JPH05247603A - Iron base soft magnetic alloy - Google Patents

Abstract

PURPOSE:To improve the magnetic properties such as magnetic permeability by using a supersendust alloy as a base, incorporating specified amounts of Zr and B therein and forming its structure into a one constituted of fine crystalline grains. CONSTITUTION:The objective high permeability soft magnetic alloy is constituted of a compsn. expressed by general formula: (Fe100-a-b-cAlaSibNic)1-(x+y))100 ZrxBy, by atom, and comprised of a structure constituted of fine crystalline grains. In the formula, a=4 to 10, b=8 to 14, c=1 to 5, x=0.5 to 3 and y=5 to 15 are satisfied. The amorphous alloy having this compsn. is preferably subjected to heat treatment to form its structure into a fine crystalline having 50 to 300Angstrom average grain diameter.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fine crystal soft magnetic alloy having a high magnetic permeability suitable for a magnetic core material such as a high frequency transformer or a choke coil.

[0002]

2. _{Description of the Related} Art Conventional Super Sendas alloy (Fe _78.9 Al
_7.5 Si _10.8 Ni _2.8 ) is known to exhibit a relatively high saturation magnetic flux density and excellent soft magnetic properties (see, for example, Journal of the Japan Institute of Metals, Vol. 40, pp. 975-981 (1976)). In order to use this for a high frequency transformer, a choke coil, etc., it is necessary to form it into a thin strip and stack it in order to reduce eddy current loss. However, as shown in Fig. 1, the coercive force of the super sendust ribbon as produced by the rapid quenching method is large. Need to lower. However, at such a high temperature, the ribbons are fused between the layers to increase iron loss, and a magnetic core with good characteristics cannot be obtained. Therefore, a highly heat resistant insulating material is interposed between the ribbons to form the ribbons. It is necessary to protect and heat-treat at a high temperature of 1100 ° C. or higher.

[0003]

As described above, in order to improve the magnetic characteristics by heat-treating the quenched soft magnetic ribbon, the ribbon is protected by interposing a high heat-resistant insulating material between the layers, and then 100
Since it is necessary to perform heat treatment at a high temperature of 0 ° C. or higher, there are disadvantages that the process is complicated, a high temperature is required, and the manufacturing cost is high. Further, since the alloy based on Super Sendust has a high melting point, the quartz nozzle for discharging the molten metal has a drawback that the consumption is severe. The present invention aims to solve these problems.

[0004]

The inventors of the present invention have conducted extensive studies to solve these problems, and as a result, by introducing specific components, that is, Zr and B, into the composition of the super sendust system, the rapid cooling method is compared. It has been found that it can be carried out at a relatively low temperature, and that the heat treatment after laminating the prepared soft magnetic ribbons into a predetermined shape can be carried out at a relatively low temperature. Therefore, there is no need to interpose a heat-resistant insulating material between the layers prior to the heat treatment, the process is simplified, and the manufacturing cost can be reduced.

Namely, the present invention has the general formula expressed by atomic ratio _{(Fe 100-abc Al a Si} b Ni c) 1- (x + y) / 100 Zr x B y ( where, a = 4 to 10, b = 8 to 14, c = 1 to 5 x = 0.5 to 3, y = 5 to 15), and a high magnetic permeability soft magnetic alloy having a fine grain structure is provided.

[0006] high-permeability soft magnetic alloy consisting of the fine grain structure of the general formula _{(Fe 100-abc Al a Si} b Ni c) 1- (x + y) / 100 Zr x B y ( here, a = 4 to 10, b = 8 to 14, c = 1 to 10 x = 0.5 to 3, y = 5 to 15), for example, in the form of a ribbon by a melt quenching method. Then, these are laminated to form a magnetic core having a predetermined shape, and then heat-treated at a temperature lower than the conventional temperature of 400 to 600 ° C., more preferably 450 ° C. to 550 ° C., so that the average particle diameter of the crystal particles is 50Å ~ 300Å, preferably 8
It can be manufactured by a manufacturing method with a fine grain structure of 0 to 200Å.

In the present invention, Fe is the basis and Al is
In addition to the basically same components as Super Sendust containing Si and Ni, Zr and B are further added and the component ratio is adjusted as described above. When Zr and B are added, a fine grain structure can be obtained after amorphization, and the melting point of the alloy based on Super Sendust and the optimum heat treatment temperature are lowered to facilitate the production, and at the same time, the magnetic permeability is improved. It can be improved significantly. B should be in the range of 5 to 15 at%. B serves to significantly lower the heat treatment temperature required for fine grain formation. If it is too large, the saturation magnetic flux density will decrease. On the other hand, Zr should be used in an amount of 0.5-3 at%.
Zr has the effect of reducing the coercive force Hc in addition to helping fine crystallization, but if it is too large, the processing temperature for fine crystallization increases. It should be noted that minute amounts of impurities that are inevitably mixed can be tolerated.

Conventionally, fine crystal grain soft magnetic alloys containing B or Zr have been known, and for example, the Japan Society for the Promotion of Science, Amorphous Committee, Research Material Vol. 30, No. 7 (1990) and JP-A-61-33900. No. Although the alloy composition described in these documents is different from that of super sendust, it has a higher magnetic permeability than super sendust (about 900 to 14000), and the heat treatment temperature Ta for fine graining is Ta. Is low (about 550 ° C). The fine crystalline soft magnetic alloy of the present invention has a magnetic permeability of 20,000 or more, which is higher than those of the fine crystalline soft magnetic alloys.

In the raw material composition of the present invention, the molten metal has a melting point (1) lower than the melting point T _{M of} super Sendust (about 1520 ° C.).
Around 350 ° C). Therefore, the consumption of the melt nozzle is reduced. Further, since the fine crystallization temperature after quenching is around 500 ° C., which is much lower than 1250 ° C. in the case of super sendust, the heat treatment is easy.

[0010]

[Explanation of Examples]

Example 1 Plate thickness of about 1 having various compositions shown in Table 1 by liquid quenching method
An 8 micron magnetic alloy ribbon was manufactured and heat-treated at the temperature shown in Table 1 to obtain a fine grain structure having an average particle size of about 80 to 200Å. Table 1 shows the results of measuring the initial magnetic permeability, the melt temperature T _M at the time of preparation, and the optimum heat treatment temperature T _a .

[0011]

[Table 1]

From Table 1, it can be seen that the amorphous magnetic material based on super sendust, to which Zr and B are added, can be melted at a lower temperature than that of super sendust at 500 ° C.
It can be seen that the heat treatment can be easily performed at a low temperature around and thus a high soft magnetic alloy having a fine magnetic grain structure with high magnetic permeability can be provided.

Next, Table 1 is listed first (Fe _78.9 Al _7.5 Si
_{For 10.8} Ni _2.8 ) _0.9 Zr ₂ B ₈ , the dependence of heat treatment temperature on initial permeability μ ₁ , coercive force Hc, average grain size D, magnetostriction constant λ _S and saturation magnetization σ _S on heat treatment temperature Ta is shown in FIG. Shown in. First, the average particle diameter D remains amorphous up to about 450 ° C., and the magnetic permeability increases due to the decrease in internal stress, but the magnetostriction remains large. Above this temperature, fine crystallization begins and magnetostriction tends to decrease. Next, the initial permeability μ ₁ is about 40
It is improved between 0 ° C. and 580 ° C., and is particularly improved around 500 ° C. Correspondingly, the holding force Hc is reduced. There is no particular change in the saturation magnetization σ _S , but the magnetostriction λ _S is improved at about 450 ° C. or higher.

Example 2 In the same manner as in Example 1 (Fe _78.9 Al _7.5 Si _10.8 Ni _2.8 ).
_{0.9-X / 100} Zr _X B ₈ (X = 0.5, 1, 1.5) was produced. When the dependence of the average crystal grain size and the coercive force on the processing temperature was examined, it was as shown in FIG. The circles, triangles, and squares in the figure are black and white, indicating the same sample. It can be seen that the coercive force is greatly reduced at the processing temperature of about 400 to 550 ° C.

[0015]

As described above, according to the present invention, the amorphous magnetic material based on super sendust, to which Zr and B are added, can be melted at a lower temperature than that of super sendust, and much better than before. It can be seen that it is possible to easily provide fine crystal grains at a low temperature and to provide a high soft magnetic alloy having a higher magnetic permeability than conventional ones.

[Brief description of drawings]

FIG. 1 is a graph showing heat treatment hardening of conventional Super Sendust.

FIG. 2 is a graph showing heat treatment temperature dependence of various characteristics of the soft magnetic material of the present invention.

FIG. 3 is a graph showing heat treatment temperature dependence of various characteristics of coercive force and crystal grain size when the amount of Zr added in the soft magnetic material of the present invention is changed.

Claims (3)

[Claims] 1. An atomic ratio of a general formula (Fe _100-abc Al _a Si _b Ni _c ).
_{1- (x + y) / 100} Zr x B y ( here, a = 4~10, b = 8~1
4, c = 1 to 5 x = 0.5 to 3 and y = 5 to 15), and a high magnetic permeability soft magnetic alloy having a fine crystal grain structure. 2. The average grain size of the fine crystal grain structure is 50Å
The high-permeability soft magnetic alloy according to claim 1, which is about 300Å. 3. An atomic ratio of a general formula (Fe _100-abc Al _a Si _b Ni _c ).
_{100- (x + y) / 100} Zr x B y ( here, a = 4~10, b = 8~
14, c = 1 to 10 x = 0.5 to 3, y = 5 to 15) until an average grain size of crystal grains becomes a fine crystal structure of 50Å to 300Å. A method for producing a high-permeability soft magnetic alloy, which comprises heat-treating at a temperature of 600 ° C. or lower.