JP7367310B2 - Iron-based metal glass alloy powder - Google Patents

Description

The present invention relates to iron-based metallic glass alloy powder.

In recent years, soft magnetic materials that can be used at large currents and high frequencies have been desired for power inductors used in power supply circuits due to the demand for smaller size and lower profile. Conventionally, ferrite-based materials, which are oxides, have been used as the main material for inductors, but this is disadvantageous for miniaturization because of its low saturation magnetization. Therefore, in recent years, metal inductors using alloy materials that have high saturation magnetization and are advantageous for miniaturization and low profile have rapidly increased. A soft magnetic alloy powder mainly made of iron is used for metal inductors, and powder magnetic cores made by mixing soft magnetic alloy powder and resin and compression molding are known. The magnetic properties of the dust core (saturation magnetization, magnetic permeability, core loss, frequency characteristics, etc.) depend on the magnetic properties, particle size distribution, filling properties, and electrical resistance of the soft magnetic alloy powder used.

Iron-based metal glass alloy powder provides excellent magnetic properties when compacted. For example, Patent Document 1 discloses an iron-based alloy powder having excellent magnetic properties that can be suitably used as an electronic material as an alloy material used in metal inductors. Moreover, in order to improve reliability as an alloy material, an iron-based metal glass alloy powder with improved corrosion resistance is disclosed in Patent Document 2. Moreover, an iron-based metal glass alloy powder imparted with ignition resistance is disclosed in Patent Document 3.

Powder pressing is generally used as a method for manufacturing metal inductors. However, in powder pressing, it is necessary to apply pressure as high as 300 to 600 MPa in order to obtain a high filling rate, so the productivity of the pressed powder is low. Therefore, there is a demand for manufacturing metal inductors using manufacturing methods with higher productivity, such as transfer molding (injection molding), which is a low-pressure molding method. To this end, higher fluidity of the slurry is required when the powder and resin are mixed than in the past. The fluidity of the slurry changes depending on the shape and surface condition of the powder, and generally a powder with a small specific surface area is required. Furthermore, in applications such as power inductors that require smaller size and higher frequency, it is required to further reduce loss. That is, an iron-based metallic glass powder having a smaller specific surface area and higher properties is required.

Japanese Patent Application Publication No. 2005-290468 Japanese Patent Application Publication No. 2014-169482 International Publication 2017/175831

An object of the present invention is to provide an iron-based metallic glass alloy powder that has a small specific surface area and high fluidity, so that high filling can be obtained even in a low-pressure molding method.

As a result of various studies, the present inventors found that by adding Al and/or Ca to the iron-based metallic glass alloy powder, the shape and surface condition of the iron-based metallic glass alloy powder were surprisingly improved. We obtained the knowledge that by reducing the specific surface area of the powder, the fluidity of the powder improves, high filling can be obtained even when using low-pressure molding, and furthermore, the properties as a magnetic material improve. The invention was completed.

That is, the present invention is the following iron-based metal glass alloy powder:
[1] Iron-based metal glass alloy powder to which at least one of Al and Ca is added and contains 0.05 to 5% by weight of Al.
[2] Iron-based metallic glass alloy powder to which at least one of Al and Ca is added and contains 0.001 to 0.03% by weight of Ca.

According to one aspect of the invention,
Al and Ca are added,
Al: 0.05 to 2% by weight, and Ca: 0.001 to 0.025% by weight
The above-described iron-based metal glass alloy powder is provided.

According to one aspect of the invention,
Al: 0.08 to 1.5% by weight, and Ca: 0.0015 to 0.025% by weight
The above-described iron-based metal glass alloy powder is provided.

According to one aspect of the invention,
The iron-based metal glass alloy powder has the following composition formula:
(Fe _1-st Co _s Ni _t ) _100-xy-z {( _Sia B _b ) _m (P _c C _d ) _n } _x (M1) _y (M2) _z
[In the formula, the composition ratio of Fe, Co and Ni is
19≦x≦22,
0≦y≦6.0,
0≦s≦0.35,
0≦t≦0.35, and s+t≦0.35,
The composition ratio of Si, B, P and C is
(0.5:1)≦(m:n)≦(6:1),
(2.5:7.5)≦(a:b)≦(5.5:4.5) and (5.5:4.5)≦(c:d)≦(9.5:0.5 ) and
M1 is Nb or Mo,
M2 is Al and/or Ca,
0<z]
The above-mentioned iron-based metal glass alloy powder having a composition represented by is provided.

According to one aspect of the present invention, the above-mentioned iron-based metallic glass alloy powder is provided, further comprising at least one selected from the group consisting of Cr and Zn.

According to one aspect of the present invention, the above-mentioned iron-based metallic glass alloy powder having a particle size (D50) of 0.5 to 50 μm is provided.

The present invention can provide an iron-based metal glass alloy powder that has high fluidity and can be highly filled even in a low-pressure molding method.

FIG. 4 is a scanning electron micrograph of an iron-based metal glass alloy powder according to Example 44. FIG. 2 is a scanning electron micrograph of iron-based metal glass alloy powder according to Blank 2. FIG. 4 is a scanning electron micrograph of an iron-based metal glass alloy powder according to Example 46. FIG. 3 is a scanning electron micrograph of iron-based metal glass alloy powder according to Blank 4.

Hereinafter, one 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 modifications within a range that does not impede the effects of the present invention. Note that in the following description, "A to B" means "more than or equal to A and less than or equal to B."

The iron-based metal glass alloy powder according to the first embodiment has at least one of Al and Ca added thereto, and contains 0.05 to 5% by weight of Al. Further, the iron-based metal glass alloy powder according to the second embodiment contains at least one of Al and Ca, and contains 0.001 to 0.03% by weight of Ca.

The iron-based metal glass alloy powder according to this embodiment is
At least one of Al and Ca is added, with Al being 0.05 to 2% by weight, preferably 0.08 to 1.5% by weight, and Ca being 0.001 to 0.025% by weight, preferably Contains 0.0015 to 0.025% by weight.
In this specification, the iron-based metallic glass alloy is a conventionally known iron-based metallic glass alloy such as a Fe-P-C metallic glass alloy or a Fe-B-Si metallic glass alloy.
By adding Al and/or Ca, the shape and surface condition of the iron-based metal glass alloy powder are improved and the specific surface area is reduced. Improving the shape and surface condition of the iron-based metal glass alloy powder means that the iron-based metal glass alloy powder has a shape closer to a true sphere, and the surface of the iron-based metal glass alloy powder has fewer undulations and is smoothed. . That is, by lowering the specific surface area, the fluidity of the iron-based metal glass alloy powder is improved.
Furthermore, the magnetic properties of the iron-based metal glass alloy powder are improved due to changes in the shape and surface condition of the iron-based metal glass alloy powder due to the reduction in specific surface area.

<Al (aluminum)>
The iron-based metal glass alloy powder according to the first embodiment contains 0.05 to 5% by weight of Al. The presence of Al in this range improves the shape of the powder. If it is less than 0.05% by weight, the above-mentioned effect will be small, and if it exceeds 5% by weight, the shape of the powder may deteriorate and the magnetic properties may be deteriorated.

<Ca (calcium)>
The iron-based metal glass alloy powder according to the second embodiment contains 0.001 to 0.03% by weight of Ca. The presence of Ca in this range reduces the amount of oxygen in the powder. If it is less than 0.001% by weight, the above-mentioned effect will be small, and if it exceeds 0.03% by weight, the magnetic properties may be deteriorated.

Although the above-mentioned effects can be achieved even when only one of Al or Ca is contained in the iron-based metal glass alloy powder, surprisingly, by containing both Al and Ca in combination, the effect can be dramatically improved. The specific surface area of the iron-based metal glass alloy powder decreases, and the amount of oxygen decreases. This is considered to be the result of a change in the surface tension of the molten metal for producing the alloy powder and a change in the amount of oxygen in the molten metal due to Al and Ca, which have a high affinity for oxygen. Note that an element that has a high affinity for oxygen like Al and Ca can produce the same effect as Al and Ca.
The iron-based metal glass alloy powder according to one embodiment, which contains both elements Al and Ca, contains 0.05 to 2% by weight of Al, preferably 0.08 to 1.5% by weight, and 0.05% by weight of Ca. 001 to 0.025% by weight, preferably 0.0015 to 0.025% by weight.

The iron-based metallic glass alloy powder according to the present embodiment has the following composition formula:
(Fe _1-st Co _s Ni _t ) _100-xyz {(Sia _{B b} ) _m (P _c C _d ) _n } _x (M1) _y (M2) _z
[In the formula, the composition ratio of Fe, Co and Ni is
19≦x≦22,
0≦y≦6.0,
0≦s≦0.35,
0≦t≦0.35, and s+t≦0.35,
The composition ratio of Si, B, P and C is
(0.5:1)≦(m:n)≦(6:1),
(2.5:7.5)≦(a:b)≦(5.5:4.5) and (5.5:4.5)≦(c:d)≦(9.5:0.5 ) and
M1 is Nb or Mo,
M2 is Al and/or Ca,
0<z]
It is preferable that it is an iron-based metal glass alloy powder having a composition represented by: z depends on the content of Al and Ca, 0<z≦10, 0<z≦7.5, 0<z≦5, 0<z≦2.5, 0<z≦1, 0<z The range may be ≦0.5, 0<z≦0.25, 0<z≦0.1, 0<z≦0.05, etc.
Since the iron-based metal glass alloy powder has the above composition, it can be manufactured at low cost and has excellent soft magnetic properties.

It is preferable that the iron-based metal glass alloy powder according to the present embodiment further contains at least one selected from the group consisting of Cr and Zn. By further containing at least one selected from the group consisting of Cr and Zn, the corrosion resistance of the iron-based metal glass alloy powder is improved, and furthermore, the flame retardance is improved. The content of at least one selected from the group consisting of Cr and Zn is 2 to 6% by weight, preferably 2.8 to 5.5% by weight, and more preferably 2.8 to 5.5% by weight, based on the total weight of the iron-based metal glass alloy powder. Preferably, it is 2.8 to 4.0% by weight.

<Other elements>
The iron-based metal glass alloy powder according to the present embodiment may contain elements such as N, S, and O as unavoidable impurities to the extent that they do not affect the desired properties.

The iron-based metal glass alloy powder according to this embodiment preferably has a particle size (D50) of 0.5 to 50 μm. "Particle size" means median diameter: D50, and is measured by a conventionally known method, for example, a laser diffraction/scattering method. The above-mentioned effects of lowering the specific surface area and improving magnetic properties of the iron-based metallic glass alloy powder can be obtained with the iron-based metallic glass alloy powder having a wide range of particle sizes. Particularly high effects can be obtained by preferably having a thickness of 0.5 to 30 μm.

[Production method]
The iron-based metal glass alloy powder according to this embodiment is preferably manufactured by a conventionally known atomization method. For example, powder can be obtained by an atomization method in which Al and Ca are added to a molten metal containing materials adjusted to a desired composition, and parameters are set to obtain desired cooling conditions and particle size. The addition of Al and Ca is performed by adding Al and Ca in the form of metals to the molten metal, and the order of addition does not matter. Since Al and Ca tend to become oxides, it is necessary to add a certain amount of Al and Ca in excess of the intended alloy composition.
Thereafter, the obtained powder is dried and classified, and if necessary, surface treatment is performed to obtain the desired iron-based metal glass alloy powder.

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

[Manufacture of iron-based metal glass alloy powder]
A raw material mixture prepared to have the following two compositions is melted in a high frequency induction furnace,
[Composition 1] (Fe _1-st Co _s Ni _t ) _100-xy {( _Sia B _b ) _m (P _c C _d ) _n } _x Nb _y
[In the formula, s=0, t=0, x=22, y=0.89, m:n=2.9:1, a:b=3.8:6.2, c:d=7. 7:2.3 and contains Cr:3.0wt%. ]
[Composition 2] (Fe _1-st Co _s Ni _t ) _100-xy {( _Sia B _b ) _m (P _c C _d ) _n } _x (M1) _y
[In the formula, s=0, t=0, x=24.5, y=0, m:n=6.9:1, a:b=5.2:4.8, c:d=0. 5:9.5]
An iron-based metal glass alloy powder was produced as a blank (comparative material) using a water atomization method.
A raw material mixture prepared in the same manner as when producing the blank (comparative material) iron-based metal glass alloy powder was melted in a high-frequency induction furnace so that the target Al and Ca compositions shown in Table 1 were obtained. Al and Ca were added and an iron-based metal glass alloy powder was obtained using a water atomization method. The conditions for the water atomization method are as follows.
<Water atomization conditions>
・Water pressure: 100MPa
・Water volume: 100L/min ・Water temperature: 20℃
・Orifice diameter: φ4mm
・Molten metal temperature: 1500℃

The obtained iron-based metal glass alloy powder was dried using a vibrating vacuum dryer (VU-60: manufactured by Chuo Kakoki). The drying conditions are as follows.
<Drying conditions>
・Temperature 100℃
- Pressure: 10 kPa or less - Time: 60 minutes Quantitative analysis of the composition of the iron-based metal glass alloy powder after drying was performed using an ICP emission spectrometer [SPS3500DD: manufactured by Hitachi High-Tech Science].

The dried iron-based metallic glass alloy powder was classified using an air classifier (turbo classifier, manufactured by Nisshin Engineering) to obtain the desired iron-based metallic glass alloy powder. The particle size (D50) of the obtained iron-based metal glass alloy powder was measured using a wet particle size analyzer [MT3300EX II: manufactured by Microtrac Bell].

The following was performed on the iron-based metal glass alloy powder produced as described above.
[Evaluation item]
1. Shape observation
The shape of the iron-based metal glass alloy powder was observed using a scanning electron microscope (SEM) [JSM7200: manufactured by JEOL Ltd.].
2. Specific surface area measurement
The specific surface area of the iron-based metal glass alloy powder was measured by the BET method using a specific surface area measuring device [BELSORP-mini: manufactured by Microtrac Bell].
3. Resistivity evaluation
The resistivity of the powder was evaluated using a four-terminal method using a powder resistance measuring unit [Hiresta UX, Loresta GX, manufactured by Mitsubishi Chemical Analytic Tech].
4. Filling rate evaluation
Granulated powder is prepared by mixing iron-based metal glass alloy powder and epoxy resin, and the granulated powder is compacted into a ring shape (molding pressure: 5 MPa) to form a powder magnetic core (outer diameter: 15 mm, inner diameter: 9 mm, thickness: 3 mm) was produced, and the filling rate was determined from the weight and external dimensions.
5. Magnetic properties (magnetic permeability measurement)
A toroidal core was prepared by bifilar-wound copper wire with a wire diameter of 0.3 mm around the powder magnetic core that had undergone the filling rate evaluation, and was used as an evaluation sample. Magnetic permeability was measured using a BH analyzer [SY8258: manufactured by Iwatsu Keizoku] under conditions of a measurement frequency of 1 MHz and a maximum magnetic flux density of 25 mT.

[Evaluation results]
The evaluation results are shown in Table 1.
The "specific surface area theoretical value magnification" in Table 1 was determined by the following method.

- Calculate the theoretical value of the specific surface area when the powder is a single true sphere using the following formula.
Calculating the volume of one true sphere Volume of one true sphere (μm ³ ) = 4/3 × Pi × Radius of true sphere (μm) ³ ...[A]
Calculation of surface area of one true sphere Surface area of one true sphere (μm ² ) = 4 × Pi × radius of true sphere (μm) ² ...[B]
Since 1 cm = 10 ⁴ μm, 1 cm ³ =10 ¹² μm ³ .
Calculation of the number of perfect spheres in 1 cm ³ Number of perfect spheres in 1 cm ³ = 10 ¹² (μm ³ ) / [A] ... [C]
Calculation of the surface area of a true sphere in 1 cm ³ Surface area of a true sphere in 1 ^{cm 3} = [B] × [C] (μm ² )...[D]
Considering that the specific gravity of a true sphere is equal to the specific gravity of powder, 7.5 g/ ^cm3 , the specific surface area of a true sphere is:
[D] / 7.5 (μm ² /g)... [E].
Since 1 m ² = 10 ¹² μm ² ,
[E] / 10 ¹² (m ² /g)...[F] The specific surface area of the true sphere was determined.
・By determining [F] for each particle size, the relationship between the specific surface area and the particle size (diameter of a true sphere) is
The following relationship was obtained: specific surface area of a true sphere (m ² /g)=0.8/particle size (μm)...[G].
- The theoretical specific surface area magnification was calculated using the following formula.
Specific surface area theoretical magnification = Actual measurement value / Theoretical value calculated from [G] ...[H]

[Calculation example-Blank-1 in Table 1]
Theoretical value calculated from [G] = 0.8/0.7 (μm)
=1.143 (m ² /g)
Specific surface area theoretical magnification calculated from [H] = 2.51 (m ² /g) / 1.143 (m ² /g)
=2.20

"Spheroidization evaluation" in Table 1 refers to the value of the theoretical specific surface area magnification of each Al and/or Ca-added sample to a blank with the same particle size (D50) ("Comparison evaluation" in Table 1). Compared to the value of the theoretical specific surface area magnification of the sample), if the reduction rate of the theoretical specific surface area magnification is 50% or more, it is ◎, and if it is 20% to 50%, it is ○, and within 20%. A case of △ is given, and a case of deterioration is given a ×.
"Magnetic property evaluation" in Table 1 refers to the measured value of magnetic permeability of each Al and/or Ca-added sample to a blank with the same particle size (D50) ("comparative sample" in Table 1). ), when the increase rate of magnetic permeability is 30% or more, it is ◎, when it is 10% to 30%, it is ○, and when it is within 10%, it is △, If the situation worsens, it is marked as ×.

As shown in Table 1, the iron-based metallic glass alloy powder according to the example has a lower specific surface area and a powder shape closer to a true sphere than the blank and the iron-based metallic glass alloy powder according to the comparative example. It can be seen that the shape of the powder has been improved because of the fact that the powder has 100% of the powder, and the fluidity has been improved because the filling rate has been improved.
Furthermore, the iron-based metal glass alloy powder according to the example has improved resistivity and magnetic permeability. That is, it can be said that the iron-based metal glass alloy powder of the present invention has excellent magnetic properties and has excellent properties as a powder compacting material for various electronic parts.
As shown in Table 1, the present invention is effective in imparting high fluidity and magnetic properties to iron-based metal glass alloy powder, regardless of the particle size (D50) of the powder. Furthermore, it can be seen that high fluidity and magnetic properties are similarly imparted to powders having different compositions. That is, it can be seen that the same effects as those shown in the Examples of the present application can be obtained even with iron-based metal glass alloy powders having other compositions.

FIG. 1 is a scanning electron micrograph of the iron-based metal glass alloy powder according to Example 44, and FIG. 3 is a scanning electron micrograph of the iron-based metal glass alloy powder according to Example 46. FIG. This is a scanning electron micrograph of an iron-based metal glass alloy powder.
As is clear from the comparison with FIGS. 1, 2, 3, and 4, the iron-based metal glass alloy powder according to the example has a shape that is clearly closer to a true sphere than the blank iron-based metal glass alloy powder. It has a smooth surface with few undulations, and has a clearly different shape. The improvement in the powder physical properties and magnetic properties shown in Table 1 can be attributed to the changes in the shape and surface condition shown in FIGS. 1 to 4.

Claims (6)

Composition formula below:
(Fe _1-st Co _s Ni _t ) _{100-x- y} { ( _Sia B _b ) _m (P _c C _d ) _n } _x (M1) _y
[In the formula, the composition ratio (atomic %) of Fe, Co and Ni is
19≦x≦22,
0≦y≦6.0,
0≦s≦0.35,
0≦t≦0.35, and s+t≦0.35,
The composition ratio (atomic %) of Si, B, P and C is
(0.5:1)≦(m:n)≦(6:1),
(2.5:7.5)≦(a:b)≦(5.5:4.5) and (5.5:4.5)≦(c:d)≦(9.5:0.5 ) and
M1 is Nb or Mo]
An iron-based metal glass alloy powder to which Al and Ca are added to a raw iron-based metal glass alloy powder having a composition represented by :
The content of Al and Ca is based on the total weight of the iron-based metal glass alloy powder,
Al: 0.05 to 2% by weight, and Ca: 0.001 to 0.027% by weight
Iron- based metal glass alloy powder. Composition formula below:
(Fe _1-st Co _s Ni _t ) _{100-x- y} { ( _Sia B _b ) _m (P _c C _d ) _n } _x (M1) _y
[In the formula, the composition ratio (atomic %) of Fe, Co and Ni is
19≦x≦22,
0≦y≦6.0,
0≦s≦0.35,
0≦t≦0.35, and s+t≦0.35,
The composition ratio (atomic %) of Si, B, P and C is
(0.5:1)≦(m:n)≦(6:1),
(2.5:7.5)≦(a:b)≦(5.5:4.5) and (5.5:4.5)≦(c:d)≦(9.5:0.5 ) and
M1 is Nb or Mo]
An iron-based metal glass alloy powder in which Ca is added to a raw iron-based metal glass alloy powder having a composition represented by :
An iron-based metallic glass alloy powder having a Ca content of 0.001 to 0.027% by weight based on the total weight of the iron-based metallic glass alloy powder. The content of Al and Ca is based on the total weight of the iron-based metal glass alloy powder,
Al: 0.05 to 2% by weight, and Ca: 0.001 to 0.025% by weight
The iron-based metal glass alloy powder according to claim 1 . The content of Al and Ca is based on the total weight of the iron-based metal glass alloy powder,
Al: 0.08 to 1.5% by weight, and Ca: 0.0015 to 0.025% by weight
The iron-based metal glass alloy powder according to claim 3. The iron-based metal glass alloy powder according to any one of claims 1 to 4, further comprising at least one selected from the group consisting of Cr and Zn in an amount of 2 to 6% by weight based on the total weight of the iron-based metal glass alloy powder. Metal glass alloy powder. The iron-based metallic glass alloy powder according to any one of claims 1 to 5, having a particle size (D50) of 0.5 to 50 μm.