JPH0249206A - Magnetic head - Google Patents

Abstract

PURPOSE:To eliminate air bubbles and to obtain the magnetic head having high reliability by disposing a core which consists of a magnetic material and has a winding groove and a core which has no winding groove to face each other and adhering the gap-facing surfaces by gap-forming glass having a prescribed compsn., thereby forming a gap. CONSTITUTION:The core 1 which consists of the magnetic material and has the winding groove 1a and the core 2 which as no winding groove are disposed to face each other and the gap G is formed by the gap-forming glass 4 consisting of 40-50mol% SiO2, 6-8mol% Al2O3, 12-15mol% Na2O, and 27-42mol% B2O3. Since the gap G is formed by the glass 4 having such compsn., the glass 4 has no occlusion of gaseous Ar at the time of a sputtering treatment in a gaseous Ar atmosphere and the release of the gaseous Ar is improved by a heat treatment; therefore, the deterioration of the characteristics of the head by the air bubble 6 is prevented and the magnetic head having the high reliability is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention is applicable to magnetic heads that require high reliability, such as magnetic heads for VTRs, magnetic heads for 70-speed disk drives, and magnetic heads used for computer hard disks. It is related to.

[Conventional technology]

Magnetic heads used for VTR70 disk drives or computer hard disk drives have a high recording frequency and are required to have high resolution. Therefore, strict processing accuracy is required in the manufacturing process, and in particular, the gap length must satisfy strict specifications.

To form the gap, various methods such as a molding method and an inflow method have been conventionally used, but recently a sputtering method has generally been used.

That is, as shown in FIGS. 1(a) and 1(b), the C core 1 has a winding groove 1a made of a magnetic material such as 7-Elite.
and I core 2 without a winding groove, and when adhering the C core 1 and core 2 using gap forming glass on the gap-opposing surface, a 5in2 film 3 is attached by sputtering on the gap-opposing surface. After that, a gap forming glass 4 is further deposited thereon by the same sputtering method.
The surfaces facing the gap are butted against each other, and a reinforcing rod 5 is inserted into the winding groove 1a and heated to melt the gap forming glass 4 and bond the surfaces facing the gap to form the gap G, as shown in FIG. As shown in (a), reinforcing plus 5 melted and filled in the vicinity of the gear knob G in the winding #a groove 1a is the mainstream not only for VTR magnetic heads but also for other magnetic heads. .

According to the gap forming method using the sputtering method, it is possible to form a highly accurate gap in the gear ring, and it is possible to satisfy the recent demands for magnetic heads.

[Problem to be solved by the invention]

If the gap is formed using the sputtering method, a magnetic head having a highly accurate gear ring can be obtained as described above, but the film forming process using the sputtering method is
Since the process is carried out in a f gas atmosphere, Ar7y gas is occluded in the SiO□ film and the formed glass film.

These occluded Ar and fs will not be released to the outside even if heat treatment is applied once after the coating is formed and before bonding, and the gap forming glass 4 for bonding and reinforcing the C core and I core
When the reinforcing glass 5 is heated to melt it, the ejected glass expands and aggregates within the molten glass 4 or 5, increasing its volume, as shown in FIG. 2(a).
, as shown in (b), bubbles 6 form and the reinforcing glass 5
It exists in the inner upward gear G.

Among these bubbles 6, those existing in the gear G open on the surface facing the medium when the surface facing the magnetic recording medium (hereinafter referred to as the medium) such as a magnetic disk is lapped.
Magnetic powder generated by sliding contact with the medium enters and becomes embedded, deteriorating the head characteristics and lowering reliability 6 In addition, air bubbles 6 existing in the reinforcing glass 5 cause deterioration of the head characteristics. This becomes the starting point for cracks during processing such as slicing of the core after adhesion.

As described above, air bubbles existing in the gap or positive region of a magnetic head are a problem in improving yield during the manufacturing of magnetic heads, and are also a major problem in preventing deterioration of head characteristics and improving reliability. This is the result.

In view of the above problems, the present invention solves the problems, and
The object is to provide a magnetic head with excellent magnetic properties and high reliability.

[Means to solve the problem]

The present invention has been made to achieve the above object, and includes a core (C core) made of a magnetic material and having a winding groove.
and a core without a winding groove (ecore), and SiO□4O-50u+o1% on the gap facing surface, A 12
O*6-8 mol%, Na, 0 12-15
A gap was formed by adhering a gap-forming glass consisting of 27 to 42 mol% of B2O, and in addition to the above-mentioned gap-forming glass, a 5in2 film was used as a base (first layer) to form a gap. It is formed on at least one of the opposing surfaces.

[For production]

The glass having the above composition as a gap forming glass is Ar
There is little occlusion of Ar and f during sputtering in a 1f gas atmosphere, and good release of Arff during heat treatment.
r, f can also be easily passed through.

Therefore, in a magnetic head whose gap is formed and reinforced using this gap-forming glass, there are fewer bubbles in the gap and the reinforced portion.

In the composition of the gap forming glass, 5iOz
50 IIol'% and AltOz 8 II
If it exceeds 1%, the softening point (Ts) will be 680°C or higher, resulting in insufficient adhesion, and if it is less than 5in240 mol% and A2□0,6IIIo1%, Arff gas will be easily occluded, so 5in240-50 mol%, A
12O36-8 mol% was closed.

Moreover, if Na2O exceeds 15 mol%, the corrosion resistance of the glass will deteriorate and discoloration will occur.

If it is less than %, the thermal expansion coefficient a will be small and the film will peel off.
Na and O were set at 12-15 moN%.

B2O3 is the balance composition for adjustment 27-421I
io1%.

〔Example〕

Using a gap-forming glass (hereinafter referred to as glass) having the composition shown in Table 1, a glass coating was formed on the surface facing the gap by sputtering in an Ar and F gas atmosphere, and then heated to examine the release of Arff gas. Ta.

"Conventional glass" in Table 1 is glass that has been commonly used in the past, "developed glass" is glass that was newly developed for use in the magnetic head of the present invention, and "comparison glass" is glass that was developed for comparison. It is a glass with a composition close to that of glass. The results of the 7R inspection are shown in Figures 3 and 4.

(Example 1) FIG. 3 is a diagram when only a positive film is formed. As can be seen from this figure, the conventional glass and comparative glass emit a large amount of Ar gas (especially the conventional glass
The newly developed glass (
1) has almost no emission, and the developed glass (2) has only a small amount of emission. As a result, the developed glass has Arf
It can be seen that the amount of occlusion of f-s is extremely small.

(Example 2) FIG. 4 is a diagram in which a SrO2 film is formed as a base by sputtering, and then a glass film is formed thereon.

As can be seen from this figure, conventional glass and comparative glass cannot be exposed to Ar without being heated to a considerably high temperature (700 to 800°C).
It is difficult to release ffs, and even if heated to 800° C., which is the heating limit for maintaining the properties of 7-Elite, which is the core material, it cannot be completely released.

On the other hand, development plus (1) and (2) are heated at 500 to 600℃.
A large amount of Ar and F gas are released in the relatively low temperature area nearby, and 65
Almost all of it is released between 0 and 750°C.

The Arff gas released in this Example 2 consists of the one absorbed in each glass and the 5iO2 formed as a base.
This is the total amount including that stored in 11R.

As can be seen from Example 1, the developed glasses (1) and (2) have almost no occlusion of Ar gas in the glass itself, so as shown in FIG. This allows Arff gas, which is to be released by heating, to pass through well and can be released in large quantities to the outside.

However, conventional plus and comparative glasses store large amounts of Ar and F in the glass itself, and moreover, cannot sufficiently pass Arff released from 5iO2tl.

【Effect of the invention〕

As mentioned above, since the magnetic head according to the present invention has a gap formed by the glass having the above composition, Ar
It would be desirable to have extremely few air bubbles due to ff gas, to prevent deterioration of head characteristics due to air bubbles, and to achieve high M stability.

[Brief explanation of the drawing]

Fig. 1(a) is a perspective view showing the state before heating the C core and the ■core facing each other, Fig. 1(b) is an enlarged front view of AH in Fig. 1(a), and Fig. 2 ( a) 1 20 cores,
1a: Winding groove, 2: I core, 3:
SiO2 film, 4: 7y lath for gap formation 5: Reinforcement lath 6: Air bubble, G: Gear rough

Claims (2)

[Claims] (1) A core made of a magnetic material with a winding groove and a core without a winding groove are made to face each other, and the gap facing surface is made of SiO_2
40-50 mol%, Al_2O_36-8.0,%,
Na_2O12-15 mol%, B_2O_327-4
A magnetic head characterized in that a gap is formed by bonding with a gap-forming glass made of 2 mol %. (2) SiO_ on at least one surface facing the gap
2. The magnetic head according to claim 1, comprising two films.