Cr2Ti 2.5 P 0.5 Co 0.8 .

2. The high magnetic saturation strength iron-silicon magnetic core according to claim 1, characterized in that, The mass ratio of MnO2 to V2O5 is 1:

3.

3. The high magnetic saturation strength iron-silicon magnetic core according to claim 1, characterized in that, The amorphous nanocrystalline atomized FeSi powder has a particle size of 20–30 μm.

4. A method for preparing a high magnetic saturation strength iron-silicon magnetic core according to any one of claims 1 to 3, characterized in that, Includes the following steps: (1) Powder pretreatment: Amorphous nanocrystalline atomized FeSi powder was pre-calcined at 370 ℃~420 ℃ in a hydrogen atmosphere to obtain pre-calcined FeSi powder. (2) Analytical pure MnO2 and V2O5 powders were ball-milled to nanoscale in a stainless steel ball mill at a speed of 400-500 r / min to obtain non-magnetic additive powder; (3) The non-magnetic additive powder obtained in step (2) is ball-milled and mixed with NiZn-ferrite powder to obtain coated powder; (4) The coating powder obtained in step (3) and the pre-calcined FeSi powder obtained in step (1) are ball-milled in a ball mill jar for insulating coating. (5) After pressing the powder obtained in step (4) into shape, heat-treat it at 600 ℃~730 ℃ for 30~60 min to obtain a high magnetic saturation strength iron-silicon magnetic core; The NiZn ferrite powder is (Ni 0.35 Zn 0.65 Fe2O4 nanopowder; The amorphous nanocrystalline atomized FeSi powder has a mass composition of Fe. 80.7 Si 7.5 B5C1Cr2Ti 2.5 P 0.5 Co 0.8 .

5. The method for preparing a high magnetic saturation strength iron-silicon magnetic core according to claim 4, characterized in that, The (Ni) 0.35 Zn 0.65 The preparation method of Fe2O4 nanopowder is as follows: An aqueous solution was obtained by mixing Zn(NO3)2·6H2O, Ni(NO3)2·6H2O and Fe(NO3)3·9H2O in the stoichiometric ratio of the target components. Citric acid solution was added at a molar ratio of metal ions to citric acid of 1:1.

2. The mixture was stirred until homogeneous, then heated at a constant temperature to evaporate into a gel. The gel was then dried by further heating and finally calcined in a high-temperature furnace.

6. The method for preparing a high magnetic saturation strength iron-silicon magnetic core according to claim 4, characterized in that, In step (2), the ball-to-material ratio is 10 to 14:

1.

7. The method for preparing a high magnetic saturation strength iron-silicon magnetic core according to claim 4, characterized in that, In step (3), the ball-to-material ratio is 1 to 3:1, and the rotation speed is 160 to 180 r / min.

8. The method for preparing a high magnetic saturation strength iron-silicon magnetic core according to claim 4, characterized in that, In step (4), the ball-to-material ratio is 1 to 3:1, and the rotation speed is 210 to 280 r / min.

9. The method for preparing a high magnetic saturation strength iron-silicon magnetic core according to claim 4, characterized in that, In step (5), the powder obtained in step (4) is pressed into shape and then heat-treated at 650 °C for 40 min to obtain a high magnetic saturation strength iron-silicon magnetic core.

Images