JPS61144711A - Production of alloy magnetic head - Google Patents

Abstract

PURPOSE:To improve gap accuracy by providing two-layered thin films consisting of quartz and lead-contg. glass on the front gap forming surface of an Fe-Al-Si alloy magnetic core and a thin Ag-Cu-In alloy film on the back gap forming surface thereof and subjecting these films to diffusion joining. CONSTITUTION:Chips 1, 2 of a pair of ship-type head pieces formed with winding grooves 6 by a diamond grindstone onto a bar-shaped Fe-Al-Si alloy magnetic core material are manufactured. The front gap surface 7 and the back gap surface 9 thereof are polished to a specular surface. The thin SiO2 films 3 are formed on both surfaces 7 and the thin lead-contg. glass film 4 is formed on the films 3. 7th thin Ag-Cu-In alloy films 5 are formed on both surfaces 8. The chips are subjected to a heat treatment in a non-oxidizing atmosphere of the softening temp. of the lead-contg. glass and the temp. at which the liquid phase of the Ag-Cu-In alloy is produced or above while the surfaces 7 and 8 are held butted to each other. The surfaces are thereby diffusively joined. The magnetic gap is thus formed with good accuracy and the mechanical joint strength is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method of manufacturing an alloy magnetic head, and more particularly to a method of forming a narrow gap in a seven-dust magnetic head compatible with a high coercive force tape for achieving high-density magnetic recording.

Conventional technology In recent years, high coercive force tapes such as metal tubes are being used to improve magnetic recording density, but magnetic heads compatible with this are using high saturation magnetic flux density magnetic core materials that are less likely to cause magnetic saturation near the core gap. is needed.

Currently, Fe-
A magnetic head with a highly accurate narrow gap using an AM-3i alloy is considered to be one of the most suitable, and its widespread use is eagerly awaited in the field of magnetic recording.

However, Fe-An-8i used as the core material
Due to the nature of the alloy, it is extremely difficult to form a narrow gap with high precision and high mechanical strength, and this has prevented the spread of the above-mentioned magnetic head. In the case of ferrite, it bonds extremely strongly with glass, but ・Fe −All
-5i alloys have poor wettability with glass, and it is difficult to bond them using this method. Therefore, in order to improve the mechanical strength of the gap area, the inner surface of the winding groove is bonded. method is being used. (For example, Special Publication No. 56-
130811, Japanese Patent Publication No. 57-60525)
In addition, in order to form the shape of a magnetic head after joining the two cores, it is necessary to go through processes such as cutting and mechanically polishing the joined rod-shaped rond, so the pack maintains the joining strength of the two cores. It is necessary that the bonding strength of the gap surface be extremely high. For this reason, normally a groove is formed on the pack gap forming surface of sendust, and a silver solder rod is placed in the groove and deposited.

(For example, Japanese Patent Publication No. 58-17530) Problems to be Solved by the Invention When quartz (SiO□) is formed on the front gap surface and a gap is formed by butting it together (
If the tape is not bonded), magnetic powder, dust, etc. that fall off as the tape runs enters the gap, causing a decrease in gap accuracy.

Furthermore, the silver brazing material used on the pack gap surface is generally a low melting point Ag-Cu-Cd-Zn brazing rod or foil in order to increase the bonding strength with the Fe-AR-8i alloy. However, the silver brazing filler metal has a large coefficient of thermal expansion (17 to 18 x 10-6/°C) and also has a large interdiffusion with the Fe-A4-Si alloy when forming the gap, so the silver brazing filler metal solidifies after melting. Sometimes Fe-Al1-8i
Cracks occurred in the system alloy part, and as a result of this, it was difficult to control the gear lubricant width and obtain parallelism. Furthermore, when wax foil is used, its thickness is 2 to 3 μm, which is very large compared to the gap length (0,3 to O, S μm), so the two cores are strongly pressed with a jig during the welding process by heat treatment. It is necessary to press out the excess filler metal. However, this operation causes the two cores to shift when the brazing filler metal melts, resulting in a decrease in the accuracy of the track width of the front gap.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention provides a pair of Fe-AI! After forming an 8102 thin film with a uniform thickness on the front gap forming surface which becomes the tape running surface of the -8i alloy chip, and further forming an example lead-containing glass thin film thereon, the bank gap forming surface opposite to the tape running surface is formed. As a silver solder alloy, A has a high melting point and a relatively similar coefficient of thermal expansion to that of Fe-An-8i alloys.
A g-Cu-In alloy thin film is formed by controlling the thickness with high precision, and heat-treated in a non-oxidizing atmosphere with the gap-forming surfaces of the same type of the left and right Fe-Ag-Si alloy chips aligned. By doing so, a method for manufacturing a magnetic head with high precision and high mechanical strength is provided.

Function The present invention has two Fe-Al plates with the above-described configuration. ,−
It was obtained by diffusion bonding 8i alloy magnetic core blocks. In other words, S
02 and a lead-containing glass thin film, S102
At the interface between lead-containing glass and lead-containing glass, a very thin compound is formed by a chemical reaction, and a gap with considerably high mechanical strength can be obtained. Furthermore, since the reaction layer occurs only on the surface, this gap width can be defined by the thickness of the 5i02 thin film and the lead-containing glass thin film. Next, since the thickness of the Aq-Cu-In alloy on the pack gap surface can be controlled to the combined thickness of the 5in2 that forms the front gap and the lead-containing glass, during heat treatment, it can be Since there is no outflow of melted wax, the two alloy magnetic cores are no longer misaligned. In addition, since mutual diffusion occurs in the Ag-Cu-In alloy at the joint with the Fe-An-8i alloy, it has become possible to form a strong and crack-free pack-gyoung joint.

Example Examples are shown below.

Example 1 A sod bead was fabricated using a Fe-Ag-8i alloy having a gap as shown in FIG. 1 by the method shown below, and examined.

First, as shown in Fig. 2a, a pair of lead made rods of Fe-AX-8i alloy with a width of 3 rrm, a height of 2 ran, and a length of 20 WaR were made with grooves for winding wires of 0.35 m in width using a diamond grindstone. Head piece chinogs 1 and 2 were prepared, and the front gap surface 7 and back gap surface 8 were mirror polished (maximum surface roughness Rmaxxool μm).

Next, as shown in Fig. 2, a thin film 3 of quartz (S 102 ) is formed on both front gap portions using a sputtering method, and a lead-containing glass thin film 4 is further formed thereon using the same sputtering method. In this case, the S
A mask was applied to prevent iO2 and lead-containing glass from entering. ) Here, the above-mentioned quartz thin film has a uniform thickness of 0.
．． It was 10 μm.

On the other hand, the lead-containing glass thin film mentioned above has a uniform thickness of 0.05 mm.
It is a glass thin film whose main components are 20% by weight of SiO2, 75% by weight of PbO, and 5% by weight of Na20. Next, using the same sputtering method, Ag-
A Cu-In alloy thin film 5 was formed.

(In this case, mask the front gear sawn part to prevent Ag-Cu-In alloy from entering.) Here, the Ag-Cu-In thin film mentioned above has a uniform thickness of 0.15 μm. The composition is A g 55% by weight, Cu 30% by weight, I
There are 6 items related to n15 weight. The front gap side (SiO2-lead-containing glass layer) and back gap side (Aq-Cu-In layer) obtained by these sputtering methods were brought into contact with each other to form a pair of Sendust chips, and then placed in a vacuum atmosphere (1 x 10-4 Torr). ) inside 90
A pair of Fe
- Diffusion bonding was performed on the thin films at the bonded portions of the gap portions of the All-Si alloy chips.

The rod-shaped rod shown in FIG. 3 obtained in this way is
Rad pieces of Fe-Al-8i alloy were obtained by cutting into thin pieces of 160 μm by cutting and mechanical polishing.

The front gap and back gap of the rad piece of the obtained Fe-Art-Si alloy were polished, and the width of the gap was measured using an optical microscope.
Both the width of Kafuro/Toyanop and the width of the back gap are 0.
．． 30 μm, and the gap planes were observed to be parallel.

Moreover, there were no cracks or chips on the joint surfaces of either the front gap or the back gap.

Furthermore, in order to examine the mechanical strength of the formed gap, the Fe-Ag-3i alloy material on both sides of the gap surface was subjected to a tensile test with a stress of 1 (+KP-H-2). It was found that the track width of the front head was 26 mm.
When machined to a diameter of μm, the magnetic tape (coercive force Hc; 1400 machining - Lusted saturation magnetic flux density Er; 3000 Gauss) was applied to this magnetic head at a relative speed of 3.45 m.
No "chips" were observed in the gap section when the vehicle was run at a speed of 1/sec. Further, when a coil was wound with 25 turns in the winding groove of this head, the reproduction output voltage of the head at 5 MHz was 240 .mu.cm (heak-to-peak).

The results are shown in sample number 1 in Table 1. Below, various test results of samples in which the composition of the lead-containing glass in the front gap portion was changed in the same manner are shown in sample numbers 2 to 4 in Table 1.

In this example, Fe, which affects the magnetic properties, was
Analysis using an X-ray microanalyzer confirmed that the composition of the -Ag1-3i alloy chip did not change by 1 OJ before and after the heat treatment. As a result, the saturation magnetic flux density Bs of the Fe-All-Si alloy is 8650 Gauss, the coercive force Ha is 0.03 Oersted, and the initial AC permeability μ is 61 (however, in the case of 200 μm thickness)
Also, no change in magnetic properties was observed due to heat treatment. In addition, the Si ion, which is the composition of the quartz film, is 0.01
It was also confirmed that there was no diffusion into the interior of the Fe-Art-8i alloy at a depth of more than μm.

For comparison, a headpiece with a gap was fabricated using a conventional forming method. That is, a quartz film is formed in the front gap part, and A is formed in the back gap part and the winding groove part.
The head piece was welded using a g-Cu-Zn-Cd based silver brazing rod, and the same Fe-All, -3 as shown in Fig. 4 was welded.
An i-based alloy head was manufactured. The gap portion of this headpiece was also tested in the same way as in the example. As a result, in a tensile test using an external force of 10 to 2 and 2 to 2, the film did not peel off, but the parallelism of the gap plane was significantly poor. The width of the front gap was 0.50 μm, and the width of the gap was 0.35 μm. Next, when the front part of the head was machined and the magnetic tape was run in the same way as in the example, chipping occurred in the gap portion.

When the coil is wound with 26 turns in the winding groove of this head, the playback output voltage of the head at 5MH2 is 60 μV.
Met. This result is also shown in sample number-p5 in Table 1.

Effects of the Invention As is clear from the above explanation and Table 1, the present invention
In the e-An-8i alloy magnetic recording head, a pair of Fe-All-3 which together form the shape of a magnetic head are used.
A thin quartz film with a high precision thickness is formed on the front gap forming surface (magnetic tape running surface) of the i-based alloy chip, a lead-containing glass thin film is further formed on top of it with a uniform thickness, and Aq-Cu is formed on the back gap surface. After forming the -1n-based thin film, the quartz thin film and the lead-containing glass thin film used chemically react at the bonding surface of the glass soft film used to form a gap having high mechanical strength. Also, Basok Gyanog's Aq-C
Since the u-In thin film and the F'e -An2-3i alloy are bonded very strongly, it is easy to form a high-precision gap, and as a result, Fe-Al is suitable for high-density magnetic recording.
! , it has become possible to realize a -3i alloy magnetic head.

In addition, in the examples, the heat treatment atmosphere for Fe-A4-8i alloy welding was carried out in vacuum, but the atmosphere is not limited to this.
(atmosphere, etc.) are all confirmed to be effective.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view of a Fe-AR-8i alloy magnetic head according to an embodiment of the present invention, and Fig. 2 (a) and (b) show gap formation in an Fe-A Q-Si alloy magnetic head. Figure 3 shows a pair of Fe-An-3i alloy chips used, Figure 3 shows a head piece made using these Fe-AR-3i alloy chips, and Figure 4 shows a conventional magnetic head. FIG. 1, 2-11-Fe-AQ-Si alloy chip, 3-
・Quartz layer, 4- ・Lead-containing glass layer, 5... A g
-Cu -In layer, 6-... winding groove, 7-- front gap section, 8-- back gap section, 9...-
Non-magnetic thin film part bonded with quartz and lead-containing glass, 1o.
-・Welded part using Ag-Cu-In alloy thin film, 11
...Aq solder welding part. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure/, 2--- FJ layer Al-5 plate 4 t. 3-Quartz layer 4--Ku layer 5--Ikkei Ichigo-1. Figure 2/
2---Ft-A no-S alloy 1, 3---Quartz eyebrow 4-11 Lead-containing strength glass layer 1? Figure 4/, 2--- Fz-A no-Si base metal tuff 3-
m-Quartz layer 1---/9 Floating capital?

Claims (1)

[Claims] In a left-right butt-type magnetic head made of Fe-Al-Si alloy magnetic core material, a two-layer thin film of quartz (SiO_2) and lead-containing glass is formed as a nonmagnetic layer on the front gap forming surfaces of the left and right alloy magnetic cores, and then After forming an Ag-Cu-In based alloy thin film on the back gap forming surfaces of the left and right alloy magnetic cores, the softening temperature of the lead-containing glass and the Ag-Cu-In based A method for manufacturing an alloy magnetic head, characterized by forming a magnetic gap by heat-treating in a non-oxidizing atmosphere at a temperature higher than the temperature at which a liquid phase of the alloy appears, and diffusion bonding left and right alloy magnetic core blocks.