JPH049453A - Amorphous alloy - Google Patents

Abstract

PURPOSE:To obtain a homogeneous amorphous Co alloy excellent in toughness and reduced in magnetostriction by specifying a composition consisting of Co, Ni, Fe, Mn, and one or more elements among C, B, P, Si, and Ge and also limiting the content of Mg as an inevitable impurity. CONSTITUTION:This alloy is an amorphous alloy which has a composition represented by a basic composition (Co1-a-b-cNiaFebMnc)xMz [where M means one or more elements among C, B, P, Si, and Ge, the symbols (x) and (z) satisfy x+z=100 and 13<=z<=28 by atomic%, and the symbols (a), (b), and (c) stand for 0<=a<=0.20, 0<=b<=0.20, and 0<=c<=0.20 by atomic ratio, respectively] and further containing, if necessary, <=8atomic% transition metal and in which saturation magnetostriction constant is regulated to a value within + or -5X10<-6> and also the content (by weight) of Mg as an inevitable impurity is limited to <=15ppm. In this alloy, superior high magnetic permeability characteristics or high rectangular hysteresis loop characteristics are produced in high frequency magnetic field and toughness necessary at the time of working is improved, and further, local brittleness is improved to uniformize quality.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to improving the toughness of a CO-based amorphous alloy that exhibits excellent high permeability or high square magnetic properties in a high frequency magnetic field.

[Conventional technology]

Conventionally, ferrite has been used for high magnetic permeability materials such as common mode choke coils, magnetic heads, and magnetic sensors of switching power supplies, and 50 N has been used for high square ratio materials such as saturable reactors and noise absorbers of switching power supplies.
Wound cores consisting of i-F e alloy strips have respectively been used.

Ferrite has the advantage of low eddy current loss, but has the disadvantages of low saturation magnetic flux density and poor temperature characteristics. Further, although the 5ONi-Fe alloy has a high saturation magnetic flux density and a high squareness ratio in a low frequency range, it has large eddy current loss and hysteresis loss, and cannot be used in high frequency applications.

Therefore, the magnetic flux density is higher than that of ferrite, and 5ON
Amorphous magnetic alloys are seen as promising high-frequency magnetic materials that have lower core loss, including eddy current loss, than crystalline metals such as J-Fe alloys, and have come to be put to practical use mainly as wound cores for the two types of applications mentioned above. Ta.

In particular, Co-based amorphous alloys with a saturation magnetostriction constant close to zero by using Go as the main element and adding a small amount of elements such as Fe, Ni, and Mn whose outermost shell electron number is close to that of Co, are It has a low magnetic force and can be said to be the best soft magnetic material. Even in high frequency bands,
Since it has a high electrical resistance and is used as a thin ribbon of 15 to 50 μm, it has low eddy current loss and has low loss characteristics equal to or higher than that of ferrite.

The above-mentioned Co-based amorphous alloy with magnetostriction of zero or close to zero can be heated and held at a temperature higher than the Curie temperature and lower than the crystallization temperature, and then rapidly cooled to room temperature at a cooling rate of 0°C/sec or higher. It can be used for common mode choke coils, magnetic heads, and various magnetic sensors by increasing the magnetic coefficient, or it can be used for saturable reactors and It is used in noise absorbers, etc. In addition, for both purposes, by including one or more transition metal elements in a broad sense other than those mentioned above as additive elements, thermal stability can be increased,
Fine adjustment of the saturation magnetostriction constant is being carried out.

[Problem to be solved by the invention]

Conventionally, various magnetic components such as inductors and sensors have been produced by manufacturing an amorphous ribbon with a thickness of 15 to 30 μm by a single roll method, and then finishing the product into a product shape mainly by the following two methods.

One is a method of forming a wound core, in which an amorphous ribbon of a predetermined width is applied with an appropriate tension (some companies' f
) ■ After winding into a toroidal shape while applying a load of 1 to several tens of kgf/m', optimal heat treatment is performed. one,
The ribbon is punched and pressed (mold) to form a laminated magnetic core.
Each core is punched out or chemically formed using strong acid or the like by photo etching, subjected to optimum heat treatment, and then laminated with adhesive or the like to form a core. In both cases, the ribbon used for processing is either manufactured to a predetermined width in advance during quenching of the molten metal, or adjusted to a predetermined width by cutting a wide ribbon with a slitter blade made of cemented carbide, high-speed steel, or the like.

Therefore, in order to process an amorphous ribbon into a product, it must be able to withstand the tension during the core winding process, have no breakage during bending during core winding routing, and ensure that the ribbon does not break or crack during punching presses or slitting. This requires that the ribbon as quenched from the molten metal has high toughness and that it is uniformly maintained. The presence of brittle parts, even locally, is undesirable because it directly leads to cracking and breakage during processing, resulting in stoppage of processing and reduction in processing yield.

In order to ensure the toughness of the amorphous ribbon, guidelines have conventionally been given based on the ability to form an amorphous state from both the chemical composition and ribbon manufacturing conditions.

In terms of composition, metalloids as amorphous forming elements,
The types, combinations, and amounts of transition metals that contribute to the improvement of thermal stability and magnetic properties have been optimized, and the correlation with the critical cooling rate to obtain amorphous and the critical maximum thickness to become amorphous has been investigated. I was asked. For example, M,
Naka, A, Inoue and T,? lasum
oto: Sci, Rep, RITUA29 (1
981) 184. Then, 5i, which is said to have the highest formation ability.
The critical thickness of the Co-5i-8 ternary alloy is experimentally determined for the metalloid combination of -B, Cott, i 5Lt-s
It is shown that the maximum value is shown at Brs. Also, M,
Hagiwara, A., Inoueand T., Ma.
sumoto: Materials 5cienc
e and Engineering + 54 (1982
) 197-207. Then, (CO1*I-1MK>1
1. *5i11. @Bl. As M, the critical thickness when 12 elements are added up to a maximum of X = 20 is reported,
To increase the critical thickness, T a + N b + V
It is stated that it is effective to add up to a certain amount of each element: +Mo + W +Fe, and the effects are higher in this order.

In terms of ribbon manufacturing conditions, there is no mention of specific manufacturing parameters for the single roll method, but for example Ken Masumoto, Kenji Suzuki, Keiyasu Fujimori, Koji Hashimoto: Fundamentals of Amorphous Metals,
Published by Ohmsha (1982) P. 34 states that it is necessary to ensure a cooling rate that exceeds the critical cooling rate specific to each composition, and P. 15 of the same document states that the cooling rate mainly depends on the cooling rate. The material of the rotating body (thermal conductivity, heat capacity, etc.) and the thickness of the melt determine the amount of ejection (depending on the nozzle hole size and ejection pressure)
It is stated that it is determined by the interrelationship between and the circumferential speed of the rotating body.

However, the above findings only describe the general influence of main elements and plate thickness on amorphous formation ability;
This method is insufficient in terms of ensuring the toughness of the amorphous ribbon and, above all, improving the local brittleness, which is the uniform quality of the amorphous ribbon. In other words, material compositions that can be actually applied are determined from the viewpoint of high-frequency magnetism after optimal heat treatment rather than toughness, so it is not necessarily the composition that will give the maximum thickness, and even if the composition is at or near the maximum thickness. Even so, there was a problem in that it did not directly lead to improvement of the local brittleness of the ribbon of 15 to 30 μI, which is effective in terms of high frequency magnetism.

The purpose of the present invention is to improve the toughness required in various processing steps leading to final products such as cores and sensors of CO-based amorphous alloy ribbons with low magnetostriction, and in particular to improve local brittleness to achieve uniform quality. It is to obtain.

[Means to solve the problem]

In view of the above object, as a result of intensive studies, the inventors of the present invention adjusted the so-called magnetostriction to zero or near zero, and performed heat treatment in a magnetic field to obtain a high squareness ratio and low loss characteristics. Alternatively, in a Co-based amorphous alloy that is put into practical use after being heated and held at a temperature higher than the Curie temperature and lower than the crystallization temperature and then rapidly cooled to room temperature at a cooling rate of 10°C/sec or higher to obtain high magnetic permeability, impurity elements The present inventors have discovered that the toughness of the Co-based amorphous alloy in a quenched molten state can be improved by reducing Mg, and have conceived the present invention.

That is, the present invention has the basic composition (Co, -a-b-c Ni, FebM
nc) , c is the atomic ratio, 0≦a≦0.20. O≦b≦0.200≦C≦0.2
It is an amorphous alloy with a saturation magnetostriction constant within ±5 × 104 having a composition shown as
It is an amorphous alloy characterized by having a g content (weight) of 15P, P, M or less. In the present invention, M
The reduction in g improves the toughness of the as-quenched amorphous ribbon.

Toughness in this case refers to the 180°
It cannot be detected by determining whether or not it is possible to bend the material in close contact, or by measuring bending strain assuming that it is a perfectly elastic-plastic material.

The toughness evaluation of the present invention is performed at any position in the longitudinal direction of the ribbon.
This is determined by the appearance of crack growth when the ribbon is torn in the width direction at a speed of 10+na+/sec or less. In other words, as shown in Figure 1, if the toughness is sufficient, the crack propagation will be the same as the tearing speed.
The fracture lines are zigzag at a minute pitch, but from a macroscopic perspective they move straight. In the brittle case shown in FIG. 2, the propagation of cracks is faster than the tearing speed, and the fracture line is straight, but macroscopically the direction may be warped or some ribbons may be chipped. A similar classification can be made, for example, by observing the fracture surface in a normal tensile test.
It is difficult to conduct many tests at slow tensile speeds of 10 m/sec or less, which requires a huge amount of man-hours.
For actual inspection, the tearing method described above is convenient. Even if the ribbon is selected for this tear test and determined to be brittle, it may be possible to bend it in close contact at 180 degrees, and the brittle portion may be limited to a part of the ribbon instead of the entire length in the ribbon direction, as shown in Figure 3. There is also.

The present inventors have newly discovered that the frequency of occurrence of the brittle portions described above is reduced by reducing the Mg content.

If there are non-metallic inclusions in the tearing part, the ribbon will become brittle, so gas components in the molten metal passing through the nozzle,
The content of AI, S, etc. is sufficiently low (e.g. 0.<50
ppm, N2<25ppm, Al<40ppm,
S<30pp111), and the area ratio of inclusions in the master alloy calculated by the JIS method is 0.012% or less, and the long ribbon is not contaminated to the extent that nonmetallic inclusions appear at various locations. It is preferable that

Although the mechanism of improvement in ribbon toughness due to Mg reduction has not been elucidated, the Mg content can be detected by analyzing impurities in the amorphous ribbon, and the results can be verified by comparing with the tear test results described above.

The amorphous alloy of the present invention having the above composition with a low Mg content can be manufactured by a process of rapidly cooling a molten metal. Industrially, an alloy is melted in a high-frequency furnace or an electric furnace, and the molten alloy is ejected from the tip hole (round or rectangular) of a crucible using gas pressure, and is solidified by contact on the surface of a rotating cooling body. The ribbon method is applied. In particular, a method called a single roll method, that is, a method in which the outer surface of a roll is used as a rotating body for cooling, is common.

Normally, a master alloy is melted in advance and this master alloy is often remelted in the crucible, so it is necessary to reduce the amount of Mg when melting the master alloy. There are various methods for this purpose, but impurities can be reduced by carefully examining the purity of raw materials, various conditions including temperature control during melting, slag removal, and casting, and sand prevention in the case of molds, especially sand molds.

The reasons for limiting the base composition for reducing the Mg content will be described below.

As mentioned above, in order to obtain low loss at high frequencies, the magnetostriction must be zero or close to zero≠, specifically, ±5×
It is necessary that the saturation magnetostriction constant be within 10'. For that purpose, Co + N l l F e + M n
All you have to do is adjust the atomic ratio of (Co, −
ab-c N i, l'eb Mne), a,
Both b and c can be combined in a range of 0 to 0.20. One or more of a, b, and c is 0
．． When the value exceeds 20, the saturation magnetostriction constant exceeds +5×10=.

Nonmetal element M is C+ B + P + S 1
! 13 atomic % or more of one or more of G e 28M
The content must be less than %.

If it is less than 13 at%, it becomes difficult to form an amorphous layer5.
If it exceeds 28 at %, it becomes difficult to form an amorphous layer and the saturation magnetization decreases significantly. Also, these C, B,
For P, Si, and Ge, the cooling rate is 10' in the normal single roll method.
~10"C/sec, only B and P can form an amorphous state by themselves, while others require the addition of two or more in combination. The 5i-B combination is the most desirable, as shown in ``Japan Institute of Metals Seminar, (1979) P. 85.

In the present invention, (Co+-5-b-cNia Feb
Mnc) as a transition element T, 3A, 4A, 5A
.

6A, Mn may be excluded < 7A, Fe, Co, and Ni may be substituted with elements of Group 8 except for Ni. One or more of these can be contained up to a total of 8 atomic % or less, but if the content exceeds 8 atomic %, the saturation magnetization will be significantly reduced or it will be difficult to form an amorphous state.

〔Example〕

Hereinafter, the details of the present invention will be explained with reference to Examples.

Example 1 In atomic %, (COD, 14 Fee, am) ya~1o
,Si,,B,.

An amorphous alloy ribbon was manufactured.

Prior to manufacturing the ribbon, the master alloy was melted. Dissolution is Co, B
After selecting two types of raw materials each, the composition was changed, and the content of impurities was changed using a total of six types of raw materials. Other Fe,
Mo was kept constant. Melt at 1450℃, 1350℃
The molten slag produced in step 1 was removed and cast into a cast iron mold at 1300°C.

2.5 pieces of the above master alloy were remelted in a quartz crucible, and 130
After making the molten metal at 0°C, it is jetted out from a rectangular slit with a width of 5w and a thickness of 0.6mm, and is rapidly solidified on a single roll of beryllium steel with a diameter of 300mm.
An amorphous alloy ribbon with a thickness of m and a length of about 3000 m was prepared.

This alloy ribbon was torn every 300 m over its entire length to evaluate its toughness. Tearing was performed 20 times at each position, and a brittle portion was determined to exist if the specimen deviated by 2 rm or more with respect to the tearing direction, and the brittle rupture rate (%) for each position was determined and compared.

Table 1 shows the M of amorphous alloys based on six types of master alloys.
The g content and the brittle rupture rate of this amorphous ribbon are shown.

The lower the Mg content, the lower the brittle fracture rate at each location.

These six types of ribbons have an outer diameter of 22IIIllφ and an inner diameter of 1.
The number of stops due to ribbon breakage during winding was determined when the ribbon was wound into a toroidal shape having a diameter of 4 mm and a thickness of 5 ttrm t. In this case, the tension applied to the ribbon is approximately 12 kgf.
/w', the ribbon changes its traveling direction three times by 180° within the apparatus by a 10 IIIR guide reel. Such a wound core manufacturing apparatus is not particularly common, and the load on the ribbon varies depending on the apparatus and product specifications, but this example is provided as a guide.

The number of breaks per 1000m length of each ribbon is:
No, ]-No, 6, 3, 9, 16, 49, 80 respectively
, 117 times.

From the above, when the Mg content is set to 15P, P, M or less, the toughness of the as-quenched ribbon is improved, particularly local brittleness is reduced, and this effect is large.

Example 2 At %, (Co, , 4Fe., 5jys 5its
Using the B10 amorphous alloy ribbon, six types of ribbons were prepared in the same manner as in Example 1 and evaluated in the same manner.

Note that two types of Go and B raw materials were similarly selected for the master alloy, and the blends were changed, resulting in a total of six types.

Table 2 shows the Mg content of amorphous alloy ribbons made from six types of master alloys and the brittle rupture rates of these amorphous ribbons.6 As the Mg content decreases, the brittle rupture rate at each position decreases. It can be seen that local embrittlement can be greatly improved by reducing the thickness to approximately 15P, P, and M.

Example 3 In atomic %, (Co., pe., ., Mn6.s
Using an amorphous alloy ribbon of +LsNb+Si, 6B, a ribbon was manufactured in the same manner as in Example 1 and evaluated.

Two types of master alloys were used by changing the B raw material. Table 3 shows the Mg content of amorphous alloy ribbons based on two types of master alloys,
Indicates brittle rupture rate.

It can be seen that in the examples of the present invention where the Mg content is low, the brittle rupture rate decreases and brittleness is improved.

Example 4 At %, (Co*, ss Fe, , Mn, , s
),, Using an amorphous alloy ribbon of Crt5111BS, a ribbon was manufactured in the same manner as in Example 1 and evaluated.

There were two types of master alloys by changing the B raw material. Table 4 shows the Mg content and brittle fracture rate of amorphous alloy ribbons made of two types of master alloys.

It can be seen that in the examples of the present invention with a low Mg content, the brittle rupture rate is reduced and the brittleness is improved.

Example 5 In atomic %, (CO*, st Nla, az Fee, s
Using an amorphous alloy ribbon of s)ysNE)g5116B11, a ribbon was manufactured in the same manner as in Example 1 and evaluated.

Two types of master alloys were created by changing the B raw material. Table 4 shows the Mg content and brittle fracture rate of amorphous alloy ribbons made of two types of master alloys.

It can be seen that in the examples of the present invention with a low Mg content, the brittle rupture rate is reduced and the brittleness is improved.

〔Effect of the invention〕

According to the amorphous alloy of the present invention, the toughness of the ribbon required in each processing process leading to the final product such as various cores for high frequency and sensors is improved, production yield and efficiency are improved, and its industrial value is high. .

[Brief explanation of drawings]

Fig. 1 is a schematic diagram showing a ribbon tearing state without local brittleness, which is the goal of the present invention, Fig. 2 is a schematic diagram showing a brittle tearing state, and Fig. 3 is a diagram showing a ribbon tearing state in which toughness and brittleness are mixed. FIG. Figure Figure Figure Leg PI-Miyakosu Misaki Ganbe I

Claims (1)

[Claims] 1 Basic composition (Co_1_-_a_-_b_-_cNi
_aFe_bMn_c)_xM_zwhere, M: one or more elements consisting of C, B, P, Si, and Ge, x and z are atomic percent, x+z=100, 13≦z≦28 a, b, and c are The atomic ratio is 0≦a≦0.20, 0≦b≦0.20, 0≦c≦0.20, and the saturation magnetostriction constant is ±5×10^-
It is an amorphous alloy with an unavoidable impurity Mg content (weight) of 15P. P. An amorphous alloy characterized by having a molecular weight of M or less. 2 Basic composition (Co_1_-_a_-_b_-_cNi
_aFe_bMn_c)_xT_yM_zwhere, T:
Transition metal, M: one or more elements consisting of C, B, P, Si, Ge, x, y, z are atomic %, x+y+z=100, y≦8, 13≦z≦28 a, b , c is the atomic ratio, and the saturation magnetostriction constant is ±5×10^-
It is an amorphous alloy with an unavoidable impurity Mg content (weight) of 15P. P. An amorphous alloy characterized by having a molecular weight of M or less.