JPH03291360A - Alloy for magnetic head - Google Patents

Abstract

PURPOSE:To obtain a wear resistant alloy for magnetic head having high magnetic permeability and high saturation magnetic flux density by specifying a composition consisting of Si, Al, Ti, and Fe. CONSTITUTION:This alloy is an alloy for magnetic head which has a composition consisting of, by weight, 4-6.5% Si, 3.5-6.0% Al, 0.01-0.15% Ti, and the balance essentially Fe and further containing, if necessary, <=0.06% B and combines saturation magnetic flux density as high as >= about 13000G with wear resistance. This alloy is produced so that solid-solution C can be fixed in the form of carbide and the phenomenon of magnetic after-effects can be removed and also high magnetic permeability can be stably obtained.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to a Fe-5i-AI alloy that has both a high saturation magnetic flux density of 13,0 OOG or more and wear resistance, particularly for use in high coercive force recording media. It is suitable for use as a core for thin-film magnetic heads, magnetic heads for prepaid cards, and the like.

(Conventional technology) In order to increase the density of magnetic recording and maintain the security of recorded information,
Recording media are required to have higher and higher coercivity. Accordingly, magnetic heads are also required to have high magnetic permeability materials with high saturation magnetic flux density, and active research and development is currently underway.

Until now, Fe-9.5wt has been used as an alloy for magnetic heads.
χ (hereinafter simply expressed as %) Si-5,5χAl alloy or amorphous alloy have been used, but the former does not have a sufficient saturation magnetic flux density for recording on recent high coercive force media, and the latter Since it is not possible to manufacture a bulk material, it is not suitable as a magnetic head for prepaid cards.

(Problems to be Solved by the Invention) In the Fe-5j-A1 alloy, the composition exhibiting maximum magnetic permeability is the above-mentioned 9°5χSi 5.5χAl-remainder F
With this composition, the saturation magnetic flux density is 10,
It is as low as about 000 Gauss (G).

At this point, 4~6.5χSi-3,5~6.0χAl-
It is known that there is a region exhibiting high magnetic permeability near the composition of the remaining Fe, and in such a composition region, the saturation magnetic flux density is also 1.
High at 3,000 to 17,000 OOG.

Therefore, when trying to obtain both high saturation magnetic flux density and high magnetic permeability with the Fe-5i-A1 alloy, the composition is limited to this range. However, according to research by the inventors, alloys in this composition range have magnetic aftereffects (D
-A) It was found that the phenomenon appeared significantly.

The purpose of this invention is to solve the above-mentioned problem of practical problems.
An object of the present invention is to provide an alloy for a magnetic head that can advantageously solve the problem A and stably obtain both high saturation magnetic flux density and high magnetic permeability.

(Means for solving the problem) Since the D-A of ferrite and amorphous alloys is relatively large, various studies have been conducted to solve this problem, but compared to this, the D-A of metal materials is generally small. Since it was considered to be small and pose no practical problem, very little research has been conducted on it to date.

Therefore, the inventors discovered that 4-6.5χSi -3,5-6.
A systematic investigation was conducted on the influence of composition and impurities on D-A of 0xAl-balance Fe alloy. the result,
It was found that within the investigated composition range, there are two composition ranges showing the maximum of D-A, and that among the impurities, C has the most adverse effect.

Therefore, the inventors next proposed that by adding trace amounts of various carbide-forming elements, from the viewpoint that this trace amount of C is not as a carbide, but as an interstitial solid solution, and is related to D/A. This invention was completed after extensive research in order to fix harmful C and thereby eliminate D-A.

That is, this invention contains Si: 4 to 6.5%, Al: 3.5 to 6.0%, and Ti: 0.01 to 0.15%, with the remainder being substantially Fe. This is an alloy for a magnetic head (first invention) having a high saturation magnetic flux density.

Moreover, this invention contains Si: 4-6.5%, Al 73.5-6.0%, and Ti: 0.01-0.15% and B: 0.06%.
This is an alloy for a magnetic head (second invention) having a high saturation magnetic flux density and containing the following, with the remainder being substantially Fe.

(Function) In this invention, the component composition is limited to the above range for the following reason.

Si: 4-6.5%, Al: 3.5-6.0%Si
and AI are elements that greatly influence the saturation magnetic flux density, magnetic permeability, and hardness required for a magnetic head, respectively. As these Si and AI decrease, the saturation magnetic flux density increases, but on the other hand, DA increases, and the magnetic permeability and hardness necessary for the wear resistance of the magnetic head also decrease. Therefore, the lower limits of Si and AI are 4% and 3%, respectively.
5%, and the upper limit is Si 6 from the point of saturation magnetic flux density.
．． 5% and AI 6.0%.

Ti: 0.0f=O, 15% Ti is a useful element that particularly effectively contributes to reducing DA among carbide forming elements, and at least 0.01% is required for this effect. However, as the amount added increases, the magnetic permeability decreases, and containing more than necessary is actually harmful, so the upper limit was set at 0.15%.

B: 0.06% or less B is a useful element that not only has the effect of increasing magnetic permeability in a very small amount, but also contributes to a small but effective reduction in D-A, especially when combined with Ti. It has an outstanding effect when used.

However, if B is contained in too large a quantity, no great effect will be obtained, and instead it will cause a decrease in the saturation magnetic flux density.
．． The content was set to be within a range of 0.06%.

In addition, carbide-forming elements such as V, Cr, Nb, Hf and Zr are also effective against DA. However, its effect is small compared to Ti, and it tends to lower the magnetic permeability, so it cannot be said to be an effective element alone, but if it is 0.1% or less, it can be combined with Ti to reduce the magnetic permeability. D-A without causing a decrease in
can be reduced.

In addition, the addition of Au, Ag, and platinum metal elements is effective in improving corrosion resistance without adversely affecting D-A and magnetic permeability, so they should be added in small amounts for applications that require corrosion resistance. Can be done.

Of the impurities, C has the effect of increasing the magnetic permeability of alternating current up to about 0.1%, but D-A increases in proportion to the amount of C. Of course, carbide that is commensurate with the amount of C Although it is possible to reduce D·A by adding a forming element, the saturation magnetic flux density and magnetic permeability decrease accordingly.

Therefore, it is preferable to reduce the amount of C mixed in as much as possible, and 0.0
It is desirable that it be 2% or less.

Further, Mn is an effective element for DA, but since it significantly lowers magnetic permeability, when added as a deoxidizing agent, etc., it is desirable to suppress it to 0.1% or less.

(Example) Using electrolytic Fe, metal AI, metal Si, metal B, and metal Ti as raw materials, 1 kg of each of the composition alloys shown in Table 1 was melted in vacuum.

After melting, it is cast in a 40IllIIφ mold with an outer diameter of 10m.
A ring sample with mφ, inner diameter 6IIIφ, and thickness [■] was prepared, and after annealing at 900°C in vacuum, the magnetic properties were measured.

Bm in the table is H=2,0000e, μz is frequency 0.3
kHz.

This is a value measured at 10 mOe. Further, for DA, μZ was measured immediately after demagnetization and after 24 hours, and calculated using the following equation (1).

μZ.

μz0: μ2 immediately after demagnetization μZza: μ2 after 24 hours As is clear from Table 1, D-A increases as the amount of Si and AI decreases and as the amount of C increases, but by including a small amount of Ti. D-A is significantly reduced and becomes so mild that it poses no problem in practice.

In addition, the invented alloy of NQ, 12, which contains a composite of Ti and B, has high magnetic permeability, and since its content is extremely small, it has little effect on the saturation magnetic flux density, making it very effective. it is obvious.

FIG. 1 shows a comparison of the results of investigating the time after demagnetization and the decreasing tendency of magnetic permeability of Comparative Example NQ5 and Invention Alloy N[112.

As is clear from the figure, No.
, 5, the magnetic permeability drops rapidly immediately after demagnetization, whereas the change in invention alloy No. 12 is gradual, and it is clear that the amount of change itself is very small.

(Effect of the invention) Thus, according to the present invention, 4
The magnetic aftereffect phenomenon of ~6.5XSi-3.5~6.0χAl-balance Fe alloy can be significantly reduced without reducing the magnetic permeability and saturation magnetic flux density, thus requiring high saturation magnetic flux density. It is extremely advantageously suited as a core material for thin-film magnetic heads and magnetic heads for prepaid cards, etc., and its contribution to the advancement of technology in the field of magnetic recording is extremely large.

[Brief explanation of the drawing]

FIG. 1 is a graph showing the relationship between the time after demagnetization and the decreasing tendency of magnetic permeability for Comparative Number 5 and Inventive Type 12.

Claims (2)

[Claims] 1. High saturation magnetic flux containing Si: 4 to 6.5 wt%, Al: 3.5 to 6.0 wt%, and Ti: 0.01 to 0.15 wt%, with the remainder being substantially Fe. An alloy for magnetic heads with density. 2. Contains Si: 4 to 6.5 wt%, Al: 3.5 to 6.0 wt%, and Ti: 0.01 to 0.15 wt% and B: 0.06 wt% or less, and the remainder is substantially An alloy for magnetic heads that has a high saturation magnetic flux density and has a composition of Fe.