JPH09268354A - Low boron amorphous alloy excellent in magnetic property and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain excellent magnetic properties in spite of low B content by specifying B content, sheet thickness, and surface roughness. SOLUTION: This alloy is an Fe-B-Si alloy which has B content as low as 6-10 atomic % and also has 15-25μm sheet thickness and in which surface roughness Ra0.8 (center line average height on the ribbon roll surface side, measured at 0.8mm cut-off value) is regulated to <=0.8μm. This is based on the knowledge that, in contrast to the case of the conventional alloy of high B content, iron loss is decreased with the increase in the improvement of the above surface roughness and, further, its dependence on it is great. Moreover, iron loss is decreased with the decrease in sheet thickness and this tendency is more remarkably observed in low B alloy than in high B alloy. Accordingly, by reducing thickness and surface roughness magnetic properties can be remarkably improved even in the case of alloys of low B content.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a low boron amorphous alloy having excellent magnetic properties and a method for producing the same, and in particular to an Fe--B--Si amorphous alloy having a low boron content, its magnetic properties are improved to reduce variations. At the same time, we are trying to achieve it.

[0002]

2. Description of the Related Art Various Fe-B-Si alloy compositions are known as amorphous alloys having excellent soft magnetic characteristics.
For example, Chen et al. And Luborsky et al. U.S. Pat. No. 4,300,950 discloses alloy compositions containing 80-84 at% iron, 12-15 at% boron and up to about 6 at% silicon. In addition, U.S. Pat.
% Alloys, 12-16 at% boron and 5-10 at% silicon are disclosed. As described above, most of the conventionally known Fe-Si-B based amorphous alloys specify the content of boron to be 10 at% or more. The reason for this is that boron is important for amorphization of this type of alloy, and the higher the boron content, the stronger the amorphous forming ability of the alloy and the better the thermal stability.

In fact, the previously reported boron content is
The magnetic properties of the Fe-Si-B based amorphous alloy of 10 at% or less were inferior to those of the composition having a boron content of 10 at% or more in both iron loss and magnetic flux density. Therefore, there have been very few reports on Fe-Si-B type amorphous alloys having a boron content of 10 at% or less, and C is added as a material for improving stability over time and amorphous forming ability.
-145964 and JP-A-58-42751, and those containing Mn as an agent for improving the surface treatment property are disclosed in JP-A-61-
No. 136660 and the one to which Cr is further added as a castability improving agent are described in JP-A-58-210154. Moreover, the characteristics of the known alloy system in the low boron region were not so good as described above.

Regarding the improvement of iron loss by controlling the plate thickness, Japanese Patent Laid-Open No. 4-333547 discloses that iron loss reduction in a high frequency band is a requirement. However, the frequency band targeted in the above publication is an extremely high band such as 100 kHz, 200 kHz, 500 kHz, 1 MHz as described in the embodiment, and most of the iron loss is high in such a high frequency band. It is a well-known fact that the eddy current loss is occupied, and it is known that the eddy current loss is reduced by reducing the plate thickness.

On the other hand, in the commercial frequency band targeted by the present invention, the effect of the plate thickness on iron loss is as follows.
In the case of Fe-Si-B type amorphous alloy, there is a certain optimum value for the plate thickness that minimizes the iron loss (Shun Sato 1993, 36 μm according to the doctoral dissertation of Tohoku University). However, there is a report (in 1993, Tohoku University doctoral dissertation) that the total iron loss value rather increases because the hysteresis loss increases.

Regarding the ribbon roughness, Japanese Patent Laid-Open No. 62-
In 192560, the improvement of the space factor by roughness control is introduced. According to this, as for the iron loss and the magnetic flux density, when the ribbon roughness is reduced, the domain wall movement becomes easier and the hysteresis loss is reduced. However, it is reported that the eddy current loss increases due to the coarsening of magnetic domains.

[0007]

As described above, the previously reported Fe-Si-B having a boron content of 10 at% or less has been reported.
The magnetic properties of the system amorphous alloys were inferior to those of compositions with a boron content of 10 at% or more in terms of both iron loss and magnetic flux density, and there was a problem in that there were significant variations.
However, since boron is an expensive element, if the boron content of 10 at% or less, which is lower than that of the conventional one, is comparable to that of the high boron content amorphous alloy, its economic effect is immeasurable. . This invention advantageously responds to the above-mentioned demands. By optimizing the plate thickness and surface roughness of the amorphous alloy, the boron content is 10 at% or more even if the boron content is 10 at% or less. It is an object of the present invention to propose a low boron amorphous alloy, which has excellent magnetic characteristics comparable to those of other alloys and has excellent magnetic characteristics with little variation, together with its advantageous manufacturing method.

[0008]

That is, the gist of the present invention is as follows. 1. Fe-B-Si based amorphous alloy with a low B content of 6 to 10 at% and a plate thickness of 15 to 25 μm, and
A low boron amorphous alloy with excellent magnetic properties, characterized by having a surface roughness Ra _0.8 (center line average roughness on the ribbon roll surface side measured at a cutoff value of 0.8 mm) of 0.8 μm or less.

[0009] 2. In the above 1, B content is 6 to 8 at
%, The plate thickness is 15 to 20 μm, and the surface roughness Ra _0.8 is 0.6 μ.
A low boron amorphous alloy with excellent magnetic properties that is m or less.

3. Low boron content with a B content of 6-10 at%
Fe-B-Si based amorphous alloy with a plate thickness of 15-25
μm and a surface roughness Ra _0.25 (center line average roughness on the ribbon roll surface side measured at a cutoff value of 0.25 mm) of 0.3 μm
A low boron amorphous alloy excellent in magnetic properties, characterized by satisfying m or less.

4. In the above 3, B content is 6 to 8 at
%, The plate thickness is 15 to 20 μm, and the surface roughness Ra _0.25 is 0.2 μ.
A low boron amorphous alloy with excellent magnetic properties that is m or less.

5. A Fe-B-Si alloy molten metal having a B content of 6 to 10 at% is rapidly solidified by a single roll method to obtain a plate thickness: 15
When producing amorphous ribbons of ~ 25 μm, low boron with excellent magnetic properties, characterized by rapid solidification under conditions of injection pressure: 0.3-0.6 kgf / cm ² and roll peripheral speed: 35 m / s or more. Amorphous alloy manufacturing method.

6. 5. The method for producing a low boron amorphous alloy excellent in magnetic characteristics as described in 5 above, wherein the thickness of the nozzle slit when producing the amorphous ribbon is 0.4 to 1.0 mm.

7. In the above 5 or 6, the gap between the nozzle and the roll when manufacturing the amorphous ribbon is
A method for producing a low boron amorphous alloy having excellent magnetic properties, characterized in that the thickness is 0.1 to 0.2 mm.

[8] 5. The method for producing a low-boron amorphous alloy having excellent magnetic properties, wherein the concentration of CO _{2 in} the atmosphere for producing the amorphous ribbon is set to 50% or more in 5, 6, or 7 above.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, experimental results which led to the present invention will be described. In Fig. 1, Fe ₇₈ Si _22-X B _X
The results of investigating the relationship between the B content of the composition amorphous alloy and the iron loss are shown. In the Fe-Si-B system amorphous alloy, when the B content is 10 at% or less, the B content is 10 at% or more. Compared with the case, not only the iron loss characteristic is deteriorated, but also its variation is increased.

Therefore, the inventors investigated the influence of various parameters on the magnetic characteristics in order to clarify the cause. As a result, as the parameters that affect the iron loss characteristics, the plate thickness and the surface roughness are extremely strong, and the iron loss W (W
_13/50 ), plate thickness t, and surface roughness Ra (cutoff value: 0.8
mm) and the relationship of the following equation (1). W = a + b · t + c · Ra --- (1) where a, b and c are coefficients determined by the composition of components such as Fe, Si, B, C, P and Mn and satisfy the following range. 0 <a <0.02, 0.001 <b <0.004, 0.05 <c <0.2

It should be noted that in the above equation (1), the surface roughness coefficient c is completely opposite between an amorphous alloy having a boron content of 10 at% or more and an amorphous alloy having a boron content of 10 at% or less. It is to show a tendency. That is, in the conventional amorphous alloy having a boron content of 10 at% or more, the coefficient c sharply increases when the surface roughness becomes 0.8 μm or less,
On the contrary, the iron loss was deteriorated. The reason for this is
As reported in Japanese Laid-open Patent Publication No. 62-192560, when the surface roughness of the ribbon is improved, the domain wall movement is facilitated, so that the hysteresis loss is reduced, but at the same time, the coarsening of the magnetic domain causes the eddy current loss to increase rather. As a result, the total iron loss increases.

On the other hand, in the case of a low boron amorphous alloy having a boron content of 10 at% or less, the coefficient c was constant for each component system and did not increase even when the surface roughness was 0.8 μm or less. Therefore, in an amorphous alloy with a boron content of 10 at% or less, further improvement of iron loss characteristics can be achieved by reducing the surface roughness to a region of 0.8 μm or less, which has been conventionally disadvantageous in terms of iron loss characteristics. You can expect it.

Therefore, the inventors have found that the boron content is particularly high.
For amorphous alloys of 10 at% or less, the effects of plate thickness and surface roughness on the iron loss characteristics and their variations were scrutinized. FIG. 2 shows the results of an examination of the relationship between plate thickness and iron loss in amorphous alloys of Fe ₇₈ Si ₁₄ B ₈ composition and Fe ₇₈ Si ₉ B ₁₃ composition. As shown in the figure, the amorphous alloy having a boron content of 10 at% or less exhibits a particularly good iron loss value in the range of 15 to 25 μm, which is somewhat thinner than the amorphous alloy having a boron content of 10 at% or more. The reason for this is that when the plate thickness exceeds 25 μm, the surface is locally crystallized, and the plate thickness is 15 μm.
It is considered that when the value is less than the above, streaks are generated due to gas entrainment in the paddle and partial clogging of the nozzle, and the surface quality is deteriorated. Therefore, in the present invention, the plate thickness of the amorphous alloy is limited to the range of 15 to 25 μm. A more preferred range is 15 to 20 μm.

Next, the effect of surface roughness on iron loss characteristics was investigated. Fe ₇₈ Si ₁₄ B ₈ composition and Fe ₇₈ Si ₁₅ B ₇
For molten alloy of composition, the plate thickness can be changed by combining various changes of injection pressure and roll peripheral speed during casting.
Samples with different surface roughness were prepared while keeping the value constant at 20 μm. FIG. 3 shows the results of examining the relationship between the surface roughness (roll surface side) of each sample and the iron loss characteristics. Also, in the same figure, for comparison, the results of the investigation on the alloy having the conventional Fe ₇₈ Si ₉ B ₁₃ composition are also shown. The surface roughness is
The center line average roughness Ra _0.8 was adopted when 0.8 mm, which is a general value, was adopted as the cutoff value λc.

As is clear from the figure, in the low boron amorphous alloy, the core loss characteristic is improved as the surface roughness Ra _0.8 becomes smaller. On the other hand, the conventional high boron amorphous alloy showed a minimum value when the surface roughness Ra was about _0.8 : 1.0 μm, and the iron loss value was rather high when the surface roughness was smaller than that.

Therefore, in the present invention, the surface roughness of the amorphous alloy is limited to a range of Ra _0.8 of 0.8 μm or less. A preferred range is 0.6 μm or less, and a more preferred range is 0.3 μm or less. The surface roughness Ra _0.8
The reason why good iron loss cannot be obtained above 0.8 μm is that when the surface becomes rough, the gas pocket ratio of the ribbon increases and the cooling rate during plate making decreases significantly. It is considered that this is due to the formation of turbulence and disorder in the magnetic domains on the surface.

As described above, the surface roughness Ra _0.8 is _0.8 μ
By limiting to m or less, the iron loss value can be effectively reduced. However, in rare cases, it was observed that the surface roughness did not match the iron loss value. Then, the inventors next investigated the cause, and found that such variation in the iron loss value was caused by the cut-off value when measuring the surface roughness. That is, as a result of investigating the relationship between the surface roughness on the ribbon roll surface side showing various iron losses and the iron loss value, different correlations were obtained depending on the cutoff values when measuring the surface roughness.

Fe ₇₈ Si ₁₄ B is shown in FIGS. 4, 5 and 6, respectively.
_{For 8} composition amorphous alloy (plate thickness: 20 μm),
The results of an investigation of the relationship between the centerline average roughness Ra and the iron loss when the cutoff values are set to 2.5 mm, 0.8 mm, and 0.25 mm are shown below. When the cutoff value is 2.5 mm shown in FIG. 4, there is no correlation between the surface roughness Ra _2.5 and the iron loss value. In this respect, as shown in FIG. 5, the cutoff value is
When it is reduced to 0.8 mm, the surface roughness Ra _0.8 and the iron loss value show a fairly strong correlation. However, there is still some variation. On the other hand, as shown in FIG. 6, when the cutoff value is 0.25 mm, the surface roughness Ra _0.25 and the iron loss value show a very good correlation.

As described above, depending on the cutoff value,
The reason for the difference in the correlation between the surface roughness and the iron loss value is considered as follows. That is, what contributes to the domain wall pinning site is a steep undulation such as an air pocket (diameter: 10 to 20 μm, depth: 1 to 2 μm) on the ribbon surface, and the plate thickness due to the sample site Mild undulations such as fluctuations and surface undulations (wavelength: 1-2 mm, depth: 2-3 μm) do not contribute to the domain wall pinning site because they do not change the magnetostatic energy abruptly. It is speculated that this is due to the fact.

In the present invention, the center line average roughness Ra used in the evaluation of the surface roughness defines a straight line connecting two points on the measurement surface which is the reference of measurement, and the surface undulations and this reference line. It is represented by the size of the area enclosed by and. The distance between these two points is called the cutoff value. When measuring with a large cutoff value, a large Ra value is displayed due to long-period undulations of the surface even in a sample without air pockets, so measurements with too large a cutoff value reflect the presence or absence of air pockets. It is hard to say that Therefore 2.5
It is considered that the measurement results at the cutoff values of mm and 0.8 mm have an unclear correlation with the magnetic properties.

On the other hand, in order to evaluate only the air pocket, it is necessary to detect the undulations at the very periphery of the air pocket and to adopt a short-distance cutoff value that does not pick up the undulations on the surface. Considered as the cutoff value: 0.25mm
This small value is more suitable for the evaluation of the presence or absence of air pockets than the cutoff value of 0.8 mm or more, so that the correlation with the magnetic properties is clearly observed.

Next, the preferable component composition range of the present invention will be described. In the present invention, any Fe-B-Si based amorphous alloy having a B content of 10 at% or less, which is a so-called low boron content, is suitable, and its preferable composition is as follows. B: 6 to 10 at% B is a useful element for improving the amorphous forming ability, but if the content is less than 6 at%, its effect is poor. On the other hand, if it exceeds 10 at%, the content of expensive ferroboron is high. Therefore, contrary to the purpose of the present invention of lowering the cost by lowering the B content, when the B content exceeds 10 at%, the dependence of the iron loss on the surface roughness becomes small, and the meaning of managing the surface roughness diminishes. The amount was limited to the range of 6-10 at%. A more preferable range is 6 to 8 at%.

Si: 10 to 17 at% Si effectively contributes to the reduction of magnetostriction and the improvement of thermal stability, but if it is less than 10 at%, its addition effect is poor, while 17 at%
%, The ribbon becomes brittle, so the Si content is 10
It is preferably set to -17 at%. Further, in the present invention,
Components such as C, Mn and P may be added to the Fe-B-Si system as appropriate, and the preferable composition range is as follows.

C: 0.1 to 2 at% C is an element effective in improving the magnetic flux density and iron loss as well as enhancing the amorphous forming ability, but if it is less than 0.1 at%, its effect of addition is poor, while it exceeds 2 at%. Therefore, the thermal stability of the ribbon decreases, so the C content is preferably 0.1 to 2 at%. A more preferable range is 0.1 to 1 at%.

Mn: 0.2 to 1.0 at% Mn effectively acts to suppress crystallization, but if it is less than 0.2 at%, its addition effect is poor, while if it exceeds 1.0 at%, the magnetic flux density decreases. Therefore, 0.2 to 1.0 at% is preferable. A more preferable range is 0.2 to 0.7 at%. P: 0.02 to 2 at%

P not only strengthens the amorphous forming ability but also contributes effectively to the improvement of the surface roughness.
%, There is no surface roughness improvement effect, while 2 at%
If it exceeds the range, embrittlement of the ribbon and deterioration of thermal stability become problems, so the content is preferably 0.02 to 2 at%. It should be noted that the range of 0.02 to 1 at% is suitable for the wide material having severe requirements for embrittlement and thermal stability.

Next, the manufacturing method according to the present invention will be described. As described above, in the present invention, the surface roughness Ra
It is important to control _0.8 to 0.8 μm or less and Ra _0.25 to 0.3 μm or less. Therefore, the inventors examined the manufacturing conditions that strongly affect the adjustment of the surface roughness, and among them, the injection pressure and the roll peripheral speed have a large influence on the surface roughness, and these are set within a predetermined range. It was found that the desired purpose can be achieved by controlling the temperature.

FIG. 7 shows a molten alloy of Fe ₇₈ Si ₁₄ B ₈ composition,
By the single roll method, under the condition that the plate thickness was kept constant at 20 μm, the relationship between the roll peripheral speed and the surface roughness when the amorphous ribbon was manufactured by simultaneously changing the roll peripheral speed and the injection pressure was investigated. Show. The other manufacturing conditions are: nozzle slit thickness: 0.7 mm, roll-nozzle gap: 0.15 mm. As is clear from the figure, the surface roughness became smaller as the roll peripheral speed increased, and Ra _0.8 could be _0.8 μm or less at the roll peripheral speed of 35 m / s or more. If the roll peripheral speed becomes too fast, the influence of rotational shake becomes large, and the surface roughness deteriorates. Therefore, the upper limit is preferably about 50 m / s or less.

Next, FIG. 8 shows the results of an investigation on the relationship between the injection pressure and the surface roughness when an amorphous ribbon was manufactured under the same conditions as in FIG. As is clear from the figure, the surface roughness decreases as the injection pressure increases, and Ra _0.8 is 0.8 when the injection pressure is 0.3 kgf / cm ² or more.
It could be less than μm. However, if the injection pressure exceeds 0.6 kgf / cm ² , there is a risk of a paddle break, so the injection pressure is 0.3 to 0.6 kgf / cm ^2.
Must be cm ² .

As described above, the roll peripheral speed is set to 35 m / s or more, and the injection pressure is 0.3 to 0.6 kgf / cm.
^By setting the value to ² , the surface roughness Ra _0.8 can be 0.8 μm or less, but for example, if the roll peripheral speed is increased, the plate thickness decreases accordingly, while if the injection pressure is increased, the plate thickness increases. The thickness of the plate was expected by this invention
It is important to select the roll peripheral velocity and injection pressure from the above ranges so as to satisfy 15 to 25 μm.

Regarding other manufacturing conditions, the nozzle slit thickness and the roll-nozzle gap are important, and the nozzle slit thickness is limited to 0.4 to 1.0 mm and the roll-nozzle gap is limited to 0.10 to 0.20 mm, respectively. It is preferable. Because the nozzle slit thickness is
If it is less than 0.4 mm, the surface roughness of the manufactured ribbon tends to increase and the iron loss tends to increase.On the other hand, if it is wider than 1.0 mm, paddle break occurs even if the injection pressure is 0.3 kgf / cm ² or less. However, there is a high possibility that it becomes impossible to make a plate with a higher injection pressure. Also, when the nozzle-roll gap is narrower than 0.1 mm, the surface roughness of the manufactured ribbon increases, which causes an increase in iron loss. There is a great risk that the plate will become impossible.

Thus, the plate thickness is 15 to 25 μm and the surface roughness is
By controlling Ra _0.8 to 0.8 μm or less, iron loss (W
_13/50 ) is less than 0.15 W / kg and the variation is standard deviation.
An amorphous ribbon excellent in iron loss of 0.03 W / kg or less can be stably obtained. Furthermore, the surface roughness Ra
Controlling _0.25 to 0.3 μm or less is more advantageous because the variation in iron loss can be reduced to 0.02 W / kg or less in standard deviation.

By the way, in the course of the above-described series of experiments, the inventors of the present invention have found that the surface roughness of the amorphous ribbon depends on the casting atmosphere, and that the CO ₂ concentration in the atmosphere is 50% or more. It was found to be extremely effective in improving roughness.

FIG. 9 shows molten alloy of Fe ₇₈ Si ₁₄ B ₈ composition,
Roll peripheral speed: 35 m / s, injection pressure: 0.4 kgf / cm ² , nozzle slit thickness: 0.7 mm, roll-nozzle gap: 0.
The results obtained by examining the relationship between the CO ₂ concentration in the atmosphere and the surface roughness Ra _0.8 when the amorphous ribbon is manufactured by rapid solidification under the condition of 15 mm are shown. As is clear from the figure, the surface roughness can be improved by setting the CO ₂ concentration in the atmosphere to 50% or more.
Ra _0.8 could be further reduced.

[0042]

The present invention was developed based on the new finding that low-boron amorphous alloys and conventional high-boron amorphous alloys have completely opposite roughness dependences. That is, conventionally, in a high boron amorphous alloy, if the surface roughness is too good, the magnetic domains are rather coarsened, and the iron loss is reduced. Therefore, it is preferable that the surface roughness be somewhat rough. On the other hand, in the low boron amorphous alloy, the iron loss decreases as the surface roughness is improved, and its dependence is extremely large. Therefore, according to the present invention, by producing an amorphous alloy having a small thickness and a small surface roughness, it is possible to dramatically improve the magnetic characteristics even in a Fe-Si-B system amorphous alloy having a low boron content.

It is known that, when the surface roughness is improved, the domain wall movement is facilitated, so that the hysteresis loss is reduced among the iron loss. However, the conventional high boron content Fe--Si--B type amorphous alloy is known. In the case of the Fe ₇₈ Si ₉ B ₁₃ alloy, which is a typical example of the above, in the range where the surface roughness Ra _0.8 on the roll surface side is 1.0 μm or less, the iron loss rather increases as the surface roughness is improved. Has been. The reason for this behavior is
It is explained that when the surface roughness is improved, the magnetic domains are coarsened, and the eddy current loss is increased more than the decrease of the hysteresis loss. Therefore, in the past, it was not necessary to improve the surface roughness more than necessary, and since the dependence of iron loss on roughness was not so large, there was no idea of controlling the surface roughness.

On the other hand, the Fe-containing low boron of the present invention
In the Si-B type amorphous alloy, the iron loss is reduced as the surface roughness is improved, and its dependence is large. Looking at the dependence of iron loss on plate thickness, iron loss decreases with plate thickness in both cases.
Si-B type amorphous alloy is larger. Therefore, especially in a low boron amorphous alloy, the plate thickness and the surface roughness have a great influence on the magnetic properties. Therefore, by controlling the plate thickness and the surface roughness within an appropriate range, it is comparable to the high boron amorphous alloy. The iron loss characteristic can be obtained.

[0045]

【Example】

Example 1 Various Fe-B-Si alloy melts having the component compositions shown in Tables 1 to 3 were rapidly solidified by the single roll method under the conditions shown in Tables 1 to 3 to produce amorphous alloy ribbons. .
The thickness and surface roughness (Ra _0.8 , R
a _0.25 ), the results of investigating iron loss and magnetic flux density,
They are also shown in Tables 1 to 3, respectively.

[0046]

[Table 1]

[0047]

[Table 2]

[0048]

[Table 3]

As is apparent from the table, the amorphous ribbon obtained according to the present invention has excellent iron loss characteristics equal to or higher than those of the conventional high B content amorphous ribbon, although the amorphous ribbon has a low B content. Has been.

Example 2 Various Fe-B-Si alloy melts having the component compositions shown in Tables 4 to 12 were rapidly cooled and solidified by the single roll method under the conditions shown in Tables 4 to 12 to give an amorphous alloy ribbon. Was produced.
The thickness and surface roughness (Ra _0.8 , R
a _0.25 ), the results of investigating iron loss and magnetic flux density,
They are also shown in Tables 4 to 12, respectively.

[0051]

[Table 4]

[0052]

[Table 5]

[0053]

[Table 6]

[0054]

[Table 7]

[0055]

[Table 8]

[0056]

[Table 9]

[0057]

[Table 10]

[0058]

[Table 11]

[0059]

[Table 12]

[0060]

As described above, according to the present invention, in a so-called low boron-containing Fe-B-Si type amorphous alloy having a boron content of 10 at% or less, the conventional high boron-containing Fe-B is used.
-It is possible to stably obtain excellent iron loss characteristics comparable to those of Si-based amorphous alloys.

[Brief description of drawings]

FIG. 1 is a graph showing the relationship between the B content and iron loss of Fe ₇₈ Si _22-X B _X composition amorphous alloys.

FIG. 2 is a graph showing the relationship between iron loss and the plate thickness of Fe ₇₈ Si ₁₄ B ₈ composition and Fe ₇₈ Si ₉ B ₁₃ composition amorphous alloys.

FIG. 3 Fe ₇₈ Si ₁₄ B ₈ composition, Fe ₇₈ Si ₁₅ B ₇ composition and Fe
₇ is a graph showing the relationship between surface roughness Ra _0.8 and iron loss of ₇₈ Si ₉ B ₁₃ composition amorphous alloy.

[Fig. 4] Surface roughness of Fe ₇₈ Si ₁₄ B ₈ composition amorphous alloy
6 is a graph showing the relationship between Ra _2.5 and iron loss.

FIG. 5: Surface roughness of Fe ₇₈ Si ₁₄ B ₈ composition amorphous alloy
6 is a graph showing the relationship between Ra _0.8 and iron loss.

[Fig. 6] Surface roughness of Fe ₇₈ Si ₁₄ B ₈ composition amorphous alloy
5 is a graph showing the relationship between Ra _0.25 and iron loss.

FIG. 7 is a graph showing the relationship between the roll peripheral speed and the surface roughness Ra _0.8 when rapidly solidifying an alloy melt of Fe ₇₈ Si ₁₄ B ₈ composition.

FIG. 8 is a graph showing the relationship between the injection pressure and the surface roughness Ra _0.8 at the time of rapidly solidifying an alloy melt of Fe ₇₈ Si ₁₄ B ₈ composition.

FIG. 9 is a graph showing the relationship between the CO ₂ concentration in the atmosphere and the surface roughness Ra _0.8 when rapidly solidifying an alloy melt of Fe ₇₈ Si ₁₄ B ₈ composition.

Front page continuation (72) Inventor Fumio Kogiku 1 Kawasaki-cho, Chuo-ku, Chiba, Chiba Prefecture Kawasaki Steel Co., Ltd. Technical Research Institute (72) Nobuyuki Shiga 1 Kawasaki-cho, Chuo-ku, Chiba Chiba Technical Research Institute of Iron Co., Ltd.

Claims (8)

[Claims] 1. A low boron content Fe having a B content of 6 to 10 at%.
-Amorphous B-Si alloy with a plate thickness of 15-25μ
m and a surface roughness Ra _0.8 (center line average roughness on the ribbon roll surface side measured at a cutoff value of 0.8 mm) of 0.8 μm
A low boron amorphous alloy with excellent magnetic properties, characterized by satisfying the following. 2. The B content according to claim 1, wherein the B content is 6 to 8 at.
%, The plate thickness is 15 to 20 μm, and the surface roughness Ra _0.8 is 0.6 μ.
A low boron amorphous alloy with excellent magnetic properties that is m or less. 3. A low boron content Fe having a B content of 6 to 10 at%.
-Amorphous B-Si alloy with a plate thickness of 15-25μ
m and a surface roughness Ra _0.25 (center line average roughness on the ribbon roll surface side measured at a cutoff value of 0.25 mm) of 0.3 μm
A low boron amorphous alloy with excellent magnetic properties, characterized by satisfying the following. 4. The B content according to claim 3, wherein the B content is 6 to 8 at.
%, The plate thickness is 15 to 20 μm, and the surface roughness Ra _0.25 is 0.2 μ.
A low boron amorphous alloy with excellent magnetic properties that is m or less. 5. A Fe-B-Si alloy melt having a B content of 6 to 10 at% is rapidly solidified by a single roll method to obtain a plate thickness of 15 to
When producing 25 μm amorphous ribbon, low boron amorphous material with excellent magnetic properties characterized by rapid solidification under conditions of injection pressure: 0.3-0.6 kgf / cm ² and roll peripheral speed: 35 m / s or more. Alloy manufacturing method. 6. The method for producing a low boron amorphous alloy having excellent magnetic properties according to claim 5, wherein the thickness of the nozzle slit in producing the amorphous ribbon is 0.4 to 1.0 mm. 7. The nozzle-roll gap in manufacturing an amorphous ribbon according to claim 5 or 6,
A method for producing a low boron amorphous alloy having excellent magnetic properties, characterized in that the thickness is 0.1 to 0.2 mm. 8. The method for producing a low boron amorphous alloy having excellent magnetic properties according to claim 5, 6 or 7, wherein the CO ₂ concentration in the atmosphere when producing the amorphous ribbon is 50% or more. .