JPS61170913A - Production of magnetic head - Google Patents

Abstract

PURPOSE:To prevent the damage of a magnetic gap under working by bonding an FeAl thin film which is formed on at least one of set of core blocks by hot press. CONSTITUTION:The flat surfaces 28 and 29 to be butted against each other excluding the part corresponding to SiO2 films 27 and 27 and a window groove 24 of half-body core blocks 20 and 21, for example, are mirror-lapped. An alloy 30 contg. 16% Al and 84% Fe is then deposited by sputtering on the flat surface 29 to be butted in about 2,000-3,000Angstrom film thickness. Then the half-body core blocks 20 and 21 are clamped by pressing plates 31 and 32, pressed on each other with a force of about 0.5kgf/cm<2>, allowed to stand in an atmosphere at 10<-6> torr vacuum, at about 800-1,000 deg.C, and for 20-40min, and bonded to each other. Consequently, the bonding of the core blocks is extremely strengthened, a back gap is eliminated, the damage of a magnetic gap during production is prevented, and the deterioration of the magnetic characteristic is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to a technology for joining cores in magnetic heads such as VTRs that require high recording density.

[Second] Cursing Technique - This type of magnetic head has conventionally used a magnetic material core having excellent magnetic properties such as high magnetic permeability, low coercive force, and high saturation magnetic flux density.

The magnetic material core is generally made of Mn--Zn ferrite, which has been praised for its excellent properties as described above, extremely high resistivity, and good high-frequency properties. However, in recent magnetic heads, the magnetic material of the magnetic recording medium is γ-Fe2O3 obtained from conventional acicular goethite particles, which has a limit in saturation magnetic flux density.
-Since the use of metal magnetic powder mainly composed of Ni has been realized, as a core material for titrating high saturation magnetic flux density corresponding to this, for example, as introduced in JP-A-58-18916, Fe A sendust alloy core whose main composition is -5i-Al is about to be put into practical use. However, the sendust alloy core has lower workability than ferrite, and has the following problems in manufacturing the core.

In other words, conventional ferrite, as shown in Figure 3,
A flat abutting portion 4 of a block piece 3 with a cutout recess 2 provided near the upper corner 1 to form a coil winding insertion window, and a block piece 6 having an upper corner 5 facing the upper corner 1. The flat abutting portion 7 of the
It is assembled by joining and fixing it.

However, when changing the material to sendust alloy, low melting point glass has poor wettability and becomes difficult to bond.

Therefore, the adhesive used is one that is compatible with Sendust alloy such as brazing filler metal. That is, as shown in Fig. 4, sendust core blocks 3' and 6' are prepared, and the flat abutting parts 4' and 7' are adhered using Ag solder 9 as an adhesive, and the upper corner part 5' is A SiO2 film IO is deposited on the abutting surfaces as a magnetic gap spacer to form a back gap h and a magnetic gap g, as shown by the broken line! ! When a closed magnetic path shown by is provided, the magnetic gap 2 dimension for operation at a short recording wavelength is set to several thousand amps.

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By the way, as mentioned above, Sendust core blocks 3' and 6
' When butt-joining using Ag solder 9,
There are the following problems. In other words, if you try to use Ag solder to bond the butt points of the magnetic gap g,
Ag in the solder diffuses into the sendust alloy,
Ag, which has diamagnetic properties, magnetically expands the gap g unnecessarily. Therefore, not only is it impossible to expect an increase in recording density, but also characteristic deterioration such as a decrease in reproduction output occurs.

Therefore, as shown in FIG. 4, the Ag solder 9 is used only on the pack gap h side. Therefore, the above Sendust alloy magnetic head has an upper corner 1' forming the magnetic gap g.
, 5' are simply butted against each other, the bonding strength is extremely low, and if track extraction is performed in a hurry, the magnetic gap is likely to be damaged. Moreover,
In order to protect the magnetic gap g, if an attempt is made to mold the guard glass by forming recesses so that the wall thickness of the upper corners 1' and 5' is equal to the trunk width, the damage of the magnetic gap will further progress. There was a problem with it.

Furthermore, when the Ag solder is heated and melted for bonding, it diffuses to the grain boundaries of the flat abutting parts 4' and 7', and the molten liquid percolates between the joint parts more than necessary, causing the back gap h In some cases, it caused an increase in

This invention was proposed to solve these problems.

. In order to solve the above-mentioned problems, this invention provides a method for butt-joining a set of sendust alloy core blocks that have been subjected to processing such as predetermined groove processing and gap spacer film formation. Fe in at least one of the core blocks
-■ It is characterized by forming a thin film in advance and joining it by hot pressure bonding.

In other words, in a magnetic head using a sendust core, the present invention does not use Ag solder, which has conventionally been used as an adhesive, when joining core blocks.

The present invention also aims to improve the problem that it is generally difficult to obtain magnetic properties as designed when cores are joined.

In this invention, the Fe-A1 thin film formed on the core block becomes a soft magnetic bonding medium when the core block is thermocompression bonded, and therefore, the Ag solder used conventionally caused a back gap. On the other hand, the bank gap can be completely eliminated. Moreover, in this invention,
Since extremely strong core bonding can be performed, it is possible to prevent magnetic gap damage even if further processing is performed after bonding.

Example 1 - Fig. 1 is a front view of each half-baked core block before thermocompression bonding, which corresponds to one embodiment of the present invention, and Fig. 2 is a conceptual diagram for explaining thermocompression bonding of the core block. . First, in this embodiment, as shown in FIG. 1, a Sendust alloy semi-dead core block 20.21 is prepared, and the winding locking grooves 22.21 are prepared in the conventional manner.
23. A window groove 24 for winding insertion is formed by cutting, and a non-magnetic material such as a 5IO2 film 27.27, which will become a magnetic gap spacer, is deposited by sputtering on the upper end corner 25.2G of the abutting surfaces.

Next, the flat abutment portions 28 and 29 of the half-dead core block 20 and 21, excluding the portions corresponding to the S + 02 films 27 and 27 and the window grooves 24, are finished with a mirror finish. After that, AllB%, Fe
84% (each wt%) of alloy 30 with a film thickness of 2000 to 30
Deposit by sputtering about 00A. Then, as shown in Fig. 2, the half-dead core block 20.21 is sandwiched between graphite pressure plates 31 and 32, and the weight of approximately 0.5 kgf is
Press with a force of about /cy/ and leave for 20 to 40 minutes at about 800'C-1000'C in an atmosphere with a vacuum degree of 10'torr to bond. The subsequent manufacturing steps are the same as those for conventional magnetic heads, so the description will be omitted to avoid duplication.

Here, in the above method, the material of the Sendust core block is a general At 6.2. St 9.6. Fe 8
When the composition is 4.2 (each wt%), the saturation magnetic flux density Bs
is 8000 ~ If, 000 Gauss, coercive force He is 20w0e + initial permeability μ is about 30,000, whereas each of the Fe-At thin films 30 has a Bs of 8000G.
auss, Hc is 20+mOe, 11 is 2,
About 900 can be obtained. Therefore, the back gear lug h (fourth
Figure number h) in the figure completely disappears.

In the above embodiment, the Fe-Tsuru thin film was attached to only one of the abutting surfaces of the semi-dead core block and bonded by thermocompression, but the present invention is of course not limited to that case, and it may be attached to both sides depending on the circumstances. It's fine.

According to this invention, the joint of the core block becomes extremely strong, and the back gear joint can be completely eliminated, thereby preventing damage to the magnetic gap and preventing deterioration of magnetic properties during manufacturing. This has the excellent effect of improving manufacturing reliability and characteristics at the same time.

[Brief explanation of drawings]

FIG. 1 is a front view of each semi-dead core block before thermocompression bonding, which is an object of an embodiment of the present invention, and FIG. 2 is a conceptual diagram for explaining thermocompression bonding of the core block. 3 and 4 are front views of a conventional ferrite core and sendust core. 20, 21... Core flock, 30...
・Fe-A thin film. d's Figure 1 Figure 2

Claims (1)

[Claims] When butt-joining a set of sendust alloy core blocks that have been subjected to processing such as predetermined groove processing and gap spacer film formation, an Fe-Al thin film is formed on at least one of the set of core blocks. A method of manufacturing a magnetic head, characterized in that the magnetic head is joined by hot press bonding.