Soft magnetic metal powder and preparation method thereof, and copper-iron co-fired inductor and preparation method thereof

Abstract

The invention relates to soft magnetic metal powder and a preparation method thereof, and a copper-iron co-fired inductor and a preparation method thereof. Raw materials of the soft magnetic metal powder comprise a pre-sintered material and an additive, the pre-sintered material is prepared from Fe2O3, MnO and Al2O4 Zn; the additive is prepared from CuO, Co2O3 and Nb2O5; according to the soft magnetic metal powder, by adopting a pre-sintered material with specific components and an additive with specific components, the initial magnetic conductivity of a test sample of the soft magnetic metal powder is preferably as high as 500 or above, the power loss is preferably as low as 200 W / m < 3 > or below, and the inductance value of a copper-iron co-fired inductor with the soft magnetic metal powder as a matrix raw material is preferably as high as 250 nH or above; the problem that an existing copper-iron co-fired integrally-formed inductor is low in inductance value is solved, and the application prospect is wider.

Description

Technical Field

[0001] The present invention relates to the technical field of magnetic functional materials and magnetic components, and in particular to a soft magnetic metal powder and a preparation method thereof, a copper-iron co-fired inductor and a preparation method thereof. Background Art

[0002] With the continuous advancement of process technology, the power consumption of CPU and GPU chips has gradually increased. At the same time, since P = U2 / R, that is, the power consumption of the circuit is proportional to the square of the voltage, when the circuit resistance remains unchanged, the current chip power supply shows a trend of low voltage and high current. At the same time, in current high current density application scenarios, in order to reduce wiring and stabilize voltage drop, vertical power supply methods are usually introduced. However, vertical power supply methods have more stringent requirements on the size of power devices in confined spaces. Currently, the technology used in the industry to cope with the above development trends mainly uses integrated molded inductors.

[0003] Currently, copper-iron co-fired integrated inductors can meet the high current requirements of magnetic components. However, the copper wire used in these integrated inductors and the external insulation coating of the inductor itself are prone to failure due to temperature rise in high-current environments, ultimately causing device damage. While existing copper-iron co-fired inductors address the high current requirements through their structure, they cannot use multi-turn coils due to structural issues, resulting in low inductance and difficulty in increasing the inductance. Therefore, those skilled in the art are urgently researching how to increase the inductance of copper-iron co-fired inductors while meeting high current requirements without changing their size.

[0004] For example, CN119811849A discloses a copper-iron co-fired inductor and its preparation method. The copper-iron co-fired inductor includes: a magnetic material, a conductor, and a filler material. The conductor is embedded within the magnetic material, and a gap exists between the magnetic material and the conductor. The filler material fills the gap. Although this copper-iron co-fired inductor has high-temperature stability and strong adaptability, its low inductance value limits its application.

[0005] For example, CN119381113A discloses a high-inductance copper-iron co-fired inductor and its preparation method. This preparation method connects nanocrystalline strips and copper conductors to form a basic framework, which is then embedded in a matrix pressed from atomized iron-nickel-molybdenum powder. Although the inductance value of the copper-iron co-fired inductor is improved to a certain extent, the preparation method has a complex process flow and is relatively costly.

[0006] Based on this, how to provide a soft magnetic metal powder with high magnetic permeability and a preparation method thereof, so as to utilize it to improve the inductance value of the copper-iron co-fired inductor, and solve the problems in the existing technology such as low inductance value or complex preparation process and high cost due to the structural limitation of only single-turn coil by optimizing the preparation process, is a key issue that needs to be studied urgently in this field. Summary of the Invention

[0007] To solve the above technical problems, the present invention provides a soft magnetic metal powder and a preparation method thereof, a copper-iron co-fired inductor and a preparation method thereof. By adjusting the component composition and content ratio of the soft magnetic metal powder, its initial magnetic permeability is improved, and the soft magnetic metal powder is combined with the optimization of the preparation process to prepare a high-inductance copper-iron co-fired inductor, which solves the problem of low inductance of the one-piece molded copper-iron co-fired inductor in the prior art, which leads to limited application.

[0008] To achieve this object, the present invention adopts the following technical solutions:

[0009] In a first aspect, the present invention provides a soft magnetic metal powder, wherein the raw materials of the soft magnetic metal powder include pre-sintered material and additives;

[0010] The pre-sintered material includes Fe2O3, MnO and Al2O4Zn; and the additives include CuO, Co2O3 and Nb2O5.

[0011] The raw materials of the soft magnetic metal powder described in the present invention are Fe2O3, MnO and Al2O4Zn as pre-sintered materials, and CuO, Co2O3 and Nb2O5 as additives. The raw materials work synergistically to improve the initial magnetic permeability of the soft magnetic metal powder and reduce losses. Compared with traditional iron-manganese-zinc soft magnetic metal powder, the present invention replaces ZnO with Al2O4Zn and utilizes the advantage that Al in Al2O4Zn can form a solid solution with other matrices to achieve the effect of promoting the formation of spinel phase. In addition, the addition of additives CuO, Co2O3 and Nb2O5 reduces the subsequent sintering temperature, improves the structural stability of the material, and further enhances the magnetic properties of the soft magnetic metal powder.

[0012] Preferably, based on the total molar amount of the pre-burned material being 100 mol%, the pre-burned material comprises 52.5-56.5 mol% Fe2O3, 38-42 mol% MnO and 3-5.5 mol% Al2O4Zn.

[0013] Among them, 52.5-56.5 mol% Fe2O3 can be, for example, 52.5 mol%, 53.5 mol%, 54.5 mol%, 55.5 mol% or 56.5 mol%; 38-42 mol% MnO can be, for example, 38 mol%, 38.5 mol%, 39 mol%, 39.5 mol%, 40 mol%, 40.5 mol%, 41 mol%, 41.5 mol% or 42 mol%; 3-5.5 mol% Al2O4Zn can be, for example, 3 mol%, 3.5 mol%, 4 mol%, 4.5 mol%, 5 mol% or 5.5 mol%;

[0014] The present invention further preferably comprises 52.5-56.5 mol% Fe2O3, 38-42 mol% MnO and 3-5.5 mol% Al2O4Zn, based on a total molar amount of the pre-sintered material being 100 mol%, thereby ensuring the stability of the magnetic properties of the soft magnetic metal powder, promoting uniform growth of grains and reducing defects.

[0015] Among them, the present invention selects the molar amount of Al2O4Zn to be 3 to 5.5 mol%, which increases the initial magnetic permeability of the soft magnetic metal powder and reduces the sintering temperature required for subsequent sintering, avoiding abnormal grain growth and structural defects caused by high-temperature sintering, thereby avoiding the problem of device damage, and reducing energy consumption.

[0016] Preferably, based on the total mass of the pre-sintered material as 100wt%, the CuO content is 0 to 500ppm, and is not 0. For example, it can be 50ppm, 100ppm, 150ppm, 200ppm, 250ppm, 300ppm, 350ppm, 400ppm, 450ppm or 500ppm, etc., preferably 400 to 500ppm.

[0017] Preferably, based on the total mass of the pre-burned material being 100wt%, the content of Co2O3 is 0 to 1200ppm, and is not 0, for example, it can be 100ppm, 200ppm, 500ppm, 800ppm, 1000ppm or 1200ppm, etc., preferably 1000 to 1200ppm.

[0018] Preferably, based on the total mass of the pre-burned material being 100wt%, the content of Nb2O5 is 0 to 200ppm, and is not 0. For example, it can be 10ppm, 30ppm, 50ppm, 100ppm, 120ppm, 150ppm, 180ppm or 200ppm, etc., preferably 100 to 200ppm.

[0019] Preferably, the raw material of the soft magnetic powder further includes a binder and / or a dispersant, preferably a combination of a binder and a dispersant.

[0020] Preferably, based on 100 wt% of the total mass of the pre-sintered material, the content of the binder is 6-10 wt%, for example, 6 wt%, 7 wt%, 8 wt%, 9 wt% or 10 wt%.

[0021] Preferably, the binder comprises polyvinyl alcohol and / or polyvinyl butyral.

[0022] Preferably, based on 100 wt% of the total mass of the pre-sintered material, the content of the dispersant is 0.5-1 wt%, for example, 0.5 wt%, 0.6 wt%, 0.7 wt%, 0.8 wt%, 0.9 wt% or 1 wt%.

[0023] Preferably, the dispersant comprises polyethylene glycol and / or a vinyl silane coupling agent.

[0024] Preferably, the median particle size D50 of the soft magnetic metal powder is 45 to 55 μm, for example, 45 μm, 48 μm, 50 μm, 52 μm or 55 μm.

[0025] Preferably, the particle size D90 of the soft magnetic metal powder is 95-105 μm, for example, 95 μm, 98 μm, 100 μm, 102 μm or 105 μm.

[0026] The soft magnetic metal powder of the present invention has a narrow particle size distribution range, that is, the grains are evenly distributed, which is also beneficial to improving the magnetic properties of the soft magnetic metal powder.

[0027] In a second aspect, the present invention provides a method for preparing the soft magnetic metal powder according to the first aspect, the method for preparing the soft magnetic metal powder comprising the following steps:

[0028] (1) ball-milling Fe2O3, MnO and Al2O4Zn and pre-sintering to obtain a pre-sintered material;

[0029] (2) CuO, Co2O3, Nb2O5 and the pre-sintered material of step (1) are mixed and spray granulated to obtain the soft magnetic metal powder.

[0030] The preparation method of the present invention firstly mixes the main components Fe2O3, MnO and Al2O4Zn by ball milling and then pre-sintering to obtain a pre-sintered material, and then mixes the additives CuO, Co2O3 and Nb2O5 with the pre-sintered material and spray granulates the pre-sintered material. The pre-sintered material has a regular shape after pre-sintering, which is conducive to the subsequent spray granulation to form more uniform particles. In addition, the pre-sintering can also reduce the agglomeration of particles, make the grain distribution uniform, and reduce the defects and stress inside the particles, which is conducive to improving the magnetic properties of the obtained soft magnetic metal powder.

[0031] Preferably, based on the total molar amount of Fe2O3, MnO and Al2O4Zn as 100 mol%, step (1) comprises ball-milling and mixing 52.5-56.5 mol% Fe2O3, 38-42 mol% MnO and 3-5.5 mol% Al2O4Zn.

[0032] Among them, 52.5-56.5 mol% Fe2O3 can be, for example, 52.5 mol%, 53.5 mol%, 54.5 mol%, 55.5 mol% or 56.5 mol%; 38-42 mol% MnO can be, for example, 38 mol%, 38.5 mol%, 39 mol%, 39.5 mol%, 40 mol%, 40.5 mol%, 41 mol%, 41.5 mol% or 42 mol%; 3-5.5 mol% Al2O4Zn can be, for example, 3 mol%, 3.5 mol%, 4 mol%, 4.5 mol%, 5 mol% or 5.5 mol%;

[0033] Preferably, the rotation speed of the ball milling mixing in step (1) is 130 to 170 r / min, for example, it can be 130 r / min, 140 r / min, 150 r / min, 160 r / min or 170 r / min.

[0034] Preferably, the ball milling mixing time in step (1) is 20 to 22 hours, for example, 20 hours, 20.5 hours, 21 hours, 21.5 hours or 22 hours.

[0035] Preferably, the pre-sintering temperature in step (1) is 850-875°C, for example, it can be 850°C, 855°C, 860°C, 865°C, 870°C or 875°C.

[0036] The present invention further prefers that the pre-sintering temperature in step (1) is 850-875°C, which is beneficial to ensure uniform grain size, improve the initial magnetic permeability and oxidation resistance of the soft magnetic metal powder, and reduce losses. If the pre-sintering temperature in step (1) is too low, the magnetic properties will be limited; if the pre-sintering temperature in step (1) is too high, abnormal grain growth and intensified particle agglomeration will occur, resulting in excessive thermal stress and defects in the obtained material, thereby affecting the magnetic properties.

[0037] Preferably, the pre-sintering time in step (1) is 3 to 6 hours, for example, it can be 3 hours, 3.5 hours, 4 hours, 4.5 hours, 5 hours, 5.5 hours or 6 hours.

[0038] Preferably, the pre-sintering in step (1) is carried out in an air atmosphere.

[0039] Preferably, based on the total mass of the pre-sintered material as 100wt%, the amount of CuO added in step (2) is 0 to 500ppm, and is not 0. For example, it can be 50ppm, 100ppm, 150ppm, 200ppm, 250ppm, 300ppm, 350ppm, 400ppm, 450ppm or 500ppm, etc., preferably 400 to 500ppm.

[0040] Preferably, based on the total mass of the pre-burned material as 100wt%, the amount of Co2O3 added in step (2) is 0 to 1200ppm, and is not 0. For example, it can be 100ppm, 200ppm, 500ppm, 800ppm, 1000ppm or 1200ppm, etc., preferably 1000 to 1200ppm.

[0041] Preferably, based on the total mass of the pre-burned material as 100wt%, the amount of Nb2O5 added in step (2) is 0 to 200ppm, and is not 0. For example, it can be 10ppm, 30ppm, 50ppm, 100ppm, 120ppm, 150ppm, 180ppm or 200ppm, etc., preferably 100 to 200ppm.

[0042] Preferably, step (2) further comprises adding a binder and / or a dispersant before the spray granulation, preferably a combination of a binder and a dispersant.

[0043] Preferably, based on 100 wt% of the total mass of the pre-sintered material, the added amount of the binder is 6-10 wt%, for example, 6 wt%, 7 wt%, 8 wt%, 9 wt% or 10 wt%.

[0044] Preferably, the binder comprises polyvinyl alcohol and / or polyvinyl butyral.

[0045] In the present invention, there is no particular limitation on the type of the adhesive, as long as it can effectively exert the bonding effect.

[0046] Preferably, based on the total mass of the pre-sintered material being 100 wt%, the added amount of the dispersant is 0.5-1 wt%, for example, 0.5 wt%, 0.6 wt%, 0.7 wt%, 0.8 wt%, 0.9 wt% or 1 wt%.

[0047] Preferably, the dispersing agent comprises polyethylene glycol.

[0048] The present invention does not impose any special restrictions on the type of the dispersant, as long as it can effectively exert the dispersing effect.

[0049] As a further preferred technical solution of the present invention, the method for preparing the soft magnetic metal powder comprises the following steps:

[0050] (1) Based on the total molar amount of Fe2O3, MnO and Al2O4Zn as 100 mol%, 52.5-56.5 mol% of Fe2O3, 38-42 mol% of MnO and 3-5.5 mol% of Al2O4Zn are ball-milled at a speed of 130-170 r / min for 20-22 h, and then pre-sintered at 850-875° C. in an air atmosphere for 3-6 h to obtain a pre-sintered material;

[0051] (2) Based on the total mass of the pre-sintered material being 100 wt%, 0-500 ppm CuO, 0-1200 ppm Co2O3, 0-200 ppm Nb2O5, the pre-sintered material of step (1), 6-10 wt% of a binder, and 0.5-1 wt% of a dispersant are mixed and spray granulated to obtain the soft magnetic metal powder;

[0052] The contents of CuO, Co2O3 and Nb2O5 are all not 0, the binder includes polyvinyl alcohol and / or polyvinyl butyral; and the dispersant includes polyethylene glycol.

[0053] In a third aspect, the present invention provides a copper-iron co-fired inductor, which comprises a first substrate, a copper conductor, and a second substrate in sequence, and the two ends of the copper conductor extend out from both sides of the first substrate and the second substrate; the first substrate and the second substrate each independently comprise the soft magnetic metal powder described in the first aspect.

[0054] The copper-iron co-fired inductor of the present invention uses the soft magnetic metal powder described in the first aspect as a base material, and utilizes the high magnetic permeability of the soft magnetic metal powder to increase the inductance value of the copper-iron co-fired inductor, thereby improving its performance.

[0055] In a fourth aspect, the present invention provides a method for preparing the copper-iron co-fired inductor according to the third aspect, the method for preparing the copper-iron co-fired inductor comprising the following steps:

[0056] S1: performing a first pressing on the first soft magnetic metal powder to obtain a first matrix;

[0057] S2: Placing a copper conductor on the first substrate in step S1, with both ends of the copper conductor extending out of both sides of the first substrate, and performing a second pressing operation on the copper conductor to obtain a second substrate, thereby obtaining a semi-finished copper-iron co-fired inductor;

[0058] S3: Sintering the semi-finished copper-iron co-fired inductor in step S2 to obtain a finished copper-iron co-fired inductor.

[0059] The method for preparing the copper-iron co-fired inductor provided by the present invention utilizes the soft magnetic metal powder described in the first aspect as a matrix raw material, and combines a first pressing, a second pressing, and a sintering process to prepare a copper-iron co-fired inductor with a high inductance value. The preparation method has a simple process flow, does not require complex equipment, and is low in cost.

[0060] Preferably, the temperature of the first pressing in step S1 is 20-30°C, for example, 20°C, 22°C, 25°C, 28°C or 30°C.

[0061] Preferably, the pressure of the first pressing in step S1 is 300-320 MPa, for example, 300 MPa, 305 MPa, 310 MPa, 315 MPa or 320 MPa.

[0062] Preferably, step S1 further includes curing the first substrate after the first pressing.

[0063] Preferably, the curing temperature is 120-150°C, for example, 120°C, 125°C, 130°C, 135°C, 140°C, 145°C or 150°C.

[0064] Preferably, the curing time is 2 to 3 hours, for example, 2 hours, 2.2 hours, 2.5 hours, 2.8 hours or 3 hours.

[0065] Preferably, the thickness of the copper conductor in step S2 is 1.1-1.3 mm, for example, 1.1 mm, 1.2 mm or 1.3 mm.

[0066] The present invention further preferably has a thickness of the copper conductor in step S2 of 1.1 to 1.3 mm to ensure a sufficient conductive path and improve the inductance value. If the thickness of the copper conductor is too thick, not only will the inductance value be reduced, but the volume of the copper-iron co-fired inductor will also be increased, which is not conducive to miniaturization. If the thickness of the copper conductor is too thin, the inductance value will be unstable or reduced, and the thermal stability will be poor, and performance degradation will be more likely to occur under high temperature or high current conditions.

[0067] Preferably, the temperature of the second pressing in step S2 is 200-250°C, for example, it can be 200°C, 205°C, 210°C, 215°C, 220°C, 225°C, 230°C, 235°C, 240°C, 245°C or 250°C.

[0068] The present invention further prefers that the temperature of the second pressing in step S2 is 200-250°C, which is beneficial to improving the density of the matrix; if the temperature of the second pressing is too low, it will lead to low matrix density and decreased performance after subsequent sintering; if the temperature of the second pressing is too high, it may cause problems such as abnormal material appearance or reduced adhesion strength.

[0069] Preferably, the second pressing pressure in step S2 is 300-320 MPa, for example, 300 MPa, 305 MPa, 310 MPa, 315 MPa or 320 MPa.

[0070] Preferably, in step S2, after the second pressing to obtain the second base body, pressure maintenance is performed.

[0071] Preferably, the pressure holding time is 4 to 6 minutes, for example, 4 minutes, 5 minutes or 6 minutes.

[0072] Preferably, the sintering temperature in step S3 is 900-950°C, for example, it can be 900°C, 905°C, 910°C, 915°C, 920°C, 925°C, 930°C, 935°C, 940°C, 945°C or 950°C.

[0073] Preferably, the sintering in step S3 is performed in an oxygen-containing inert gas atmosphere.

[0074] Preferably, the oxygen content in the oxygen-containing inert gas atmosphere is 150-200 ppm, for example, 150 ppm, 160 ppm, 170 ppm, 180 ppm, 190 ppm or 200 ppm.

[0075] Preferably, the inert gas includes nitrogen and / or argon.

[0076] The present invention further preferably performs the sintering in step S3 in an oxygen-containing inert gas atmosphere, and further preferably the oxygen content in the oxygen-containing inert gas atmosphere is 150 to 200 ppm, in order to control the valence state of the matrix elements; if the oxygen content is abnormal, the valence state of the matrix elements will change, and ultimately the magnetic properties of the product will be reduced.

[0077] Preferably, the sintering time in step S3 is 5 to 8 hours, for example, 5 hours, 6 hours, 7 hours or 8 hours.

[0078] Preferably, after the sintering in step S3, the finished copper-iron co-fired inductor is further subjected to post-processing.

[0079] Preferably, the post-processing includes cooling, sandblasting, foot folding and insulation processing performed in sequence.

[0080] The purpose of the sandblasting is to increase the surface roughness to ensure the insulation effect and remove the oxide layer on the copper surface.

[0081] The folding foot includes bending the two ends of the copper conductor extending from both sides of the first substrate and the second substrate so that the two ends of the copper conductor are symmetrically attached to the surface of the second substrate to form electrode pins.

[0082] Optionally, the insulation treatment includes impregnation.

[0083] Optionally, the impregnating liquid includes any one of epoxy resin paint, phenolic resin paint or silicone resin paint, or a combination of at least two of them, wherein typical but non-limiting combinations include a combination of epoxy resin paint and phenolic resin paint, a combination of phenolic resin paint and silicone resin paint, or a combination of epoxy resin paint and silicone resin paint, etc.

[0084] As a further preferred technical solution of the present invention, the method for preparing the copper-iron co-fired inductor comprises the following steps:

[0085] S1: performing a first pressing on a first soft magnetic metal powder at a temperature of 20 to 30° C. and a pressure of 300 to 320 MPa to obtain a first matrix, and curing the first matrix at a temperature of 120 to 150° C. for 2 to 3 hours;

[0086] S2: placing a copper conductor with a thickness of 1.1 to 1.3 mm on the first substrate in step S1, with both ends of the copper conductor extending out of both sides of the first substrate, and performing a second pressing of a second soft magnetic metal powder on the copper conductor at a temperature of 200 to 250° C. and a pressure of 300 to 320 MPa to obtain a second substrate, followed by maintaining the pressure for 4 to 6 minutes to obtain a semi-finished copper-iron co-fired inductor;

[0087] S3: Sintering the semi-finished copper-iron co-fired inductor of step S2 for 5-8 hours at 900-950° C. in an inert gas atmosphere with an oxygen content of 150-200 ppm, followed by cooling, sandblasting, leg folding, and insulation to obtain a finished copper-iron co-fired inductor; the inert gas includes nitrogen and / or argon.

[0088] Compared with the prior art, the present invention has at least the following beneficial effects:

[0089] (1) The soft magnetic metal powder provided by the present invention uses Fe2O3, MnO and Al2O4Zn as pre-sintered materials, and CuO, Co2O3 and Nb2O5 as additives. The raw materials are compounded synergistically, and the addition amount of each raw material and the addition of a binder and a dispersant are further selected to jointly improve the magnetic permeability of the soft magnetic metal powder and reduce the loss. The initial magnetic permeability (f = 1kHz, 0.25V) is preferably as high as 500 or more, and the power loss (1194A / m, 25°C) is preferably as low as 200W / m 3 The following makes the device prepared using it have excellent performance.

[0090] (2) The preparation method of the soft magnetic metal powder provided by the present invention is to prepare a soft magnetic metal powder with uniform grain distribution and narrow distribution range, high magnetic permeability and low loss by pre-sintering the pre-fired material and then adding additives for spray granulation. The preparation method has a simple process flow, relatively low raw material cost, and is easy to mass produce.

[0091] (3) The copper-iron co-fired inductor provided by the present invention adopts the above-mentioned soft magnetic metal powder as the base material and copper as the conductor. The high magnetic permeability of the soft magnetic metal powder is utilized to significantly improve the inductance. Compared with the commercially available copper-iron co-fired inductor, the inductance is increased by 20% to 50%. The inductance (f = 1kHz, 0.25V) is preferably as high as 250nH or more.

[0092] (4) The preparation method of the copper-iron co-fired inductor provided by the present invention utilizes the above-mentioned soft magnetic metal powder as the matrix material and copper as the conductor, and combines the first pressing, second pressing and sintering processes to prepare a high-inductance copper-iron co-fired inductor. The preparation method has a simple process flow, does not require complex equipment, and is low in cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0093] Figure 1 is a SEM image of the soft magnetic metal powder provided in Example 1 of the present invention;

[0094] Figure 2 Schematic diagram of the cross-sectional structure of the semi-finished copper-iron co-fired inductor provided in Application Example 1 of the present invention;

[0095] Figure 3Schematic diagram of the cross-sectional structure of the finished copper-iron co-fired inductor provided in Application Example 1 of the present invention;

[0096] In the figure: 1, first substrate; 2, copper conductor; 3, second substrate. DETAILED DESCRIPTION

[0097] The technical solution of the present invention will be further described below with reference to the accompanying drawings and through specific embodiments. However, the following examples are merely simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention shall be subject to the claims.

[0098] 1. Example 1

[0099] Example 1

[0100] This embodiment provides a soft magnetic metal powder, the raw materials of which include pre-burned material and additives; the pre-burned material is 54.5 mol% Fe2O3, 40 mol% MnO and 5.5 mol% Al2O4Zn; based on the total mass of the pre-burned material being 100 wt%, the additives are 450 ppm CuO, 1100 ppm Co2O3 and 150 ppm Nb2O5, and based on the total mass of the pre-burned material being 100 wt%, the soft magnetic metal powder also includes 8 wt% polyvinyl alcohol and 0.8 wt% polyethylene glycol.

[0101] like Figure 1 As shown, the soft magnetic metal powder provided in this embodiment has a uniform particle size distribution, a median particle size D50 of 50 μm, and a particle size D90 of 100 μm.

[0102] This embodiment also provides a method for preparing the soft magnetic metal powder, the method comprising the following steps:

[0103] (1) 54.5 mol% Fe2O3, 40 mol% MnO and 5.5 mol% Al2O4Zn were ball-milled at a speed of 150 r / min for 20 h, and then pre-sintered at 860°C in an air atmosphere for 4 h to obtain a pre-sintered material;

[0104] (2) Based on the total mass of the pre-sintered material being 100 wt%, 450 ppm CuO, 1100 ppm Co2O3, 150 ppm Nb2O5, the pre-sintered material of step (1), 8 wt% polyvinyl alcohol and 0.8 wt% polyethylene glycol are mixed and spray granulated to obtain the soft magnetic metal powder.

[0105] Example 2

[0106] This embodiment provides a soft magnetic metal powder, the raw materials of which include pre-burned material and additives; the pre-burned material includes 56.5 mol% Fe2O3, 39 mol% MnO and 4.5 mol% Al2O4Zn; based on the total mass of the pre-burned material being 100 wt%, the additives include 400 ppm CuO, 1000 ppm Co2O3 and 100 ppm Nb2O5, and based on the total mass of the pre-burned material being 100 wt%, the soft magnetic metal powder also includes 6 wt% polyvinyl butyral and 0.5 wt% polyethylene glycol.

[0107] The soft magnetic metal powder provided in this embodiment has a uniform particle size distribution, a median particle size D50 of 45 μm, and a particle size D90 of 95 μm.

[0108] This embodiment also provides a method for preparing the soft magnetic metal powder, the method comprising the following steps:

[0109] (1) 56.5 mol% Fe2O3, 39 mol% MnO and 4.5 mol% Al2O4Zn were ball-milled at a speed of 145 r / min for 22 h, and then pre-sintered at 850°C in an air atmosphere for 6 h to obtain a pre-sintered material;

[0110] (2) Based on the total mass of the pre-sintered material being 100 wt%, 400 ppm CuO, 1000 ppm Co2O3, 100 ppm Nb2O5, the pre-sintered material of step (1), 6 wt% polyvinyl butyral and 0.5 wt% vinyl silane coupling agent are mixed and spray granulated to obtain the soft magnetic metal powder.

[0111] Example 3

[0112] This embodiment provides a soft magnetic metal powder, the raw materials of which include pre-burned material and additives; the pre-burned material includes 55 mol% Fe2O3, 42 mol% MnO and 3 mol% Al2O4Zn; based on the total mass of the pre-burned material being 100 wt%, the additives include 500 ppm CuO, 1200 ppm Co2O3 and 200 ppm Nb2O5, and based on the total mass of the pre-burned material being 100 wt%, the soft magnetic metal powder also includes 10 wt% polyvinyl butyral and 1 wt% polyethylene glycol.

[0113] The soft magnetic metal powder provided in this embodiment has a uniform particle size distribution, a median particle size D50 of 45 μm, and a particle size D90 of 95 μm.

[0114] This embodiment also provides a method for preparing the soft magnetic metal powder, the method comprising the following steps:

[0115] (1) 55 mol% Fe2O3, 42 mol% MnO and 3 mol% Al2O4Zn were ball-milled at a speed of 170 r / min for 20 h, and then pre-sintered at 875°C in an air atmosphere for 3 h to obtain a pre-sintered material;

[0116] (2) Based on the total mass of the pre-sintered material being 100 wt%, 100 ppm CuO, 400 ppm Co2O3, 80 ppm Nb2O5, the pre-sintered material of step (1), 10 wt% polyvinyl butyral and 1 wt% polyethylene glycol are mixed and spray granulated to obtain the soft magnetic metal powder.

[0117] Example 4

[0118] This embodiment provides a soft magnetic metal powder, the raw material of which is 2.5 mol% Al2O4Zn, and the reduced Al2O4Zn is distributed to Fe2O3 and MnO according to corresponding molar ratios. Except for the corresponding change in the ratio of the pre-sintered material, the rest of the preparation method is the same as Example 1.

[0119] Example 5

[0120] This embodiment provides a soft magnetic metal powder, the raw material of which is 6 mol% Al2O4Zn, and the increased Al2O4Zn reduces the amount of Fe2O3 and MnO according to the corresponding molar ratio. Except for the corresponding change in the ratio of the pre-sintered material, the rest of the preparation method is the same as Example 1.

[0121] Example 6

[0122] This embodiment provides a method for preparing soft magnetic metal powder. The preparation method is the same as that of Example 1 except that the pre-sintering is performed at 840°C.

[0123] Example 7

[0124] This embodiment provides a method for preparing soft magnetic metal powder. The preparation method is the same as that of Example 1 except that the pre-sintering is performed at 880°C.

[0125] 2. Comparative Example

[0126] Comparative Example 1

[0127] This comparative example provides a soft magnetic metal powder. The raw materials of the soft magnetic metal powder are the same as those of Example 1, except that Al2O4Zn is replaced by ZnO and the preparation method changes the composition of the pre-sintered material accordingly.

[0128] 3. Application Examples

[0129] Application Example 1

[0130] This application example provides a copper-iron co-fired inductor. Figure 2 and Figure 3 As shown, the copper-iron co-fired inductor includes a first substrate 1, a copper conductor 2, and a second substrate 3 in sequence, and the two ends of the copper conductor 2 extend out of both sides of the first substrate 1 and the second substrate 3; the raw materials of the first substrate 1 and the second substrate 3 are both the soft magnetic metal powder described in Example 1.

[0131] This application example also provides a method for preparing the copper-iron co-fired inductor, the method comprising the following steps:

[0132] S1: performing a first pressing on the first soft magnetic metal powder at 25° C. and a pressure of 310 MPa to obtain a first matrix 1, and baking the first matrix 1 at 130° C. for 2 h;

[0133] S2: A copper conductor 2 with a thickness of 1.2 mm is placed on the first substrate 1 in step S1, with both ends of the copper conductor 2 extending out of both sides of the first substrate 1, and a second soft magnetic metal powder is pressed on the copper conductor 2 at a pressure of 310 MPa at 220°C to obtain a second substrate 3, and then the pressure is maintained for 5 minutes to obtain a semi-finished copper-iron co-fired inductor (such as Figure 2 shown);

[0134] S3: Sinter the semi-finished copper-iron co-fired inductor described in step S2 for 6 hours at 920°C in a nitrogen atmosphere with an oxygen content of 180ppm, and then cool, sandblast, fold the legs and insulate to obtain a finished copper-iron co-fired inductor (such as Figure 3 shown);

[0135] In step S1 , both the first soft magnetic powder and the second soft magnetic powder are soft magnetic metal powders prepared by the preparation method described in Example 1.

[0136] Application Example 2

[0137] This application example provides a copper-iron co-fired inductor, which includes a first substrate, a copper conductor, and a second substrate in sequence, and the two ends of the copper conductor extend out of both sides of the first substrate and the second substrate; the raw materials of the first substrate and the second substrate are both the soft magnetic metal powder described in Example 2.

[0138] This application example also provides a method for preparing the copper-iron co-fired inductor, the method comprising the following steps:

[0139] S1: performing a first pressing on a first soft magnetic metal powder at 20° C. and a pressure of 320 MPa to obtain a first matrix, and baking the first matrix at 120° C. for 2.5 hours;

[0140] S2: Placing a 1.1 mm thick copper conductor on the first substrate obtained in step S1, with both ends of the copper conductor extending out of both sides of the first substrate, and performing a second pressing operation on the copper conductor using a second soft magnetic metal powder at 200° C. and a pressure of 320 MPa to obtain a second substrate. Subsequently, maintaining the pressure for 4 minutes to obtain a semi-finished copper-iron co-fired inductor;

[0141] S3: sintering the semi-finished copper-iron co-fired inductor of step S2 at 900° C. in a nitrogen atmosphere with an oxygen content of 200 ppm for 7 hours, followed by cooling, sandblasting, leg bending, and insulation treatment to obtain a finished copper-iron co-fired inductor;

[0142] In step S1 , both the first soft magnetic powder and the second soft magnetic powder are soft magnetic metal powders prepared by the preparation method described in Example 2.

[0143] Application Example 3

[0144] This application example provides a copper-iron co-fired inductor, which includes a first substrate, a copper conductor, and a second substrate in sequence, and the two ends of the copper conductor extend out of both sides of the first substrate and the second substrate; the raw materials of the first substrate and the second substrate are both the soft magnetic metal powder described in Example 3.

[0145] This application example also provides a method for preparing the copper-iron co-fired inductor, the method comprising the following steps:

[0146] S1: performing a first pressing on a first soft magnetic metal powder at 30° C. and a pressure of 300 MPa to obtain a first matrix, and baking the first matrix at 150° C. for 2.8 hours;

[0147] S2: Placing a 1.3 mm thick copper conductor on the first substrate obtained in step S1, with both ends of the copper conductor extending out of both sides of the first substrate, and performing a second pressing operation on the copper conductor using a second soft magnetic metal powder at 250° C. and a pressure of 300 MPa to obtain a second substrate. Subsequently, maintaining the pressure for 6 minutes to obtain a semi-finished copper-iron co-fired inductor;

[0148] S3: sintering the semi-finished copper-iron co-fired inductor described in step S2 at 950° C. in an argon atmosphere with an oxygen content of 150 ppm for 7.5 hours, followed by cooling, sandblasting, leg bending, and insulation treatment to obtain a finished copper-iron co-fired inductor;

[0149] In step S1 , both the first soft magnetic powder and the second soft magnetic powder are soft magnetic metal powders prepared by the preparation method described in Example 3.

[0150] Application Examples 4 to 7

[0151] Based on Application Example 1, the preparation methods of the copper-iron co-fired inductors provided in Application Examples 4 to 7 only replace the first soft magnetic powder and the second soft magnetic powder with the soft magnetic metal powders prepared by the preparation methods described in Example 4, Example 5, Example 6 and Example 7, respectively, and the rest are the same as in Application Example 1.

[0152] Application Example 8

[0153] This application example provides a method for preparing a copper-iron co-fired inductor. The preparation method is the same as that of Application Example 1, except that the thickness of the copper conductor in step S2 is 1 mm.

[0154] Application Example 9

[0155] This application example provides a method for preparing a copper-iron co-fired inductor. The preparation method is the same as that of Application Example 1, except that the thickness of the copper conductor in step S2 is 1.5 mm.

[0156] Application Example 10

[0157] This application example provides a method for preparing a copper-iron co-fired inductor. The preparation method is the same as that of Application Example 1, except that the temperature of the second pressing in step S2 is 180° C.

[0158] Application Example 11

[0159] This application example provides a method for preparing a copper-iron co-fired inductor. The preparation method is the same as that of Application Example 1, except that the temperature of the second pressing in step S2 is 260° C.

[0160] Application Example 12

[0161] This application example provides a method for preparing a copper-iron co-fired inductor. The preparation method is the same as that of Application Example 1, except that the sintering in step S3 is performed in a nitrogen atmosphere with an oxygen content of 100 ppm.

[0162] Application Example 13

[0163] This application example provides a method for preparing a copper-iron co-fired inductor. The preparation method is the same as that of Application Example 1, except that the sintering in step S3 is performed in a nitrogen atmosphere with an oxygen content of 220 ppm.

[0164] 4. Comparative Application Examples

[0165] Comparative Application Example 1

[0166] This comparative application example 1 provides a preparation method for a copper-iron co-fired inductor. The preparation method is the same as that of application example 1, except that the first metal powder and the second metal powder are soft magnetic metal powders prepared by the preparation method provided in comparative example 1.

[0167] V. Test and its results

[0168] The soft magnetic metal powder samples obtained in the above embodiments and comparative examples were tested and their initial magnetic permeability (LCR bridge, CHROMA, model 11050, test conditions: f = 1 kHz, 0.25 V) and power loss value (power loss test equipment (Iwasaki SY-8218), test conditions: 1194 A / m, 25 ° C) were calculated. The inductance of the copper-iron co-fired inductor provided by the above application examples and comparative application examples was also tested (LCR bridge, CHROMA, model 11050, test conditions: f = 1 kHz, 0.25 V). The results are shown in Tables 1 and 2.

[0169] Table 1

[0170]

[0171]

[0172] Table 2

[0173] project Inductance / nH Application Example 1 270 Application Example 2 260 Application Example 3 263 Application Example 4 188 Application Example 5 195 Application Example 6 167 Application Example 7 175 Application Example 8 177 Application Example 9 169 Application Example 10 172 Application Example 11 189 Application Example 12 191 Application Example 13 195 Comparative Application Example 1 157

[0174] From the data in Table 1 and Table 2, we can see that:

[0175] (1) It can be seen from Examples 1 to 3 and Application Examples 1 to 3 that the soft magnetic metal powder and its preparation method, the copper-iron co-fired inductor and its preparation method provided by the present invention, by selecting specific raw materials and specific preparation process parameters, the initial magnetic permeability of the sample prepared from the obtained soft magnetic metal powder is preferably as high as 500 or more, and the power loss is as low as 200W / m 3 The following, and using it as a base material, combined with a specific pressing and sintering process, the inductance of the obtained copper-iron co-fired inductor is as high as over 250nH.

[0176] (2) Combining Example 1 with Examples 4 to 5 and Application Example 1 with Application Example 4 to 5, it can be seen that: the amount of Al2O4Zn in the raw material of the soft magnetic metal powder in Example 4 is relatively low, resulting in a decrease in its initial magnetic permeability and an increase in power loss, thereby resulting in a decrease in the inductance of the copper-iron co-fired inductor prepared using the same; the amount of Al2O4Zn in the raw material of the soft magnetic metal powder in Example 5 is relatively high, but its initial magnetic permeability does not increase significantly, and the inductance of the copper-iron co-fired inductor prepared using the same does not increase significantly. This shows that the present invention further prefers that the raw material of the soft magnetic metal powder includes 3 to 5.5 mol% Al2O4Zn, which further improves the magnetic properties of the soft magnetic metal powder, thereby improving the inductance of the copper-iron co-fired inductor prepared using the same.

[0177] (3) From Example 1, Example 6 to Example 7, and Application Example 1, Application Example 6 to Application Example 7, it can be seen that the pre-sintering temperature in Example 6 or Example 7 is too low or too high, which leads to a decrease in the initial magnetic permeability of the all-ceramic metal powder and an increase in power loss, and then leads to a decrease in the inductance of the copper-iron co-fired inductor prepared using the same. This shows that the preparation method of the soft magnetic metal powder of the present invention further preferably sets the pre-sintering temperature to 850-875°C, which further improves the magnetic properties of the obtained soft magnetic metal powder, thereby further improving the inductance of the obtained copper-iron co-fired inductor.

[0178] (4) From Application Example 1 and Application Examples 8 to 11, it can be seen that the thickness of the copper conductor in Application Example 8 or Application Example 9 is too thin or too thick, or the temperature of the second pressing in Application Example 10 or Application Example 11 is too low or too high, which leads to a decrease in the inductance of the obtained copper-iron co-fired inductor. This shows that the present invention further preferably sets the thickness of the copper conductor to 1.1 to 1.3 mm, and further preferably sets the temperature of the second pressing to 200 to 250° C., which further increases the inductance of the obtained copper-iron co-fired inductor, thereby improving its performance.

[0179] (5) From the combination of Application Example 1, Application Example 12 and Application Example 13, it can be seen that the oxygen content in the sintering atmosphere in step S3 of Application Example 12 is too low or too high, which leads to a change in the valence state of the matrix elements after sintering, thereby causing a decrease in inductance. This shows that the present invention further preferably performs the sintering in step S3 in an inert gas atmosphere with an oxygen content of 150 to 200 ppm, thereby further improving the inductance of the obtained copper-iron co-fired inductor.

[0180] (6) From Example 1 and Comparative Example 1, as well as Application Example 1 and Comparative Application Example 1, it can be seen that the present invention replaces ZnO used in the traditional soft magnetic metal powder preparation method with Al2O4Zn, which significantly improves the initial magnetic permeability of the soft magnetic metal powder and reduces its power loss, thereby significantly improving the inductance of the copper-iron co-fired inductor prepared using it as a matrix raw material.

[0181] The applicant declares that the above is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention fall within the scope of protection and disclosure of the present invention.

Claims

1. A soft magnetic metal powder, characterized in that The raw materials of the soft magnetic metal powder include pre-sintered material and additives; The pre-sintered material includes Fe2O3, MnO and Al2O4Zn; and the additives include CuO, Co2O3 and Nb2O5.

2. The soft magnetic metal powder according to claim 1, characterized in that Based on the total molar amount of the pre-calcined material being 100 mol%, the pre-calcined material comprises 52.5 to 56.5 mol% of Fe2O3, 38 to 42 mol% of MnO and 3 to 5.5 mol% of Al2O4Zn; Preferably, based on the total mass of the pre-sintered material being 100 wt%, the content of CuO is 0 to 500 ppm, and is not 0, preferably 400 to 500 ppm; Preferably, based on the total mass of the pre-burned material being 100 wt%, the content of Co2O3 is 0 to 1200 ppm, and is not 0, preferably 1000 to 1200 ppm; Preferably, based on the total mass of the pre-sintered material being 100 wt%, the content of Nb2O5 is 0 to 200 ppm, and is not 0, preferably 100 to 200 ppm; Preferably, the raw material of the soft magnetic powder further comprises a binder and / or a dispersant, preferably a combination of a binder and a dispersant; Preferably, the content of the binder is 6-10 wt % based on the total mass of the pre-sintered material being 100 wt %; Preferably, the binder comprises polyvinyl alcohol and / or polyvinyl butyral; Preferably, based on 100 wt% of the total mass of the pre-sintered material, the content of the dispersant is 0.5-1 wt%.

3. The soft magnetic metal powder according to claim 1 or 2, characterized in that The median particle size D50 of the soft magnetic metal powder is 45 to 55 μm; Preferably, the particle size D90 of the soft magnetic metal powder is 95-105 μm.

4. A method for preparing the soft magnetic metal powder according to any one of claims 1 to 3, characterized in that: The preparation method of the soft magnetic metal powder comprises the following steps: (1) ball-milling Fe2O3, MnO and Al2O4Zn and pre-sintering to obtain a pre-sintered material; (2) CuO, Co2O3, Nb2O5 and the pre-sintered material of step (1) are mixed and spray granulated to obtain the soft magnetic metal powder.

5. The method for preparing soft magnetic metal powder according to claim 4, characterized in that: Based on the total molar amount of Fe2O3, MnO and Al2O4Zn as 100 mol%, step (1) comprises ball-milling 52.5-56.5 mol% of Fe2O3, 38-42 mol% of MnO and 3-5.5 mol% of Al2O4Zn; Preferably, the rotation speed of the ball milling mixing in step (1) is 130 to 170 r / min; Preferably, the ball milling mixing time in step (1) is 20 to 22 hours; Preferably, the pre-sintering temperature in step (1) is 850-875°C; Preferably, the pre-sintering time in step (1) is 3 to 6 hours; Preferably, the pre-sintering in step (1) is carried out in an air atmosphere.

6. The method for preparing soft magnetic metal powder according to claim 4 or 5, characterized in that: Based on the total mass of the pre-sintered material as 100wt%, the amount of CuO added in step (2) is 0 to 500ppm, and is not 0, preferably 400 to 500ppm; Preferably, based on the total mass of the pre-burned material being 100 wt%, the amount of Co2O3 added in step (2) is 0 to 1200 ppm, and is not 0, preferably 1000 to 1200 ppm; Preferably, based on the total mass of the pre-sintered material being 100 wt%, the amount of Nb2O5 added in step (2) is 0 to 200 ppm, and is not 0, preferably 100 to 200 ppm; Preferably, step (2) further comprises adding a binder and / or a dispersant before the spray granulation, preferably a combination of a binder and a dispersant; Preferably, the amount of the binder added is 6 to 10 wt % based on the total mass of the pre-sintered material being 100 wt %; Preferably, based on 100 wt% of the total mass of the pre-sintered material, the added amount of the dispersant is 0.5-1 wt%.

7. A copper-iron co-fired inductor, characterized in that: The copper-iron co-fired inductor includes a first substrate, a copper conductor, and a second substrate in sequence, and the two ends of the copper conductor extend out of both sides of the first substrate and the second substrate; the first substrate and the second substrate each independently include the soft magnetic metal powder according to any one of claims 1 to 3.

8. A method for preparing a copper-iron co-fired inductor according to claim 7, characterized in that: The preparation method of the copper-iron co-fired inductor comprises the following steps: S1: performing a first pressing on the first soft magnetic metal powder to obtain a first matrix; S2: Placing a copper conductor on the first substrate in step S1, with both ends of the copper conductor extending out of both sides of the first substrate, and performing a second pressing operation on the copper conductor to obtain a second substrate, thereby obtaining a semi-finished copper-iron co-fired inductor; S3: Sintering the semi-finished copper-iron co-fired inductor in step S2 to obtain a finished copper-iron co-fired inductor.

9. The method for preparing a copper-iron co-fired inductor according to claim 8, characterized in that: Step S1: the temperature of the first pressing is 20-30°C; Preferably, the pressure of the first pressing in step S1 is 300-320 MPa; Preferably, step S1 further comprises curing the first substrate after the first pressing; Preferably, the curing temperature is 120-150°C; Preferably, the curing time is 2 to 3 hours; Preferably, the thickness of the copper conductor in step S2 is 1.1 to 1.3 mm; Preferably, the temperature of the second pressing in step S2 is 200-250°C; Preferably, the second pressing pressure in step S2 is 300-320 MPa; Preferably, in step S2, after the second pressing to obtain the second base body, pressure maintenance is performed; Preferably, the pressure holding time is 4 to 6 minutes.

10. The method for preparing a copper-iron co-fired inductor according to claim 8 or 9, characterized in that: The sintering temperature in step S3 is 900-950°C; Preferably, the sintering in step S3 is performed in an oxygen-containing inert gas atmosphere; Preferably, the oxygen content in the oxygen-containing inert gas atmosphere is 150 to 200 ppm; Preferably, the sintering time in step S3 is 5 to 8 hours; Preferably, after the sintering in step S3, the finished copper-iron co-fired inductor is further subjected to post-processing; Preferably, the post-processing includes cooling, sandblasting, foot folding and insulation processing performed in sequence.

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