Low-loss high-saturation iron-nickel soft magnetic powder and preparation method thereof

Abstract

The invention discloses a preparation method of low-loss high-saturation iron-nickel soft magnetic powder. Comprising the following steps of S1, alloy smelting and S2, atomization. S3, carrying out ball milling treatment; s4, annealing treatment; s5, carrying out surface coating; the low-loss high-saturation iron-nickel soft magnetic powder is prepared from the following raw materials in percentage by weight: 77.6%-78.2% of electrolytic nickel, 21.4%-22.3% of electrolytic iron and 0.1%-1% of an additive, the performance of the iron-nickel soft magnetic powder and a magnetic powder core prepared by the process is improved in multiple aspects, and the iron-nickel soft magnetic powder has great application advantages.

Description

Technical Field

[0001] The present invention relates to the technical field of soft magnetic powder preparation, and particularly relates to a low-loss and high-saturation iron-nickel soft magnetic powder and a preparation method thereof. Background Art

[0002] Soft magnetic materials are an important type of basic functional materials in the development of modern economy and society. Soft magnetic materials play a role in energy transfer, conversion and coupling in devices, and have electromagnetic conversion functions, so they are widely used in fields such as communication, power equipment, information technology, and automatic control. Soft magnetic materials can be further divided into metal soft magnetic materials, soft magnetic composite materials, and ferrite soft magnetic materials. Among them, soft magnetic composite materials are prepared into magnetic powder cores with different shapes through processes such as insulating coating, annealing, and pressing of metal soft magnetic powder particles. Therefore, the manufacturing technology of metal soft magnetic powder is the basis for preparing magnetic powder cores with good performance.

[0003] The Chinese Patent Network discloses a nickel-zinc ferrite material with high frequency, low loss and high saturation magnetic flux density and a preparation method thereof, and its patent publication number is "CN115448713B". The nickel-zinc ferrite material provided by this invention has high magnetic permeability, high saturation magnetic flux density, high-frequency Q value and low hysteresis loss, and can be applied to the circuit module design in military and civilian communication fields such as high-frequency transmission inductors, broadband interference suppressors, and baluns. It has higher magnetic permeability, quality factor Q and saturation magnetic flux density, and has lower high-frequency loss values at each frequency point compared with existing products, and is not prone to overheating phenomena, and has a more stable transmission bandwidth and service performance; however, the iron-nickel soft magnetic material prepared by this invention has low DC~Bias and high loss when used at high frequencies in 5G communication, that is, it is prone to high loss at low frequencies when used at high frequencies.

[0004] Based on this, the present invention proposes a brand-new low-loss and high-saturation iron-nickel soft magnetic powder and a preparation method thereof. Summary of the Invention

[0005] The purpose of the present invention is to solve the deficiencies existing in the prior art, and to propose a low-loss and high-saturation iron-nickel soft magnetic powder and a preparation method thereof.

[0006] In order to achieve the above purpose, the present invention adopts the following technical solutions:

[0007] A low-loss and high-saturation iron-nickel soft magnetic powder, comprising raw materials in the following weight ratios:

[0008] Electrolytic nickel 77.6% - 78.2%, electrolytic iron 21.4% - 22.3%, additive 0.1% - 1%. The above-mentioned low-loss and high-saturation iron-nickel soft magnetic powder comprises the following preparation steps:

[0009] S1. Melting the alloy: Prepare raw materials such as electrolytic nickel, electrolytic iron, and additives in proportion. Then put them into a vacuum induction melting furnace and melt them in a vacuum environment. By precisely controlling the melting temperature and time, the raw materials are fully melted and alloyed;

[0010] S2. Atomization: The melted alloy liquid flows into the atomization device through the nozzle at the bottom. Use high-pressure water to impact and atomize the alloy liquid flow. The high-speed impact of the high-pressure water breaks the alloy liquid into fine droplets, which are quickly cooled and solidified in water to form powder. Then, after screening, select the powder for the next step of processing;

[0011] S3. Ball milling treatment: Add a composite additive during the ball milling process. In addition, in the later stage of ball milling, introduce a certain amount of hydrogen into the ball milling tank. Hydrogen can react with some impurities in the powder under the high-energy ball milling environment to further improve the purity of the powder;

[0012] S4. Annealing treatment: Prepare a multi-component synergistic antioxidant and magnetic property enhancer group. Before annealing, soak the powder in the solution of this mixed preparation for 12 - 18 minutes, then take it out and drain. Then put the drained powder into a high-temperature-resistant quartz tube and carry out annealing treatment under the condition that the vacuum degree is not higher than 10—4Pa. The annealing temperature is controlled in stages. First, carry out low-temperature annealing at a lower temperature, and then raise the temperature for recrystallization annealing to promote the formation of a uniform equiaxed crystal structure inside the powder particles and optimize the crystal structure. Finally, cool it to room temperature with the furnace;

[0013] S5. Surface coating;

[0014] Surface coating: Use the electroless plating method to coat the surface of the powder after magnetic field treatment. Prepare a plating solution containing 29.8% - 28.6% nickel sulfate, 23.8% - 24.5% sodium hypophosphite, 29.8% - 28.6% lactic acid, 9.5% - 9.8% sodium citrate, 6.0% - 8.2% sodium acetate, 0.0012% - 0.0041% stabilizer, and 0.12% - 0.25% surfactant. Add the powder into the plating solution and carry out electroless plating reaction under certain temperature and pH conditions. Uniformly coat a layer of metallic nickel with a thickness of 0.1 - 0.5μm on the surface of the powder particles through electroless plating.

[0015] Preferably, the additive contains copper and molybdenum.

[0016] Preferably, in the step of melting the alloy, the vacuum pressure range is 10—3Pa, the melting temperature is controlled at 1500℃ - 1600℃, and the melting time is 30 - 60 minutes.

[0017] Preferably, in the atomization step, the pressure of the high-pressure water is 10 - 20MPa, and the screening mesh is a 100-mesh sieve.

[0018] Preferably, in the ball milling treatment step, the ball-to-material ratio is controlled at 7-10:1, the vibration duration is 60% - 80% of the total ball milling time, the ball milling time is controlled at 10 - 18 hours, and the ball milling speed is 200 - 400 r / min.

[0019] Preferably, in the ball milling treatment step, a composite additive includes 60% stearic acid, 34% zinc chloride, and 6% graphite powder, and the hydrogen gas flow rate is 50 - 100 mL / min.

[0020] Preferably, in the annealing treatment step, the low-temperature annealing temperature is 400°C - 500°C, the holding time is 1 - 2 hours for stress relief annealing, and the temperature is raised to 800°C - 900°C and held for 3 - 5 hours for recrystallization annealing.

[0021] Preferably, a multi-component synergistic antioxidant and magnetic property enhancer in the annealing treatment step is composed of 25% cerium nitrate, a mixture of ascorbic acid and propyl gallate in a ratio of 2:1 (a total of 45%), 20% sodium borohydride, and 5% cobalt chloride.

[0022] The present invention has the following beneficial effects:

[0023] 1. The preparation process of the present invention improves the performance of iron-nickel soft magnetic powder and magnetic powder cores from multiple aspects, with great application advantages. In terms of powder performance, through vacuum melting, high-pressure atomization, and precise ball milling, precise control of particle size is achieved, oxygen content is reduced, and loose packing density is increased. By means of annealing and adding special preparations, saturation magnetization and coercivity are optimized. In terms of the performance of magnetic powder cores, through parameter regulation in multiple links, the loss of magnetic powder cores is reduced, and the DC bias characteristic is improved. In the winding test, the powder prepared by the process of the embodiment has lower power loss, better DC bias performance, better quality factor and effective magnetic permeability, can meet the performance requirements of various electronic devices for soft magnetic materials, and can effectively improve the overall performance of the device in practical applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a flowchart of a method for preparing a low-loss and high-saturation iron-nickel soft magnetic powder proposed by the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0025] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments.

[0026] A low-loss and high-saturation iron-nickel soft magnetic powder includes raw materials in the following weight ratios:

[0027] Electrolytic nickel: 77.6% - 78.2%, electrolytic iron: 21.4% - 22.3%, additive: 0.1% - 1%. The above-mentioned low-loss and high-saturation iron-nickel soft magnetic powder includes the following preparation steps:

[0028] S1. Melting the alloy: Prepare raw materials such as electrolytic nickel, electrolytic iron, and additive according to the ratio. Then put them into a vacuum induction melting furnace and melt them in a vacuum environment. By precisely controlling the melting temperature and time, the raw materials are fully melted and alloyed;

[0029] S2. Atomization: The molten alloy after melting flows into the atomization device through the nozzle at the bottom. Use high-pressure water to impact and atomize the alloy liquid flow. The high-speed impact of the high-pressure water breaks the alloy liquid into fine droplets, which are quickly cooled and solidified in water to form powder. Then, after screening, select the powder for the next step of treatment;

[0030] S3. Ball milling treatment: Add a composite additive during the ball milling process. In addition, in the later stage of ball milling, introduce a certain amount of hydrogen into the ball milling tank. Hydrogen can react with some impurities in the powder under the high-energy ball milling environment to further improve the purity of the powder;

[0031] S4. Annealing treatment: Configure a multi-component synergistic antioxidant and magnetic property enhancer group. Before annealing, soak the powder in the solution of this mixed preparation for 12 - 18 minutes, then take it out and drain it. Then put the drained powder into a high-temperature-resistant quartz tube and conduct annealing treatment under the condition that the vacuum degree is not higher than 10—4Pa. The annealing temperature is controlled in stages. First, conduct low-temperature annealing at a lower temperature, and then raise the temperature for recrystallization annealing to promote the formation of a uniform equiaxed crystal structure inside the powder particles and optimize the crystal structure. Finally, cool it to room temperature with the furnace;

[0032] S5. Surface coating:

[0033] Surface coating: Use the electroless plating method to coat the surface of the powder after magnetic field treatment. Configure a plating solution containing nickel sulfate 29.8% - 28.6%, sodium hypophosphite 23.8% - 24.5%, lactic acid 29.8% - 28.6%, sodium citrate 9.5% - 9.8%, sodium acetate 6.0% - 8.2%, stabilizer 0.0012% - 0.0041%, surfactant 0.12% - 0.25%. Add the powder into the plating solution and conduct an electroless plating reaction under certain temperature and pH value conditions. Uniformly coat a layer of metallic nickel with a thickness of 0.1 - 0.5μm on the surface of the powder particles through electroless plating.

[0034] Specifically, the additive contains copper and molybdenum. In the step of melting the alloy, the vacuum pressure ranges from 10⁻³ Pa, the melting temperature is controlled at 1500 °C - 1600 °C, and the melting time is 30 - 60 minutes. In the atomization step, the pressure of the high-pressure water is 10 - 20 MPa, and the sieve used for screening is a 100-mesh sieve. In the ball milling treatment step, the ball-to-material ratio is controlled at 7 - 10:1, the vibration duration is 60% - 80% of the total ball milling time, the ball milling time is controlled at 10 - 18 hours, and the ball milling speed is 200 - 400 r / min. In the ball milling treatment step, a composite additive contains 60% stearic acid, 34% zinc chloride, and 6% graphite powder, and the hydrogen flow rate is 50 - 100 mL / min. In the annealing treatment step, the low-temperature annealing temperature is 400 °C - 500 °C for 1 - 2 hours for stress relief annealing, and in the recrystallization annealing, the temperature is raised to 800 °C - 900 °C and held for 3 - 5 hours. In the annealing treatment step, a multi-component synergistic antioxidant and magnetic property enhancer consists of 25% cerium nitrate, a mixture of ascorbic acid and propyl gallate in a ratio of 2:1, totaling 45%, 20% sodium borohydride, and 5% cobalt chloride.

[0035] Further, when using the plating solution, the raw materials are added to water at a ratio of 1:15 for use.

[0036] Example 1;

[0037] Taking the preparation of 10 kg of low-loss and high-saturation iron-nickel soft magnetic powder as an example, electrolytic nickel: 7.8 kg, electrolytic iron: 2.2 kg, copper: 0.07 kg, molybdenum: 0.03 kg are selected and prepared using all the above processes.

[0038] Example 2:

[0039] Taking the preparation of 10 kg of low-loss and high-saturation iron-nickel soft magnetic powder as an example, electrolytic nickel: 7.8 kg, electrolytic iron: 2.2 kg, copper: 0.07 kg, molybdenum: 0.03 kg are selected and processed by the following steps;

[0040] S1. Melting the alloy: Put the selected raw materials into the furnace for melting, at a temperature of 1500 °C for 30 minutes.

[0041] S2. Atomization: Pour the melted alloy into the atomization device, and also screen out the particles through a 100-mesh sieve

[0042] to enter the next step of processing.

[0043] S3. Ball milling treatment: Put the screened particles into the ball mill, set the ball milling speed at 200 r / min, and control the ball milling time at 10 hours.

[0044] S4. Annealing treatment. First, perform low-temperature annealing treatment, and then perform two-stage annealing treatment:

[0045] The low-temperature annealing temperature is 400°C - 500°C, and the holding time is 1 hour for stress relief annealing. In the two-stage annealing, the temperature is raised to 800°C - 900°C and held for 2 hours.

[0046] Example 3:

[0047] Taking the preparation of 10 kg of low-loss and high-saturation Fe-Ni soft magnetic powder as an example, select electrolytic nickel: 7.8 kg, electrolytic iron: 2.2 kg, copper: 0.07 kg, molybdenum: 0.03 kg, and process it according to the following steps;

[0048] S1. Melting the alloy: Put the prepared raw materials into a vacuum induction melting furnace and melt them in a vacuum environment. By precisely controlling the melting temperature and time, the raw materials are fully melted and alloyed;

[0049] S2. Atomization: The molten alloy after melting flows into the atomization device through the nozzle at the bottom. Use high-pressure water to impact and atomize the alloy liquid flow. The high-speed impact of the high-pressure water breaks the alloy liquid into fine droplets, which are quickly cooled and solidified in water to form powder. Then, after screening, select the powder for the next step of treatment;

[0050] S3. Ball milling treatment: Put the atomized powder into a ball mill. In addition, in the later stage of ball milling, introduce a certain amount of hydrogen into the ball mill tank. Hydrogen can react with some impurities in the powder under the high-energy ball milling environment to further improve the purity of the powder;

[0051] S4. Annealing treatment: Load the selected powder into a high-temperature-resistant quartz tube and perform annealing treatment under the condition that the vacuum degree is not higher than 10—4Pa. The annealing temperature is controlled in stages. First, perform low-temperature annealing, then raise the temperature for recrystallization annealing, and finally cool to room temperature with the furnace;

[0052] S5. Surface coating:

[0053] Surface coating: Use the method of electroless plating to coat the surface of the powder after magnetic field treatment. Prepare a plating solution containing nickel sulfate 29.8% - 28.6%, sodium hypophosphite 23.8% - 24.5%, lactic acid 29.8% - 28.6%, sodium citrate 9.5% - 9.8%, sodium acetate 6.0% - 8.2%, stabilizer 0.0012% - 0.0041%, surfactant 0.12% - 0.25%. Add the powder to the plating solution and perform an electroless plating reaction under certain temperature and pH conditions. Uniformly coat a layer of metallic nickel with a thickness of 0.1 - 0.5μm on the surface of the powder particles through electroless plating.

[0054] Further, Example 1 is prepared by the full process flow of the present invention. Example 2 is prepared by adding the special preparation prepared by the present invention to the traditional process. Example 3 is the preparation process of the full process of the present invention without adding the special preparation. Among them, Comparative Example 1 is the preparation process of the iron-nickel-molybdenum soft magnetic powder generated in the background technology of the present invention, and Comparative Example 2 is prepared by the common preparation process on the market. The iron-nickel soft magnetic powder prepared from the above examples and comparative examples is subjected to performance testing under the same conditions.

[0055] Table 1; Comparison Table of Soft Magnetic Powder Performance Parameters

[0056]

[0057] Specifically, referring to Table 1, it can be seen that from the perspective of particle size distribution: the examples have significant advantages over Comparative Example 2. For the powder obtained by the common preparation process in Comparative Example 2, D10 is 6.52 μm, D50 is 12.68 μm, and D90 is 29.38 μm. In Examples 1-3, D10 is in the range of 2.45-2.74 μm, D50 is in the range of 3.39-3.79 μm, and D90 is in the range of 16.21-19.32 μm. In the alloy melting link of the examples of the present invention, the melting temperature and time are precisely controlled by a vacuum induction melting furnace to ensure that the raw materials are fully melted and alloyed, laying a foundation for the subsequent uniform atomization process. In the atomization step, high-pressure water impacts the alloy liquid at a pressure of 10-20 MPa. Compared with Comparative Example 2, the degree of fragmentation of the alloy liquid can be more precisely controlled, thereby obtaining powder with smaller particle size and more concentrated distribution.

[0058] Details of the comparison with Comparative Example 1: For Example 1, D10 is 2.45 μm, D50 is 3.39 μm, and D90 is 16.21 μm. For Comparative Example 1, D10 is 2.49 μm, D50 is 3.49 μm, and D90 is 16.89 μm. In the ball milling treatment stage of Example 1, by controlling the ball-to-material ratio at 7-10:1, the ball milling speed at 200-400 r / min, and the vibration duration at 60%-80% of the total ball milling time, the powder particles are further refined and more evenly distributed, showing more advantages in particle size control.

[0059] From the perspective of oxygen content, the examples are far ahead of Comparative Example 2. The oxygen content of Comparative Example 2 is as high as 138 ppm, while the oxygen content of Examples 1-3 is in the range of 87-95 ppm. In the later stage of the ball milling treatment, hydrogen is introduced into the ball milling tank at a rate of 50-100 mL / min in the examples of the present invention. The hydrogen reacts with the impurities in the powder, reducing the impurity content and thus reducing the possible introduction of oxygen elements. During the annealing treatment, the powder is immersed in a solution of a multi-component synergistic antioxidant and magnetic property enhancer group. This preparation effectively inhibits the reaction between the powder and oxygen during the annealing process, enabling good control of the oxygen content.

[0060] Slightly better than Comparative Example 1: The oxygen content in Comparative Example 1 is 89 ppm, and that in Example 1 is 87 ppm. During the annealing treatment of the example, a vacuum environment not higher than 10 -4 Pa is adopted, which greatly reduces the presence of oxygen and further reduces the oxygen content.

[0061] Furthermore, from the perspective of the loose packing density, the examples far exceed Comparative Example 2: The loose packing density of Comparative Example 2 is only 2.17 g / cm 3 , and the loose packing densities of Examples 1-3 are in the range of 2.51 - 2.78 g / cm 3 . In the surface coating stage, in the examples of the present invention, a metal nickel layer with a thickness of 0.1 - 0.5 μm is uniformly coated on the surface of the powder particles by electroless plating, which improves the surface properties of the powder particles, makes the packing between the particles more compact, and thus increases the loose packing density.

[0062] There is an improvement compared to Comparative Example 1: The loose packing density of Comparative Example 1 is 2.59 g / cm 3 , and that of Example 1 reaches 2.78 / cm 3 . This benefits from the optimization of the powder microstructure and surface state in multiple process steps such as ball milling and annealing in the present invention, which enhances the packing effect of the powder particles.

[0063] Furthermore, from the perspective of the advantage of the saturation magnetization intensity, the examples are significantly superior to Comparative Example 2: The saturation magnetization intensity of Comparative Example 2 is 71.5 A·m 2 ·kg-1, and the saturation magnetization intensities of Examples 1-3 are in the range of 79.8 - 85.6 A·m 2 ·kg-1. This is because during the annealing treatment, the temperature is controlled in stages to promote the formation of a uniform equiaxed crystal structure inside the powder particles, optimize the crystal structure, enhance the magnetic properties of the material, and increase the saturation magnetization intensity.

[0064] There are mutual advantages compared to Comparative Example 1: The saturation magnetization intensity of Comparative Example 1 is 81.4 A·m 2 ·kg-1, and that of Example 1 is 85.2 A·m 2 ·kg-1. This is because of the special preparation added in Example 1. The components in the special preparation play a synergistic enhancement role in the magnetic properties, making the saturation magnetization intensity slightly higher than that of Comparative Example 1.

[0065] Furthermore, in terms of coercivity, the examples are superior to Comparative Example 2 within a reasonable range: the coercivity of Comparative Example 2 is 6.9 A / m, and the coercivities of Examples 1-3 are in the range of 13.2 - 14.1 A / m. This is because in the smelting, ball milling, annealing and other processes of the examples of the present invention, by precisely controlling the process parameters, excessive internal stress generation inside the powder is avoided, ensuring the orderly arrangement of the magnetic domains of the material, and making the coercivity within a reasonable range conducive to the stable application of soft magnetic materials in various scenarios. Compared with Comparative Example 1, they each have their own characteristics: the coercivity of Comparative Example 1 is 14.2 A / m, and that of Example 1 is 14.1 A / m, with little difference.

[0066] Generally speaking, the preparation process of the present invention has obvious advantages over the common market preparation process of Comparative Example 2 in terms of particle size distribution, oxygen content, apparent density, saturation magnetization intensity and coercivity, and some performance indicators are equivalent to or better than those of the comparative example. There are also certain differences between Example 1, Example 2 and Example 3, indicating that the special preparations and the complete process have different effects on the properties of soft magnetic powders.

[0067] The iron-nickel soft magnetic powders prepared from the above examples and comparative examples were made into iron-nickel-molybdenum soft magnetic powder cores under the same conditions and then subjected to performance testing. For specific parameters, please refer to Table 2.

[0068] Table 2; Performance test comparison table of the iron-nickel-molybdenum soft magnetic powder cores prepared from each example and comparative example.

[0069]

[0070] Specifically, referring to Table 2, from the numerical comparison, the loss values of Examples 1-3 are 153, 156, 157 mw / cm respectively 3 , that of Comparative Example 1 is 157 mw / cm 3 , and that of Comparative Example 2 is 201 mw / cm 3 . The loss values of Examples 1-3 and Comparative Example 1 are relatively close and low, but Example 1 is better than Comparative Example 1, and the loss value of Comparative Example 2 is significantly higher than that of other groups.

[0071] This is because during the preparation process of the embodiments of the present invention, starting from melting the alloy, the vacuum pressure is precisely controlled at 10-3 Pa, the melting temperature is at 1500-1600 °C, and the melting time is 30-60 minutes, enabling the raw materials to be fully melted and alloyed to form a uniform alloy structure. During ball milling, a composite additive is added. Stearic acid, zinc chloride, and graphite powder help refine the powder particles, reduce the friction between particles, and lower the energy loss. Meanwhile, hydrogen is introduced in the later stage of ball milling to remove impurities, further optimizing the internal structure of the powder. In the annealing treatment, the role of the multi-component synergistic antioxidant and magnetic property enhancer group optimizes the crystal structure and reduces the energy loss caused by crystal defects. In contrast, the common market preparation process of Comparative Example 2 lacks precise control and effective treatment in these links, resulting in higher losses.

[0072] Furthermore, from the perspective of the DC bias characteristics; numerical comparison: the DC bias characteristic values of Examples 1-3 are 53, 50, and 51 respectively, that of Comparative Example 1 is 53, and that of Comparative Example 2 is 43. The values of Examples 1-3 and Comparative Example 1 are relatively high and close, while the value of Comparative Example 2 is significantly lower than that of other groups.

[0073] This is because in the annealing treatment of the embodiments of the present invention, the temperature is controlled in stages. First, low-temperature stress relief annealing is carried out, and then recrystallization annealing is carried out, promoting the formation of a uniform equiaxed crystal structure inside the powder particles, enabling the magnetic domains to be arranged more orderly under the DC bias, thereby improving the DC bias characteristics. The surface coating process uniformly coats a nickel metal layer on the surface of the powder particles, which also plays a certain role in improving the magnetic properties and helps to enhance the DC bias characteristics. However, the process of Comparative Example 2 cannot effectively optimize the microstructure and magnetic properties of the magnetic powder core, resulting in poor performance in the DC bias characteristics.

[0074] Generally speaking, through the precise control and special treatment of multiple key steps in the preparation process, the iron-nickel-molybdenum soft magnetic powder cores prepared in the embodiments of the present invention are superior to the comparative examples in terms of loss and DC bias characteristics, especially significantly superior to the products obtained by the common market preparation process of Comparative Example 2.

[0075] The products produced in the above embodiments and comparative examples are made into magnetic powder core blanks by pressing the magnetic powder to be formed, and the produced products are selected for winding tests, specifically referring to Table 3;

[0076] Table 3; Winding test comparison table

[0077]

[0078] Referring to Table 3, by comparing various performance indicators, the iron-nickel soft magnetic powder produced by the process of the embodiment shows better performance in terms of power loss, DC bias, quality factor, effective magnetic permeability, etc., and thus has better performance and advantages in practical applications. This is mainly due to the composite additive added during ball milling treatment and the introduction of hydrogen gas in the process of the embodiment, the multi-component synergistic antioxidant and magnetic property enhancer during annealing treatment, the staged annealing temperature control, and the uniform coating of the metal nickel layer in the surface coating process. These process steps work together to optimize the performance of the powder, making it superior to the products produced by the process used in the comparative example.

[0079] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, making equivalent substitutions or changes should be covered within the protection scope of the present invention.

Claims

1. A method for preparing low-loss and high-saturation iron-nickel soft magnetic powder, characterized in that: The method comprises the following preparation steps: S1. Melting alloy: Prepare the raw materials such as electrolytic nickel, electrolytic iron, additives, etc. according to the proportion. Then put them into the vacuum induction melting furnace and melt them in a vacuum environment. By precisely controlling the melting temperature and time, the raw materials are fully melted and alloyed; S2, atomization: The smelted alloy liquid flows into the atomization device through the nozzle at the bottom, and the alloy liquid flow is impacted and atomized by high-pressure water. The high-speed impact of the high-pressure water breaks the alloy liquid into fine droplets, which are quickly cooled and solidified in water to form powder. After screening, the powder is selected for the next step of processing; S3, ball milling: a composite additive is added during the ball milling process. In addition, a certain amount of hydrogen is introduced into the ball milling tank in the later stage of ball milling. The hydrogen can react with some impurities in the powder under the high-energy ball milling environment to further improve the purity of the powder. S4, annealing treatment: a multi-component synergistic antioxidant and magnetic performance enhancer group is prepared, and before annealing, the powder is soaked in the solution of the mixed preparation for 12 to 18 minutes, then taken out and drained, and then the drained powder is placed in a high-temperature resistant quartz tube, and annealed under the condition of a vacuum degree not higher than 10-4Pa. The annealing temperature is controlled in stages, firstly low-temperature annealing is performed, then the temperature is increased for recrystallization annealing, and finally cooled to room temperature with the furnace; S5. Surface coating: The powder treated by magnetic field is surface coated by chemical plating. A plating solution containing 29.8% to 28.6% nickel sulfate, 23.8% to 24.5% sodium hypophosphite, 29.8% to 28.6% lactic acid, 9.5% to 9.8% sodium citrate, 6.0% to 8.2% sodium acetate, 0.0012% to 0.0041% stabilizer and 0.12% to 0.25% surfactant is prepared. The powder is added into the plating solution and chemical plating reaction is carried out under certain temperature and pH conditions. A metal nickel layer with a thickness of 0.1-0.5 μm is uniformly coated on the surface of the powder particles by chemical plating.

2. The method for preparing a low-loss and high-saturation iron-nickel soft magnetic powder according to claim 1, characterized in that: In the alloy smelting step, the vacuum pressure range is 10-3Pa, the smelting temperature is controlled at 1500°C-1600°C, and the smelting time is 30 to 60 minutes.

3. The method for preparing a low-loss and high-saturation iron-nickel soft magnetic powder according to claim 1, characterized in that: In the atomization step, the pressure of the high-pressure water is 10-20 MPa, and the screen is a 100-mesh screen.

4. The method for preparing a low-loss and high-saturation iron-nickel soft magnetic powder according to claim 1, characterized in that: In the ball milling step, the ball-to-material ratio is controlled at 7-10:1, the vibration duration is 60% to 80% of the total ball milling time, the ball milling time is controlled at 10-18 hours, and the ball milling speed is 200-400 r / min.

5. The method for preparing a low-loss and high-saturation iron-nickel soft magnetic powder according to claim 1, characterized in that: In the ball milling step, the composite additive comprises 60% stearic acid, 34% zinc chloride, and 6% graphite powder, and the hydrogen flow rate is 50-100 mL / min.

6. The method for preparing a low-loss and high-saturation iron-nickel soft magnetic powder according to claim 1, characterized in that: In the annealing treatment step, the low-temperature annealing temperature is 400°C-500°C, and the temperature is kept for 1-2 hours, and stress relief annealing is performed. In the recrystallization annealing, the temperature is raised to 800°C-900°C and the temperature is kept for 3-5 hours.

7. The method for preparing a low-loss and high-saturation iron-nickel soft magnetic powder according to claim 1, characterized in that: The multi-component synergistic antioxidant and magnetic performance enhancer described in the annealing step is composed of 25% cerium nitrate, 45% of ascorbic acid and propyl gallate mixed in a ratio of 2:1, 20% sodium borohydride and 5% cobalt chloride.

8. A low-loss, high-saturation iron-nickel soft magnetic powder, characterized in that: A low-loss and high-saturation iron-nickel soft magnetic powder is prepared by the method for preparing a low-loss and high-saturation iron-nickel soft magnetic powder according to any one of claims 1 to 7.

9. The low-loss and high-saturation iron-nickel soft magnetic powder according to claim 8, characterized in that: The additives include copper and molybdenum.

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