Nickel-zinc copper ferrite and preparation method and application thereof

Abstract

The application relates to a nickel-zinc-copper ferrite and a preparation method and application thereof, the nickel-zinc-copper ferrite comprising main components and auxiliary components; the main components comprise Fe2O3 64-66.7 mol%, NiO 9-12 mol%, ZnO 13.5-19 mol% and CuO 3-9.5 mol% with the total mole percentage being 100 mol%; the auxiliary components comprise Bi2O3 0.3-1.5 wt%, Co2O3 0.1-0.6 wt%, CaCO3 0.03-0.08 wt% and ZrO2 less than or equal to 0.1 wt% with the total mass percentage of the main components being taken as a standard. The content of Fe2O3, ZnO, NiO and CuO is controlled, the content of the auxiliary components is matched and adjusted, the prepared nickel-zinc-copper ferrite has high saturation magnetic induction intensity, high magnetic permeability, high Curie temperature, low residual magnetic induction intensity and low specific temperature coefficient, and can be better applied to power inductance or common-mode inductance.

Description

Technical Field

[0001] This invention relates to the field of soft magnetic ferrite technology, specifically to a nickel-zinc-copper ferrite, its preparation method, and its application. Background Technology

[0002] With the rapid development and iteration of electronic product technology in recent years, ferrite cores have been widely used in medical devices, wireless charging, new energy vehicle charging piles, LED lighting, smart homes, and high-performance computers. The trend towards miniaturization and thinning of components has placed higher demands on the magnetoelectric performance of nickel-zinc materials, the mainstream ferrite material. Specifically, the components used in these components need to possess excellent characteristics such as high permeability, high stability, and long lifespan.

[0003] Currently, nickel-zinc soft magnetic ferrite materials in existing technologies have high permeability, but low Curie temperature and saturation magnetic induction intensity. This results in products made from nickel-zinc materials exhibiting disadvantages such as low inductance after superimposed current, low energy conversion efficiency, and high losses during use.

[0004] CN 104529423A discloses a low-temperature-factor, stress-resistant nickel-zinc ferrite with an initial permeability of 500 for power inductors and its preparation method. The main components of this nickel-zinc ferrite, calculated as oxides, are: Fe2O3 43.8–48.2 mol%, NiO 15.3–20.2 mol%, ZnO 28.8–31.2 mol%, and CuO 4.3–6.1 mol%; the secondary components are: nano-SiO2 0.90–1.3 wt%, nano-Bi2O3 0.13–0.25 wt%, Co3O4 0.05–0.08 wt%, TiO2 0.10–0.25 wt%, and talc 0.10–0.45 wt%. The ferrite provided by this invention has a permeability of up to 600, meeting the requirement of high permeability, but it does not possess a high Bs value.

[0005] CN 109369168A discloses a ferrite composition whose main components consist of 40.0–49.8 mol% iron oxide (based on Fe2O3), 5.0–14.0 mol% copper oxide (based on CuO), 0–32.0 mol% zinc oxide (based on ZnO), and the balance being nickel oxide. Relative to the main components, it contains 0.5–4.0 mol% tin oxide (based on SnO2), 0.10–1.00 mol% bismuth oxide (based on Bi2O3), and 0.21–3.00 mol% cobalt oxide (based on Co3O4) as secondary components per 100 wt%. Although the material of this invention has a permeability of around 500, meeting the requirement of high permeability, its saturation magnetic induction, remanence, and remanence are relatively low, and its coercivity and dielectric loss are high.

[0006] CN 101169996A discloses a Mn-Zn ferrite magnetic material and its preparation method. The main components and contents of this Mn-Zn ferrite magnetic material, calculated as oxides, are: Fe2O3 52-56 mol%; ZnO 2-10 mol%; MnO 38-42 mol%; auxiliary components are: CaO: 400-800 ppm, Nb2O5: 100-400 ppm, ZrO2: 100-800 ppm, Co2O3: 1000-5000 ppm, or a combination thereof. It is a Mn-Zn ferrite magnetic material with high saturation magnetic induction intensity and excellent electromagnetic properties of low power consumption under ultra-high temperature conditions. This patent simultaneously adds numerous impurities to the main ferrite components Fe2O3, NiO, ZnO, and CuO to achieve high saturation magnetic induction intensity and high Curie temperature. However, its magnetic permeability after sintering is relatively low, and its temperature stability needs further investigation.

[0007] Therefore, in view of the shortcomings of the existing technology, there is an urgent need to provide a nickel-zinc-copper ferrite with high permeability, high Curie temperature, low remanent magnetic induction and low specific temperature coefficient. Summary of the Invention

[0008] The purpose of this invention is to provide a nickel-zinc-copper ferrite, its preparation method and application. By limiting the reasonable ratio of raw materials, the nickel-zinc-copper ferrite obtained has the characteristics of high magnetic permeability, high Curie temperature, low remanent magnetic induction intensity and low specific temperature coefficient.

[0009] To achieve this objective, the present invention employs the following technical solution:

[0010] In a first aspect, the present invention provides a nickel-zinc-copper ferrite, the nickel-zinc-copper ferrite comprising a main component and auxiliary components; the main component, calculated as a total molar percentage of 100 mol%, comprises: Fe2O3 64-66.7 mol%, NiO 9-12 mol%, ZnO 13.5-19 mol%, CuO 3-9.5 mol%; the auxiliary components, calculated as the total mass percentage of the main component, comprise: Bi2O3 0.3-1.5 wt%, Co2O3 0.1-0.6 wt%, CaCO3 0.03-0.08 wt%, ZrO2 ≤0.1 wt%.

[0011] This invention achieves high magnetic permeability and Curie temperature in nickel-zinc-copper ferrites by controlling the contents of Fe2O3, ZnO, and CuO. To ensure high saturation magnetic induction and low specific temperature coefficient, the contents of Fe2O3, ZnO, NiO, and CuO need to be adjusted accordingly. The auxiliary component Ca... 2+ and Bi 3+The combined substitution of Ca can improve magnetic permeability and achieve high-frequency charging efficiency; 2+ Co 3+ A small amount of substitution can reduce the imaginary part of the magnetic permeability, achieving low-loss characteristics; through Ca... 2+ Co 3+ and Bi 3+ or Zr 4+ The combination of substitutions can regulate the saturation magnetic flux density to achieve device applicability in extreme environments. The nickel-zinc-copper ferrite prepared by this invention has high saturation magnetic flux density, high permeability, high Curie temperature, low remanent magnetic flux density, and low specific temperature coefficient, which can be better applied in power inductors or common-mode inductors.

[0012] The molar percentage of Fe2O3 in the main component is 64-66.7 mol%, for example, it can be 64 mol%, 64.6 mol%, 65.6 mol%, 66.2 mol%, or 66.7 mol%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0013] The molar percentage of NiO in the main component is 9-12 mol%, for example, it can be 9 mol%, 9.5 mol%, 10.3 mol%, 11.5 mol%, or 12 mol%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0014] The molar percentage of ZnO in the main component is 13.5-19 mol%, for example, it can be 13.5 mol%, 15.5 mol%, 16.7 mol%, 18.6 mol%, or 19 mol%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0015] The molar percentage of CuO in the main component is 3-9.5 mol%, for example, it can be 3 mol%, 4.3 mol%, 7.8 mol%, 8.4 mol%, or 9.5 mol%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0016] The mass percentage of Bi2O3 in the auxiliary component is 0.3-1.5 wt% of the total mass percentage of the main component, for example, it can be 0.3 wt%, 0.5 wt%, 0.8 wt%, 1.2 wt% or 1.5 wt%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0017] The mass percentage of Co2O3 in the auxiliary component is 0.1-0.6 wt% of the total mass percentage of the main component, for example, it can be 0.1 wt%, 0.2 wt%, 0.3 wt%, 0.4 wt% or 0.6 wt%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0018] The mass percentage of CaCO3 in the auxiliary component is 0.03-0.08 wt% of the total mass percentage of the main component, for example, it can be 0.03 wt%, 0.04 wt%, 0.05 wt%, 0.06 wt% or 0.08 wt%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0019] The mass percentage of ZrO2 in the auxiliary components is less than or equal to 0.1 wt% of the total mass percentage of the main components. For example, it can be 0.1 wt%, 0.08 wt%, 0.05 wt%, 0.03 wt%, or 0.01 wt%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0020] Preferably, the total molar percentage of Fe2O3+ZnO+CuO in the main components is 88.5-90.5 mol%, for example, it can be 88.5 mol%, 89 mol%, 89.5 mol%, 90 mol%, or 90.5 mol%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0021] In this invention, it is necessary to control the total amount of Fe2O3, ZnO, and CuO within a reasonable range. If the amount exceeds the limit, even if the content of each major component is within the required range, the magnetic permeability and saturation magnetic induction intensity Bs of the prepared nickel-zinc-copper ferrite will be reduced.

[0022] Preferably, the total mass percentage of Co2O3+CaCO3 in the auxiliary components is 0.2-0.6 wt% of the total mass percentage of the main components, for example, it can be 0.2 wt%, 0.3 wt%, 0.4 wt%, 0.5 wt% or 0.6 wt%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0023] In this invention, it is necessary to control the total amount of Co2O3 and CaCO3 within a reasonable range. If the amount exceeds the limit, even if the content of each auxiliary component is within the required range, the magnetic permeability of the prepared nickel-zinc-copper ferrite will be reduced.

[0024] Secondly, the present invention provides a method for preparing nickel-zinc-copper ferrite as described in the first aspect, the method comprising the following steps:

[0025] (1) The main components of the wet ball milling formula are mixed and the resulting ball milled material is pre-calcined after first spray granulation to obtain pre-calcined material;

[0026] (2) The auxiliary ingredients, liquid medium, additives and the pre-burned material obtained in step (1) are subjected to first grinding and second grinding in sequence. The resulting grinding material is granulated by second spraying and then shaped and sintered to obtain the nickel-zinc-copper ferrite.

[0027] The method for preparing nickel-zinc-copper ferrite provided by this invention, by selecting a reasonable pre-calcination temperature and then controlling the grinding parameters of the pre-calcined material, is beneficial to the refinement of the magnetic domains of the nickel-zinc-copper ferrite obtained by subsequent sintering, thereby ensuring that the nickel-zinc-copper ferrite has high saturation magnetic induction, high permeability, high Curie temperature, low remanent magnetic induction and low specific temperature coefficient, thus meeting the high performance requirements as a soft magnetic ferrite material.

[0028] Preferably, the mass ratio of the main component, the ball milling medium and the liquid medium in the wet ball milling mixture in step (1) is 1:(4-8):(0.5-1.2), for example, it can be 1:4:0.5, 1:5:0.6, 1:6:0.8, 1:7:1 or 1:8:1.2, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0029] Preferably, the milling media comprises zirconium balls.

[0030] Preferably, the liquid medium comprises deionized water.

[0031] Preferably, the wet ball milling mixing time in step (1) is 20-60 min, for example, it can be 20 min, 30 min, 40 min, 50 min or 60 min, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0032] Preferably, the preheating temperature in step (1) is 780-950℃, for example, it can be 780℃, 800℃, 820℃, 850℃, 880℃, 900℃ or 950℃, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0033] Preferably, the preheating time in step (1) is 2-4 hours, for example, 2 hours, 2.5 hours, 3 hours, 3.5 hours or 4 hours, but not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0034] Preferably, the additive in step (2) includes any one or a combination of at least two of the following: adhesive, dispersant or defoamer. Typical but non-limiting combinations include a combination of adhesive and dispersant, a combination of dispersant and defoamer, or a combination of adhesive, dispersant and defoamer, preferably a combination of adhesive, dispersant and defoamer.

[0035] Preferably, when the additive in step (2) is a combination of binder, dispersant and defoamer, the mass ratio of the pre-burned material, liquid medium, binder, dispersant and defoamer is 100:(40-150):(4-20):(0.1-2):(0.001-0.0025), for example, it can be 100:40:4:0.1:0.001, 100:70:7:0.5:0.0012, 100:100:10:1:0.0015, 100:120:15:1.5:0.002 or 100:150:20:2:0.0025, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0036] Preferably, the liquid medium in step (2) includes deionized water.

[0037] Preferably, the adhesive comprises any one or a combination of at least two of polyvinyl alcohol, polyvinyl butyral, hydroxycellulose, or polyacrylate. Typical but non-limiting combinations include a combination of polyvinyl alcohol and polyvinyl butyral, a combination of polyvinyl butyral, hydroxycellulose, and polyacrylate, or a combination of polyvinyl alcohol, polyvinyl butyral, hydroxycellulose, and polyacrylate.

[0038] Preferably, the dispersant comprises any one or a combination of at least two of citrate, sodium stearate, polyacrylic acid, or triethanolamine. Typical but non-limiting combinations include a combination of citrate and sodium stearate, a combination of sodium stearate and polyacrylic acid, or a combination of citrate, sodium stearate, polyacrylic acid, and triethanolamine.

[0039] Preferably, the defoamer comprises any one or a combination of at least two of n-octanol, tributyl phosphate, hard fatty acid, or polyethylene glycol. Typical but non-limiting combinations include a combination of n-octanol and tributyl phosphate, a combination of hard fatty acid and polyethylene glycol, or a combination of n-octanol, tributyl phosphate, hard fatty acid, and polyethylene glycol.

[0040] Preferably, the rotation speed of the first grinding in step (2) is 140-260 rpm, for example, it can be 140 rpm, 180 rpm, 200 rpm, 220 rpm or 260 rpm, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0041] Preferably, the grinding time in step (2) is 8-12 min, for example, it can be 8 min, 9 min, 10 min, 11 min or 12 min, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0042] Preferably, the rotation speed of the second grinding in step (2) is 270-320 rpm, for example, it can be 270 rpm, 290 rpm, 300 rpm, 310 rpm or 320 rpm, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0043] Preferably, the second grinding time in step (2) is 0.5-2h, for example, it can be 0.5h, 0.8h, 1h, 1.5h or 2h, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0044] Preferably, the median particle size X50 of the abrasive in step (2) is 0.5-0.8 μm, and the cumulative percentage of particle size X90 is 1.25-1.8 μm.

[0045] The median particle size X50 of the abrasive is 0.5-0.8μm, for example, it can be 0.5μm, 0.6μm, 0.7μm or 0.8μm, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0046] The lower median particle size X50 of the abrasive material is beneficial for refining the magnetic domains of the nickel-zinc-copper ferrite obtained by subsequent sintering, thereby improving the magnet strength.

[0047] The cumulative percentage of the abrasive is 90% with a particle size of 1.25-1.8 μm x 90, for example, it can be 1.25 μm, 1.5 μm, 1.6 μm, 1.7 μm or 1.8 μm, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0048] Preferably, the average particle size of the particles obtained by the second spray granulation in step (2) is 30-200μm, for example, it can be 30μm, 60μm, 100μm, 150μm or 200μm, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0049] Preferably, the molding in step (2) includes molding a standard sample ring blank.

[0050] The density of the standard sample ring blank is 3.1-3.25 g / cm³. 3 The dimensions are H25*15*10mm.

[0051] Preferably, the sintering in step (2) is carried out in a pusher kiln.

[0052] Preferably, the sintering in step (2) includes a first heating, a second heating, a first cooling and a second cooling in sequence.

[0053] Preferably, the specific steps of the first heating include: heating from room temperature to 550-750℃ in an air atmosphere at a heating rate of 0.5-2℃ / min, and holding at that temperature for 2-7 hours.

[0054] The heating rate of the first heating is 0.5-2℃ / min, for example, it can be 0.5℃ / min, 0.8℃ / min, 1℃ / min, 1.5℃ / min or 2℃ / min, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0055] The so-called normal temperature refers to a temperature of 20-25℃.

[0056] The endpoint of the first temperature rise is 550-750℃, for example, it can be 550℃, 600℃, 650℃, 700℃ or 750℃, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0057] The holding time for the first heating is 2-7 hours, for example, it can be 2 hours, 3 hours, 5 hours, 6 hours or 7 hours, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0058] Preferably, the specific steps of the second heating include: continuing to heat to 950-1050℃ at a heating rate of 1-3℃ / min, and holding at that temperature for 2-5 hours.

[0059] The second heating rate is 1-3℃ / min, for example, it can be 1℃ / min, 1.5℃ / min, 2℃ / min, 2.5℃ / min or 3℃ / min, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0060] The second temperature rise endpoint is 950-1050℃, for example, it can be 950℃, 980℃, 1000℃, 1020℃ or 1050℃, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0061] The second heating and holding time is 2-5 hours, for example, it can be 2 hours, 2.5 hours, 3 hours, 4 hours or 5 hours, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0062] Preferably, the specific steps of the first cooling include: cooling to 590-610°C in an air atmosphere at a cooling rate of 2-6°C / min.

[0063] The cooling rate of the first cooling is 2-6℃ / min, for example, it can be 2℃ / min, 3℃ / min, 4℃ / min, 5℃ / min or 6℃ / min, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0064] The first cooling temperature endpoint is 590-610℃, for example, it can be 590℃, 595℃, 600℃, 605℃ or 610℃, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0065] Preferably, the specific steps of the second cooling include: continuing to cool down to 45-55°C at a cooling rate of 1-5°C / min.

[0066] The second cooling rate is 1-5℃ / min, for example, it can be 1℃ / min, 2℃ / min, 3℃ / min, 4℃ / min or 5℃ / min, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0067] The second cooling temperature endpoint is 45-55℃, for example, it can be 45℃, 48℃, 50℃, 52℃ or 55℃, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0068] The sintering process employs an air atmosphere sintering method in a pusher kiln, which enables large-scale production of magnetic core samples and achieves low-cost production. Simultaneously, by using a two-stage heating and two-stage cooling method, the magnetic permeability can be significantly improved, the magnet densification can be enhanced, and thus the saturation magnetic induction intensity Bs of the magnetic core can be increased.

[0069] Thirdly, the present invention provides an application of the nickel-zinc-copper ferrite as described in the first aspect, wherein the nickel-zinc-copper ferrite is used in power inductors or common-mode inductors.

[0070] The nickel-zinc-copper ferrite provided by this invention solves the problems of magnetic permeability stability at low and high temperatures, and low saturation magnetic induction intensity and high remanent magnetic induction intensity, thereby improving the applicability of power magnetic products such as common mode inductors and multilayer magnetic beads / inductors, and can be better applied to industries such as aerospace electronics, automotive electronics, and communication electronics.

[0071] Compared with the prior art, the present invention has the following beneficial effects:

[0072] This invention achieves high magnetic permeability and Curie temperature in nickel-zinc-copper ferrites by controlling the contents of Fe2O3, ZnO, and CuO. To ensure high saturation magnetic induction and low specific temperature coefficient, the contents of Fe2O3, ZnO, NiO, and CuO need to be adjusted accordingly. The auxiliary component Ca... 2+ and Bi 3+ The combined substitution of Ca can improve magnetic permeability and achieve high-frequency charging efficiency; 2+ Co 3+ A small amount of substitution can reduce the imaginary part of the magnetic permeability, achieving low-loss characteristics; through Ca... 2+ Co 3+ and Bi 3+ or Zr 4+ The combination of substitutions can regulate the saturation magnetic flux density to achieve device applicability in extreme environments. The nickel-zinc-copper ferrite prepared by this invention has high saturation magnetic flux density, high permeability, high Curie temperature, low remanent magnetic flux density, and low specific temperature coefficient, which can be better applied in power inductors or common-mode inductors. Attached Figure Description

[0073] Figure 1 This is a SEM image of the nickel-zinc-copper ferrite provided in Embodiment 1 of the present invention. Detailed Implementation

[0074] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0075] Example 1

[0076] This embodiment provides a nickel-zinc-copper ferrite, which includes main components and auxiliary components. Based on a total molar percentage of 100 mol%, the main components include: Fe₂O₃ 64.6 mol%, NiO 10.3 mol%, ZnO 16.7 mol%, and CuO 8.4 mol%. Based on the total mass percentage of the main components, the auxiliary components include: Bi₂O₃ 0.6 wt%, Co₂O₃ 0.17 wt%, CaCO₃ 0.05 wt%, and ZrO₂ 0.08 wt%.

[0077] The total molar percentage of Fe2O3+ZnO+CuO in the main components is 89.7 mol%; the total mass percentage of Co2O3+CaCO3 in the auxiliary components is 0.22 wt% of the total mass percentage of the main components.

[0078] The preparation method of the nickel-zinc-copper ferrite includes the following steps:

[0079] (1) The main components of the wet ball milling mixture are mixed for 40 min. The mass ratio of the main components, zirconium balls and deionized water in the wet ball milling mixture is 1:6:0.8. The resulting ball milling material is pre-calcined at 850℃ for 3 h after the first spray granulation to obtain the pre-calcined material.

[0080] (2) The auxiliary ingredients, polyvinyl alcohol, citrate amine, n-octanol, deionized water and the pre-calcined material obtained in step (1) are successively ground at 200 rpm for 10 min and at 300 rpm for 1.5 h to obtain abrasive material with a median particle size X50 of 0.7 μm and a cumulative percentage of 90% of the particles with a particle size X90 of 1.5 μm; the abrasive material is then subjected to a second spray granulation to obtain particles with an average particle size of 100 μm, and then shaped and sintered in a pusher kiln to obtain the nickel-zinc-copper ferrite;

[0081] The mass ratio of the pre-burned material, deionized water, polyvinyl alcohol, citrate amine, and n-octanol is 100:100:10:1:0.002;

[0082] The sintering process includes a first heating, a second heating, a first cooling, and a second cooling, performed sequentially. The first heating step includes heating from room temperature to 650°C in an air atmosphere at a heating rate of 1°C / min and holding at that temperature for 5 hours. The second heating step includes heating to 1000°C at a heating rate of 2°C / min and holding at that temperature for 3 hours. The first cooling step includes cooling to 600°C in an air atmosphere at a cooling rate of 4°C / min. The second cooling step includes cooling to 50°C at a cooling rate of 3°C / min.

[0083] The molding process includes molding a standard sample ring blank; the density of the standard sample ring blank is 3.2 g / cm³. 3 The dimensions are H25*15*10mm.

[0084] The SEM image of the nickel-zinc-copper ferrite prepared in this embodiment is shown below. Figure 1 As shown in the figure, the grain size is uniform and the grains are relatively dense.

[0085] Example 2

[0086] This embodiment provides a nickel-zinc-copper ferrite, which includes main components and auxiliary components. Based on a total molar percentage of 100 mol%, the main components include: Fe₂O₃ 65.6 mol%, NiO 11.5 mol%, ZnO 18.6 mol%, and CuO 4.3 mol%. Based on the total mass percentage of the main components, the auxiliary components include: Bi₂O₃ 0.6 wt%, Co₂O₃ 0.15 wt%, CaCO₃ 0.05 wt%, and ZrO₂ 0.05 wt%.

[0087] The total molar percentage of Fe2O3+ZnO+CuO in the main components is 88.5 mol%; the total mass percentage of Co2O3+CaCO3 in the auxiliary components is 0.2 wt% of the total mass percentage of the main components.

[0088] The preparation method of the nickel-zinc-copper ferrite includes the following steps:

[0089] (1) The main components of the wet ball milling mixture are mixed for 20 min. The mass ratio of the main components, zirconium balls and deionized water in the wet ball milling mixture is 1:4:0.5. The resulting ball milling material is pre-calcined at 780℃ for 4 h after the first spray granulation to obtain the pre-calcined material.

[0090] (2) The auxiliary ingredients, polyvinyl alcohol, triethanolamine, n-octanol, deionized water and the pre-calcined material obtained in step (1) are successively ground at 260 rpm for 8 min and at 320 rpm for 0.8 h to obtain abrasive material with a median particle size X50 of 0.5 μm and a cumulative percentage of 90% of the particle size X90 of 1.25 μm; the abrasive material is then spray-granulated to obtain particles with an average particle size of 30 μm, and then shaped and sintered in a pusher kiln to obtain the nickel-zinc-copper ferrite;

[0091] The mass ratio of the pre-burned material, deionized water, polyvinyl alcohol, triethanolamine, and n-octanol is 100:40:4:0.1:0.001.

[0092] The sintering process includes a first heating, a second heating, a first cooling, and a second cooling, performed sequentially. The first heating step includes heating from room temperature to 550°C at a heating rate of 0.5°C / min in an air atmosphere and holding at that temperature for 7 hours. The second heating step includes heating to 950°C at a heating rate of 1°C / min and holding at that temperature for 5 hours. The first cooling step includes cooling to 610°C at a cooling rate of 2°C / min in an air atmosphere. The second cooling step includes cooling to 55°C at a cooling rate of 1°C / min.

[0093] The molding process includes molding a standard sample ring blank; the density of the standard sample ring blank is 3.2 g / cm³. 3 The dimensions are H25*15*10mm.

[0094] Example 3

[0095] This embodiment provides a nickel-zinc-copper ferrite, which includes main components and auxiliary components. Based on a total molar percentage of 100 mol%, the main components include: Fe₂O₃ 66.7 mol%, NiO 9.5 mol%, ZnO 16 mol%, and CuO 7.8 mol%. Based on the total mass percentage of the main components, the auxiliary components include: Bi₂O₃ 1 wt%, Co₂O₃ 0.525 wt%, CaCO₃ 0.075 wt%, and ZrO₂ 0.08 wt%.

[0096] The total molar percentage of Fe2O3+ZnO+CuO in the main components is 90.5 mol%; the total mass percentage of Co2O3+CaCO3 in the auxiliary components is 0.6 wt% of the total mass percentage of the main components.

[0097] The preparation method of the nickel-zinc-copper ferrite includes the following steps:

[0098] (1) The main components of the wet ball milling mixture are mixed for 60 min. The mass ratio of the main components, zirconium balls and deionized water in the wet ball milling mixture is 1:8:1.2. The resulting ball milling material is pre-calcined at 950℃ for 2 h after the first spray granulation to obtain the pre-calcined material.

[0099] (2) The auxiliary ingredients, polyvinyl butyral, polyacrylic acid, polyethylene glycol, deionized water and the pre-calcined material obtained in step (1) are successively ground at 140 rpm for 12 min and at 270 rpm for 2 h to obtain abrasive material with a median particle size X50 of 0.8 μm and a cumulative percentage of 90% of the particles with a particle size X90 of 1.8 μm; the abrasive material is then subjected to a second spray granulation to obtain particles with an average particle size of 200 μm, and then shaped and sintered in a pusher kiln to obtain the nickel-zinc-copper ferrite;

[0100] The mass ratio of the pre-burned material, deionized water, polyvinyl butyral, polyacrylic acid, and polyethylene glycol is 100:150:20:2:0.0025.

[0101] The sintering process includes a first heating, a second heating, a first cooling, and a second cooling, performed sequentially. The first heating step includes heating from room temperature to 750°C in air at a heating rate of 2°C / min and holding for 2 hours. The second heating step includes heating to 1050°C at a heating rate of 3°C / min and holding for 2 hours. The first cooling step includes cooling to 590°C in air at a cooling rate of 6°C / min. The second cooling step includes cooling to 45°C at a cooling rate of 5°C / min.

[0102] The molding process includes molding a standard sample ring blank; the density of the standard sample ring blank is 3.2 g / cm³. 3 The dimensions are H25*15*10mm.

[0103] Example 4

[0104] This embodiment provides a nickel-zinc-copper ferrite, which differs from Example 1 in that, based on a total molar percentage of 100 mol%, the main components are adjusted to: Fe2O3 65 mol%, NiO 12 mol%, ZnO 17.57 mol%, CuO 5.43 mol%, resulting in a total molar percentage of Fe2O3+ZnO+CuO of 88 mol%, while the rest are the same as in Example 1.

[0105] Example 5

[0106] This embodiment provides a nickel-zinc-copper ferrite, which differs from Example 1 in that, based on a total molar percentage of 100 mol%, the main components are adjusted to: Fe2O3 66.2 mol%, NiO 9 mol%, ZnO 15.5 mol%, CuO 9.3 mol%, resulting in a total molar percentage of Fe2O3+ZnO+CuO of 91 mol%, while the rest are the same as in Example 1.

[0107] Example 6

[0108] This embodiment provides a nickel-zinc-copper ferrite, which differs from Embodiment 1 in that, based on the total mass percentage of the main components, the auxiliary components are adjusted to: Bi2O3 0.3wt%, Co2O3 0.1wt%, CaCO3 0.03wt%, ZrO2 0.1wt%, adapting to obtain a total mass percentage of Co2O3+CaCO3 of 0.13wt% of the total mass percentage of the main components. The rest are the same as in Embodiment 1.

[0109] Example 7

[0110] This embodiment provides a nickel-zinc-copper ferrite, which differs from Embodiment 1 in that, based on the total mass percentage of the main components, the auxiliary components are adjusted to: Bi2O3 1.5wt%, Co2O3 0.6wt%, CaCO3 0.08wt%, ZrO2 0.05wt%, adapting to obtain a total mass percentage of Co2O3+CaCO3 of 0.68wt% of the total mass percentage of the main components. The rest are the same as in Embodiment 1.

[0111] Example 8

[0112] This embodiment provides a nickel-zinc-copper ferrite. The preparation method of the nickel-zinc-copper ferrite is different from that of Embodiment 1. Except for adjusting the pre-firing temperature in step (1) to 750°C, the rest is the same as that of Embodiment 1.

[0113] Example 9

[0114] This embodiment provides a nickel-zinc-copper ferrite. The preparation method of the nickel-zinc-copper ferrite is different from that of Embodiment 1. Except for adjusting the pre-firing temperature in step (1) to 980°C, the rest is the same as that of Embodiment 1.

[0115] Example 10

[0116] This embodiment provides a nickel-zinc-copper ferrite. The difference between the preparation method of the nickel-zinc-copper ferrite and that of Embodiment 1 is that the sintering in step (2) is adjusted to be a sequential heating and cooling process. The specific steps of the heating process include: heating from room temperature to 1000℃ in an air atmosphere at a heating rate of 1.5℃ / min and holding at that temperature for 8 hours; the specific steps of the cooling process include: cooling to 50℃ in an air atmosphere at a cooling rate of 3.5℃ / min. The rest are the same as in Embodiment 1.

[0117] Comparative Example 1

[0118] This comparative example provides a nickel-zinc-copper ferrite, which differs from Example 1 in that, based on a total molar percentage of 100 mol%, the main components are adjusted to: Fe2O3 63.8 mol%, NiO 9.4 mol%, ZnO 18.7 mol%, CuO 8.1 mol%, thus achieving a total molar percentage of Fe2O3+ZnO+CuO of 90.6 mol%. The rest are the same as in Example 1.

[0119] Comparative Example 2

[0120] This comparative example provides a nickel-zinc-copper ferrite, which differs from Example 1 in that, based on a total molar percentage of 100 mol%, the main components are adjusted to: Fe2O3 66.8 mol%, NiO 9.2 mol%, ZnO 16.6 mol%, CuO 7.4 mol%, thus achieving a total molar percentage of Fe2O3+ZnO+CuO of 90.8 mol%. The rest are the same as in Example 1.

[0121] Comparative Example 3

[0122] This comparative example provides a nickel-zinc-copper ferrite, which differs from Example 1 in that, based on a total molar percentage of 100 mol%, the main components are adjusted to: Fe2O3 66 mol%, NiO 8.5 mol%, ZnO 18 mol%, CuO 7.5 mol%, thus achieving a total molar percentage of Fe2O3+ZnO+CuO of 91.5 mol%. The rest are the same as in Example 1.

[0123] Comparative Example 4

[0124] This comparative example provides a nickel-zinc-copper ferrite, which differs from Example 1 in that, based on a total molar percentage of 100 mol%, the main components are adjusted to: Fe2O3 65 mol%, NiO 12.2 mol%, ZnO 17.37 mol%, CuO 5.43 mol%, resulting in a total molar percentage of Fe2O3+ZnO+CuO of 87.8 mol%. The rest are the same as in Example 1.

[0125] Comparative Example 5

[0126] This comparative example provides a nickel-zinc-copper ferrite, which differs from Example 1 in that, based on a total molar percentage of 100 mol%, the main components are adjusted to: Fe2O3 66 mol%, NiO 11.8 mol%, ZnO 13.2 mol%, CuO 9 mol%, thus achieving a total molar percentage of Fe2O3+ZnO+CuO of 88.2 mol%, while the rest are the same as in Example 1.

[0127] Comparative Example 6

[0128] This comparative example provides a nickel-zinc-copper ferrite, which differs from Example 1 in that, based on a total molar percentage of 100 mol%, the main components are adjusted to: Fe2O3 65.3 mol%, NiO 11.6 mol%, ZnO 19.2 mol%, CuO 3.9 mol%, resulting in a total molar percentage of Fe2O3+ZnO+CuO of 88.4 mol%. The rest are the same as in Example 1.

[0129] Comparative Example 7

[0130] This comparative example provides a nickel-zinc-copper ferrite, which differs from Example 1 in that, based on a total molar percentage of 100 mol%, the main components are adjusted to: Fe2O3 66.6 mol%, NiO 12 mol%, ZnO 18.9 mol%, CuO 2.5 mol%, thus achieving a total molar percentage of Fe2O3+ZnO+CuO of 88 mol%, while the rest are the same as in Example 1.

[0131] Comparative Example 8

[0132] This comparative example provides a nickel-zinc-copper ferrite, which differs from Example 1 in that, based on a total molar percentage of 100 mol%, the main components are adjusted to: Fe2O3 65.6 mol%, NiO 9.5 mol%, ZnO 15.3 mol%, CuO 9.6 mol%, thus achieving a total molar percentage of Fe2O3+ZnO+CuO of 90.6 mol%. The rest are the same as in Example 1.

[0133] Comparative Example 9

[0134] This comparative example provides a nickel-zinc-copper ferrite, which differs from Example 1 in that, based on the total mass percentage of the main components, the auxiliary components are adjusted to: Bi2O3 1.2wt%, Co2O3 0.15wt%, CaCO3 0.025wt%, ZrO2 0.05wt%, adapting to obtain a total mass percentage of Co2O3+CaCO3 of 0.175wt% of the total mass percentage of the main components. The rest are the same as in Example 1.

[0135] Comparative Example 10

[0136] This comparative example provides a nickel-zinc-copper ferrite, which differs from Example 1 in that, based on the total mass percentage of the main components, the auxiliary components are adjusted to: Bi2O3 1wt%, Co2O3 0.65wt%, CaCO3 0.1wt%, adapting to obtain a total mass percentage of Co2O3+CaCO3 of 0.75wt% of the total mass percentage of the main components. The rest are the same as in Example 1.

[0137] Comparative Example 11

[0138] This comparative example provides a nickel-zinc-copper ferrite, which differs from Example 1 in that, based on the total mass percentage of the main components, the auxiliary components are adjusted to: Bi2O3 0.2wt%, Co2O3 0.15wt%, CaCO3 0.03wt%, adapting to obtain a total mass percentage of Co2O3+CaCO3 of 0.18wt% of the total mass percentage of the main components. All other aspects are the same as in Example 1.

[0139] Performance testing

[0140] The nickel-zinc-copper ferrites provided in Examples 1-10 and Comparative Examples 1-11 were tested using an Agilent E4991 inductor. The real and imaginary parts of the permeability μi were calculated based on the size factor. The Curie temperature Tc and the permeability of each temperature zone were tested using an LCR magnetic material tester and a high-low temperature controllable oven. The specific temperature coefficient at each temperature was calculated. The results are shown in Table 1.

[0141] The saturation magnetic induction intensity Bs and the remanent magnetic induction intensity Br were measured using the SY8218 instrument from Iwasaki Corporation, Japan. The results are shown in Table 1.

[0142] Table 1

[0143]

[0144]

[0145] As can be seen from Table 1, the nickel-zinc-copper ferrite provided by the present invention has advantages such as high Curie temperature, high saturation magnetic induction intensity, low remanent magnetic induction intensity, and low specific temperature coefficient, and can be better applied to power inductors or common-mode inductors.

[0146] A comparison of Examples 1 and 4-7 shows that when the content of each main component and auxiliary component is within the specified range, but the total amount of some components exceeds the specified range, the magnetic permeability and Curie temperature will decrease. A comparison of Examples 1 and 8 and 9 shows that if the pre-sintering temperature is too low or too high, it is not conducive to the sintering and densification of the magnetic core, resulting in a decrease in magnetic permeability. A comparison of Examples 1 and 10 shows that sintering involves one heating and one cooling cycle, which, compared to two heating and two cooling cycles, results in a lower magnetic permeability.

[0147] A comparison of Example 1 and Comparative Examples 1-11 shows that when the content of the main component or auxiliary component exceeds the specified range, and the total amount of some components also exceeds the specified range, the saturation magnetic induction intensity and Curie temperature of the nickel-zinc-copper ferrite will be significantly reduced, while the remanent magnetic induction intensity and specific temperature coefficient will be increased. Furthermore, by adding Bi₂O₃, this invention can uniformly grow FeBi₂O₄ with a spinel structure, due to Co… 3+The K1 value is relatively large, so the content of CoFe2O4 in the composition largely determines the imaginary part of the complex permeability of nickel-zinc-copper ferrite. Controlling the content of CoFe2O4 within a reasonable range can reduce the loss of ferrite and ensure high permeability performance at high frequencies. When Bi-Ca and nickel-zinc-copper ferrite undergo a solid-state reaction, they mainly grow on the grain boundaries. However, when the content of Bi2O3 in the solution is higher than 1.5wt%, it will cause crystallization on the surface of the magnet, which will result in a decrease in permeability and an increase in remanent magnetic induction.

[0148] In summary, this invention achieves high permeability and Curie temperature in nickel-zinc-copper ferrites by controlling the contents of Fe2O3, ZnO, and CuO. To ensure high saturation magnetic induction and low specific temperature coefficient, the contents of Fe2O3, ZnO, NiO, and CuO need to be adjusted accordingly. The auxiliary component Ca... 2+ and Bi 3+ The combined substitution of Ca can improve magnetic permeability and achieve high-frequency charging efficiency; 2+ Co 3+ A small amount of substitution can reduce the imaginary part of the magnetic permeability, achieving low-loss characteristics; through Ca... 2+ Co 3+ and Bi 3+ or Zr 4+ The combination of substitutions can regulate the saturation magnetic flux density to achieve device applicability in extreme environments. The nickel-zinc-copper ferrite prepared by this invention has high saturation magnetic flux density, high permeability, high Curie temperature, low remanent magnetic flux density, and low specific temperature coefficient, which can be better applied in power inductors or common-mode inductors.

[0149] The above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A nickel-zinc-copper ferrite, characterized in that, The nickel-zinc-copper ferrite comprises main components and auxiliary components; based on a total molar percentage of 100 mol%, the main components include: Fe2O3 64-66.7 mol%, NiO 9-12 mol%, ZnO 13.5-19 mol%, CuO 3-9.5 mol%; based on the total mass percentage of the main components, the auxiliary components include: Bi2O3 0.3-1.5 wt%, Co2O3 0.1-0.6 wt%, CaCO3 0.03-0.08 wt%, ZrO2 ≤0.1 wt%. The total mass percentage of Co2O3+CaCO3 in the auxiliary components is 0.2-0.6 wt% of the total mass percentage of the main components.

2. The nickel-zinc-copper ferrite according to claim 1, characterized in that, The total molar percentage of Fe2O3+ZnO+CuO in the main components is 88.5-90.5 mol.

3. A method for preparing nickel-zinc-copper ferrite as described in any one of claims 1-2, characterized in that, The preparation method includes the following steps: (1) The main components of the wet ball milling mixture are mixed and the resulting ball milled material is pre-calcined after the first spray granulation to obtain pre-calcined material; (2) The auxiliary ingredients, liquid medium, additives and the pre-burned material obtained in step (1) are subjected to first grinding and second grinding in sequence. The resulting grinding material is granulated by second spraying and then shaped and sintered to obtain the nickel-zinc-copper ferrite.

4. The preparation method according to claim 3, characterized in that, In step (1), the mass ratio of the main components, the milling media, and the liquid media in the wet ball milling mixture is 1:(4-8):(0.5-1.2).

5. The preparation method according to claim 3, characterized in that, The wet ball milling mixing time in step (1) is 20-60 min.

6. The preparation method according to claim 3, characterized in that, The preheating temperature in step (1) is 780-950℃.

7. The preparation method according to claim 3, characterized in that, The preheating time in step (1) is 2-4 hours.

8. The preparation method according to claim 3, characterized in that, The additives in step (2) include any one or a combination of at least two of the following: adhesives, dispersants or defoamers.

9. The preparation method according to claim 8, characterized in that, The additives mentioned in step (2) are a combination of adhesives, dispersants and defoamers.

10. The preparation method according to claim 9, characterized in that, When the additive in step (2) is a combination of binder, dispersant and defoamer, the mass ratio of the pre-burned material, liquid medium, binder, dispersant and defoamer is 100:(40-150):(4-20):(0.1-2):(0.001-0.0025).

11. The preparation method according to claim 3, characterized in that, The liquid medium in step (2) includes deionized water.

12. The preparation method according to claim 3, characterized in that, Step (2) The rotation speed of the first grinding is 140-260 rpm.

13. The preparation method according to claim 3, characterized in that, Step (2) The first grinding time is 8-12 min.

14. The preparation method according to claim 3, characterized in that, In step (2), the rotation speed of the second grinding is 270-320 rpm.

15. The preparation method according to claim 3, characterized in that, Step (2) The second grinding time is 0.5-2h.

16. The preparation method according to claim 3, characterized in that, The median particle size X50 of the abrasive in step (2) is 0.5-0.8 μm, and the cumulative percentage of particle size X90 is 1.25-1.8 μm.

17. The preparation method according to claim 3, characterized in that, In step (2), the average particle size of the particles obtained by the second spray granulation is 30-200 μm.

18. The preparation method according to claim 3, characterized in that, The sintering described in step (2) is carried out in a pusher kiln.

19. The preparation method according to claim 3, characterized in that, The sintering in step (2) includes a first heating, a second heating, a first cooling and a second cooling in sequence.

20. The preparation method according to claim 19, characterized in that, The specific steps of the first heating process include: heating to 550-750°C in an air atmosphere at a heating rate of 0.5-2°C / min, and holding at that temperature for 2-7 hours.

21. The preparation method according to claim 19, characterized in that, The specific steps of the second heating process include: continuing to heat to 950-1050℃ at a heating rate of 1-3℃ / min, and holding at that temperature for 2-5 hours.

22. The preparation method according to claim 19, characterized in that, The specific steps of the first cooling process include: cooling to 590-610°C in an air atmosphere at a cooling rate of 2-6°C / min.

23. The preparation method according to claim 19, characterized in that, The specific steps of the second cooling process include: continuing to cool down to 45-55℃ at a cooling rate of 1-5℃ / min.

24. An application of the nickel-zinc-copper ferrite as described in any one of claims 1-2, characterized in that, The nickel-zinc-copper ferrite is used in power inductors or common-mode inductors.

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