JP3534218B2 - Method for producing Fe-based soft magnetic metallic glass sintered body - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an Fe-based soft magnetic metallic glass sintered body which is applicable to a magnetic head, a transformer or a core of a motor and has excellent magnetic characteristics.

[0002]

2. Description of the Related Art Soft magnetic alloy materials conventionally used for this kind of application include, for example, Fe-Si and Fe-Si.
-Al alloys (Sendust), Ni-Fe alloys (Permalloy), Fe-based and Co-based amorphous materials, and the like. By the way, when a soft magnetic alloy material is applied to a core of a DC motor, it is advantageous to have a high-density bulk shape. Conventionally, the above-mentioned amorphous alloy material is produced by quenching a molten metal. Has been done,
The shapes obtained were limited to ribbons, wires, powders and thin films. Therefore, a method has been developed to sinter the raw material powder obtained by crushing the quenched ribbon and solidify it into a bulk shape.However, in order to prevent the raw material powder from crystallizing during sintering, a relatively low temperature is used. However, there is a problem that a high-density sintered body cannot be obtained because it must be sintered in.

In view of the above background, the present invention has an object to provide an Fe-based soft magnetic metallic glass sintered body having good soft magnetic properties at room temperature and having a high compaction density.

[0004]

In order to solve the above-mentioned problems, the Fe-based soft magnetic metallic glass sintered body of the present invention has ΔT _x =
Fe-based soft magnetic metallic glass in which the temperature interval ΔT _x of the supercooled liquid represented by the formula T _x −T _g (where T _x is the crystallization start temperature and T _g is the glass transition temperature) is 35 K or more. It is a powder of an alloy that is sintered, has good soft magnetic properties at room temperature, and has a high compaction density. The temperature interval ΔT _x of the supercooled liquid is more preferably 40 K or more, and 50
More preferably, it is K or more. In particular, it is preferable that the powder of the Fe-based soft magnetic metallic glass alloy is sintered by the discharge plasma sintering method at a temperature rising rate of 40 ° C./min or more.

In the present invention, the Fe-based soft magnetic metallic glass sintered body is characterized by containing a metal element other than Fe and a metalloid element. In the present invention, the semimetal element is preferably at least one kind of P, C, B and Ge. Or as a metalloid element,
You may contain Si and at least 1 sort (s) or more of P, C, B, and Ge. In the present invention, the other metal element is preferably at least one kind of metal elements belonging to Group IIIB and Group IVB of the periodic table. Specifically, the other metal element is preferably at least one kind selected from Al, Ga, In and Sn. In the present invention, the composition of the Fe-based soft magnetic metallic glass sintered body is atomic%
Al: 1-10%, Ga: 0.5-4%, P: 9-
15%, C: 5 to 7%, B: 2 to 10%, Fe: balance. Alternatively, the composition of the Fe-based soft magnetic metallic glass sintered body is atomic% and Al: 1 to 10% Ga:
0.5-4%, P: 9-15%, C: 5-7%, B: 2
It may be -10%, Si: 0 to 15%, and Fe: balance.

In the present invention, the composition of the Fe-based soft magnetic metallic glass sintered body may contain Ge in an atomic% of 4% or less, preferably 0.5 to 4%. In the present invention, in the composition of the Fe-based soft magnetic metallic glass sintered body, N in atomic% is used.
At least one kind of b, Mo, Hf, Ta, W, Zr and Cr may be contained in an amount of 7% or less. In the present invention, the composition of the Fe-based soft magnetic metallic glass sintered body may contain at least one of Ni of 10% or less and Co of 30% or less in atomic%. The Fe-based soft magnetic metallic glass sintered body of the present invention is characterized in that the X-ray diffraction image has a halo pattern. The Fe-based soft magnetic metallic glass sintered body of the present invention has a sintered body obtained by sintering of 300 to 50
It may be heat-treated in the temperature range of 0 ° C.

According to the manufacturing method of the present invention, ΔT _x = T _x
The temperature interval ΔT _x of the supercooled liquid represented by the formula −T _g (where T _x is the crystallization start temperature and T _g is the glass transition temperature) is 35 K or more, and the composition ratio is atomic%.
Al: 1 to 10%, Ga: 0.5 to 4%, P: 9 to 1
5%, C: 5 to 7%, B: 2 to 10%, Fe: balance.
Sinter powder of Fe-based soft magnetic metallic glass alloy
By heat treatment in the temperature range of 00 to 500 ° C.,
An Fe-based soft magnetic metallic glass sintered body having good soft magnetic properties at room temperature and a high compaction density can be obtained. In particular, Fe
It is preferable that the powder of the base soft magnetic metallic glass alloy is sintered at a temperature rising rate of 40 ° C./min or more by a discharge plasma sintering method. The sintering temperature is preferably in a temperature range that satisfies the relationship of T ≦ Tx, where Tx is the crystallization start temperature and T is the sintering temperature.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an essential part of an example of a discharge plasma sintering apparatus suitable for use in manufacturing the Fe-based soft magnetic metallic glass sintered body according to the present invention. Cylindrical die 1 and this die 1
An upper punch 2 and a lower punch 3 which are inserted into the inside of the chamber, a punch electrode 4 which supports the lower punch 3 and serves as one electrode when a pulse current described later is passed, and the upper punch 2 is pressed downward to generate a pulse. Punch electrode 5 to be the other electrode for passing current
The thermocouple 7 for measuring the temperature of the powder raw material 6 sandwiched between the upper and lower punches 2 and 3 is mainly configured.

FIG. 3 shows the overall structure of the spark plasma sintering apparatus. The spark plasma sintering apparatus A shown in FIG. 3 is a kind of spark plasma sintering machine called Model SPS-2050 manufactured by Sumitomo Coal Mining Co., Ltd., and has the structure shown in FIG. 1 as a main part. . In the device shown in FIG.
It has an upper base 11 and a lower base 12, and a chamber 13 is provided in contact with the upper base 11, and most of the structure shown in FIG. It is connected to a vacuum exhaust device and an atmosphere gas supply device, and holds the raw material powder (powder or granule) 6 filled between the upper and lower punches 2 and 3 in a desired atmosphere such as an inert gas atmosphere. It is configured to be able to. Although the energizing device is omitted in FIGS. 1 and 3, a separately provided energizing device is connected to the upper and lower punches 2 and 3 and the punch electrodes 4 and 5, and as shown in FIG. A large pulse current can be passed through the punches 2 and 3 and the punch electrodes 4 and 5.

In order to manufacture a Fe-based soft magnetic metallic glass sintered body using the discharge plasma sintering apparatus having the above-mentioned structure, raw material powder for molding is prepared. This raw material powder is produced by melting an Fe-based soft magnetic metallic glass alloy having a predetermined composition described later and then casting it, or by a quenching method using a single roll or twin rolls, and further by a submerged spinning method or a solution extraction method. Alternatively, it can be obtained by a step of producing various shapes such as a bulk shape, a ribbon shape, a linear body, and a powder by a high-pressure gas atomization method, and a step of pulverizing and powdering other than the powder shape.

The Fe-based soft magnetic metallic glass alloy used in the present invention has a temperature interval ΔT _x of the supercooled liquid of the alloy of 3
5K or more, 40K or more, and even 50K depending on the composition
It has a remarkable temperature interval as described above, which is completely unexpected from the Fe-based alloys known from the findings so far. Moreover, it also has excellent properties in terms of soft magnetism at room temperature, and it is a completely new one that has not been found in the knowledge so far.

The composition of the Fe-based soft magnetic metallic glass alloy used in the present invention can be shown as a composition containing Fe as a main component and further containing other metal and semimetal. Of these, the other metals are IIA in the periodic table.
Group IIIA and IIIB Group IVA and IVB
The metal element can be selected from group III, group VA, group VIA, and group VIIA. Among them, group IIIB and group IVB metal elements are preferred. For example, Al (aluminum), Ga (gallium), In (indium), S
n (tin). Further, with respect to the Fe-based soft magnetic metallic glass alloy used in the present invention, Ti, Hf, Cu, Mn,
One or more metal elements selected from Nb, Mo, Cr, Ni, Co, Ta, W and Zr can be blended. Examples of the metalloid elements include P (phosphorus) and C
Examples include (carbon), B (boron), Si (silicon), and Ge (germanium). More specifically, the Fe-based soft magnetic metallic glass alloy used in the present invention has an atomic% composition, Al: 1-10%, Ga: 0.5-4.
%, P: 9 to 15%, C: 5 to 7%, B: 2 to 10%,
Fe: Fe-based metallic glass alloy which is the balance and may contain unavoidable impurities.

Further, when Si is further added, the temperature interval ΔT _x of the supercooled liquid increases, the crystallization start temperature also rises, and it becomes thermally more stable amorphous. If the Si content is too large, the supercooled liquid region disappears and a high-density amorphous sintered body cannot be obtained, so 15% or less is preferable. More specifically, the Fe-based soft magnetic metallic glass alloy used in the present invention has an atomic% composition of Al: 1 to
10%, Ga: 0.5-4%, P: 9-15%, C: 5
~ 7%, B: 2 to 10%, Si: 0 to 15%, Fe: the balance Fe, which may contain unavoidable impurities
It is a base metal glass alloy.

The above composition may further contain Ge in an amount of 4% or less in atomic%, preferably 0.5 to 4%. Further, in the above composition, N
At least one of b, Mo, Cr, Hf, W, and Zr may be contained in an amount of 7% or less in atomic%, and further, Ni 10%
Hereafter, Co may be contained at 30% or less. Further, in the above composition, one or more elements of Pt and platinum group may be added. The addition amount of these elements is preferably 5% or less because a uniform amorphous phase cannot be obtained if the addition amount is too large. By containing Al, Cr, Pt, and the platinum group element, the corrosion resistance of the obtained Fe-based soft magnetic metallic glass sintered body is improved.

The Fe-based soft magnetic metallic glass alloy of the above-mentioned composition used in the present invention has magnetism at room temperature and exhibits better magnetism by heat treatment.
It is possible to obtain a high specific resistance value of 1.5 μΩm or more. Incidentally, when an additional note method for producing the Fe-based soft magnetic glassy alloy, the composition of the alloy, and the size of the unit and product for the manufacture, the shape, etc., but the preferred cooling rate is determined, is generally 1 to 10 ² A range of about K / s can be used as a guide. And, in reality, Fe ₃ B and Fe as a crystal phase are added to the glassy phase.
It can be determined by confirming whether or not phases such as ₂ B and Fe ₃ P are precipitated.

Next, if the raw material powder having the above composition is prepared, it is put between the upper and lower punches 2 and 3 of the spark plasma sintering apparatus shown in FIG. 1 or 3, and the inside of the chamber 13 is evacuated. At the same time, pressure is applied from above and below by the punches 2 and 3, and simultaneously, for example, a pulse current as shown in FIG. In this spark plasma sintering process, the raw material powder can be quickly heated at a predetermined rate by the energizing current, and the temperature of the raw material powder can be strictly controlled according to the value of the energizing current. The temperature can be controlled much more accurately than the above, and as a result, sintering can be performed under conditions close to ideal as designed in advance.

In the present invention, the sintering temperature is required to be 300 ° C. or higher in order to solidify and mold the raw material powder, but the Fe-based soft magnetic metallic glass alloy used as the raw material powder is greatly overcooled. Liquid temperature interval ΔT _x (T _x −T
_g ), it is possible to preferably obtain a high-density sintered body by pressure sintering in this temperature range. However, if the sintering temperature is close to the crystallization start temperature, magnetic anisotropy is generated due to the initiation of crystal nucleus formation (structural short-range ordering) and the initiation of crystal precipitation, which may deteriorate the soft magnetic properties. In addition, because of the mechanism of the spark plasma sintering device, the sintering temperature monitored is the temperature of the thermocouple installed in the mold, and is therefore lower than the temperature applied to the powder sample. Therefore, when the crystallization start temperature is Tx and the sintering temperature is T, the sintering temperature in the present invention is preferably in the range of T ≦ Tx.

Further, particularly when Si is added to the Fe-based soft magnetic metallic glass alloy, the crystallization start temperature T _x rises,
Since the temperature interval ΔT _x of the supercooled liquid increases, it becomes a more thermally stable amorphous material. Therefore, this F
By pulverizing the e-based soft magnetic metallic glass alloy and performing pressure sintering, the density of the bulk Fe-based soft magnetic metallic glass sintered body is higher than that in the case of using the raw material powder containing no Si. It is possible to obtain

In the present invention, the rate of temperature increase during sintering is preferably 40 ° C./minute or more because a crystalline phase is produced at a slow rate of temperature increase. Further, the pressure during sintering is preferably 3 t / cm ² or more because a sintered body cannot be formed if the applied pressure is too low. Further, the obtained sintered body may be subjected to heat treatment, whereby the magnetic characteristics can be enhanced. The heat treatment temperature at this time is not lower than the Curie temperature and not higher than the temperature at which crystals deteriorating the magnetic characteristics are precipitated.
To 500 ° C. is preferable, and more preferably 300 to
It is set to 450 ° C.

Since the sintered body thus obtained has the same composition as the Fe-based soft magnetic metallic glass alloy used as the raw material powder, it has excellent soft magnetic properties at room temperature, Further, it exhibits better magnetism by heat treatment, and particularly has a high specific resistance value of 1.5 μΩm or more. Therefore, as a material with excellent soft magnetic characteristics (soft magnetic characteristics), this sintered body is widely applied to magnetic head cores, transformer cores, and magnetic parts such as magnetic needles of pulse motors. Therefore, it is possible to obtain a magnetic component having excellent characteristics as compared with the conventional material.

In the above description, the method of forming the raw material powder of the Fe-based soft magnetic metallic glass alloy by discharge plasma sintering is used, but the present invention is not limited to this, and pressure sintering is performed by a method such as an extrusion method. By the bulk Fe
A base soft magnetic metallic glass sintered body can be obtained.

[0022]

EXAMPLES Fe, Al and Ga, Fe-C alloy, Fe-
A predetermined amount of each of P alloy and B was weighed, and these raw materials were melted by a high-frequency induction heating device under a reduced pressure Ar atmosphere, and the atomic composition ratio was Fe ₇₃ Al ₅ Ga ₂ P ₁₁ C ₅ B ₄
The ingot of was produced. The ingot was placed in a crucible and melted, and a single-roll method in which the melt was blown from a nozzle of the crucible to a rotating roll to quench the melt was used to obtain a quenched ribbon of an amorphous single-phase structure under a reduced pressure Ar atmosphere. This was pulverized by crushing it in the air using a rotor mill. Particle size among the obtained powder is 53-105μ
m was selected and used as a raw material powder in the subsequent steps.

Approximately 2 g of the raw material powder was filled in a WC die using a hand press, and then loaded in the die 1 shown in FIG. 1, and the inside of the chamber was 3 × 10 ^-5 to.
In the atmosphere of rr, pressure was applied by the upper and lower punches 2 and 3, and a pulse wave was applied to the raw material powder from the energizing device to heat it. As for the pulse waveform, as shown in FIG. 2, 12 pulses are allowed to flow and then 2 pulses are paused, and the maximum is 4700 to 4800.
The raw material powder was heated with the current of A. Sintering is 6.5 for the sample
Sintering was carried out by heating the sample from room temperature to the sintering temperature under a pressure of t / cm ² and holding it for about 5 minutes. The heating rate was 100 ° C./min.

FIG. 4 shows Fe₇₃Al_FiveGa₂P₁₁C_FiveB_FourBecome
Raw powder obtained by crushing a quenched amorphous alloy ribbon
DSC curve (Differential scanning caloriemeter:
FIG. 5 shows a curve based on differential scanning calorimetry).
Is the result of spark plasma sintering of this powder at a sintering temperature of 430 ° C.
It shows a DSC curve of the obtained sintered body. Also
Figure 6 shows the TMA curve (Th
ermo MechanicalAnalysis curve). Figure
From the DSC curve of No. 4, T of the raw material powder_x= 512 ° C, T_g=
465 ° C, ΔT_x= 47 ° C. is required. Conclude like this
There is a supercooled liquid region in a wide temperature range below the crystallization temperature and Δ
T_x= T_x-T_gThe value indicated by is large.
It can be seen that the alloy has a high amorphous forming ability.
Moreover, from the DSC curve of FIG._x= 512
℃, T_g= 465 ° C, ΔT _x= 47 ° C. is required. Figure 4
From the results of FIG. 5 and FIG.
Of T_x, T_g, ΔT_xIt turns out that are the same. further
In the TMA curve shown in FIG. 6, the temperature range of 440 to 480 ° C.
In the region, the sample may grow rapidly as the temperature rises.
Recognize. This means that in the supercooled liquid temperature range
Indicates that the softening phenomenon is occurring. like this
If solidification is performed by utilizing the phenomenon that the amorphous alloy softens
This is advantageous for increasing the density.

In FIG. 7, raw material powders are sintered at a temperature of 380 ° C., 4
X of the sintered body in the as-sintered state at the time of spark plasma sintering at 00 ° C., 430 ° C. and 460 ° C.
The line diffraction test result is shown. 380 ° C, 400 ° C, and 4
The samples sintered at 30 ° C. all have a halo pattern, which shows that they have an amorphous single-phase structure. On the other hand, in the sample sintered at 460 ° C., a sharp peak-shaped diffraction line showing a crystal phase is obtained.

FIG. 8 shows the sintering temperature at the time of sintering using the discharge plasma sintering method, the density of the obtained sintered body, and the bulk material subjected to heat treatment at 350 ° C. for 15 minutes after sintering. And the magnetic permeability (μe), the coercive force (Hc), and the saturation magnetic flux density (Bs). As shown in this figure, the density of the sintered body increases as the sintering temperature rises, and by sintering at a sintering temperature of 430 ° C. or higher,
A high-density sintered body having a relative density of 99.7% or more is obtained. If the pressure during sintering is increased, it is possible to obtain a high-density molded body even at a lower temperature. Regarding the magnetic properties, the coercive force (Hc) is almost constant up to a sintering temperature of about 430 ° C., and the magnetic permeability (μe) and the saturation magnetic flux density (Bs) improve as the temperature rises. Excellent soft magnetic properties are obtained at a temperature of 430 ° C. On the other hand, when the sintering temperature is 460 ° C., the saturation magnetic flux density is decreased, the coercive force is increased, and the magnetic permeability is decreased, so that the soft magnetic characteristics are largely deteriorated.

From these results, in the present embodiment, the sintering temperature is in the temperature range of 430 ° C. or lower (in other words, when the crystallization start temperature is Tx and the sintering temperature is T, the range is T ≦ Tx).
It can be seen that, by setting the above, a sintered body having a high density, an amorphous single-phase structure in the as-sintered state, and good soft magnetic properties after heat treatment can be obtained.

[0028]

As described above, according to the present invention, the powder of the Fe-based soft magnetic metallic glass alloy in which the temperature interval ΔTx of the supercooled liquid is 35 K or more is sintered, so that it has soft magnetic characteristics at room temperature. Therefore, a bulk Fe-based metallic glass alloy sintered body having a high specific resistance can be provided. Further, according to the present invention, the powder of Fe-based soft magnetic metallic glass alloy having ΔTx of 35 K or more is sintered by the discharge plasma sintering method.
A Fe-based soft magnetic metallic glass sintered body having a high compacting density, a high saturation magnetic flux density, and an excellent magnetic permeability can be obtained, which can be sintered by heating at a temperature of ° C / min or more.

As a preferable composition system, a metal element other than Fe and a metalloid element are contained, and the metalloid element to be added is at least one of P, C, B and Ge. Or P, C, B and Ge
At least one or more of these and Si can be used, and as the other metal element, at least one or more of the metal elements of Group IIIB and IVB of the periodic table can be used, and the other metal element can be Al. , Ga, In, and Sn. Especially S
When i is added, the crystallization start temperature T _x rises and the temperature interval ΔT _x of the supercooled liquid increases, so that it becomes a more thermally stable amorphous material. It is possible to obtain a soft magnetic metallic glass sintered body. Furthermore, if the obtained sintered body is heat-treated, a sintered body having further excellent soft magnetic characteristics can be obtained.

When the crystallization start temperature is Tx and the sintering temperature is T, sintering is performed in a temperature range that satisfies the relationship of T≤Tx, whereby excellent soft magnetic characteristics and high density are combined. A sintered body is obtained. Further, by setting the pressure during sintering to 3 t / cm ² or more, the molding density can be sufficiently increased.

[Brief description of drawings]

FIG. 1 is a sectional view showing a main part structure of an example of a discharge plasma sintering apparatus used for carrying out a method of the present invention.

2 is a diagram showing an example of a pulse current waveform applied to the raw material powder in the discharge plasma sintering apparatus shown in FIG.

FIG. 3 is a front view showing the overall configuration of an example of a discharge plasma sintering apparatus.

FIG. 4 is a diagram showing a DSC curve of raw material powders in Examples.

FIG. 5 is a diagram showing a DSC curve of a sintered body in an example.

FIG. 6 is a TMA of a quenched amorphous alloy ribbon in an example.
It is a figure which shows a curve.

FIG. 7 is a diagram showing an X-ray diffraction pattern of a sintered body obtained by sintering at 380 ° C. to 460 ° C. in Examples.

FIG. 8 is a diagram showing the sintering temperature dependence of the density, magnetic permeability, coercive force, and saturation magnetic flux density of the sintered bodies obtained in the examples.

[Explanation of symbols]

A discharge plasma sintering device 1 die A few punches 6 powder raw materials 4, 5 punch electrodes 7 thermocouple 11 foundation 12 foundation 13 chambers

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Akihiro Makino 1-7 Yukiya Otsuka-cho, Ota-ku, Tokyo Alps Electric Co., Ltd. (72) Akihisa Inoue 35 Kawachi, Aoba-ku, Sendai-shi, Miyagi Kawauchi Kawauchi Housing 11-806 (56) Reference JP-A-3-36243 (JP, A) JP-A-7-135106 (JP, A) JP-A-7-122414 (JP, A) JP-A-5-5164 (JP , A) JP 8-333660 (JP, A) JP 9-320827 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H01F 1/12-1/375 B22F 3/14 C22C 33/02 C22C 38/00 C22C 45/02

Claims (4)

(57) [Claims] 1. The temperature interval ΔT _x of the supercooled liquid represented by the formula ΔT _x = T _x −T _g (where T _x is the crystallization start temperature and T _g is the glass transition temperature) is 35 K or more. Is
At the same time, the composition ratio is atomic%, Al: 1 to 10%, G
a: 0.5-4%, P: 9-15%, C: 5-7%,
B: 2 to 10%, Fe: the balance of the Fe-based soft magnetic metallic glass alloy powder is sintered, and further heat-treated at a temperature range of 300 to 500 ° C., Fe-based soft magnetic metallic glass sintering Body manufacturing method. 2. The Fe-based soft magnetic metallic glass alloy powder is sintered by a discharge plasma sintering method at a temperature rising rate of 40 ° C./minute or more. Method for producing Fe-based soft magnetic metallic glass sintered body. 3. The method for producing an Fe-based soft magnetic metallic glass sintered body according to claim 1 or 2, wherein T ≦ Tx when the crystallization starting temperature is Tx and the sintering temperature is T. The method for producing a Fe-based soft magnetic metallic glass sintered body is characterized in that the temperature range satisfies the relationship of. 4. The method for producing a Fe-based soft magnetic metallic glass sintered body according to claim 1, wherein 3 t / c is used.
A method for producing an Fe-based soft magnetic metallic glass sintered body, which comprises sintering at a pressure of m ² or more.