JPS59107062A - Low iron loss amorphous alloy - Google Patents

Abstract

PURPOSE:To provide a titled alloy which is suitable for a magnetic core for a high frequency used in the state of a high magnetic flux density and has a small iron loss by specifying the compsn. consisting of Fe, Ni, Si and B and subjecting the same to rolling and quick cooling. CONSTITUTION:An alloy consisting of (Fe1-aNia)100-x-ySixBy (where 0.2<=a <=0.7, 1<=x<=20, 5<=y<=9.5, 15<=x+y<=30) is ejeced by pressurizied gaseous argon in a molten stage from a quartz nozzle into the space between the two rolls under high speed rotation, whereby a low iron loss amorphous alloy is obtd. The resin for limiting the compsn. components in the above-mentioned alloy lies in that Ni contributes to a decrease in iron loss at a high frequency but that, if it is <0.2atom%, the effect is lessened, and at >0.7%, the magnetic flux density decreases, thus making the alloy impractical. The magnetic flux density is additionally improved with correspondingly decreased iron loss if the Ni is incorporated at the range of 0.3<=a<=0.45. If B is not added within the above- mentioned range, it is difficult to obtain an amorphous alloy and the iron loss is considerably decreased by incorporating the same at the range of 5<=y<=7. Si assists the formation of the amorphous alloy and decreases the iron loss in the above-mentioned range.

Description

[Detailed Description of the Invention] The present invention relates to a low-loss amorphous alloy used for magnetic cores of electromagnetic devices, and particularly relates to a low-loss amorphous alloy suitable for high-frequency magnetic cores such as switching regulators. .

Conventionally, crystalline materials such as permalloy and ferrite have been used as magnetic cores used in high frequency applications such as switching regulators. However, permalloy has a drawback of high iron loss at high frequencies due to its low resistivity. Further, although ferrite has a small loss at high frequencies, the magnetic flux density is as low as 5.0 OOG at most, so when used at a high operating magnetic flux density, it approaches saturation and the iron loss increases.

Transformers used at high frequencies, such as power supply transformers used in switching regulators, are desired to be made smaller and therefore require an increase in operating magnetic flux density, but the increased iron loss of the ferrite in this case is practically impossible. It had become a problem.

Amorphous magnetic alloys without a crystalline structure, which have recently attracted attention, are known to exhibit excellent soft magnetic properties such as high magnetic permeability and low coercive force. These amorphous magnetic alloys include Fe,
It is based on Co and N+, and contains P, C, B, 81, Al, Ge, etc. as amorphous elements (metacalcoids), but it is generally assumed that these have low iron loss at high frequencies. do not have. For example, Fe-based amorphous alloy has 5
At low frequencies from 0 to 60 Hz, it exhibits a very small iron loss of ~1/4 that of silicon, but at high frequencies from 10 to 50 kHz, it exhibits a significantly large iron loss, making it very suitable for high frequency applications such as switching regulators. It couldn't be called anything.

In view of the above points, it is an object of the present invention to provide a low-loss amorphous alloy that is suitable for high-frequency magnetic cores used in low-pressure applications with a high magnetic flux density of 1 yen and has low iron loss. .

The present invention is (Fe+-a N'a)+oo-x-y Slx
It is a low-loss amorphous alloy consisting of By, especially when B is 5 and y<7.
．． By setting Nl to o, 3<:a>04s, the iron loss at high frequencies can be further reduced.

The reasons for limiting the compositional components of the low-loss amorphous alloy in the present invention are as follows.

N1 has the effect of reducing iron loss at high frequencies, but 02
If it is less than 0.07 atomic %, the effect is not so great, and if it exceeds 0.7 atomic %, the Curie point becomes extremely small and the magnetic flux density becomes less than 5.0 OOCII, making it impractical, so the above range is selected. More preferably, N1 is 0
．． By setting 3<a to 0.45, it is possible to obtain an element with an even higher magnetic flux density and a smaller iron loss.

The reason why B is still limited to 5 to 9.5 atomic percent is that outside this range, it becomes difficult to produce an amorphous alloy, and the effect of reducing iron loss becomes less noticeable. In particular, when B is set to 5 < Y < 7, the core loss becomes significantly small, and it is preferable for practical purposes to set it within this range.

Si is an element that has the effect of promoting amorphization and reducing iron loss, but if it is less than 1 atom%, it has no particular effect, and if it exceeds 20 atom%, it becomes difficult to create an amorphous alloy. Therefore, this range was chosen.

Hereinafter, the present invention will be explained in detail based on Examples.

Example 1 (Fe0.6 N'0.4) +1OS' 14 B
6 An amorphous alloy was produced using a rolling quenching method. That is,
The molten alloy is jetted between two high-speed rotating rolls from a quartz tube nozzle using argon gas pressure, and is rapidly cooled to a width of 2.
A ribbon sample with a thickness of 30 μm and a length of 10 rn was prepared. A length of 140 cm was cut from this sample, and a diameter of 2
Wrap it around a 0φ alumina bobbin and heat it at 400°C for 30 minutes.
After the heat treatment, iron loss was measured using a 70-turn wattmeter for both the primary coil and the secondary coil. The saturation magnetization was also measured using a sample vibrating shadow dynamometer. Magnetic flux density Bm=3kG
The iron loss at frequencies 10 kHz and 20 kHz
Table 1 shows the saturation magnetization for z. For comparison, Table 1 also shows the results for Mn-Zn ferrite conventionally used for switching power supplies. As can be seen from the table, the amorphous alloy of the present invention has a larger magnetic flux density than ferrite and exhibits smaller iron loss than ferrite.

Example 2 Amorphous alloys shown in Table 1 were produced using the same method as in Example 1, and core loss was evaluated. It can be seen that the amorphous alloy of the present invention exhibits small iron loss.

Table 1 Example 3 (Feaff8 N'0.41) 78 st,, -y
A By amorphous alloy was produced using the same method as in Example 1, and the core loss was measured.

Figure 1 shows the dependence of iron loss on the amount of B at Bm = 3 kG and a frequency of 20 kHz. As you can see from the diagram, B
exhibits particularly small iron loss in the range of 5 to 9.5 at%.

As described above, the amorphous alloy of the present invention has a higher magnetic flux density than ferrite and is also superior to ferrite in core loss, especially at high frequencies, and therefore can be miniaturized for high frequency transformers, etc., and is industrially useful.

[Brief explanation of the drawing]

FIG. 1 is a curve diagram showing the loss of the amorphous alloy according to the present invention.

Claims (1)

[Claims] 1) (F'1-a N'a)+oo-x-y 8
A low-loss amorphous alloy characterized by consisting of 1xBy. 2. A low-loss amorphous alloy according to claim 1, characterized in that B is 5 x y<7. 3) In claim 1 or 2, N1
A low-loss amorphous alloy characterized in that 0.3 < 8 < 0.45.