TW202041693A - Soft magnetic alloy powder, electronic component and manufacturing method thereof - Google Patents

Abstract

The present invention provides a soft magnetic alloy powder that can miniaturize electronic components for use in a high temperature environment, and also provides electronic components. The soft magnetic alloy powder contains Si and Al in amounts satisfying the relationship of Si ≥ 2% by weight, Al ≥ 1% by weight, and Si+Al ≤ 12% by weight, and the remainder is Fe and unavoidable impurities. Using this soft magnetic alloy powder, electronic component such as a magnetic powder core, an electromagnetic wave absorption shield, or an electromagnetic wave absorber can be obtained.

Description

Soft magnetic alloy powder, electronic part and manufacturing method thereof

The present invention relates to soft magnetic alloy powder, electronic parts and manufacturing methods thereof.

In recent years, as power inductors used in power supply circuits, there is a demand for a soft magnetic material that can be used at high currents and high frequencies in response to requirements for miniaturization and low height. Conventionally, ferrite-based materials belonging to oxides are used as the main material of inductors, but they are not conducive to miniaturization due to low saturation magnetization. Therefore, in recent years, there has been a rapid increase in metal inductors using alloy-based materials that have high saturation magnetization and are advantageous for miniaturization and low profile. Among the metal inductors, there are known powder cores obtained by using soft magnetic alloy powder mainly made of iron, mixing the soft magnetic alloy powder and resin, and performing compression molding.

In the process of increasing interest in energy issues, the electrification of automobiles and the power saving of electronic equipment have been promoted, and powder magnetic cores that can be smaller and have less energy loss are required. To give a specific example, in order to cope with the advanced control used to achieve high environmental performance and driving performance in automobiles, it is accompanied by the installation of ECU (Electronic Control Unit) on actuators such as motors and solenoids. "Integration", the need to install ECUs in power generator rooms with higher temperature environments is increasing, and there is a demand for a powder core that can be used in higher temperature environments for ECUs.

The existing electronic parts such as powder cores using soft magnetic alloy powders have known that the core loss increases as the temperature rises, and the temperature of the core itself increases due to heat generated by the core loss during use. As the temperature rises, the core loss increases and heat generation increases. Repeating this process sometimes causes thermal runaway. Therefore, research is under way to improve the temperature characteristics of the core loss in the high-temperature region. For example, Patent Document 1 describes that a formed body is heat-treated, and the forming system is obtained by press-forming Fe-Si-Al alloy powder having a specific composition; The Fe-Si-Al alloy powder has soft magnetic alloy powder with an insulating film formed on the surface. However, Fe-Si-Al alloy powders are hard and have poor plastic deformability, so it is difficult to high-density molding, and it is difficult to obtain a high saturation magnetic flux density that is advantageous for miniaturization of electronic parts. [Prior Technical Literature] [Patent Literature]

Patent Document 1: International Publication No. 2011/016207 Patent Document 2: Japanese Patent Laid-Open No. 2012-9825

(The problem to be solved by the invention)

The object of the present invention is to provide soft magnetic alloy powder that can reduce the size of electronic parts and can be used in a high-temperature environment, and further provide electronic parts. (Technical means to solve the problem)

As a result of various studies conducted by the inventors, they discovered the composition of an Fe-Si-Al alloy having high saturation magnetic flux density and negative core loss temperature characteristics, and completed the present invention.

That is, the present invention is a soft magnetic alloy powder that contains Si and Al in an amount that satisfies the relationship of Si≧2% by weight, Al≧1% by weight, and Si+Al≦12% by weight, and the remainder is Fe. Impurities to avoid.

According to an aspect of the present invention, the above-mentioned soft magnetic alloy powder is provided, which has a negative core loss temperature characteristic at 25°C to 120°C.

According to an aspect of the present invention, the above-mentioned soft magnetic alloy powder is provided, which contains Si and Al in amounts satisfying the relationship of Si≧3.5% by weight, Al≧2.5% by weight, and Si+Al≦12% by weight.

According to one aspect of the present invention, the above-mentioned soft magnetic alloy powder is provided, which has a negative core loss temperature characteristic at 120°C to 150°C.

According to one aspect of the present invention, the above-mentioned soft magnetic alloy powder is provided, the particle size (D50) of which is 1-50 μm.

According to an aspect of the present invention, there is provided an electronic component containing the above-mentioned soft magnetic alloy powder.

According to an aspect of the present invention, there is provided the above-mentioned electronic component, which is a powder magnetic core, an electromagnetic wave absorbing shield body, or an electromagnetic wave absorbing body.

According to an aspect of the present invention, there is provided a method of manufacturing an electronic component, which includes: forming a film on the surface of the soft magnetic alloy powder described above to obtain granulated powder; and pressing the granulated powder to obtain a compact Step; and a step of heat-treating the formed body at a temperature of 550°C to 950°C.

According to one aspect of the present invention, there is provided a method of manufacturing an electronic component, which includes: forming a film on the surface of the soft magnetic alloy powder described above to obtain granulated powder; and injection molding the granulated powder to obtain a molded body ; And the step of heat-treating the formed body at a temperature of 550°C to 950°C. (Compared with the effect of previous technology)

The present invention can provide soft magnetic alloy powder that can reduce the size of electronic parts and can be used in a high-temperature environment.

Hereinafter, an embodiment of the present invention will be described in detail. The present invention is not limited to the following embodiments, and can be implemented with appropriate changes within a range that does not impair the effects of the present invention. In addition, in the following description, "A-B" means "A or more and B or less".

The soft magnetic alloy powder of this embodiment contains Si and Al in amounts satisfying the relationship of Si≧2% by weight, Al≧1% by weight, and Si+Al≦12% by weight, and the remainder is Fe and unavoidable Impurities. The soft magnetic alloy powder of the present embodiment preferably contains Si and Al in an amount satisfying the relationship of Si≧3.5% by weight, Al≧2.5% by weight, and Si+Al≦12% by weight. By including Si and Al in amounts satisfying the above relationship, the saturation magnetic flux density (Bs) and permeability of the soft magnetic alloy powder are improved. Due to this effect, the soft magnetic alloy powder of this embodiment contributes to the miniaturization of electronic parts.

<Other elements> In the soft magnetic alloy powder of the present embodiment, elements such as N, S, and O can be contained as unavoidable impurities to the extent that the target characteristics are not affected.

In addition, a soft magnetic alloy powder containing Si and Al in amounts satisfying the above relationship, and the remainder being Fe and inevitable impurities, has a negative core loss temperature characteristic at 25°C to 120°C. The soft magnetic alloy powder of the present embodiment, which contains Si and Al in an amount satisfying the relationship of Si≧3.5% by weight, Al≧2.5% by weight, and Si+Al≦12% by weight, also has properties at 120°C to 150°C Negative core loss temperature characteristics.

(Negative core loss temperature characteristics) The negative core loss temperature characteristic means that the core loss of the soft magnetic alloy powder has a negative coefficient with respect to temperature, that is, the core loss of the soft magnetic alloy powder decreases as the temperature rises. The actual form of the soft magnetic alloy powder with negative core loss temperature characteristics, because the core loss decreases as the temperature rises, it can suppress the increase in the temperature of the core itself caused by the heat generated by the core loss during use. It has suitable characteristics as a material for electronic parts such as powder magnetic cores, which are conventionally difficult to use in high-temperature environments. The soft magnetic alloy powder of the present embodiment has a negative core loss temperature characteristic, which is considered to be because the magnetostriction constant determined by the composition has a positive value.

The soft magnetic alloy powder of the present embodiment preferably has a particle size (D50) of 1 to 50 μm. "Particle diameter" refers to the median diameter: D50, which can be measured by a conventionally known method, such as a laser diffraction-scattering method. Regarding the effects of the saturation magnetic flux density (Bs), magnetic permeability, and negative core loss temperature characteristics of the soft magnetic alloy powder described above, it can be obtained in soft magnetic alloy powders with a wide range of particle sizes, but the particle size (D50) It is 1 to 50 μm, preferably 2 to 40 μm, more preferably 2.5 to 35 μm, still more preferably 3 to 30 μm, and particularly high effects can be obtained.

(Manufacturing method) The soft magnetic alloy powder of this embodiment can be produced by a conventionally known method exemplified below as the production method of metal powder. However, as long as it has the composition of this embodiment, it has the above-mentioned magnetic properties. There is no particular limitation. ・Atomization method: water atomization method, gas atomization method, centrifugal force atomization method, etc. ・Mechanical treatment method: crushing method, mechanical alloying method, etc. ・Melt spinning method ・Rotating electrolysis method (REP method): Plasma REP method, etc. ・Chemical treatment methods: oxide reduction method, chloride reduction method, hydrometallurgical technology, carbonyl reaction method, etc.

Among the manufacturing methods exemplified above, in particular, the atomization method can mass-produce small-diameter and spherical soft magnetic alloy powders under atmospheric pressure. Among them, if the water atomization method is adopted, it can be manufactured at low cost. When the soft magnetic alloy powder is produced by the water atomization method, the molten material obtained by melting the material adjusted to the required composition is sprayed with a high pressure setting the parameters so that the required cooling conditions and particle size Water can scatter and solidify the melt to obtain powder. Then, the obtained powder is dried, classified, and surface treated as necessary to obtain the target soft magnetic alloy powder.

The electronic component of this embodiment contains the soft magnetic alloy powder described above. The electronic components of this embodiment are not only commonly used electronic components such as motors, reactors, and transformers, but also used as solenoid valves, solenoids, sensors, etc. in a wide and diverse industrial field such as transportation equipment such as automobiles. Electronic parts used. In addition, the electronic component of the present embodiment is an electromagnetic wave absorption mask or electromagnetic wave absorber used for the purpose of absorbing electromagnetic waves of a specific frequency. The electronic component of this embodiment is preferably a powder magnetic core, an electromagnetic wave absorption mask body, or an electromagnetic wave absorber.

The powder magnetic core, electromagnetic wave absorption mask, or electromagnetic wave absorber of this embodiment contains the soft magnetic alloy powder described above. Preferably, the powder magnetic core of the present embodiment contains soft magnetic alloy powder in a form in which it is mixed with resin or the like that imparts insulating properties and moldability, and then granulated. Preferably, at least a part of the electromagnetic wave absorption mask of this embodiment is coated with a paste prepared by mixing soft magnetic alloy powder, resin, ink, and the like. Preferably, at least a part of the electromagnetic wave absorber of the present embodiment is adhered to a sheet of a mixture of soft magnetic alloy powder, resin, rubber, etc., and formed into a desired thickness.

The method of manufacturing an electronic component of the present embodiment includes: forming an insulating film on the surface of the soft magnetic alloy powder described above to obtain granulated powder; pressing the granulated powder to obtain a compact; and at 550 The step of heat-treating the formed body at a temperature of from ℃ to 950°C. The temperature in the step of performing the heat treatment is 550°C to 950°C, preferably 600°C to 900°C. In addition, the heating time is preferably set to about 30 minutes to 2 hours. For the soft magnetic alloy powder that constitutes the molded body before the heat treatment, by press molding, strain is introduced, which is one of the main causes of the decrease in magnetic permeability and the increase in hysteresis loss of the magnetic core. The formed body is heat-treated to sufficiently remove strain. The heat treatment is preferably performed in an inert gas environment such as a nitrogen environment, or a reduced pressure environment.

The method of manufacturing an electronic component of the present embodiment includes: forming an insulating film on the surface of the soft magnetic alloy powder described above to obtain granulated powder; injection molding the granulated powder to obtain a molded body; and at 550 The step of heat-treating the formed body at a temperature of from ℃ to 950°C. The temperature in the step of performing the heat treatment is 550°C to 950°C, preferably 600°C to 900°C. In addition, the heating time is preferably set to about 30 minutes to 2 hours. By injection molding, it is possible to form complex shapes with higher precision. After the forming process, degreasing, heat treatment, etc. are carried out as needed to obtain electronic parts with the desired shape and characteristics. [Example]

The following shows examples of the present invention. The content of the present invention is not limited and interpreted by these embodiments.

(Manufacturing of soft magnetic alloy powder) The materials adjusted to each composition shown in Table 1 were melted in a high-frequency induction furnace, and soft magnetic alloy powder was obtained by a water atomization method. The conditions of the water spray method are as follows. ＜Water spray conditions＞ ・Water pressure: 100MPa ・Water volume: 100L/min ・Water temperature: 20℃ ・Aperture: φ4mm ・Molten temperature: 1800℃

The obtained soft magnetic alloy powder was dried using a vibration vacuum dryer (VU-60: manufactured by Central Chemical Machinery). The drying conditions are as follows. ＜Drying conditions＞ ・Temperature: 100℃ ・Pressure: 10kPa or less ・Time: 60 minutes The composition of the dried soft magnetic alloy powder was quantitatively analyzed using an ICP emission analyzer (SPS3500DD: manufactured by Hitachi High-Technologies).

The dry soft magnetic alloy powder was classified by an air current classifier (TURBO-CLASSIFIER: Nissin Engineering Co., Ltd.) to obtain the target soft magnetic alloy powder. The particle diameter (D50) of the obtained soft magnetic alloy powder was measured using a wet particle size analyzer (MT3300EX II: manufactured by Microchick Bayer).

(Production of sample) The soft magnetic alloy powder produced in the above-mentioned manner is mixed with silicone resin and acrylic resin to produce granulated powder. The blending amount of soft magnetic alloy powder, silicone resin and acrylic resin is based on the weight ratio, soft magnetic alloy powder: silicone resin: acrylic resin = 98.5: 0.5: 1.0. Each granulated powder was pressed into a ring shape (molding pressure: 980MPa) to produce a powder core (outer diameter: 15mm, inner diameter: 9mm, thickness: 3mm), and it was performed at the core firing temperature shown in Table 1. Heat treatment. The following evaluations were performed on each dust core. (Evaluation item) 1. Magnetic core filling rate Calculate the core filling rate based on the weight and external dimensions of each powder core. 2. Magnetic properties 2-1. Saturation magnetization Using a sample vibration magnetometer (model VSM-C7-10A: manufactured by Toei Industrial Co., Ltd.), the saturation magnetization value (Bs) was measured from the magnetization curve of each dust core. 2-2. Magnetic permeability, core loss A toroidal magnetic core with a wire diameter: 0.3mm copper wire double-wire wound on the powder magnetic core was made and used as an evaluation sample. Using a BH analyzer (SY8258: manufactured by Iwatogyo Co., Ltd.), the magnetic permeability and core loss were measured in the temperature range of 25℃～150℃ under the conditions of measuring frequency: 100kHz and maximum magnetic flux density: 100mT.

(Evaluation results) The evaluation results are shown in Table 1. The signs such as ◎ and ○ in the "conducive to miniaturization" in Table 1 mean: when the saturation magnetization value (Bs) is less than 1.1T (Tesla), it is ×; at 1.1T (Tesla) ) Or more and less than 1.4T (Tesla) is △; more than 1.4T (Tesla) and less than 1.6T (Tesla) is 0; and more than 1.6T is ◎. The symbols such as ◎ and ○ in the "temperature characteristics" in Table 1 refer to the case where the core loss increases as the temperature increases; it has a negative core loss temperature characteristic in the temperature range of 25°C to 120°C , But when the core loss increases in the temperature range over 120℃, it is △; when it has negative core loss temperature characteristics in the temperature range of 120℃～150℃, it is ○; in the temperature range of 120℃～150℃ It has negative core loss temperature characteristics, and compared with the core loss at 25°C and 150°C, the case where the core loss is reduced by more than 20% is ◎. The symbols such as ◎ and ○ in the "magnetic properties" in Table 1 refer to: Under the following conditions, 1) the permeability at 25°C is 60 or more, and 2) the core loss at 25°C is 800kw/m ³ Below, the case where both are not satisfied is ×; the case where either is satisfied is △; the case that both is satisfied is ○, and the case that both of the following conditions are satisfied is ◎, 1) The permeability at 25°C is 60 Above and 2) The core loss at 25°C is 650kw/m ³ or less.

[Table 1]

As shown in Table 1, the powder magnetic core using the soft magnetic alloy powder of the example and the soft magnetic alloy powder using the comparative example (the so-called Sendust) is a known existing Fe-Si-Al Compared with the powder cores based on alloys), it is surprising that despite the same Fe-Si-Al alloy powders, they have a high saturation magnetization value and the core filling rate is also improved. That is, the soft magnetic alloy powder of the present invention can be formed at a high density and obtain a high saturation magnetic flux density, so it has excellent characteristics for miniaturization of the powder magnetic core. In addition, the powder magnetic core using the soft magnetic alloy powder of the example is surprisingly negative not only in the temperature range of 25°C to 120°C, but also in the very high temperature range of 120°C to 150°C. The core loss temperature characteristics. That is, the soft magnetic alloy powder of the present invention has excellent characteristics as a material for a powder magnetic core that can be used in a high-temperature environment. As shown in Table 1, it can be seen that the present invention does not depend on the particle size (D50) of the powder and can achieve the above-mentioned effects. As described above, the soft magnetic alloy powder of the present invention has excellent characteristics that can achieve miniaturization of the powder magnetic core and use in a high-temperature environment.

(Modification) In the above-mentioned embodiment, as an electronic component using the soft magnetic alloy powder of one embodiment, a powder magnetic core manufactured by press molding has been described as an example, but one embodiment is not limited to this example. For example, it may be an electronic component manufactured by injection molding. It can also be seen from the results of the foregoing examples that electronic components using the soft magnetic alloy powder of the present invention having a negative core loss temperature characteristic can be suitably used in a high-temperature environment.

As another example of the electronic component of one embodiment, an electromagnetic wave absorption mask or an electromagnetic wave absorber may be mentioned. The electromagnetic wave absorption mask system is used for the purpose of cutting electromagnetic waves of a specific frequency. For example, it can be installed in the case of mobile devices such as mobile phones. The electromagnetic wave absorption mask system is obtained by preparing and mixing magnetic powder, resin, ink, etc. into a paste in a way to obtain the target characteristics, and coating the paste on an appropriate part. In addition, in order to promote the dispersion of the magnetic powder when making the paste, vacuum degassing may also be performed.

The electromagnetic wave absorber is used for the purpose of cutting electromagnetic waves of a specific frequency. For example, it is used in an anechoic chamber used in ETC (electronic toll collection system) entrances and exits or EMC tests. The electromagnetic wave absorption system is obtained by preparing magnetic powder, resin, and rubber, mixing, and forming into a sheet in a way to obtain the target characteristics, and then sticking the sheet on the appropriate part.

Claims (9)

A soft magnetic alloy powder containing Si and Al in an amount satisfying the relationship of Si≧2% by weight, Al≧1% by weight, and Si+Al≦12% by weight, and the remainder is Fe and unavoidable impurities. Such as the soft magnetic alloy powder of claim 1, which has a negative core loss temperature characteristic at 25°C to 120°C. For example, the soft magnetic alloy powder of claim 1 or 2 contains Si and Al in amounts satisfying the relationship of Si≧3.5% by weight, Al≧2.5% by weight, and Si+Al≦12% by weight. The soft magnetic alloy powder according to any one of claims 1 to 3, which has a negative core loss temperature characteristic at 120°C to 150°C. The soft magnetic alloy powder of any one of claims 1 to 4 has a particle size (D50) of 1 to 50 μm. An electronic component comprising the soft magnetic alloy powder of any one of claims 1 to 5. For example, the electronic parts of claim 6, which are powder magnetic cores, electromagnetic wave absorption shields or electromagnetic wave absorbers. A manufacturing method of electronic parts, which includes: The step of forming a film on the surface of the soft magnetic alloy powder of any one of claims 1 to 5 to obtain granulated powder; The step of press-forming the granulated powder to obtain a shaped body; and A step of heat-treating the formed body at a temperature of 550°C to 950°C. A manufacturing method of electronic parts, which includes: The step of forming a film on the surface of the soft magnetic alloy powder of any one of claims 1 to 5 to obtain granulated powder; A step of injection molding the granulated powder to obtain a molded body; and A step of heat-treating the formed body at a temperature of 550°C to 950°C.