Soft magnetic material for electromagnetic switches and method for producing the same

Abstract

The application discloses a soft magnetic material for electromagnetic switch and a preparation method thereof, relates to the technical field of soft magnetic materials, and comprises iron alloy magnetic powder and soft ferrite powder, wherein the soft ferrite powder accounts for 0.1wt%-1wt% of the total weight of the soft magnetic material; the composition of the iron alloy magnetic powder comprises Nb, Co, Ni, Hf, Ga, B, Si and Fe; the soft ferrite powder is R-Fe-Co-Mn-Zn-M-O, wherein R is a rare earth element, and M is at least two of Sc, Sr, Cu and Zr. The soft magnetic material for electromagnetic switch disclosed by the application has excellent magnetic permeability, soft magnetic performance and saturation magnetic induction intensity, and low loss and coercive force.

Description

Technical Field

[0001] This invention relates to the field of soft magnetic materials technology, and in particular to a soft magnetic material for electromagnetic switches and its preparation method. Background Technology

[0002] An electromagnetic switch is a switch controlled by an electromagnet; it's a combination of an electromagnet and a switch. When the electromagnet coil is energized, it generates an electromagnetic force, which pushes or pulls the switch contacts to close, thus connecting the controlled circuit. Electromagnetic switches have wide applications in various industries, most commonly in starters in industrial applications. The starter electromagnetic switch is a key component of the starter motor, and its design quality directly affects the starter's reliability. The properties of the soft magnetic material used in the electromagnetic switch determine the magnitude of the magnetic field energy and electromagnetic force generated by the starter motor during operation, which is crucial for developing new, high-efficiency, low-energy-consumption starter motors.

[0003] Currently, most soft magnetic materials used in electromagnetic switches for electric motors are made of 10# steel through processes such as cold extrusion and cold drawing (cold drawing), possessing a magnetic permeability μ max The low permeability (1000-2000 Gs / Oe) and high coercivity (300-800 A / m) of the electromagnetic switch hinder further improvements in motor performance. Firstly, the high Hc results in high hysteresis losses, easily leading to increased heat generation during operation, especially during prolonged start-up times or multiple consecutive starts, where the temperature rises significantly. Secondly, the low permeability increases the magnetic reluctance of the electromagnetic switch, slowing down the electromagnetic response. Furthermore, other types of soft magnetic materials used in commercially available electromagnetic switches also suffer from higher losses to varying degrees, and their soft magnetic properties, permeability, and saturation magnetic induction all require further improvement.

[0004] To address the aforementioned problems, Chinese invention patent CN104399984B discloses a method for preparing iron-based powder metallurgy soft magnetic materials for magnetic poles and electromagnetic switches. First, a forming agent at 0.3-0.6 wt.% of the powder mass is added to pure iron powder or a mixture of pure iron powder and alloying element powder for mixing. After uniform mixing, the mixture is molded to obtain a compact. Then, the compact is sintered in a protective atmosphere using a multi-stage sintering process. The sintering process is as follows: first, holding at 400-650℃ for 0.5-3 hours; then, holding at 1120-1200℃ for 1-4 hours; and finally, holding at 800-910℃ for 0.5-4 hours, followed by furnace cooling to below 200℃ before unloading. This invention offers high production efficiency, low manufacturing cost, and high material utilization. The soft magnetic material prepared using domestically produced reduced iron powder and water-atomized pure iron powder exhibits high permeability, low coercivity, and medium density (7.2-7.5 g / cm³). 3It fully meets the requirements for use in automotive starters and start-stop motors, and is suitable for mass production. However, its losses, soft magnetic properties, and saturation magnetic induction intensity need further improvement.

[0005] It is evident that there is still a need in this field for a soft magnetic material for electromagnetic switches with excellent permeability, soft magnetic properties, saturation magnetic induction, low loss and coercivity, which fully meets the requirements for use in starters, and a method for its preparation. Summary of the Invention

[0006] The main objective of this invention is to provide a soft magnetic material for electromagnetic switches with excellent permeability, soft magnetic properties, and saturation magnetic induction, as well as low loss and coercivity, which fully meets the requirements for use in starters, and a method for preparing the same.

[0007] To achieve the above objectives, the present invention provides a soft magnetic material for electromagnetic switches, comprising ferroalloy magnetic powder and soft ferrite powder, wherein the soft ferrite powder accounts for 0.1wt%-1wt% of the total weight of the soft magnetic material; the ferroalloy magnetic powder comprises Nb, Co, Ni, Hf, Ga, B, Si and Fe; the soft ferrite powder is R-Fe-Co-Mn-Zn-MO, wherein R is a rare earth element and M is at least two of Sc, Sr, Cu and Zr.

[0008] Preferably, the weight percentages of each component in the ferroalloy magnetic powder are as follows: Nb 0.01-0.03%, Co 1-2%, Ni 0.8-1.6%, Hf 0.03-0.05%, Ga 0.08-0.12%, B 0.1-0.15%, Si 0.8-1.2%, with the balance being Fe.

[0009] Preferably, the rare earth elements are Dy, Gd, and Ce mixed in a mass ratio of (0.8-1.2):(0.6-1):(1-2).

[0010] Preferably, the mass ratio of R, Fe, Co, Mn, Zn, and M in the R-Fe-Co-Mn-Zn-MO is (0.03-0.07):(2-3):(0.2-0.4):(0.3-0.5):(0.5-0.8):(0.08-0.12).

[0011] Preferably, M is a mixture of Sc, Sr, Cu, and Zr in a mass ratio of 0.5:(0.1-0.3):(0.2-0.4):1.

[0012] Another object of the present invention is to provide a method for preparing the soft magnetic material for the electromagnetic switch, comprising the following steps:

[0013] Step S1: Nb-Co-Ni-Hf-Ga-B-Si-Fe iron alloy magnetic powder is prepared by gas atomization, followed by ball milling and grinding to obtain powder with an average particle size of 20-100μm.

[0014] Step S2: Using nitrates containing R, Fe, Co, Mn, Zn, and M respectively as raw materials, R-Fe-Co-Mn-Zn-MO soft ferrite powder is prepared according to the Sol-gel self-propagating powder method;

[0015] Step S3: Mix the powder prepared in step S1 with the soft ferrite powder prepared in step S2, add it to a high-speed ball mill jar for ball milling, and then perform molding.

[0016] Step S4: Sintering and cooling yields a soft magnetic material for electromagnetic switches.

[0017] Preferably, the Sol-gel self-propagating powder method in step S2 is as follows: the raw materials are mixed according to the formula to obtain a raw material mixture, added to deionized water and stirred evenly, then citric acid is added, sealed and stirred at 85-92℃ for 2-4 hours, cooled to room temperature, and the pH is adjusted to 7 with ammonia water; then dried at 93-100℃ to form a dry gel, and finally self-propagating combustion is carried out.

[0018] Preferably, the mass ratio of the raw material mixture, deionized water, and citric acid is 1:(6-8):2.38.

[0019] Preferably, the ball milling speed in step S3 is 300 r / min-600 r / min, and the time is 1 h-3 h.

[0020] Preferably, the compression molding pressure in step S3 is 500-700 MPa.

[0021] Preferably, the sintering in step S4 is carried out in a protective atmosphere furnace, specifically: first, sintering at 500-700℃ for 1-2 hours, then sintering at 1150-1300℃ for 2-4 hours, followed by sintering at 850-950℃ for 1-2 hours, and finally cooling in the furnace to below 160℃ before being removed from the furnace.

[0022] Preferably, the protective atmosphere is a hydrogen protective atmosphere.

[0023] Due to the application of the above technical solution, the present invention has the following beneficial effects:

[0024] (1) The method for preparing soft magnetic materials for electromagnetic switches disclosed in this invention is simple, easy to operate, has high product size consistency and product precision, high production efficiency, high finished product qualification rate and high material utilization rate, low dependence on equipment, and is suitable for mass production.

[0025] (2) The soft magnetic material for electromagnetic switches disclosed in this invention is composed of iron alloy magnetic powder and soft ferrite powder. Through the combination of the two types of magnetic materials and the reasonable selection of their respective formulas, the final product has excellent permeability, soft magnetic properties and saturation magnetic induction intensity, low loss and coercivity, and fully meets the requirements for use in starters.

[0026] (3) The soft magnetic material for electromagnetic switches disclosed in this invention comprises the following components in the iron alloy magnetic powder: Nb 0.01-0.03%, Co 1-2%, Ni 0.8-1.6%, Hf 0.03-0.05%, Ga 0.08-0.12%, B 0.1-0.15%, Si 0.8-1.2%, with the balance being Fe. Through the synergistic effect of the components, the magnetic powder can be endowed with excellent electromagnetic properties, effectively improving permeability and reducing core loss and coercivity.

[0027] (4) The soft magnetic material for electromagnetic switches disclosed in this invention is R-Fe-Co-Mn-Zn-MO, wherein R is a rare earth element and M is at least two of Sc, Sr, Cu and Zr. By rationally selecting the raw materials and formula, they can better interact with each other, so that the product not only has excellent soft magnetic properties, but also improves the uniformity of ferrite grains, promotes sintering, improves the microstructure of the material, and further improves the electromagnetic performance.

[0028] (5) The soft magnetic material for electromagnetic switches disclosed in this invention can effectively reduce losses, increase compaction density, and reduce impurity content by reasonably selecting the preparation process parameters, thereby improving the comprehensive magnetic properties and performance stability of the soft magnetic material. Detailed Implementation

[0029] The following description is intended to disclose the invention and enable those skilled in the art to implement it. The preferred embodiments described below are merely examples, and other obvious variations will occur to those skilled in the art. Example 1

[0030] A soft magnetic material for electromagnetic switches comprises ferroalloy magnetic powder and soft ferrite powder, wherein the soft ferrite powder accounts for 1 wt% of the total weight of the soft magnetic material; the ferroalloy magnetic powder comprises Nb, Co, Ni, Hf, Ga, B, Si and Fe; and the soft ferrite powder is R-Fe-Co-Mn-Zn-MO, wherein R is a rare earth element.

[0031] The weight percentages of each component in the ferroalloy magnetic powder are as follows: Nb 0.01%, Co 1%, Ni 0.8%, Hf 0.03%, Ga 0.08%, B 0.1%, Si 0.8%, with the balance being Fe.

[0032] The rare earth elements are Dy, Gd, and Ce mixed in a mass ratio of 0.8:0.6:1; the mass ratio of R, Fe, Co, Mn, Zn, and M in the R-Fe-Co-Mn-Zn-MO is 0.03:2:0.2:0.3:0.5:0.08; and M is Sc, Sr, Cu, and Zr mixed in a mass ratio of 0.5:0.1:0.2:1.

[0033] A method for preparing the soft magnetic material for the electromagnetic switch includes the following steps:

[0034] Step S1: Nb-Co-Ni-Hf-Ga-B-Si-Fe iron alloy magnetic powder is prepared by gas atomization, followed by ball milling and grinding to obtain powder with an average particle size of 40μm.

[0035] Step S2: Using nitrates containing R, Fe, Co, Mn, Zn, and M respectively as raw materials, R-Fe-Co-Mn-Zn-MO soft ferrite powder is prepared according to the Sol-gel self-propagating powder method;

[0036] Step S3: Mix the powder prepared in step S1 with the soft ferrite powder prepared in step S2, add it to a high-speed ball mill jar for ball milling, and then perform molding.

[0037] Step S4: Sintering and cooling yields a soft magnetic material for electromagnetic switches.

[0038] The Sol-gel self-propagating powder method described in step S2 is as follows: the raw materials are mixed according to the formula to obtain a raw material mixture, which is then added to deionized water and stirred evenly. Citric acid is then added, and the mixture is sealed and stirred at 85°C for 2 hours. After cooling to room temperature, the pH is adjusted to 7 with ammonia. The mixture is then dried at 93°C to form a dry gel, and finally self-propagating combustion is performed. The mass ratio of the raw material mixture, deionized water, and citric acid is 1:6:2.38.

[0039] In step S3, the ball milling speed is 300 r / min and the time is 1 h; the molding pressure is 500 MPa.

[0040] Preferably, the sintering in step S4 is carried out in a protective atmosphere furnace, specifically: first, sintering at 500°C for 1 hour, then sintering at 1150°C for 2 hours, followed by sintering at 850°C for 1 hour, and finally cooling with the furnace to below 160°C before being removed from the furnace; the protective atmosphere is a hydrogen protective atmosphere. Example 2

[0041] A soft magnetic material for electromagnetic switches comprises ferroalloy magnetic powder and soft ferrite powder, wherein the soft ferrite powder accounts for 1 wt% of the total weight of the soft magnetic material; the ferroalloy magnetic powder comprises Nb, Co, Ni, Hf, Ga, B, Si and Fe; and the soft ferrite powder is R-Fe-Co-Mn-Zn-MO, wherein R is a rare earth element.

[0042] The weight percentages of each component in the ferroalloy magnetic powder are as follows: Nb 0.015%, Co 1.2%, Ni 1%, Hf 0.035%, Ga 0.09%, B 0.12%, Si 0.9%, with the balance being Fe. The rare earth elements are Dy, Gd, and Ce mixed in a mass ratio of 0.9:0.7:1.2; the mass ratio of R, Fe, Co, Mn, Zn, and M in the R-Fe-Co-Mn-Zn-MO mixture is 0.04:2.3:0.25:0.35:0.6:0.09; and M is Sc, Sr, Cu, and Zr mixed in a mass ratio of 0.5:0.15:0.25:1.

[0043] A method for preparing the soft magnetic material for the electromagnetic switch includes the following steps:

[0044] Step S1: Nb-Co-Ni-Hf-Ga-B-Si-Fe iron alloy magnetic powder is prepared by gas atomization, followed by ball milling and grinding to obtain powder with an average particle size of 40μm.

[0045] Step S2: Using nitrates containing R, Fe, Co, Mn, Zn, and M respectively as raw materials, R-Fe-Co-Mn-Zn-MO soft ferrite powder is prepared according to the Sol-gel self-propagating powder method;

[0046] Step S3: Mix the powder prepared in step S1 with the soft ferrite powder prepared in step S2, add it to a high-speed ball mill jar for ball milling, and then perform molding.

[0047] Step S4: Sintering and cooling yields a soft magnetic material for electromagnetic switches.

[0048] The Sol-gel self-propagating powder method described in step S2 is as follows: the raw materials are mixed according to the formula to obtain a raw material mixture, which is then added to deionized water and stirred evenly. Citric acid is then added, and the mixture is sealed and stirred at 87°C for 2.5 hours. After cooling to room temperature, the pH is adjusted to 7 with ammonia. The mixture is then dried at 95°C to form a dry gel, and finally subjected to self-propagating combustion. The mass ratio of the raw material mixture, deionized water, and citric acid is 1:6.5:2.38.

[0049] In step S3, the ball milling speed is 400 r / min and the time is 1.5 h; the molding pressure is 550 MPa.

[0050] The sintering described in step S4 is carried out in a protective atmosphere furnace, specifically: first, sintering is performed at 550°C for 1.2 hours, then at 1200°C for 2.5 hours, followed by sintering at 880°C for 1.2 hours, and finally cooled to below 160°C in the furnace before being removed from the furnace; the protective atmosphere is a hydrogen protective atmosphere. Example 3

[0051] A soft magnetic material for electromagnetic switches comprises ferroalloy magnetic powder and soft ferrite powder, wherein the soft ferrite powder accounts for 1 wt% of the total weight of the soft magnetic material; the ferroalloy magnetic powder comprises Nb, Co, Ni, Hf, Ga, B, Si and Fe; and the soft ferrite powder is R-Fe-Co-Mn-Zn-MO.

[0052] The weight percentages of each component in the ferroalloy magnetic powder are as follows: Nb 0.02%, Co 1.5%, Ni 1.2%, Hf 0.04%, Ga 0.1%, B 0.13%, Si 1%, with the balance being Fe.

[0053] The rare earth elements are Dy, Gd, and Ce mixed in a mass ratio of 1:0.8:1.5; the mass ratio of R, Fe, Co, Mn, Zn, and M in the R-Fe-Co-Mn-Zn-MO mixture is 0.05:2.5:0.3:0.4:0.65:0.1; and M is Sc, Sr, Cu, and Zr mixed in a mass ratio of 0.5:0.2:0.3:1.

[0054] A method for preparing the soft magnetic material for the electromagnetic switch includes the following steps:

[0055] Step S1: Nb-Co-Ni-Hf-Ga-B-Si-Fe iron alloy magnetic powder is prepared by gas atomization, followed by ball milling and grinding to obtain powder with an average particle size of 40μm.

[0056] Step S2: Using nitrates containing R, Fe, Co, Mn, Zn, and M respectively as raw materials, R-Fe-Co-Mn-Zn-MO soft ferrite powder is prepared according to the Sol-gel self-propagating powder method;

[0057] Step S3: Mix the powder prepared in step S1 with the soft ferrite powder prepared in step S2, add it to a high-speed ball mill jar for ball milling, and then perform molding.

[0058] Step S4: Sintering and cooling yields a soft magnetic material for electromagnetic switches.

[0059] The Sol-gel self-propagating powder method described in step S2 is as follows: the raw materials are mixed according to the formula to obtain a raw material mixture, which is then added to deionized water and stirred evenly. Citric acid is then added, and the mixture is sealed and stirred at 89°C for 3 hours. After cooling to room temperature, the pH is adjusted to 7 with ammonia. Then, the mixture is dried at 97°C to form a dry gel, and finally, self-propagating combustion is carried out. The mass ratio of the raw material mixture, deionized water, and citric acid is 1:7:2.38.

[0060] In step S3, the ball milling speed is 450 r / min and the time is 2 h; the molding pressure is 600 MPa.

[0061] The sintering described in step S4 is carried out in a protective atmosphere furnace, specifically: first, sintering at 600°C for 1.5 hours, then sintering at 1230°C for 3 hours, followed by sintering at 900°C for 1.5 hours, and finally cooling with the furnace to below 160°C before being removed from the furnace; the protective atmosphere is a hydrogen protective atmosphere. Example 4

[0062] A soft magnetic material for electromagnetic switches comprises ferroalloy magnetic powder and soft ferrite powder, wherein the soft ferrite powder accounts for 1 wt% of the total weight of the soft magnetic material; the ferroalloy magnetic powder comprises Nb, Co, Ni, Hf, Ga, B, Si and Fe; and the soft ferrite powder is R-Fe-Co-Mn-Zn-MO, wherein R is a rare earth element.

[0063] The weight percentages of each component in the ferroalloy magnetic powder are as follows: Nb 0.025%, Co 1.8%, Ni 1.4%, Hf 0.045%, Ga 0.11%, B 0.14%, Si 1.1%, with the balance being Fe; the rare earth elements are Dy, Gd, and Ce mixed in a mass ratio of 1.1:0.9:1.8.

[0064] In the R-Fe-Co-Mn-Zn-MO, the mass ratio of R, Fe, Co, Mn, Zn, and M is 0.06:2.8:0.35:0.45:0.75:0.11; and M is a mixture of Sc, Sr, Cu, and Zr in a mass ratio of 0.5:0.25:0.35:1.

[0065] A method for preparing the soft magnetic material for the electromagnetic switch includes the following steps:

[0066] Step S1: Nb-Co-Ni-Hf-Ga-B-Si-Fe iron alloy magnetic powder is prepared by gas atomization, followed by ball milling and grinding to obtain powder with an average particle size of 40μm.

[0067] Step S2: Using nitrates containing R, Fe, Co, Mn, Zn, and M respectively as raw materials, R-Fe-Co-Mn-Zn-MO soft ferrite powder is prepared according to the Sol-gel self-propagating powder method;

[0068] Step S3: Mix the powder prepared in step S1 with the soft ferrite powder prepared in step S2, add it to a high-speed ball mill jar for ball milling, and then perform molding.

[0069] Step S4: Sintering and cooling yields a soft magnetic material for electromagnetic switches.

[0070] The Sol-gel self-propagating powder method described in step S2 is as follows: the raw materials are mixed according to the formula to obtain a raw material mixture, which is then added to deionized water and stirred evenly. Citric acid is then added, and the mixture is sealed and stirred at 90°C for 3.5 hours. After cooling to room temperature, the pH is adjusted to 7 with ammonia. The mixture is then dried at 99°C to form a dry gel, and finally subjected to self-propagating combustion. The mass ratio of the raw material mixture, deionized water, and citric acid is 1:7.5:2.38.

[0071] In step S3, the ball milling speed is 550 r / min and the time is 2.5 h; the molding pressure is 650 MPa.

[0072] The sintering described in step S4 is carried out in a protective atmosphere furnace, specifically: first, sintering is performed at 650°C for 1.8 hours, then at 1280°C for 3.5 hours, followed by sintering at 940°C for 1.8 hours, and finally, the furnace is cooled to below 160°C before being removed from the furnace; the protective atmosphere is a hydrogen protective atmosphere. Example 5

[0073] A soft magnetic material for electromagnetic switches comprises ferroalloy magnetic powder and soft ferrite powder, wherein the soft ferrite powder accounts for 1 wt% of the total weight of the soft magnetic material; the ferroalloy magnetic powder comprises Nb, Co, Ni, Hf, Ga, B, Si and Fe; and the soft ferrite powder is R-Fe-Co-Mn-Zn-MO, wherein R is a rare earth element.

[0074] The weight percentages of each component in the ferroalloy magnetic powder are as follows: Nb 0.03%, Co 2%, Ni 1.6%, Hf 0.05%, Ga 0.12%, B 0.15%, Si 1.2%, with the balance being Fe; the rare earth elements are Dy, Gd, and Ce mixed in a mass ratio of 1.2:1:2.

[0075] In the R-Fe-Co-Mn-Zn-MO, the mass ratio of R, Fe, Co, Mn, Zn, and M is 0.07:3:0.4:0.5:0.8:0.12; and M is a mixture of Sc, Sr, Cu, and Zr in a mass ratio of 0.5:0.3:0.4:1.

[0076] A method for preparing the soft magnetic material for the electromagnetic switch includes the following steps:

[0077] Step S1: Nb-Co-Ni-Hf-Ga-B-Si-Fe iron alloy magnetic powder is prepared by gas atomization, followed by ball milling and grinding to obtain powder with an average particle size of 40μm.

[0078] Step S2: Using nitrates containing R, Fe, Co, Mn, Zn, and M respectively as raw materials, R-Fe-Co-Mn-Zn-MO soft ferrite powder is prepared according to the Sol-gel self-propagating powder method;

[0079] Step S3: Mix the powder prepared in step S1 with the soft ferrite powder prepared in step S2, add it to a high-speed ball mill jar for ball milling, and then perform molding.

[0080] Step S4: Sintering and cooling yields a soft magnetic material for electromagnetic switches.

[0081] The Sol-gel self-propagating powder method described in step S2 is as follows: the raw materials are mixed according to the formula to obtain a raw material mixture, which is then added to deionized water and stirred evenly. Citric acid is then added, and the mixture is sealed and stirred at 92°C for 4 hours. After cooling to room temperature, the pH is adjusted to 7 with ammonia. The mixture is then dried at 100°C to form a dry gel, and finally subjected to self-propagating combustion. The mass ratio of the raw material mixture, deionized water, and citric acid is 1:8:2.38.

[0082] In step S3, the ball milling speed is 600 r / min and the time is 3 h; the molding pressure is 700 MPa.

[0083] The sintering described in step S4 is carried out in a protective atmosphere furnace, specifically: first, sintering at 700°C for 2 hours, then sintering at 1300°C for 4 hours, followed by sintering at 950°C for 2 hours, and finally cooling with the furnace to below 160°C before being removed from the furnace; the protective atmosphere is a hydrogen protective atmosphere.

[0084] Comparative Example 1

[0085] A soft magnetic material for electromagnetic switches is basically the same as that in Example 1, except that Hf, Ga and R are not added.

[0086] Comparative Example 2

[0087] A soft magnetic material for electromagnetic switches is basically the same as that in Example 1, except that Nb and M are not added.

[0088] To further illustrate the beneficial technical effects of the soft magnetic materials for electromagnetic switches prepared according to the various embodiments of the present invention, the soft magnetic materials for electromagnetic switches prepared in Examples 1-5 and Comparative Examples 1-2 were subjected to relevant performance tests according to the current national standards or conventional methods in my country. The test results are shown in Table 1. The power loss data was obtained under the test conditions of 100kHz, 200mT, and 25℃; the magnetization intensity B50 was obtained under the test conditions of 5000A / m.

[0089] Table 1

[0090]

[0091] As can be seen from Table 1, the soft magnetic material for electromagnetic switches disclosed in the embodiments of the present invention has lower losses and better overall soft magnetic properties compared with the comparative product. The addition of Hf, Ga, R, Nb and M is beneficial to improving the above performance.

[0092] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention. The scope of protection claimed by the appended claims and their equivalents is defined.

Claims

1. A soft magnetic material for electromagnetic switches, characterized in that, The material comprises ferroalloy magnetic powder and soft ferrite powder, wherein the soft ferrite powder accounts for 0.1wt%-1wt% of the total weight of the soft magnetic material; the ferroalloy magnetic powder comprises Nb, Co, Ni, Hf, Ga, B, Si, and Fe; the soft ferrite powder is R-Fe-Co-Mn-Zn-MO, where R is a rare earth element; the weight percentages of each component in the ferroalloy magnetic powder are as follows: Nb 0.01-0.03%, Co 1-2%, Ni 0.8-1.6%, Hf 0.03-0.05%, Ga 0.08-0.12%, B 0.1-0.15%, Si 0.8-1.2%, with the balance being Fe; the rare earth elements are Dy, Gd, and Ce mixed in a mass ratio of (0.8-1.2):(0.6-1):(1-2); the mass ratio of R, Fe, Co, Mn, Zn, and M in R-Fe-Co-Mn-Zn-MO is (0.03-0.07):(2-3):(0.2-0.4):(0.3-0.5):(0.5-0.8):(0.08-0.12); the M is Sc, Sr, Cu, and Zr mixed in a mass ratio of 0.5:(0.1-0.3):(0.2-0.4):

1.

2. A method for preparing a soft magnetic material for an electromagnetic switch according to claim 1, characterized in that, Includes the following steps: Step S1: Nb-Co-Ni-Hf-Ga-B-Si-Fe iron alloy magnetic powder is prepared by gas atomization, followed by ball milling and grinding to obtain powder with an average particle size of 20-100μm. Step S2: Using nitrates containing R, Fe, Co, Mn, Zn, and M respectively as raw materials, R-Fe-Co-Mn-Zn-MO soft ferrite powder is prepared according to the Sol-gel self-propagating powder method; Step S3: Mix the powder prepared in step S1 with the soft ferrite powder prepared in step S2, add it to a high-speed ball mill jar for ball milling, and then perform molding. Step S4: Sintering and cooling yields a soft magnetic material for electromagnetic switches.

3. The method for preparing soft magnetic material for electromagnetic switches according to claim 2, characterized in that, The Sol-gel self-propagating powder method described in step S2 is as follows: the raw materials are mixed according to the formula to obtain a raw material mixture, which is then added to deionized water and stirred evenly. Citric acid is then added, and the mixture is sealed and stirred at 85-92℃ for 2-4 hours. After cooling to room temperature, the pH is adjusted to 7 with ammonia. Then, the mixture is dried at 93-100℃ to form a dry gel, and finally, self-propagating combustion is carried out. The mass ratio of the raw material mixture, deionized water, and citric acid is 1:(6-8):2.

38.

4. The method for preparing soft magnetic material for electromagnetic switches according to claim 2, characterized in that, The ball milling speed in step S3 is 300 r / min-600 r / min, and the time is 1 h-3 h; the molding pressure in step S3 is 500-700 MPa.

5. The method for preparing soft magnetic material for electromagnetic switches according to claim 2, characterized in that, The sintering described in step S4 is carried out in a protective atmosphere furnace, specifically: first, sintering is carried out at 500-700℃ for 1-2 hours, then at 1150-1300℃ for 2-4 hours, followed by sintering at 850-950℃ for 1-2 hours, and finally, the furnace is cooled to below 160℃ before being removed from the furnace.

6. The method for preparing the soft magnetic material for electromagnetic switches according to claim 5, characterized in that, The protective atmosphere is a hydrogen protective atmosphere.

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