JPH01203240A - Magnetic head - Google Patents

Abstract

PURPOSE:To sufficiently exhibit the capacity of a magnetic material and to improve its reliability by using bonding glass having a specified composition to bond the magnetic cores of a magnetic head or to bond the magnetic core to a slider member. CONSTITUTION:The bonding glass consisting of (a) wt.% PbO, (b) wt.% SiO2, (c) wt.% B2O3, (d) wt.% Bi2O3, and (e) wt.% Na2O and/or K2O is used to bond magnetic cores or to bond a magnetic core to a slider member to form a magnetic head (where 49<=a<=69, 10<=b<=28, 6<=c<=10, 5<=d<=8, and 0<e<=12). By this method, a couple of the magnetic cores constituting a closed magnetic circuit are abutted on each other, and a recording and reproducing head is fixed to an erasing head as in the magnetic head for a floppy disk. Meanwhile, a guard material is bonded to a magnetic core constituting a closed magnetic circuit as the magnetic head for a floppy disk, and a magnetic core is embedded in a slider member by using such bonding glass.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic head in which a magnetic core, a slider member, etc. are glass-fused.

[Summary of the invention]

In the present invention, the magnetic core, slider member, etc. are made of PBO.

By fusing S i Ch+BtOs+B 1tos with a bonding glass containing at least one of Na, O, and 0, a magnetic head with high reliability is provided.

[Conventional technology]

Generally, a magnetic head consists of two magnetic cores made of an oxide magnetic material such as Mn-Zn ferrite, or a magnetic core made of a composite of an oxide magnetic material or a non-magnetic oxide material such as ceramics and a metal magnetic material such as sendust. They are constructed by bonding them together using bonding glass. For example, the operating gap of a magnetic head is constructed by heating and melting glass to a working temperature above its melting point, pouring it between magnetic cores, and cooling it to fuse the glass between these magnetic cores. Ru.

In addition, in floppy disk drives and hard disk drives, there are magnetic heads in which a non-magnetic member called a slider is further bonded and integrated with glass to an integrated magnetic core, and the magnetic core is bonded with glass in the slider. A magnetic head embedded by bonding is used.

As described above, glass fusing is an essential element in normal magnetic heads, but in these magnetic heads, the thermal expansion coefficient of the bonding glass used for fusing is different from that of oxide magnetic materials, metal magnetic materials, and non-magnetic materials. If the coefficient of thermal expansion is significantly different from that of the oxide material, residual stress will be accumulated when the magnetic core etc. are joined, and glass cracks etc. will easily occur.

Therefore, it is necessary to match the thermal expansion coefficient of the glass used with these adherends, and the thermal expansion coefficient α = 90X1
A material of the order of 0-7 to 130 Because the magnetic properties deteriorate significantly,
Low melting point glass must be used.

However, high thermal expansion coefficient [especially thermal expansion coefficient α≧11]
0 x 10-"C-' or higher" is significantly inferior in water resistance and hardness compared to high-melting point glass. Therefore, when trying to fabricate a magnetic head using such low-melting point glass, Problems arise in that elution and glass cracks occur frequently.

[Problem to be solved by the invention]

As described above, conventional magnetic heads have many problems in terms of reliability due to the bonding glass used for fusing.
Improvements are awaited.

Therefore, the present invention was proposed in view of the conventional situation, and an object of the present invention is to provide a magnetic head that can fully utilize the capabilities of magnetic materials and has high reliability. .

[Means to solve the problem]

In order to achieve the above object, the magnetic head of the present invention has the following features:
PbOa weight % for joining magnetic cores or joining magnetic cores and slider members.

5tozb weight%, B, O, c weight%, BtzO3d weight%, Na, 0 and/or Oe weight% (however, 49
≦a≦69.10≦b≦28, 6≦c≦10.5≦d≦
8.0<e≦12).

Here, joining of magnetic cores means, for example, butting together a pair of magnetic cores forming a closed magnetic path, or fixing a recording/reproducing head part and an erasing head part as in a magnetic head for a floppy disk. In the latter case, a center core made of a magnetic material or a non-magnetic material may be interposed therebetween.

In this case, the magnetic core may be a single oxide magnetic material such as ferrite, or a composite of a metal magnetic material such as Fe-Affi-3t alloy, an oxide magnetic material, and a non-magnetic oxide material. Good too. Also, the bonding glass used for bonding may be used as a gap spacer,
A gap spacer such as Sing may be formed in advance on the bonding surface of the magnetic core, and the glass may be used only for mechanical bonding.

On the other hand, joining a magnetic core and a slider member means joining a guard material to a magnetic core forming a closed magnetic path as in a magnetic head for a floppy disk, or embedding a magnetic core in a slider member as in a magnetic head for a hard disk. etc. However, in this case, it is preferable that the glass transition point of the glass used to bond the magnetic cores to each other is higher than the fusion temperature of the bonding glass.

[Effect]

P b O+ S 10t+ B tos+ B l
In a glass made of goz and NazO (KtO), an increase or decrease in the content of NazO (KtO) has a large effect on an increase or decrease in the coefficient of thermal expansion of the glass. O(K
By selecting the content of zO), the coefficient of thermal expansion of the glass is controlled to an optimal value. In addition, the increase in the content of 5iCh results in lower reliability due to the addition of N a z O (K z O).

Recover deviations in working temperature and vitrification range.

By using such glass to join magnetic cores or magnetic cores and slider materials, residual stress due to fusion is suppressed, the mechanical strength and reliability of the joint is ensured, and at the same time the performance of the magnetic material is improved. It is fully demonstrated.

〔Example〕

The present invention will be described below based on specific examples.

FIG. 1 shows an embodiment in which the present invention is applied to a so-called ferrite head, in which a pair of magnetic cores (1) and (2) made of an oxide magnetic material such as Mn-Zn ferrite are used.
) are gap-bonded by a bonding glass (3), and a magnetic gap g is constructed using the bonding glass (3) as a gap spacer.

Here, the bonding glass (3) includes 8% by weight of Pb, 8% by weight of SiOgb, % by weight of B, O, c, Bi2O
3d% by weight, Na2O and/or KzOe% by weight, and the composition range is 49≦a≦69 10≦b≦28 6≦c≦10 5≦d≦8 0de≦12 .

In the bonding glass (3) having the above composition, lead oxide (pbo) is a component that lowers the melting point of the glass, and its composition ratio is increased or decreased in order to control the working temperature of the bonding glass (3) obtained. .

However, if PbO is less than 49% by weight, the working temperature will be 600%.
If the temperature exceeds °C and PbO exceeds 69% by weight, the working temperature will drop below 500°C and the water resistance of the resulting glass will deteriorate, so the PbO content should be in the range of 49 to 69% by weight. It is preferable to do so.

Although this is not a problem in this example, when used for joining a magnetic core having a sendust core part as in the example described later, the heat treatment of the sendust core is performed at the same time as the glass fusion. The fusing temperature is 50
Must be between 0 and 600°C.

Furthermore, 5iOz is a component that expands the vitrification range, increases the melting point of the glass, and improves the reliability (water resistance, corrosion resistance, etc.) of the glass. This Sin
, the content is preferably in the range of 10 to 28% by weight from the viewpoint of glass reliability, working temperature, etc. If the content of SiO□ is less than 10% by weight, the working temperature will be less than 500°C, and the resulting glass will have poor water resistance.

Corrosion resistance and wear resistance deteriorate. Moreover, it crystallizes, making it difficult to draw, and the wettability deteriorates. Sin.

If the content exceeds 28% by weight, the working temperature will exceed 600°
If it exceeds C, the lineability deteriorates.

BzCh is also a component that expands the vitrification range, reduces viscosity and improves wettability. For example, lowering the viscosity of glass with PbO increases the coefficient of thermal expansion, but B x Oz is a unique substance that lowers the viscosity without increasing the coefficient of thermal expansion. However, this 820. The content of is 6
If it is less than 10% by weight, the obtained glass will crystallize, making it difficult to draw and the wetting property will deteriorate, and if it exceeds 10% by weight, the wetting property will become too good and corrosion to ferrite will increase. It is preferable to set it within the range of 6 to 10% by weight.

Bi, O, are components similar to PbO, but PbO
It has the property of lowering the viscosity of glass.

The composition range of Bi and O is 5 to 8% by weight. When the content of Bi and O is less than 5% by weight, the working temperature exceeds 600° C. and the wettability of the glass deteriorates. On the other hand, if the content of Bit's exceeds 8% by weight, the wetting properties of the obtained glass will be too good and there is a risk that it will corrode ferrite and the like.

NatO is a component that significantly increases the coefficient of thermal expansion of the glass obtained, but if it is contained in a large amount, it lowers the reliability of the glass and lowers its melting point.

Moreover, it becomes difficult to draw the line as it deviates from the vitrification range. Therefore, in the present invention, when the content of NatO is increased, the contents of St and O are simultaneously increased to raise the melting point and secure a predetermined melting point, widen the vitrification range, and improve reliability. . However, if the Na2O content exceeds 12% by weight, the water resistance and corrosion resistance of the glass will deteriorate, and the glass will crystallize and deteriorate its lineability, which makes it difficult to draw, so it should be kept below 12% by weight. is preferable, and the thermal expansion coefficient of the glass can be controlled by increasing or decreasing the contents of Na and O, but if the NazO content is 0% by weight, the compatibility with ferrite and ferromagnetic metal materials is poor. Become. From this point of view, the content e of NatO is set to 0% by weight and 8512% by weight. In this case, some or all of the above Na and O are replaced by
It may be replaced with O. However, when using K and O, it is necessary to increase the content slightly; in order to obtain the same effect as containing 12% by weight of Na2O, the content of KtO needs to be about 15% by weight. be.

The bonding glass (3) having the above composition has a glass transition point (temperature at which the coefficient of thermal expansion changes) of 370 to 420.
°C2 yielding point (temperature beyond which the glass shape does not return even if cooled if the temperature is increased) 420 to 450 °C2 fusion temperature (working temperature) 500 to 650 °C, and the amount of NatO and KzO added By increasing or decreasing the coefficient of thermal expansion (all coefficients of thermal expansion described in this specification are 10
The value is from 0 to 350°C. ) is 90X10”~130
X10-F ("C-'). Therefore, the magnetic core (1).

The amount of Na, O, and O added is controlled according to the thermal expansion coefficient of (2), and the thermal expansion coefficient of bonding glass (3) is adjusted to the thermal expansion coefficient of these magnetic cores (1) and (2). Bye.

The fusing temperature varies depending on the shape of the magnetic head and the fusing method; for example, it is 580 to 600°C when forming a rad gap from a glass groove to a sink, and 600 to 63°C when applying glass evenly on a flat surface.
Set to 0°C.

In the magnetic head integrated by bonding using the bonding glass (3) as described above, the magnetic core (1).

Because the difference in thermal expansion coefficient between (2) and bonding glass (3) is small, there is no occurrence of cracks, etc. Also, because the joint made of bonding glass (3) has sufficient water resistance and hardness , resulting in a highly reliable and precise magnetic head.

Next, another example of a magnetic head to which the present invention is applied will be described.

In Fig. 2, one magnetic core (11) is a metal magnetic thin film (l).
1a) and a ferrite core part (llb), and the other magnetic core (12) is made of a single ferrite. This is an example of a so-called metal-in-gap type magnetic head. In the magnetic head of this example, the 5ift film is the gap material (
13) These magnetic cores (11).

(12), and the bonding glass (14) is formed on the bonding interface of these magnetic cores (11), (12).
) is intended for mechanical connection only.

The bonding glass (14) is P as in the previous example.
b O+ S i O□, B! 03+ B 1 g
It is a glass made of os and NatO (KIO).

This magnetic head has high reliability as in the previous embodiment, but it also has a bonding glass (14).
Since the melting point of gold is low, metal magnetic thin films (l
la)'s magnetic properties are not deteriorated, and its capabilities are maximized.

Figure 3 shows a magnetic head for a floppy disk to which the present invention is applied, with a magnetic core (21) made of ferrite.
, (22) and the magnetic cores (23), (24) are respectively joined and integrated to constitute a recording/reproducing head section and an erasing head section, and at the same time, these recording/reproducing head section and erasing head section are integrally fixed, Furthermore, guard members (25) made of ceramics or the like are bonded to both sides in the running direction of the magnetic recording medium.

That is, the magnetic cores (21), (22) and the magnetic cores (23), (24) are bonded and integrated by the primary fusion glass (26), and the recording/reproducing head section and the erasing head section [magnetic core (22) and the magnetic core (23)) are fixed by a secondary image forming glass (27). Furthermore, the guard material (25) is joined by a tertiary imaging glass (28).

Here, a glass having the above-mentioned composition is used for the secondary image forming glass (27). This secondary fused glass (2
By using the above-mentioned glass in 7), the reliability of the adhesion between the recording/reproducing head section and the erasing/rad section becomes high. In addition, in such a magnetic head for a floppy disk,
It is necessary that the glass transition point of the primary imaging glass (26) is higher than the fusing temperature of the secondary imaging glass (27), but the secondary imaging glass (27) has a low melting point. Therefore, the range of choices for the primary imaging glass (26) is widened.

In this example, a glass having the above composition is used as the secondary image forming glass (27), but the same effect can be obtained even if the glass is used as the tertiary image forming glass (28).

4 and 5 show the application of the present invention to a magnetic head for a hard disk, in which a magnetic head portion in which a pair of magnetic cores (31) and (32) are joined and integrated is a slider member. (33) It is embedded inside.

That is, the slider member (33) is provided with a notch corresponding to the magnetic head portion, and the magnetic core (31) is inserted into the notch.
, (32) is fitted therein.

In the magnetic head section, in order to regulate the track width, the vicinity of the sliding contact surface of the magnetic recording medium is shaved off along the medium running direction, and glass (35) is poured into this stepped portion (34). Then, the buried portion is polished so that the magnetic recording medium sliding surface of the magnetic head section is flush with the sliding surface (33a) of the slider member (33), and the working gap g is set on this magnetic recording medium sliding surface. is exposed.

Therefore, the gap material (36) of the working gap g is 1
Next image-attached glass, glass poured into the stepped portion (34) (
35) is the secondary imaged glass.

In such a magnetic head, the glass (35) contains P b O, S i Ot, Bz
By using glass made of Ox+Bi20a and Na to (KzO), a magnetic head that does not generate cranks and has high reliability can be obtained. Furthermore, this example is advantageous in ensuring the abrasion resistance of the glass (35).

The present inventors actually developed a ferrite material having a high magnetic flux density and a high coefficient of thermal expansion (coefficient of thermal expansion α = 130X 10-"C
-') glasses shown in Table 1 (Samples 1 to 1)
A magnetic head was prototyped using Sample 3), and its characteristics were evaluated.

The configuration of the prototype magnetic head is shown in FIG. This magnetic head is a full erase head in which a pair of ferrite cores (41) and (42) are butted together with a center core (43) in between, and a back core (44) is further bonded with epoxy resin. It is.

A coil bobbin (45) around which a coil is wound is fitted into the center core (43), and each core (41)
.

(42), (43) gap fused glass (46)
Samples 1 to 3 are used in , (47).

The composition of the fused glass used is as shown in Table 1,
Further, its thermal expansion coefficient and glass transition point are shown in Table 2.

(See blanks below) Table 1 Table 2 In the prototype magnetic head, there was no glass elution due to grinding water (and no glass cracks due to grinding resistance or differences in thermal expansion coefficient).

Moreover, since it is possible to select glass having a coefficient of thermal expansion that minimizes adhesive stress, it has been possible to complete a magnetic head that can maximize the magnetic properties of the ferrite material.

In other words, since the fusing temperature was kept constant at 590°C during the trial production of the magnetic head, all differences in magnetic properties due to heating were canceled out, and in the magnetic head using samples 1 to 3, the thermal expansion of these glasses was 6 For example, differences in magnetic properties (electrical properties) can be obtained only by differences in coefficients.
Impedance at frequency 300kHz is 240Ω
When Q was measured for this head, the results shown in Table 3 were obtained.

Table 3 Accordingly, by using the glass of Sample 2, the magnetic properties of the ferrite material are maximized in the magnetic head of this example.

Although specific embodiments of the present invention have been described above, it goes without saying that the present invention is not limited to these embodiments and can be modified without departing from the gist of the present invention. Materials of magnetic core, slider parts, etc.
The dimensions of the shape 9, etc. can be changed as appropriate.

〔Effect of the invention〕

As is clear from the above description, the magnetic head of the present invention has an optimal thermal expansion coefficient, low melting point, high hardness, and high water resistance for joining magnetic cores or joining magnetic cores to a slider member. Since glass is used which has excellent properties such as hardness, it is possible to provide a highly reliable magnetic head without glass cracks, glass elution, film peeling, etc.

Additionally, since the fusing temperature (working temperature) can be maintained at a constant temperature, the magnetic properties of the magnetic material that makes up the magnetic core can be maximized, making it possible to create a high-performance magnetic head. be.

[Brief explanation of the drawing]

1 to 6 each show an embodiment of a magnetic head to which the present invention is applied. FIG. 1 is a schematic perspective view of a ferrite head, and FIG. 2 is a schematic diagram of a metal-in-gap type magnetic head. 3 is a plan view of a magnetic head for a floppy disk, FIG. 4 is a schematic perspective view of a magnetic head for a hard disk, and FIG. 5 is an enlarged perspective view of its main parts;
FIG. 6 is a schematic side view of the full erase head. 1.2.11.12.21, 22.23, 24, 31,
32,41.42.43...Magnetic core 25...Guard material 33...Slider member 3.14...Bonding glass 26.27.28...Fusion glass 35...Glass

Claims (2)

[Claims] (1) PbOa weight%, SiO_ for bonding between magnetic cores
2b weight%, B_2O_3c weight%, Bi_2O_3d
weight%, Na_2O and/or K_2Oe weight% (however, 49≦a≦69, 10≦b≦28, 6≦c≦10, 5
A magnetic head characterized in that a bonding glass having the following relationship: d≦8, 0<e≦12) is used. (2) PbOa weight %, SiO_2b weight %, B_2O_3c weight % for joining the magnetic core and the slider member. Bi_2O_3d wt%, Na_2O and/or K_2
Oe weight% (however, 49≦a≦69, 10≦b≦28,
A magnetic head characterized in that a bonding glass satisfying the following conditions: 6≦c≦10, 5≦d≦8, 0<e≦12) is used.