KR20200115187A - Soft magnetic alloy powder, electronic component and manufacturing method therof - Google Patents

Abstract

Provided are soft magnetic alloy powder capable of downsizing electronic components and enabling use in a high temperature environment, and further an electronic component. The soft magnetic alloy powder contains Si and Al in an amount of satisfying a relationship of Si >= 2 wt%, Al >= 1 wt%, and Si+Al <= 12 wt%. The remainder is Fe and inevitable impurities. Electronic components such as a powder core, an electromagnetic wave-absorbing shield, or an electromagnetic wave absorber can be obtained using the soft magnetic alloy powder.

Description

Soft magnetic alloy powder, electronic component, and manufacturing method thereof {SOFT MAGNETIC ALLOY POWDER, ELECTRONIC COMPONENT AND MANUFACTURING METHOD THEROF}

The present invention relates to a soft magnetic alloy powder, an electronic component, and a method of manufacturing the same.

As power inductors used in power supply circuits in recent years, soft magnetic materials that can be used at high currents and high frequencies have been demanded from the demand for miniaturization and reduction in power. Conventionally, a ferritic material, which is an oxide, has been used as the main material of the inductor, but it is disadvantageous for miniaturization because of low saturation magnetization. Therefore, in recent years, the number of metal inductors using alloy-based materials having high saturation magnetization and advantageous for miniaturization and reduction in size has increased rapidly. As a metal inductor, a soft magnetic alloy powder made of iron as a main material is used, and a powdered magnetic core formed by compression molding by mixing a soft magnetic alloy powder and a resin is known.

Amid increasing interest in energy issues, electrification of automobiles and power savings in electronics are being promoted, and a compact core with less energy loss is required. Specifically, for example, in order to cope with the advanced control for realizing high environmental performance and driving performance in automobiles, higher temperatures are accompanied by ``mechanism integration'' that mounts ECUs (Electronic Control Units) on actuators such as motors and solenoids. There is a growing demand to install an ECU in the engine room, which is an environment, and there is a demand for a powder core for ECU that can be used in a higher temperature environment.

It is known that in conventional electronic components such as a powdered magnetic core using soft magnetic alloy powder, 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. Due to this temperature increase, core loss increases and heat generation increases, and thermal runaway may occur by repeating this. For this reason, it has been studied to improve the temperature characteristics of core loss in a high temperature region. For example, in Patent Document 1, heat treatment is performed on a molded article obtained by press-molding an Fe-Si-Al alloy powder having a specific composition, and Patent Document 2 discloses that the surface of an Fe-Si-Al alloy powder having a specific composition is applied. A soft magnetic alloy powder formed with an insulating film is described. However, since the Fe-Si-Al alloy powder is hard and lacks plastic deformability, high-density molding is difficult, and it is difficult to obtain a high saturation magnetic flux density advantageous for miniaturization of electronic parts.

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

It is an object of the present invention to provide a soft magnetic alloy powder capable of miniaturizing an electronic component and enabling use in a high temperature environment, and further to provide an electronic component.

As a result of conducting various studies, the present inventors have found a composition of an Fe-Si-Al alloy having a high saturation magnetic flux density and negative iron loss temperature characteristics, and have come to complete the present invention.

That is, the present invention contains 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 balance is Fe and inevitable impurities soft magnetic alloy powder to be.

According to an aspect of the present invention, the soft magnetic alloy powder is provided having a negative iron loss temperature characteristic at 25°C to 120°C.

According to an aspect of the present invention, there is provided the soft magnetic alloy powder containing 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.

According to an aspect of the present invention, the soft magnetic alloy powder is provided having a negative iron loss temperature characteristic at 120°C to 150°C.

According to an aspect of the present invention, the soft magnetic alloy powder having a particle diameter (D50) of 1 to 50 μm is provided.

According to an aspect of the present invention, an electronic component including the soft magnetic alloy powder is provided.

According to an aspect of the present invention, there is provided the electronic component, which is a powdered magnetic core, an electromagnetic wave absorbing shield, or an electromagnetic wave absorber.

According to an aspect of the present invention, a step of forming a film on the surface of the soft magnetic alloy powder to obtain a granulated powder, a step of pressing the granulated powder to obtain a molded body, and a molded body at a temperature of 550°C to 950°C. A method of manufacturing an electronic component including a step of performing heat treatment is provided.

According to one aspect of the present invention, a step of forming a film on the surface of the soft magnetic alloy powder to obtain a granulated powder, a step of obtaining a molded body by injection molding the granulated powder, and a heat treatment of the molded body at a temperature of 550°C to 950°C are provided. A method of manufacturing an electronic component to be included is provided.

The present invention can downsize electronic components and also provide a soft magnetic alloy powder that enables use 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 carried out with appropriate changes within the range not impairing the effects of the present invention. In addition, in the following description, "A to B" means "A or more and B or less."

The soft magnetic alloy powder according to this embodiment contains 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 balance is Fe and inevitable impurities. to be. The soft magnetic alloy powder according to 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 an amount 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 according to the present embodiment is advantageous for miniaturization of electronic components.

<Other elements>

The soft magnetic alloy powder according to the present embodiment may contain elements such as N, S, O, etc. as unavoidable impurities to an extent that does not affect target properties.

Further, the soft magnetic alloy powder containing positive Si and Al that satisfies the above relationship, the balance being Fe and inevitable impurities, has a negative iron loss temperature characteristic at 25°C to 120°C. The soft magnetic alloy powder according to the present embodiment containing 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 is further added at 120°C to 150°C. It has a negative iron loss temperature characteristic.

[Negative iron loss temperature characteristics]

The negative iron loss temperature characteristic refers to a characteristic in which the iron loss of the soft magnetic alloy powder has a negative coefficient with respect to temperature, that is, the iron loss of the soft magnetic alloy powder decreases with an increase in temperature. In the soft magnetic alloy powder according to the present embodiment having negative iron loss temperature characteristics, since the core loss decreases with the increase in temperature, the increase in the temperature of the core itself due to heat generation due to the core loss during use is suppressed. It has properties suitable as a material for electronic components such as a powder core used in a high-temperature environment. It is believed that the reason why the soft magnetic alloy powder according to the present embodiment has a negative iron loss temperature characteristic is that the magnetostriction constant determined according to the composition has a positive value.

It is preferable that the soft magnetic alloy powder according to the present embodiment has a particle diameter (D50) of 1 to 50 μm. The "particle diameter" means a median diameter: D50, and is measured by a conventionally known method, for example, a laser diffraction/scattering method. The effect on the saturation magnetic flux density (Bs), permeability, and negative iron loss temperature characteristics of the soft magnetic alloy powder described above is obtained from the soft magnetic alloy powder having a wide particle diameter, and the particle diameter (D50) is 1 to 50 μm, preferably It is 2 to 40 μm, more preferably 2.5 to 35 μm, still more preferably 3 to 30 μm, so that a particularly high effect can be obtained.

[Manufacturing method]

The soft magnetic alloy powder according to the present embodiment can be produced by a conventionally known method exemplified below as a method for producing a metal powder, but the production method is not particularly limited because it has the above-described magnetic properties if it has the composition of this embodiment. Does not.

・Atomization method: Water atomization method, gas atomization method, centrifugal force atomization method, etc.

Mechanical process method: grinding method, mechanical alloying method, etc.

·Melt spinning method

·Rotation electrolysis (REP method): Plasma REP method, etc.

Chemical process method: oxide reduction method, chloride reduction method, wet metallurgy technology, carbonyl reaction method, etc.

Among the manufacturing methods exemplified above, in particular, the atomization method is capable of mass-producing small-diameter and spherical soft magnetic alloy powder under atmospheric pressure. Among them, it can be manufactured at low cost by adopting the water atomization method.

In the case of producing soft magnetic alloy powder using the water atomization method, the molten metal is scattered and solidified by spraying high-pressure water with parameters set so that the desired cooling condition or particle diameter is applied to the molten metal in which the material adjusted to the desired composition is dissolved. You can get a powder. After that, the obtained powder is dried and classified, and if necessary, surface treatment is performed to obtain the target soft magnetic alloy powder.

The electronic component according to the present embodiment contains the soft magnetic alloy powder described above. The electronic parts according to the present embodiment are not only electronic parts generally used such as motors, reactors, transformers, etc., but also electronic parts used in a wide variety of industrial fields such as transportation equipment such as automobiles as solenoid valves, solenoids, and sensors. Further, the electronic component according to the present embodiment is an electromagnetic wave absorption shield or electromagnetic wave absorber used for the purpose of absorbing electromagnetic waves of a specific frequency.

The electronic component according to the present embodiment is preferably a powdered magnetic core, an electromagnetic wave absorbing shield, or an electromagnetic wave absorber.

The powdered magnetic core, electromagnetic wave absorbing shield, or electromagnetic wave absorber according to the present embodiment contains the soft magnetic alloy powder described above. Preferably, the green magnetic core according to the present embodiment contains a soft magnetic alloy powder in a granulated form mixed with a resin that imparts insulation or molding processability. Preferably, in the electromagnetic wave absorption shield according to the present embodiment, a paste prepared by mixing soft magnetic alloy powder, resin, ink, or the like is applied to at least a part of the paste. Preferably, in the electromagnetic wave absorber according to the present embodiment, a sheet formed by mixing soft magnetic alloy powder, resin, rubber, or the like to a desired thickness is affixed to at least a part of the sheet.

The electronic component manufacturing method according to the present embodiment includes a step of forming an insulating film on the surface of the soft magnetic alloy powder described above to obtain a granulated powder, a step of pressing the granulated powder to obtain a molded article, and a molded article having a temperature of 550°C to 950°C. It includes a process of heat treatment at a temperature.

The temperature in the heat treatment process is preferably 550°C to 950°C, preferably 600°C to 900°C. In addition, the heating time is preferably about 30 minutes to 2 hours. The soft magnetic alloy powder constituting the molded body before heat treatment has a deformation that causes a decrease in permeability and an increase in hysteresis loss, which is one of the factors of iron loss, due to pressure molding, and the deformation can be sufficiently removed by heat treating the molded body under the above conditions. I can. The heat treatment is preferably performed in an inert gas atmosphere such as a nitrogen atmosphere or a reduced pressure atmosphere.

The electronic component manufacturing method according to the present embodiment includes a step of forming an insulating film on the surface of the soft magnetic alloy powder described above to obtain a granulated powder, a step of injection molding the granulated powder to obtain a molded article, and a molded article at 550°C to 950°C. It includes a process of heat treatment at a temperature.

The temperature in the heat treatment process is preferably 550°C to 950°C, preferably 600°C to 900°C. In addition, the heating time is preferably about 30 minutes to 2 hours. By injection molding, it can be molded into a complex shape with high precision.

After the molding process, if necessary, degreasing, heat treatment, or the like is performed to obtain an electronic component having a desired shape and characteristics.

Example

Examples of the present invention are shown below. The content of the present invention is not interpreted as being limited by these examples.

[Production of soft magnetic alloy powder]

The material adjusted to each composition shown in Table 1 was dissolved in a high-frequency induction furnace, and a soft magnetic alloy powder was obtained using a water atomization method. The conditions of the water atomization method are as follows.

<Water atomization conditions>

Water pressure: 100 MPa

·Quantity: 100L/min

·Water temperature: 20℃

·Orifice diameter: φ4mm

·Melt temperature: 1800℃

The obtained soft magnetic alloy powder was dried with a vibration vacuum dryer (VU-60: manufactured by Chuokakoki). Drying conditions are as follows.

<Drying conditions>

·Temperature 100℃

Pressure 10 kPa or less

・Time 60 minutes

Quantitative analysis of the composition of the soft magnetic alloy powder after drying was performed with an ICP emission analyzer [SPS3500DD: manufactured by Hitachi High-Tech Science].

The soft magnetic alloy powder after drying was classified by an air classifier (turbo classifier: manufactured by Nissin Engineering) 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: Microtrac-Bell product].

[Preparation of sample]

Each soft magnetic alloy powder prepared as described above was mixed with a silicone resin and an acrylic resin to prepare a granulated powder. The blending amount of the soft magnetic alloy powder, the silicone resin, and the acrylic resin was soft magnetic alloy powder: silicone resin: acrylic resin = 98.5:0.5:1.0 by weight.

Each granulated powder was compacted into a ring shape (molding pressure: 980 MPa) to prepare a compact magnetic core (outer diameter: 15 mm, inner diameter: 9 mm, thickness: 3 mm), and heat treatment was performed at the core firing temperature shown in Table 1.

The following evaluation was performed about each green powder core.

[Evaluation items]

1. Core filling rate

The core filling rate was calculated from the weight and external dimensions of each green powder core.

2. Magnetic properties

2-1. Saturation magnetization

Using a sample vibration type magnetometer [model number VSM-C7-10A: manufactured by Toei Kogyo Co., Ltd.], the saturation magnetization value (Bs) was measured from the magnetization curve of the magnetic core of each green powder.

2-2. Permeability, iron loss

A toroidal core in which a copper wire having a wire diameter: 0.3 mm was wound on a powdered magnetic core was manufactured as a test sample. Permeability and iron loss were measured in a temperature range of 25° C. to 150° C. under conditions of a measurement frequency: 100 kHz and a maximum magnetic flux density: 100 mT using a BH analyzer [SY8258: manufactured by Iwatsu Measurement].

[Evaluation results]

Table 1 shows the evaluation results.

Symbols such as ◎ and ○ in ``contribution to miniaturization'' in Table 1 indicate △, 1.4 when the saturation magnetization value (Bs) is less than 1.1T (Tesla) and less than 1.1T (Tesla) and less than 1.4T (Tesla). A case of T (Tesla) or more and less than 1.6T (Tesla) is ○, and a case of 1.6T or more is ◎.

Symbols such as ◎ and ○ in "Temperature Characteristics" in Table 1 indicate that when the iron loss increases with temperature increase, it has negative iron loss temperature characteristics in the temperature range of 25℃ to 120℃, but exceeds 120℃. When the iron loss rises in the temperature range △, the case has negative iron loss temperature characteristics in the temperature range of 120°C to 150°C ○, the case has negative iron loss temperature characteristics in the temperature range 120°C to 150°C, and also 25°C It means that the case where the iron loss is reduced by 20% or more by comparing the iron loss at 150℃ is ◎.

Symbols such as ◎ and ○ in "magnetic properties" in Table 1 are

1) The permeability at 25℃ is more than 60 and

2) Iron loss at 25℃ below 800kw/㎥

If neither of the conditions of is satisfied is ×, the case of satisfying either is △, and the case of satisfying both is ○,

1) The permeability at 25℃ is more than 60 and

2) Iron loss at 25℃ is less than 650kw/㎥

It means that the case of satisfying both of the conditions of is ◎.

As shown in Table 1, the powdered magnetic core using the soft magnetic alloy powder according to the Example was compared to the powdered magnetic core using the soft magnetic alloy powder (a conventional Fe-Si-Al alloy known as Sendust) according to the comparative example. Surprisingly, despite the same Fe-Si-Al alloy powder, it has a high saturation magnetization value and an improved core filling rate. That is, since the soft magnetic alloy powder of the present invention can be formed at high density and obtain a high saturation magnetic flux density, it has excellent characteristics for miniaturization of the powdered magnetic core.

Further, the powdered magnetic core using the soft magnetic alloy powder according to the embodiment surprisingly has a negative iron loss temperature characteristic not only in a temperature range of 25°C to 120°C, but also in a very high temperature range of 120°C to 150°C. That is, the soft magnetic alloy powder of the present invention has excellent properties as a material for a compact magnetic core that can be used in a high temperature environment.

As shown in Table 1, it can be seen that the present invention exhibits the above-described effects without depending on the particle diameter (D50) of the powder.

As described above, the soft magnetic alloy powder of the present invention has excellent properties that allow the compact magnetic core to be compacted and used in a high temperature environment.

(Modification example)

In the above examples, a powdered magnetic core manufactured by pressure molding as an electronic component using the soft magnetic alloy powder of one embodiment has been described as an example, but one embodiment is not limited to this example. For example, it is an electronic component manufactured by injection molding. It is also clear from the results of the above examples that the electronic component in which the soft magnetic alloy powder of the present invention having negative iron loss temperature characteristics is used can be suitably used in a high temperature environment.

As another example of the electronic component of one embodiment, an electromagnetic wave absorbing shield and an electromagnetic wave absorber are mentioned. The electromagnetic wave absorption shield is used for the purpose of cutting electromagnetic waves of a specific frequency, and is installed, for example, in a case of a mobile device such as a mobile phone. The electromagnetic wave-absorbing shield can be obtained by preparing and mixing magnetic powder, resin, ink, and the like so as to obtain desired properties to form a paste, and then applying the paste to an adapted location. In addition, when producing a paste, vacuum defoaming may be performed in order to promote dispersion of the magnetic powder.

The electromagnetic wave absorber is used for the purpose of cutting electromagnetic waves of a specific frequency, and is used, for example, in a radio wave darkroom used in a gate of an ETC (electronic toll collection system) or an EMC test. The electromagnetic wave absorber can be obtained by preparing and mixing magnetic powder, resin, and rubber so as to obtain desired properties, forming a sheet shape, and attaching this sheet to an adaptation site.

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, the balance being Fe and unavoidable impurities. The method according to claim 1,
Soft magnetic alloy powder having a negative iron loss temperature characteristic at 25 ℃ to 120 ℃. The method according to claim 1 or 2,
A soft magnetic alloy powder containing 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. The method according to any one of claims 1 to 3,
Soft magnetic alloy powder having a negative iron loss temperature characteristic at 120 ℃ to 150 ℃. The method according to any one of claims 1 to 4,
Soft magnetic alloy powder with a particle diameter (D50) of 1 to 50 μm. An electronic component containing the soft magnetic alloy powder according to any one of claims 1 to 5. The method of claim 6,
Electronic components that are powdered magnetic cores, electromagnetic wave absorbing shields, or electromagnetic wave absorbers. A step of forming a film on the surface of the soft magnetic alloy powder according to any one of claims 1 to 5 to obtain a granulated powder,
The process of obtaining a molded body by pressing the granulated powder and
An electronic component manufacturing method comprising a step of heat-treating the molded body at a temperature of 550°C to 950°C. A step of forming a film on the surface of the soft magnetic alloy powder according to any one of claims 1 to 5 to obtain a granulated powder,
The process of obtaining a molded body by injection molding granulated powder and
An electronic component manufacturing method comprising a step of heat-treating the molded body at a temperature of 550°C to 950°C.