JPS59179749A - Amorphous alloy for magnetic head - Google Patents

Abstract

PURPOSE:To provide an amorphous alloy for a magnetic head having a high crystallization temp. and an excellent magnetic characteristic and wear resistance by incorporating a specific amt. of Y and B in a Co-Fe-Ni alloy consisting essentially of Co and making the alloy amorphous. CONSTITUTION:The melt of a Co-Fe-Ni alloy consisting essentially of Co expressed by the formula (1) is quickly cooled at an extremely high cooling rate and is made amorphous. The amt. (m) of the Y to be added in the formula (1) is set within a range of 2<=m<=10 in atom concn. The amorphous alloy for a magnetic head which does not crystallize at the melting temp. of glass in the stage of adhering securely the amorphous alloy as a magnetic head material to the glass and has excellent wear resistance against friction with a magnetic medium and an excellent magnetic characteristic is obtd.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to an amorphous alloy for a magnetic head, and more specifically, an amorphous alloy having a high crystallization temperature and excellent wear characteristics against friction with a magnetic medium. This relates to an amorphous alloy for magnetic heads showing the following characteristics.

[Technical background of the invention and 4 points] Conventionally, magnetic heads used in magnetic recording devices, etc. have been made of, for example, Fe-Ni alloy (permalloy), F”e-8i-k1 alloy (sendust), or Mn. -Zn A perishable material having a ferrite-rich crystal structure is used.

However, although the Fe-Ni alloy has a high 6 magnetism, it has poor wear resistance, and the Fe-8i-AI3 alloy has a high saturation magnetic flux density, but is weak and
It is extremely difficult to perform plastic processing due to its brittle nature.2) Father, M.
Although n=Zn ferrite has poor wear resistance,
While the saturation magnetic flux density is low, it has a -q point.

In contrast, it has recently been discovered that amorphous alloys with crystalline properties have excellent magnetic properties, and are attracting attention as new materials for magnetic heads. There is.

However, in general, magnetic heads used in VTR pans are stable, strong, and free from stiffness, and bonding with glass is particularly desirable. However, glass bonding requires heat treatment at +n IJI- of 400° C. or higher and subsequent slow cooling. In this respect, amorphous alloys always have a crystallization temperature (T This poses a major problem in practice. Therefore, as an excellent amorphous alloy for a magnetic head, it is desirable to have a material that exhibits a high crystallization temperature and that does not deteriorate its properties after bonding to glass.

At the same time, due to high-speed friction between the magnetic medium and the alloy magnetic head, a striped pattern is generated on the medium sliding surface of the head, which causes a reduction in the reproduction output of the head. This was discovered as a result of research by Nagisa, the inventor of the present invention, and has become a major problem in practice. Therefore, it is desirable that an excellent amorphous alloy for a magnetic head be a material that does not cause striped WAS no matter what conditions the magnetic medium is run on.

[Purpose of the invention]

The purpose of the present invention is to solve the above-mentioned problems, have excellent sleep properties, exhibit a high crystallization temperature, maintain good quality even when subjected to heat treatment accompanied by slow cooling, and exhibit low effective magnetic permeability in the ribs. Firstly, to provide an amorphous alloy for a magnetic head of 1-J nop↓, which causes a striped pattern even in 10 rows of z-class 4-halm bodies under any Φ condition. be.

[Decay of invention, essential]

The amorphous c-gold for magnetic heads of the present invention is (COI-a-b
Fe a Ni b ) + oo -m-n Y
m BnO≦ a ≦ 0.20 0 ≦ b ≦ 0.15 05 ≦ m ≦ 10 3 S n ≦ 25.

In addition, the amorphous alloy for magnetic spatula l-' of the present invention is particularly characterized in that the addition of Y, Sf:I+: shown in the above formula, satisfies 2≦m≦10 in terms of atomic concentration. 1. The present invention will be described below in terms of if:i.

In the amorphous alloy shown in the present invention, the reasons for the addition of the valley element, the two composition ratios, and their limiters ゛, 1'! 1! The reason is as follows.

The amorphous alloy of the present invention is mainly composed of cobalt ((?0). The reason why it is mainly composed of Co is that it has low magnetostriction and high magnetic permeability, making it optimal as a material for magnetic heads. It depends.

Regarding the additive elements in the amorphous alloy of the present invention, iron (Fe) has the effect of increasing the magnetic permeability of the amorphous alloy, but it may be omitted and 0≦a≦ 0.20
is within the range of When a exceeds 0.2, the magnetic permeability goes up.

Nickel (Nj) acts to increase the magnetic permeability of the amorphous alloy together with Fe, but even when it is not included, high magnetic permeability can be obtained, and the range is 0≦b≦0.15.

When b exceeds 0.15, the saturation magnetic flux density becomes low.

Yield (Y) greatly contributes to increasing the crystallization temperature of the amorphous alloy of the present invention, and the atomic concentration in the alloy, represented by m, is in the range of 0.5≦m≦10. It is. If n] is less than 0.5, the effect of the addition will not be sufficient. At the same time, Y has an even greater effect of suppressing the occurrence of the striped pattern described in ^11, and this effect becomes particularly noticeable in the range of m=2≦m6r). On the other hand, when m exceeds 10, it becomes easy to oxidize at high temperatures, making it difficult to produce an amorphous alloy or resulting in IG.

Next, boron (B), which is a nonmetallic element, will be explained. B has an effective effect on making the alloy of the present invention amorphous. The atomic concentration in the alloy denoted by n is
The range is 3≦n≦25.

If n is less than 3, it will be difficult to make it amorphous, and if it exceeds 25, the rust resistance will deteriorate, which is not preferable.

In addition, silicon (Si) is also generally known as a nonmetallic element that has an effective effect on amorphization, but Si has a significantly lower saturation magnetic flux density than when B is added. , is preferable because it has the effect of promoting the formation of striped patterns.

The amorphous alloy for magnetic heads of the present invention includes the above-mentioned CO, F,
After mixing each component of e, Ni, Y, and 13 in a predetermined ratio, it is melted, and this is made into an amorphous alloy by, for example, a liquid quenching method or a sputtering method, and heat treatment is performed as necessary. This makes it easy to manufacture.

[Embodiments of the invention]

Examples Five types of amorphous alloys with compositions shown in Table 1 (sample numbers 1 to 1)
5) were each produced by a liquid quenching method. That is, a molten alloy having the above composition is placed on the surface of a single roll rotating at high speed in an argon atmosphere, and is heated by argon gas pressure (
1.0 to 2.2 kg/cm''), and the resulting ribbons were rapidly cooled to obtain amorphous alloy ribbon samples with a ridge of 30 μm and a width of 12 mm.The five types obtained. A thin strip sample was punched out into a ring shape having an outer diameter of 10 mmφ and an inner diameter of 8 mmφ, and 10 sheets of each were laminated with an interlayer insulator interposed.Then, this laminate was heated at 550°C.
After performing heat treatment for 30 minutes, the core was slowly cooled at a rate of 3° C. per minute to obtain a laminated core. A secondary coil and a secondary coil were wound around a laminated core using each amorphous alloy, and the effective magnetic permeability, coercive force, and saturation magnetic flux density were measured.

Note that the effective magnetic permeability μ' was measured using an impedance meter and determined by calculation. For coercive force and saturation magnetic flux density, measure the DC magnetization curve using the automatic self-recording magnetic flux side,
Obtained by calculation.

Next, each amorphous alloy ribbon sample was cut to form a magnetic rad core for a VTR, a prototype magnetic head was manufactured, and its abrasion resistance was measured. Wear resistance was evaluated by mounting the prototype head on a commercially available v′v
A V'l'R cassette tape coated with 2eg was run for 500 hours, and the change in the tape sliding surface of the head before and after was measured using an optical microscope from the side to determine the amount of wear, and this was measured per 100 hours. I did the conversion.

The crystallization temperature was measured using a differential thermal analyzer, and was defined as the temperature at which the first exothermic peak that appeared during heating started.

These results are shown in Table 1 along with the composition. Note that the effective magnetic permeability is a value at 5 MHz.

Comparative Example Three types (
Amorphous alloy ribbon samples of sample numbers 6 to 8) were obtained.

Note that sample numbers 6 and 7 do not contain Y at all, but contain Sl. Sample No. 8 also contains no Y and no Si at all.

Regarding these samples, effective magnetic permeability, coercive force, saturation magnetic flux density, wear amount, and crystallization temperature were measured in the same manner as in Example 1. Their composition and test results are
It is shown in the table together with examples.

Sample number 9 is Mn-Zn ferrite, which is a head material used in current home VTRs. General data excluding crystallization temperature are shown in Table 1 as a comparative example.

As shown by k′ and kana, the crystallization vortex r of the amorphous alloy of the present invention is higher than the crystallization temperature of the amorphous alloy that does not contain Y.
is- was confirmed to be as high as about 130°C to 380°C. Moreover, after heat treatment with slow cooling, the magnetic properties of the amorphous alloy of the present invention deteriorated compared to those of the comparative example in terms of the effective magnetic permeability μ' (5 MHz) at 14-'f. It can be seen that this is not seen.

Furthermore, it can be seen that the amount of wear of the amorphous alloy of the present invention is smaller than that of the comparative examples (Samples 6I No. 6 and 7) containing no Y but containing Sl. The stiffness is the stripes 1f on the head sliding surface.
s This is due to the fact that the outbreak of 4M was suppressed.

[7 Effects of invention]

By adding yttrium, the amorphous e1 alloy for hot gas heads of the present invention has a crystallization temperature of 75" 4N
Moreover, even if heat treatment with slow cooling is performed, the crystal orientation, especially the effective magnetic permeability, will not decrease (2). Due to the synergistic effect, the occurrence of striped patterns on the moving surface of the magnetic medium of the head is suppressed, and excellent wear characteristics are exhibited. If it is 2% or more, it becomes 1.'lJR.

The amorphous alloy for magnetic heads of the present invention has excellent suitability as a material for I34 heads.

Claims (2)

[Claims] (1) (Co+ -a-b Pe a N1b)to
o −m−n Ym BnO≦a≦0.20 0≦b≦0.15 0.5≦m≦10 3≦n≦25 An amorphous alloy for a magnetic head. (2) The amorphous alloy for a magnetic head according to item 1 of the claimed patent application, characterized in that the amount m of Y added satisfies 2≦m≦10 in terms of atomic concentration.