JPS6150201A - Production of alloy magnetic head - Google Patents

Abstract

PURPOSE:To improve both accuracy and strength of a narrow gap by forming a nonmagnetic ceramic layer on the front gap face of an Fe-Al-Si alloy magnetic core set at right and left sides or forming a glass layer on said ceramic layer and then forming an Ag-Cu-In alloy layer on the back gap face of said magnetic core to bond these layers together. CONSTITUTION:A pair of chips 1 and 2 of boat-shaped head pieces which are grooved for winding are provided on a rod type Fe-Al-Si alloy. A nonmagnetic ceramic thin film 7 is formed on both sides of a bonded part of a front gap part 5 by a sputtering process. While an Ag-Cu-In alloy thin film 9 is formed on both sides of a bonded part of a back gap part 6 by a sputtering process. Both chips are put together to form a pair of head piece chips. Then the heat treatment is applied to this chip in a non-oxidizable atmosphere of an atmospheric pressure level and at a temperature higher than a level where the liquid phase of the Ag-Cu-In alloy is produced. Thus the thin film formed at the bonded parts of both gap pars are put together with dispersion.

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 gap with high precision.

Conventional configuration and its problems In recent years, magnetic recording has been moving toward higher density. In order to achieve high-density recording, it is necessary to make the spread of the magnetic field as narrow as possible from the point of view of recording demagnetization. Precision processing and high saturation magnetic flux density magnetic core materials that are less likely to cause magnetic saturation in the vicinity of the magnetic core gap (contraction that requires the use of high coercive force magnetic recording media from the point of view of self-demagnetization) are desired.

Currently, 84.2% by weight of iron (Fe) and 84.2% by weight of aluminum (Az) are used as core materials for such high-performance magnetic heads.
, 2% by weight and silicon (Si) by 9.6% by weight (Sendust), which has a highly accurate narrow gap, is considered to be one of the most suitable.
Its widespread use is eagerly awaited in the field of magnetic recording.

However, due to the nature of the Fe-Az-Si alloy used as the core material, it is extremely difficult to form a highly accurate narrow gap in the Sendust magnetic head, and this has prevented the above-mentioned magnetic head from becoming widespread. For example, an example of a gap forming method for a conventional Fe-Al-Si alloy (Sendust) magnetic head is as shown in Figure 1.
A quartz (Sin2) film 3 is formed on the gap forming surface (tape running surface) of e-At-3t alloy (Sendust) Step 1 by sputtering, and then a low melting point silver foil (for example, silver-copper film) is formed on the gap forming surface (tape running surface). It was formed by using a cadmium-zinc based alloy (4) and bonding it to the other Fe-Az-st gold alloy (sendust) chip 2.

However, in the above method, the gap part (
Quartz (S i02
) and Fe-At-Si alloy (sendust), because their coefficients of thermal expansion differ widely (the coefficient of thermal expansion of quartz is 1.
7X 10-6X℃, Thermal expansion coefficient of F e At-5i alloy 13.5 It was the cause. In other words, this caused a gap. Also, the gap on the opposite side of the tape running surface (pack gap)
The silver brazing material 4 used is general KFe-At-5.
Low melting point silver-copper-cadmium and umu-zinc brazing materials are used to increase the bonding strength with the i-alloy. This brazing material has a large coefficient of thermal expansion (approximately 17 to 18 x 10-6
℃) Moreover, when the gap is formed, the interdiffusion with the 1c Fe-At-5i alloy is large, so when the silver brazing material solidifies after melting, cracks occur in the Fe-Az-si alloy part, and as a result, the gear tooth width decreases. This method has the disadvantage that it is difficult to control and obtain parallelism.

OBJECTS OF THE INVENTION An object of the present invention is to provide a method for manufacturing an Fe-Az-Si alloy magnetic head that allows a narrow magnetic gap to be formed with high precision and the formed gap to have high mechanical strength. This is what we provide.

Structure of the Invention The Fe-Al-3t alloy magnetic head and the manufacturing method thereof of the present invention provide a pair of Fe-Al-3t alloy magnetic heads that together form the shape of a magnetic head.
- ZrOMgOMg0-A with a uniform thickness on the front gap forming surface which becomes the tape running surface of the At-Si alloy chip.
A thin film consisting of l2O2') yi2 + 1 or a thin film of 5i02-Pb0-N a 20 series glass with a uniform thickness on top of the 5i02-Pb0-N a
After forming a glass thin film containing 20 to 80% by weight of 102, a Fe-At- Ag-Cu-In close to 3t alloy
system alloy thin film (Cu: 10-50% by weight, In: 1-30% by weight)
% by weight) by controlling the thickness with high precision, and with the gears of the same type on the left and right Fe-Al-3t alloy tips aligned, a pair of While holding the sendust chip, it is treated in a non-oxidizing atmosphere of 1 atm or less, which is higher than the softening point of glass and the liquid phase appearance temperature of Ag-Cu-In alloy, and by diffusion bonding the above-mentioned combined films. This forms a narrow gap.

Thermal expansion coefficient of the non-magnetic ceramic thin film on the front gap surface (Zr02'', 10 x 1o-67'C,
MgO”.

12 x 10-6/℃, MgO・Al2O3:1o
×10-6/°C) is in good agreement with the Fe-Al-Si alloy, so a gap can be obtained without peeling at the joint surface. In addition, when glass is formed on a non-magnetic ceramic thin film, the surface of the non-magnetic ceramic thin film and the very surface of the glass thin film become eroded by a chemical reaction.A thin compound layer is formed, resulting in considerably high mechanical strength. It is possible to obtain a gap with .

Furthermore, since the reaction layer occurs only on the very surface, the gap width can be defined by the thickness of the nonmagnetic ceramic thin film and the glass thin film. Next, back gyasso 1
7) Mutual diffusion occurs in the Aq-Cu-4n alloy at the joint with the Fe-Al-5t alloy, making it possible to bond the bank gap firmly and without cracking.

Description of examples Examples of the present invention will be described below.

(Example 1) By the method shown below, Fe-
Rad pieces were made from Az-Si alloy and examined.

First, as shown in Figure 2 a, the width is 3 cm, the height is 2 cm, and the length is 2 C) a.
Prepare the tips 1 and 2 of a pair of ship-shaped headpieces on which a winding groove with a width of 0.35 m was made on a Fe-At-5L alloy rod-shaped with a diamond%7 diamond grindstone. Then, the back gap surface 6 was mirror polished (maximum surface roughness RmaxxO 101 μm). Next, as shown in Figure 2, zirconium oxide (Z
(In this case, a mask was applied to the bank gap to prevent ZrO2 from entering.) Here, the above-mentioned zirconium oxide thin film was formed with a uniform thickness of 0.16 μm. It was hot. Next, using the same sputtering method, Ag was added to both the back gap joints.
-Cu-In alloy thin film 9 was formed. (In this case, mask the front gap so that the Ag-Cu-In alloy does not enter.)
The n thin film has a uniform float of Q, 16 μm, and its composition is 1
975% by weight, 10% by weight of Cu, and 15% by weight of In. The front gap side (Z r 02 layer) and back gap side (A
g-Cu-4n layer) were abutted against each other to form a pair of Herad piece chips, and treated in a N2 atmosphere of 1 atm at a temperature of 900°C for 1 hour to form a pair of Fe
- The thin films at the bonded portions of the gap portions of the -Az-Si alloy chips were subjected to diffusion bonding treatment.

The thus obtained rod-shaped rondo having the cross section of the headpiece shown in FIG.
It was made into a thin flake of 0 μm to obtain a Fe-AL-Si alloy rad piece.

The front gap portion and the pack gap portion of the obtained thin Fe-Al-3i alloy headpiece were polished, and the width of the gap was measured using an optical microscope.

As a result, it was observed that both the width of the front gap and the width of the back gap were o, 30 μm, and the gap planes were parallel. Moreover, since the thermal expansion coefficients of the front gap and back gap materials were close to that of the Fe-At-Si alloy, no cracks were generated on the joint surfaces. Furthermore, in order to examine the mechanical strength of the gap formed, we added 1 Fe-At-Si alloy material on both sides of the 1-gap surface.
A tensile test was performed at a stress of 0 Ky-mn, but it was found that the material did not peel off at the gap joint surface and had excellent mechanical strength. Next, set the track width of the front head to 25μ.
m and this magnetic head has a magnetic tape (coercive force HC; 1400 Oersted saturation magnetic flux density B
r; 3000 Gauss) at a relative speed of 3.45 m/sec, no "chips" were observed at the gap. Also, add 25 coils to the windings of this head.
The reproduction output voltage of the head at 5 MHz when the winding was completed was 250 μV (peak-to-peak).

The results are shown in sample number 2 in Table 1.

In the same manner, samples with different compositions of the material of the nonmagnetic layer in the front gap part and the Ag-Cu-4n alloy in the back gap part were prepared using sample numbers 1 and 3 to 12 in Table 1.
Shown below.

In addition, in this example, Fe-
Analysis using an X-ray microanalyzer confirmed that the composition of the At-Si alloy TEP did not change at all before and after the heat treatment. As a result, the saturation magnetic flux density Bs of Sendust is 8660 Gauss, and the coercive force Hc is 0.
．． 03 Oersted, AC initial magnetic permeability μ was 61 (however, in the case of 200 μm thickness), and no change in magnetic properties was observed due to heat treatment. In addition, the composition of the non-ferromagnetic ceramic film, such as ions such as q, AI, and Zr, is 0.01 μm.
We were also able to confirm that it had not spread deeper into Sendust.

Here, the composition of the Ag-Cu-In thin film effective for bonding is as shown in Table 1, with a Cu content of 10 to 50% by weight and an In content of 1 to 50% by weight.
It can be seen that the weight is within the range of the 3Q weight estimate. Those with compositions outside this range were unsuitable because of insufficient wettability with the Fe-Az-Si alloy or high liquid phase appearance temperature. Since Sample No. 1 was not bonded to the sample shown as a comparative example, it was not possible to observe the width of the lug, conduct a tape running test, and measure magnetic properties. Further, since black 6 was peeled off during machining after joining, it was not possible to measure the characteristics.

(Comparative Example 1) For comparison, a head piece with a gap was produced using a conventional forming method. That is, a hard quartz film with a thickness of 0.15 μm is formed on the front gap portion, and a head piece is attached using Ag-Cu-Zn-Cd alloy foil with a thickness of 1 μm on the back gap portion. A Fe-Al-Si alloy head similar to that shown in Figure 1 was fabricated. The gear knob portion of this headpiece was also tested in the same way as in the example.

As a result, it did not peel off in a tensile test under a stress of 10 to 9. However, the parallelism of the gap planes was extremely poor. The width of the front gap was 0.53 μm, and the width of the bank gap was 0.24 μm.

Next, when the front head part was machined and when the magnetic tape was run, chips occurred in the gap area.

Also, when a coil is wound with 25 turns in the winding groove of this head, the reproduction output voltage of the head at 5MHz is 50μ■p-
It was p.

The results are shown in sample number 13 in Table 1.

Margins below (Example 2) A Fe-Al-5i alloy was processed in the same manner as in Example 1 to produce a pair of ship-shaped hefed piece chips.

Next, as shown in Fig. 2C, zirconium oxide (Z r 02
A thin M7 was formed thereon, and a glass thin film 8 was further formed thereon by the same sputtering method. (In this case, a mask was applied to the back gap portion to prevent Z r O 2 and glass from entering.) Thus, the above-mentioned zirconium oxide thin film had a uniform thickness of 0.10 μm. On the other hand, the above-mentioned glass thin film has a uniform thickness of 0.06 μm, and its composition is as follows: 20% by weight of S s O 2 and 7% by weight of PbO.
5% by weight and 6% by weight of Na20.

Next, an Ag--Cu--In based alloy thin film 9 was formed on both of the bonding parts of the back gap part by the same sputtering method. (In this case, the front gap part has Ag-Cu-I
(Mask is applied to prevent n-based alloys from entering) The above-mentioned Ag-Cu-In thin film is coated with a uniform thickness of 0.1 mm.
5μm, its composition is Aq 65% by weight, Cu 30% by weight
, In15. It is the amount of i.

The front gap side (ZrO2-glass layer) and bank gap side (Ag-
A pair of sendust chips were formed by abutting the Cu-In layers) against each other and forming a pair of Sendust chips in a vacuum atmosphere (1X 10-'
Torr) at a temperature of 900[deg.] C. for 1 hour to perform diffusion bonding of the thin films at the bonded joint portions of the pair of Fe-AL-3t alloy chips.

The thus obtained bar-shaped rod having the cross section of the headpiece shown in Fig. 3 was cut and mechanically polished for 15 minutes.
Rad pieces of Fe-At-3i alloy were obtained by cutting into thin pieces of 0 μm.

The front gap portion and back gap portion of the obtained thin Fe-Al, -3i alloy rad piece were polished, and the width of the gap was measured using an optical microscope. As a result, both the width of the front gap and the width of the back gap are 0.3.
0 μm, and the gap planes were observed to be parallel. Also, since the thermal expansion coefficients of the front gap and back gap materials were close to that of the Fe-Al-3i alloy, no cracks were generated on the joint surfaces. Furthermore, in order to examine the mechanical strength of the gap formed in 1, the Fa-Al-31 alloy material on both sides of the gap surface was
A tensile test was performed at a stress of y-6-2, but it was found that the material did not peel off at the gap joint surface and had excellent mechanical strength. Next, when the track width of the front head was machined to 25 μm and the magnetic tape was attached to this magnetic head (coercive force Ha: 1400 Oersted saturation magnetic flux density Br: 3
000 Gauss) was run at a relative speed of 3.4E5 m/SOC, no chipping was observed in the gap.Also, when a coil was wound with 25 turns in the winding groove of this head, the 5MHz The repopulation output voltage of the head at is 2
The voltage was 50 μV (heat-to-peak).

The results are shown in sample number 15 in Table 1.

Below, various test results of samples in which the material of the nonmagnetic layer in the front gap portion, R, and the composition of the S 102 P b ON a 20 glass were changed in the same manner are shown in Sample Nos. 14 and 16 to 23 of Dragon 2.

In this example, Fe, which affects the magnetic properties, was
Analysis using an X-ray microanalyzer confirmed that the composition of the -Az-Si alloy chip did not change at all before and after the heat treatment. As a result, Sendust's saturation magnetic flux density Bs f'18650 Gauss, coercive force Ha is 0.03 Oersted, and AC initial permeability μ is 61.
(However, in the case of a thickness of 200 μm), and no change in magnetic properties was observed due to heat treatment. In addition, the ions of Mq, At, Zr, etc., which are the composition of non-ferromagnetic ceramic films, are 0.
It was also confirmed that the particles were not diffused deeper than 0.01 μm into the sendust.

Here, S 102 P b○-N a reacts with the ceramic thin film of the front gap to form a strong gap.
As shown in Table 2, the composition of the 20 series glass was when S102 was 2Q to 80% by weight.

When the amount of SiO2 is small (the amount of Pbo is extremely large (sample shop 14)), the strength of the glass itself is very weak, causing gap collapse when the tape runs.Also, S > 024
When there is a large amount of iI (sample 19), sufficient softening does not occur under the treatment conditions of 900t, so no reaction with the ceramic thin film occurs, and in this case too, SiO2 A suitable amount is 20-80% by weight.

The following margin - [Effects of the Invention As is clear from the above explanation and Tables 1 and 2, the present invention provides a Fe-A4-5i alloy magnetic recording head in which a pair of Fe-Al-- 3
A non-ferromagnetic ceramic thin film is formed with a high precision thickness on the front gap forming surface (magnetic tape running surface) of the T-alloy chip, and then a silver alloy (Ag-Cu-I) is formed on the back gap surface.
After forming a thin film (n type), with the same gap surfaces butted against each other, while holding the pair of Fe-At-3i chips, heat the non-oxidizing film at a temperature above the melting temperature of the silver solder and below 1 atm. The Fe-At-5i
Strong bonds between like-minded people are possible. Here, the thermal expansion coefficients of the Fe-AL-3i alloy in the front gap and the non-magnetic ceramic thin film are well matched (and due to force, the bonding surface 7
7) In the joint surfaces of the 5-thick thin film, the area of the back gap forming surface is much larger than that of the front gap forming surface, and the bonding is strong. The front gap, which is formed by butting ferromagnetic ceramic thin films, also has quite strong mechanical strength due to the bonding force of the back gap.

Next, a non-ferromagnetic ceramic thin film is formed on the front gap forming surface, and then a 5102
After forming a PbONa2O based glass thin film and forming an Ag-Cu-In based thin film on the puncture gap surface, a non-oxidizing atmosphere of 1 atm or less above the softening point of the glass used and above the temperature at which the silver solder melts. In the front gap when bonded by processing under certain conditions, a ceramic thin film and a glass thin film chemically react at the bonding surface, and a gap having high mechanical strength can be obtained. From the above, by controlling the film thickness during nonmagnetic thin film formation, it becomes easier to control the gear lug width, which was previously considered difficult.
Regarding gap formation in the -At-3i alloy magnetic head, it has become possible to easily form a narrow gap with high mechanical strength and high precision.

This makes it possible to easily manufacture a Fe-AL-3t alloy magnetic head having a gear jib suitable for a high-density magnetic arrangement head.

Note that in claim 2, the non-magnetic ceramic thin film is made of zirconium oxide or magnesium oxide.

The reason why we limited it to spinel is that it has a specific to thermal tensile coefficient close to that of Fe-Al-3i alloy (ZrO21oX1o-6/l:
, Mg012
310×1 o-'7/1: ) Since the hardness of L is high, it is difficult for the gap to "chip" when the tape runs.

Furthermore, in claim 5, the composition of the glass is S.
i 02-P b O-N a The reason why it is limited to 20 series is the thermal expansion coefficient of the above glass (approximately 11×10-6/°C)
is Fe-Aj-3i alloy or Z r O2, M g
O.

This is because it matches well with that of MqO.Al2O3, and therefore is less prone to thermal strain and can provide strong adhesive strength.

Here, the first step is SiO2-P b O-N a 2
0 series, but the thermal expansion coefficient is Fe-At-3t alloy, Z r O2, M g O, M g O-A
It has been confirmed that Kana 9 strong adhesion can be obtained with glasses other than those listed above as long as they conform to Z 203.

In addition, in the examples, the heat treatment atmosphere for Fe-A4-3t alloy welding was performed in N2 and vacuum, but it is not limited to this, and any non-oxidizing atmosphere (for example, Ar atmosphere) is effective. It has been confirmed that there is.

In addition, Ag-
A similar effect can be obtained by welding a Fe-Az-Si alloy magnetic core through a Cu-In thin film, but the HIP equipment itself is expensive and requires high temperature and high pressure use (e.g. 90o C,
Since it is 1000K1000Kf-, sufficient care must be taken when handling it. In contrast, the treatment method using a non-oxidizing atmosphere has a simple apparatus and is easy to handle, so it is a method with excellent mass productivity. Furthermore, Ag-Cu=In
Although the amount of alloy diffused into the Fe-At-9i alloy magnetic core is smaller than that of the HIP-treated product, it has sufficient strength, so the condition of the joint surface and the parallelism of the gap are also excellent. This is an excellent method.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the magnetic core of a conventional Fe'-Al-3i alloy magnetic henode, and FIG. A pair of Fe-A1. -St alloy chips and FIG. 3 are diagrams showing head beads produced using these Fe-At-81 alloy chips. 1.2...Fe-At-3t alloy chip, 3.
...Hard quartz film completely formed in the gap, 4...
...Welded part using silver alloy foil, 6...
...Front gap part, 6...Back gap part, 7...Nonmagnetic ceramic thin film part, 8...
...Glass thin film part, 9...Silver-copper-indium alloy thin film part. Name of agent: Patent attorney Toshio Nakao and 1 other person 2nd
Figure 4

Claims (5)

[Claims] (1) Made of an iron-aluminum-silicon alloy magnetic core material that has a front gap with a magnetic gap on the tape running surface side and a back gap, which is a gap for the purpose of bonding, on the side opposite to the tape running surface side. In a left-right butt type magnetic head, a ceramic layer or a glass layer is formed on the ceramic layer as a non-magnetic thin film layer on the front gap surfaces of the left and right iron-aluminum-silicon alloy magnetic cores, and then a glass layer is formed on the ceramic layer. After forming a silver-copper-indium alloy thin film layer on the back gap surface of the alloy magnetic core, the silver-copper-indium A method for manufacturing an alloy magnetic head, characterized in that a magnetic gap is formed by heat treatment in a non-oxidizing atmosphere at a temperature higher than the temperature at which the liquid phase of the alloy appears and lower than 1 atm, and by diffusion bonding the left and right magnetic core blocks. . (2) The nonmagnetic ceramic thin film is made of zirconium oxide (Z
rO_2), magnesium oxide (MgO), spinel (
2. The method of manufacturing an alloy magnetic head according to claim 1, wherein the magnetic head is made of one of MgO.Al_2O_3. (3) The nonmagnetic ceramic thin film is made of zirconium oxide (Z
rO_2), magnesium oxide (MgO), spinel (
2. The method of manufacturing an alloy magnetic head according to claim 1, further comprising forming a glass thin film layer on the thin film. (4) Silver-copper-indium alloy film contains copper (Cu) by 10
50% by weight and 1 to 30% by weight of indium (In), the method for manufacturing an alloy magnetic head according to claim 1. (5) Silicon dioxide (SiO_2) as a glass thin film
4. The method of manufacturing an alloy magnetic head according to claim 1, wherein the lead oxide (PbO)-sodium oxide (Na_2O) system contains 20 to 80% by weight of SiO_2.