JPS607698B2 - High permeability alloy - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in Fe-A〆-Si based high magnetic permeability alloys.

Fe-A-Si based high magnetic permeability alloy is usually called Sendust, and conventionally, the one with the best properties is Si9.6.
%, A〆5.4%, balance Fe.

This alloy has an initial permeability of 35100 and a maximum permeability of 11750.
0, coercive force is 0.0X, saturation magnetic flux density is about 1100, specific electrical resistance is 80.0. It has excellent magnetic sensitivity, high saturation magnetic flux density, and relatively high electrical resistance, and combined with its high hardness, it has ideal properties as a core material for magnetic heads. That is, permalloy and soft ferrite are currently mainly used as analog and digital magnetic recording and reproducing magnetic heads, but the former has problems in wear resistance.
Furthermore, some of the wear-resistant permalloys that have been put into practical use have a drawback in that their magnetic flux density is low.

On the other hand, soft ferrite has a definite limit in magnetic flux density, and the generation of noise peculiar to ferrite has become a problem. Compared to these, Fe-A〆-Si based high magnetic permeability alloy,
As mentioned above, the so-called Sendust alloy has no problem with magnetism.

Furthermore, although it is somewhat inferior to ferrite in terms of wear resistance, it is significantly superior to permalloy-based materials, so it has recently become widely used as head material for magnetic recording and reproducing devices. .

However, since Sendust alloy is hard and brittle, it cannot be plastically worked, and in order to form it into a magnetic head chip, a cast material is usually formed by processing means such as cutting and grinding.

However, this alloy is single-phase from room temperature to high temperature, and it is not possible to refine the crystal grains by utilizing so-called phase transformation, so it is generally used to process the alloy as it is after casting. In general, high magnetic permeability alloys deteriorate their magnetic properties due to the presence of impurities in solid solution, so they are melted in vacuum or inert gas, or the alloys are inherently brittle and the ingot is cooled. Because it is necessary to slow down the cooling rate of the ingot after casting in order to prevent cracks from forming, the cast structure of the Sengst alloy has extremely coarse grains. the result,
In the process of forming an ingot into a head chip through processing such as cutting and grinding, chipping at the edges of the workpiece or peeling on the surface of the workpiece occurs, resulting in extremely low product yields, which is a major problem in practice. It becomes.
The present invention relates to improvement of the above-mentioned drawbacks of Sendust alloy.

In other words, in order to reduce chipping or peeling of the workpiece that occurs when processing sendust alloy into head chips,
It is effective to make the crystal grains of ingots finer, and it is known that for this purpose it is possible to obtain ingots with significantly finer grains by adding a small amount of impurities to sendust alloy. It is based on That is, according to the present invention, A content of 2.5 to 17% by weight and Si
High magnetic permeability alloy consisting of 4-6% balance Fe, N25-1
000 skin, CIOO~3000 side, B50~300 blood, one or more types selected from 5~5~
By adding 500 ml of Ni, an alloy having fine crystal grains can be obtained without substantially impairing the magnetic properties. Here, the optimal amount of A is 5 to 6% (weight ratio: the same below), but from the relationship with Sj and other alloying elements, it is 2.5%.
Even in the range of ~17%, the magnetic properties are sufficiently good, so the lower limit is set at 2.5% and the upper limit is set at 17%.

The optimum amount of Si is 8 to 11%, but even in the range of 4 to 16% it has a sufficiently good magnetic permeability, so the lower limit is set to 4%.
, the upper limit is set to 16%.

In addition, if N2 exceeds 100 blood, and C and B exceed 3000 skin, the magnetic properties deteriorate significantly and become impractical, so N2 was set at 1000 willow, and C and B were set at 3000 feet.

In addition, the effect is not clear when N2 is less than 5 skins, C is less than 10 skins, and B is less than 50 skins, so N2 is 5 Yanagi C is 1 skin.
0 blood, B set the lower limit to the five-legged plate.

Note that the method for producing the alloy of the present invention is not particularly limited, and conventional methods for melting this type of alloy can be effectively utilized. That is, to give an example, Fe, Si, A, C
, B, the desired ingot can be obtained by melting and casting in a vacuum or an inert gas atmosphere, and when adding N2, the desired amount and amount of N2 to be added can be obtained. The desired ingot can be obtained by dissolving the necessary amount of N2 gas in a vacuum or in an atmosphere containing an inert gas. These N2, C, and B are finely dispersed in the molten metal by combining with highly reactive Si and A, and have the effect of making the crystal grains of the ingot extremely fine.

The present invention will be described below based on Examples, but the present invention is not limited by the Examples.

Example After weighing the raw materials of Sj with a purity of 99.99%, A-so with a purity of 99.99%, and Fe with a purity of 99.99% to a desired component ratio, the Fe was dissolved in a vacuum, and then Si was introduced after introducing a filler. ,A
After adding the final ingredient and C or B and making it sufficiently uniform, it was cast into a mold to obtain a steel ingot.

Note that when N2 was added, the amount of N2 gas required to achieve the desired addition amount was added at the same time as Ar was introduced. The obtained steel ingot was made into a head chip by electrical discharge machining and machining. Table 1 shows the composition of the test material, crystal grain size, clutch, chipping, etc. occurrence rate (product defect rate) when the head chip 60 was manufactured, and frequency I.
Effective magnetic permeability Ae, IKHz, coercive force Hc at KHz
, the magnetic flux density B in an applied magnetic field of e of 1.

shows. Table 1 As is clear from Table 1, No. 1 according to the present invention. 1~
No. 9, and sample No. In contrast to the conventional material No. 10, which had a large crystal grain size of 1,000 French and a high product defect rate of 6.5%, sample No. 2, the grain size is 150r,
The product defect rate was 2.7%, and sample No.
．． 8 has a crystal grain size of 100 French and a product defect rate of 2.1%, which not only has excellent machinability, but also
It can be seen that the magnetic properties are comparable to those of conventional materials.

For reference, sample No. No. 10 (Joujo Village) and sample No. The microstructure of Sample No. 8 (material of the present invention) is shown in FIGS. 1 and 2. As described in detail above, it can be seen that the present invention has an extremely large industrial effect in the sense of improving the machinability of sendust.

[Brief explanation of the drawing]

FIGS. 1 and 2 are micrographs of the conventional material and the alloy of the present invention. Figure 1 Figure 2

Claims (1)

[Scope of Claims] 1 An alloy consisting of 25 to 17% Al, 4 to 16% Si, and the balance Fe, in terms of weight ratio, contains one or two selected from the following: N_2 5 to 1000 ppm C 100 to 3000 ppm B 50 to 3000 ppm Total amount of seeds or more: 5~
A high magnetic permeability alloy characterized by adding 5000 ppm.