High inductance copper-iron co-fired inductor and preparation method thereof

Abstract

The application provides a high-inductance copper-iron co-fired inductor, which comprises soft magnetic metal powder, a copper conductor and nanocrystalline strip material, the copper conductor is connected perpendicularly with the nanocrystalline strip material and is embedded in the soft magnetic metal powder, and the copper conductor extends out of the soft magnetic metal powder at both ends; the soft magnetic metal powder comprises mixed powder of different particle size gas atomized iron-nickel-molybdenum powder, a passivating agent, a coating agent and a lubricant; the passivating agent is a mixed solution of oxalic acid and nitric acid; the coating agent is a mixture of fluorosilicon resin, titanium trifluoride, aluminum trifluoroacetyl acetonate and nanometer barium titanate acetone solution; the lubricant is a mixture of gas phase aluminum oxide and niobium diselenide; the thickness of the nanocrystalline strip material is 1-1.5 um, and the width is 2-4 mm. The application uses the gas atomized iron-nickel-molybdenum powder with the highest magnetic permeability in the soft magnetic metal powder, so that the inductance value of the inductor reaches the maximum value, and the gas atomized iron-nickel-molybdenum powder has very low loss and excellent stability, so that the inductor has good loss performance and excellent reliability.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of magnetic functional materials, and particularly relates to a high-sensitivity copper-iron co-fired inductor and a preparation method thereof. BACKGROUND

[0002] Chip inductors are key components of chip power supply modules, and play a role in front-end power supply for chips such as GPUs and CPUs. With the development of electronic products towards high efficiency, high power density and miniaturization, the improvement of chip inductor performance and the optimization of volume have become urgent problems to be solved.

[0003] The latest chip inductor is a copper-iron co-fired inductor. The copper-iron co-fired inductor is a process that combines a magnetic powder core and an integrally formed inductor. The copper wire or copper sheet embedded in the soft magnetic metal powder is formed by high-pressure pressing. This can achieve high density and high permeability of the magnetic powder core material, and also achieve the advantages of "iron wrapping copper" magnetic shielding and mechanical mass production of integrally formed inductors. However, due to the immaturity of the copper-iron co-fired inductor technology, the inductor performance still needs to be improved. The most obvious disadvantage is the low inductance value of the copper-iron co-fired inductor. Because the copper-iron co-fired inductor basically uses a single copper conductor combined with soft magnetic metal powder, the inductance value of the inductor is proportional to the square of the number of turns of the coil and proportional to the magnetic permeability of the soft magnetic metal powder. Under the premise of not improving the structure, it is difficult to improve the inductance value of the single-turn copper conductor. SUMMARY

[0004] The technical problem to be solved by the application is how to improve the inductance value of the copper-iron co-fired inductor.

[0005] The application solves the above technical problems by the following technical means:

[0006] The first aspect of the application provides a high-sensitivity copper-iron co-fired inductor, which comprises soft magnetic metal powder, a copper conductor and a nanocrystalline strip material. The copper conductor is connected perpendicularly to the nanocrystalline strip material and embedded in the soft magnetic metal powder. The copper conductor extends out of the soft magnetic metal powder at both ends. The soft magnetic metal powder comprises a mixture of different particle size gas atomized iron-nickel-molybdenum powder, a passivation agent, a coating agent and a lubricant. The passivation agent is a mixed solution of oxalic acid and nitric acid. The coating agent is a mixture of fluorosilicon resin, titanium trifluoride, aluminum trifluoroacetyl acetonate and nanometer barium titanate in acetone. The lubricant is a mixture of gas phase aluminum oxide and niobium diselenide. The thickness of the nanocrystalline strip material is 1-1.5 um, and the width is 2-4 mm.

[0007] Beneficial effects: The application uses the gas atomized iron-nickel-molybdenum powder with the highest magnetic permeability in the soft magnetic metal powder to make the inductance value of the inductor reach the highest value. At the same time, the gas atomized iron-nickel-molybdenum powder has very low loss and excellent stability, so the inductor has good loss performance and excellent reliability.

[0008] The application forms a basic framework by connecting the nanocrystalline strip with the copper conductor, the nanocrystalline strip plays a role of stable support in the inductor, greatly improves the strength of the inductor product, the nanocrystalline strip has a permeability much higher than that of the soft magnetic metal powder and a loss much lower than that of the soft magnetic metal powder, so that the inductance value of the inductor is obviously increased.

[0009] The lubricant used in the application is a mixture of fumed aluminum oxide and niobium diselenide, after the fumed aluminum oxide is mixed with the gas-atomized iron-nickel-molybdenum powder, it can be orderly combined on the surface of the powder particles to form a shell layer, which can effectively reduce the electrostatic attraction between the particles, avoid the powder adhesion caused by van der Waals force, moisture absorption and particle friction, thereby improving the flowability of the powder and the inductance value of the inductor.

[0010] Preferably, the different particle sizes are D50=28-35 mu m, D50=10-14 mu m and D50=3-5 mu m, and the different particle sizes of the gas-atomized iron-nickel-molybdenum powder account for 60%, 20% and 20% of the mixed powder, respectively.

[0011] More preferably, the different particle sizes are D50=30 mu m, D50=12 mu m and D50=4.8 mu m.

[0012] Beneficial effects: the application uses three kinds of particle sizes of gas-atomized iron-nickel-molybdenum powder to mix, so that the sphericity of the gas-atomized iron-nickel-molybdenum mixed powder is good, the dense contact between the powder particles is increased, and the gas-atomized iron-nickel-molybdenum powder with the mass ratio and particle size ratio of the application can realize high-density filling of magnetic powder and high inductance performance.

[0013] Preferably, the mass of oxalic acid accounts for 0.2-0.4% of the mixed powder, and the mass of nitric acid accounts for 0.05-0.1% of the mixed powder.

[0014] Preferably, the mass of fluorosilicon resin accounts for 1.0-1.5% of the mixed powder, the mass of titanium trifluoride accounts for 0.05-0.2% of the mixed powder, the mass of aluminum trifluoroacetylacetate accounts for 0.1-0.5% of the mixed powder, the mass of nano-barium titanate accounts for 0.05-0.15% of the mixed powder, and the mass of acetone accounts for 8-10% of the mixed powder.

[0015] Preferably, the mass of fumed aluminum oxide accounts for 0.02-0.04% of the mixed powder, and the mass of niobium diselenide accounts for 0.2-0.4% of the mixed powder.

[0016] The second aspect of the application provides a preparation method of the high inductance copper-iron co-fired inductor, comprising the following steps:

[0017] (1) using a blending method to prepare a soft magnetic metal powder, vertically fixing a nanocrystalline strip on the surface of a copper conductor, and then placing the copper conductor in the soft magnetic metal powder, the copper conductor extending out of the soft magnetic metal powder at both ends, to obtain a magnetic powder core;

[0018] (2) two-way pressing the magnetic powder core through a mold, gradient annealing the magnetic powder core in a reducing atmosphere, and finally immersing the magnetic powder core in a resin solution, and after washing and baking, obtaining a high inductance copper-iron co-fired inductor.

[0019] Preferably, the blending specifically comprises the following steps: mixing the gas atomized iron-nickel-molybdenum powders with different particle sizes, and then sequentially mixing the powders with a passivation agent, a coating agent and a lubricant, to obtain the soft magnetic metal powder.

[0020] Preferably, the gradient annealing comprises three stages, the first stage is to raise the temperature from room temperature to 400-450 DEG C, the holding time is 30-40 min; the second stage is to raise the temperature to 500-520 DEG C, the holding time is 30-40 min; the third stage is to raise the temperature to 540-570 DEG C, the holding time is 30-40 min, and finally rapidly cooling to room temperature.

[0021] Preferably, the pressure of the two-way pressing is 1600-2200 Mpa; the reducing atmosphere is a mixed gas of hydrogen and argon, wherein the volume of hydrogen accounts for 5-10% of the volume of the mixed gas, and the volume of argon accounts for 90-95% of the volume of the mixed gas.

[0022] Preferably, the immersion is vacuum immersion, the resin solution is an acetone solution of fluorosilicon resin, the immersion time is 30-50 min, the washing time after the immersion is 0.5-1.0 min, and the baking condition is 160-180 DEG C for 60-80 min.

[0023] Beneficial effects: the nanocrystalline strip has high magnetic permeability and low loss only after annealing, and the nanocrystalline strip without heat treatment has very poor soft magnetic properties; the magnetic powder core is pressed at high pressure, and a large amount of internal stress is left, resulting in low magnetic permeability and high loss, and only annealing can achieve the purpose of stress relief and loss reduction.

[0024] The gradient annealing in the reducing atmosphere of the present application makes the nanocrystallization curve of the nanocrystalline strip coincide with the stress relief annealing curve, which can complete the nanocrystallization of the nanocrystalline strip and eliminate the internal stress of the iron-nickel-molybdenum powder after being pressed into an inductor, and thus the inductance of the inductor is improved.

[0025] The application uses a mixed solution of oxalic acid and nitric acid as a passivation agent, wherein the nitric acid provides acidity and oxidation to promote the passivation reaction of oxalic acid and the aerosolized iron-nickel-molybdenum powder, and the generated iron oxalate will be decomposed into iron oxide in high-temperature annealing, so as to be uniformly coated on the surface of the powder, improve the insulation performance of the powder, reduce the eddy current loss between the powders, and further reduce the total loss of inductance. Similarly, the added aluminum trifluoroacetylacetate will also be decomposed into aluminum oxide in high-temperature annealing, and uniformly grow on the surface of the powder, effectively reducing the inductance loss.

[0026] The application uses titanium trifluoride in the coating agent, which has very good insulation and thermal stability and will not be decomposed due to heating in high-temperature annealing, ensuring the stability of the coating layer. More importantly, titanium trifluoride has a certain negative thermal expansion coefficient, that is, it will not expand in volume due to heating in high-temperature annealing, but will shrink in volume due to heating, which can better avoid the problem of film layer rupture caused by the expansion of the coating, ensuring the integrity of the film layer. The application uses niobium diselenide in the lubricant, which rapidly changes into a liquid lubricating film due to the sharp increase of pressure and temperature in the two-way pressing process of the magnetic powder core, playing a lubricating role. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 is a schematic diagram of a high-inductance copper-iron co-fired inductor structure in the embodiment;

[0028] Figure 2 is a schematic diagram of the arrangement of the copper conductor and the nanocrystalline strip in the high-inductance copper-iron co-fired inductor in the embodiment;

[0029] In the figure: 1-copper conductor; 2-nanocrystalline strip; 3-soft magnetic metal powder. DETAILED DESCRIPTION

[0030] To make the purpose, technical solutions and advantages of the embodiments of the application clearer, the technical solutions in the embodiments of the application will be described clearly and completely below in combination with the embodiments of the application. Obviously, the described embodiments are part of the embodiments of the application, rather than all the embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the application.

[0031] The test materials and reagents used in the following embodiments, unless otherwise specified, can be obtained from commercial channels.

[0032] If the specific techniques or conditions are not specified in the embodiments, they can be performed according to the techniques or conditions described in the literature in the art or according to the product instructions.

[0033] Embodiment 1

[0034] This embodiment provides a method for preparing a high-inductance copper-iron co-fired inductor and the method for obtaining the inductor; specifically, it includes the following steps:

[0035] (1) Preparation of soft magnetic metal powder: 60g of D50=30μm, 20g of D50=12μm and 20g of D50=4.8μm gas-atomized iron-nickel-molybdenum powder were mixed evenly; 0.20g of oxalic acid and 0.05g of nitric acid and an appropriate amount of distilled water were added to the mixed powder, stirred and heated to 110℃, and cooled to room temperature after the powder was dried; 1.0g of fluorosilicone resin, 0.05g of titanium trifluoride, 0.1g of aluminum trifluoroacetylpyruvate, 0.05g of nano barium titanate and 10g of acetone solution were added to the cooled powder, stirred and heated to 50℃, and cooled to room temperature after the powder was dried to obtain coated powder; 0.02g of fumed alumina and 0.2g of niobium diselenide were added to the coated powder and mixed evenly to obtain soft magnetic metal powder.

[0036] (2) Preparation of magnetic powder core: A nanocrystalline ribbon with a thickness of 1.0 μm and a width of 2.0 mm is perpendicularly attached to the surface of the copper conductor, such as... Figure 2 As shown, it is then placed in soft magnetic metal powder, with both ends of the copper conductor extending out of the soft magnetic metal powder to obtain a magnetic powder core.

[0037] (3) The magnetic powder core is placed in a mold and subjected to bidirectional pressing at 1800 MPa to obtain the pressed product; the pressed product is subjected to gradient annealing in a mixture of hydrogen and argon, wherein the volume of hydrogen accounts for 10% of the volume of the mixture and the volume of argon accounts for 90% of the volume of the mixture. The specific operation of the gradient annealing is to raise the temperature from room temperature to 400℃, hold for 30 min, raise the temperature to 500℃ and hold for 35 min, raise the temperature to 540℃ and hold for 30 min, and finally rapidly cool to room temperature; the annealed product is vacuum-immersed in a fluorosilicone resin solution for 40 min, then washed with acetone for 1 min, and baked at 180℃ for 70 min to obtain a high-inductance copper-iron co-fired inductor, such as Figure 1 As shown.

[0038] In this embodiment, a high-inductance copper-iron co-fired inductor was prepared and its characteristics were tested. The results of the characteristic tests are shown in Table 1.

[0039] Example 2

[0040] This embodiment provides a method for preparing a high-inductance copper-iron co-fired inductor and the method for obtaining the inductor; specifically, it includes the following steps:

[0041] (1) Soft magnetic metal powder preparation: 60 g of D50 = 30 μm, 20 g of D50 = 12 μm and 20 g of D50 = 4.8 μm gas atomized iron-nickel-molybdenum powder are mixed uniformly; 0.3 g of oxalic acid and 0.1 g of nitric acid are added to the mixed powder, and an appropriate amount of distilled water is stirred and heated to 110°C, and after the powder is dried, it is cooled to room temperature; 1.5 g of fluorosilicon resin, 0.12 g of titanium trifluoride, 0.30 g of aluminum trifluoroacetylacetate, 0.15 g of nano-barium titanate and 10 g of acetone solution are added to the cooled powder, stirred and heated to 50°C, and after the powder is dried, it is cooled to room temperature to obtain a coated powder; 0.04 g of fumed aluminum oxide and 0.3 g of niobium diselenide are added to the coated powder and mixed uniformly to obtain a soft magnetic metal powder.

[0042] (2) Magnetic powder core preparation: a nanocrystalline strip with a thickness of 1.5 μm and a width of 3.0 mm is vertically attached to the surface of a copper conductor as shown in Figure 2 , and then placed in the soft magnetic metal powder, with the copper conductor extending out of the soft magnetic metal powder at both ends to obtain a magnetic powder core.

[0043] (3) The magnetic powder core is placed in a mold for bidirectional pressing at 2000 MPa to obtain a pressed product; the pressed product is subjected to gradient annealing in a mixed gas of hydrogen and argon, with the volume of hydrogen accounting for 5% of the volume of the mixed gas and the volume of argon accounting for 95% of the volume of the mixed gas, and the gradient annealing is specifically operated by heating from room temperature to 420°C, holding for 40 min, then heating to 510°C and holding for 35 min, then heating to 570°C and holding for 30 min, and finally rapidly cooling to room temperature; the annealed product is vacuum-impregnated in a fluorosilicon resin solution for 40 min, then washed with acetone for 0.5 min, and baked at 160°C for 60 min to obtain a high inductance copper-iron co-fired inductor as shown in Figure 1 .

[0044] The high inductance copper-iron co-fired inductor prepared in this example is subjected to property testing, and the property testing results are shown in Table 1.

[0045] Comparative Example 1

[0046] This comparative example provides a high inductance copper-iron co-fired inductor preparation method and the inductor prepared thereby, and the difference between this comparative example and Example 1 is that the mixed powder used in step (1) is 100 g of D50 = 30 μm gas atomized iron-nickel powder.

[0047] The high inductance copper-iron co-fired inductor prepared in this comparative example is subjected to property testing, and the property testing results are shown in Table 1.

[0048] Comparative Example 2

[0049] The comparative example provides a preparation method of a high inductance copper-iron co-fired inductor and the inductor prepared thereby. The comparative example differs from example 1 in that the passivation agent used in step (1) is 0.25 g of phosphoric acid.

[0050] The comparative example provides a preparation method of a high inductance copper-iron co-fired inductor and the inductor prepared thereby. The comparative example differs from example 1 in that the passivation agent used in step (1) is 0.25 g of phosphoric acid.

[0051] Comparative example 3

[0052] The comparative example provides a preparation method of a high inductance copper-iron co-fired inductor and the inductor prepared thereby. The comparative example differs from example 1 in that the passivation agent used in step (1) is 0.25 g of phosphoric acid.

[0053] The comparative example provides a preparation method of a high inductance copper-iron co-fired inductor and the inductor prepared thereby. The comparative example differs from example 1 in that the passivation agent used in step (1) is 0.25 g of phosphoric acid.

[0054] Comparative example 4

[0055] The comparative example provides a preparation method of a high inductance copper-iron co-fired inductor and the inductor prepared thereby. The comparative example differs from example 1 in that the passivation agent used in step (1) is 0.25 g of phosphoric acid.

[0056] The comparative example provides a preparation method of a high inductance copper-iron co-fired inductor and the inductor prepared thereby. The comparative example differs from example 1 in that the passivation agent used in step (1) is 0.25 g of phosphoric acid.

[0057] Comparative example 5

[0058] The comparative example provides a preparation method of a high inductance copper-iron co-fired inductor and the inductor prepared thereby. The comparative example differs from example 1 in that the passivation agent used in step (1) is 0.25 g of phosphoric acid.

[0059] The comparative example provides a preparation method of a high inductance copper-iron co-fired inductor and the inductor prepared thereby. The comparative example differs from example 1 in that the passivation agent used in step (1) is 0.25 g of phosphoric acid.

[0060] Comparative example 6

[0061] The comparative example provides a preparation method of a high inductance copper-iron co-fired inductor and the inductor prepared thereby. The comparative example differs from example 1 in that the passivation agent used in step (1) is 0.25 g of phosphoric acid.

[0062] The comparative example provides a preparation method of a high inductance copper-iron co-fired inductor and the inductor prepared thereby. The comparative example differs from example 1 in that the passivation agent used in step (1) is 0.25 g of phosphoric acid.

[0063] Comparative example 7

[0064] The comparative example provides a preparation method of a high inductance copper-iron co-fired inductor and the inductor prepared thereby. The comparative example differs from example 1 in that the passivation agent used in step (1) is 0.25 g of phosphoric acid.

[0065] The high inductance copper-iron co-fired inductor prepared in the present comparative example was subjected to property test, and the property test results are shown in Table 1.

[0066] Comparative Example 8

[0067] The present comparative example provides a preparation method of high inductance copper-iron co-fired inductor and the inductor prepared thereby. The present comparative example differs from Example 1 in that no gradient heating is used in the annealing process in step (3). Specifically, the temperature is raised from room temperature to 540°C and kept for 30 min, and then the furnace is cooled to room temperature.

[0068] The high inductance copper-iron co-fired inductor prepared in the present comparative example was subjected to property test, and the property test results are shown in Table 1.

[0069] Comparative Example 9

[0070] The present comparative example provides a preparation method of high inductance copper-iron co-fired inductor and the inductor prepared thereby. The present comparative example differs from Example 2 in that the mixed powder used in step (1) is 60 g of water-atomized iron-silicon-chromium powder with D50 = 30 μm, 20 g of water-atomized iron-silicon-chromium powder with D50 = 12 μm, and 20 g of water-atomized iron-silicon-chromium powder with D50 = 4.8 μm.

[0071] The high inductance copper-iron co-fired inductor prepared in the present comparative example was subjected to property test, and the property test results are shown in Table 1.

[0072] Comparative Example 10

[0073] The present comparative example provides a preparation method of high inductance copper-iron co-fired inductor and the inductor prepared thereby. The present comparative example differs from Example 2 in that the mixed powder used in step (1) is 100 g of carbonyl iron powder with D50 = 12 μm.

[0074] The high inductance copper-iron co-fired inductor prepared in the present comparative example was subjected to property test, and the property test results are shown in Table 1.

[0075] Comparative Example 11

[0076] The present comparative example provides a preparation method of high inductance copper-iron co-fired inductor and the inductor prepared thereby. The present comparative example differs from Example 2 in that 0.4 g of nitric acid is additionally added after the mixed powder is passivated in step (1).

[0077] The high inductance copper-iron co-fired inductor prepared in the present comparative example was subjected to property test, and the property test results are shown in Table 1.

[0078] Comparative Example 12

[0079] The present comparative example provides a preparation method of high inductance copper-iron co-fired inductor and the inductor prepared thereby. The present comparative example differs from Example 2 in that the coating agent used in step (1) is 2.07 g of fluorosilicon resin in acetone solution.

[0080] The high inductance copper-iron co-fired inductor prepared in the comparative example was tested for characteristics, and the results are shown in Table 1.

[0081] Comparative Example 13

[0082] The comparative example provides a preparation method of a high inductance copper-iron co-fired inductor and the inductor prepared thereby. The difference between the comparative example and Example 2 is that the amorphous strip material used in step (2) has a thickness of 1.5 um and a width of 3.0 mm.

[0083] The high inductance copper-iron co-fired inductor prepared in the comparative example was tested for characteristics, and the results are shown in Table 1.

[0084] Comparative Example 14

[0085] The comparative example provides a preparation method of a high inductance copper-iron co-fired inductor and the inductor prepared thereby. The difference between the comparative example and Example 2 is that the amorphous strip material used in step (2) has a thickness of 2.5 um and a width of 5.5 mm.

[0086] The high inductance copper-iron co-fired inductor prepared in the comparative example was tested for characteristics, and the results are shown in Table 1.

[0087] Experimental Example

[0088] The high inductance copper-iron co-fired inductors prepared in Examples 1-2 and Comparative Examples 1-14 were tested for inductance value and power loss performance. In this experimental example, the WK6500B precision impedance analyzer of Wenke was used to test the inductance value, and the SY8218BH analyzer of Yanrui was used to test the loss value. The results of the characteristic test are shown in Table 1.

[0089] Table 1: Results of characteristic test of Examples 1-2 and Comparative Examples 1-14

[0090]

[0091] According to Table 1, compared with Comparative Examples 1-8, the use of three particle sizes of aerosolized iron-nickel-molybdenum powder mixed, passivated and coated in the application, combined with the addition of nanocrystalline narrow strips, can obtain a high inductance copper-iron co-fired inductor with relatively low power loss.

[0092] Compared with Example 1, the high permeability and low loss of the gas atomized iron-nickel-molybdenum mixed powder after particle size matching are obvious in Comparative Example 1, Comparative Example 2 and Comparative Example 3. Compared with Example 1, the influence of passivation and coating of the gas atomized iron-nickel-molybdenum mixed powder on the permeability and loss is significant, and the change of the material leads to the change of the performance in Comparative Example 4, Comparative Example 5 and Comparative Example 6. Compared with Example 1, the nano-crystalline narrow band can obviously improve the inductance, and other materials cannot improve the inductance in Comparative Example 6.

[0093] Compared with Example 1, the inductance is low and the loss is high in Comparative Example 7 because pure nitrogen is used in the annealing process, and the oxidation problem caused by high temperature in the powdering process cannot be reduced due to the lack of reducing property. Compared with Example 1, the appropriate temperature curve can realize nano-crystallization and eliminate internal stress of the nano-crystalline strip, but the rapid heating speed cannot realize nano-crystallization and eliminate internal stress, leading to the increase of power loss in Comparative Example 8.

[0094] Compared with Example 2, the high permeability and low loss of the gas atomized iron-nickel-molybdenum mixed powder after particle size matching are obvious in Comparative Example 9 and Comparative Example 10. Compared with Example 2, the influence of passivation and coating of the gas atomized iron-nickel-molybdenum mixed powder on the permeability and loss is significant, and the change of the material leads to the change of the performance in Comparative Example 11 and Comparative Example 12. Compared with Example 2, the nano-crystalline narrow band can obviously improve the inductance, and other materials cannot improve the inductance in Comparative Example 13.

[0095] Compared with Example 2, only the nano-crystalline narrow band can obviously improve the inductance because the gap between the nano-crystalline narrow bands is large, and the gas atomized iron-nickel-molybdenum mixed powder has good adhesion, so the prepared inductance is not easy to crack. When the width and thickness of the nano-crystalline strip are large, the gap between the nano-crystalline strips is small, and the adhesion of the gas atomized iron-nickel-molybdenum mixed powder is small, so the prepared inductance is easy to crack, leading to the decrease of the inductance and the increase of the power loss, and the inductance cannot be used in Comparative Example 14.

[0096] The above examples are only used to illustrate the technical solutions of the present application, but not limit the same; although the present application has been described in detail with reference to the foregoing examples, it should be understood by those skilled in the art that the technical solutions recorded in the foregoing examples can be modified, or some technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A high inductance copper-iron co-fired inductor, characterized by, The soft magnetic metal powder, the copper conductor and the nanocrystalline strip material, the copper conductor is vertically connected with the nanocrystalline strip material and is embedded in the soft magnetic metal powder, and the copper conductor extends out of the soft magnetic metal powder at both ends; The soft magnetic metal powder comprises mixed powder of different particle size gas atomized iron-nickel-molybdenum powder, a passivation agent, a coating agent and a lubricant; the passivation agent is a mixed solution of oxalic acid and nitric acid; the coating agent is fluorosilicon resin, titanium trifluoride, aluminum trifluoroacetyl acetonate and an acetone solution of nanometer barium titanate; and the lubricant is a mixture of fumed aluminum oxide and niobium diselenide. The nanocrystalline strip material has a thickness of 1-1.5 um and a width of 2-4 mm.

2. The high inductance value copper-iron co-fired inductor according to claim 1, characterized in that, The different particle sizes are D50=28-35 um, D50=10-14 um and D50=3-5 um, and the different particle size gas atomized iron-nickel-molybdenum powder accounts for 60%, 20% and 20% of the mixed powder, respectively.

3. The high inductance value copper-iron co-fired inductor of claim 1, wherein, The mass of the oxalic acid accounts for 0.2-0.4% of the mixed powder, and the mass of the nitric acid accounts for 0.05-0.1% of the mixed powder.

4. The high inductance value copper-iron co-fired inductor of claim 1, wherein, The mass of the fluorosilicon resin accounts for 1.0-1.5% of the mixed powder, the mass of the titanium trifluoride accounts for 0.05-0.20% of the mixed powder, the mass of the aluminum trifluoroacetyl acetonate accounts for 0.1-0.5% of the mixed powder, the mass of the nanometer barium titanate accounts for 0.05-0.15% of the mixed powder, and the mass of the acetone accounts for 8-10% of the mixed powder.

5. The high inductance value copper-iron co-fired inductor of claim 1, wherein, The mass of the fumed aluminum oxide accounts for 0.02-0.04% of the mixed powder, and the mass of the niobium diselenide accounts for 0.2-0.4% of the mixed powder.

6. The method for preparing a high-inductance copper-iron co-fired inductor as described in any one of claims 1-5, characterized in that, The method comprises the following steps: (1) using a blending method to prepare a soft magnetic metal powder, vertically fixing a nanocrystalline strip material on the surface of a copper conductor, and then placing the copper conductor in the soft magnetic metal powder, wherein the copper conductor extends out of the soft magnetic metal powder at both ends, to obtain a magnetic powder core; (2) performing bidirectional compression molding on the magnetic powder core through a mold, performing gradient annealing on the magnetic powder core in a reducing atmosphere, and finally immersing the magnetic powder core in a resin solution, and then performing washing and baking to obtain a high-inductance copper-iron co-fired inductor.

7. The method for preparing a high-inductance copper-iron co-fired inductor according to claim 6, characterized in that, The blending operation is specifically as follows: first, mixing different particle size gas atomized iron-nickel-molybdenum powder, and then sequentially mixing the passivation agent, the coating agent and the lubricant to obtain the soft magnetic metal powder.

8. The method for preparing a high-inductance copper-iron co-fired inductor according to claim 6, characterized in that, The gradient annealing comprises three stages, the first stage is to raise the temperature from room temperature to 400-450 DEG C, the holding time is 30-40 min, the second stage is to raise the temperature to 500-520 DEG C, the holding time is 30-40 min, the third stage is to raise the temperature to 540-570 DEG C, the holding time is 30-40 min, and finally the temperature is rapidly cooled to room temperature.

9. The method for preparing a high-inductance copper-iron co-fired inductor according to claim 6, characterized in that, The pressure of the bidirectional compression is 1600-2200 Mpa; the reducing atmosphere is a mixed gas of hydrogen and argon, wherein the volume of hydrogen accounts for 5-10% of the volume of the mixed gas, and the volume of argon accounts for 90-95% of the volume of the mixed gas.

10. The method for preparing a high-inductance copper-iron co-fired inductor according to claim 6, characterized in that, The immersion is vacuum immersion, the resin solution is a fluorosilicon resin acetone solution, the immersion time is 30-50 min, the washing time after immersion is 0.5-1.0 min, and the baking condition is 160-180 DEG C for 60-80 min.

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