JPS59231714A - Magnetic head - Google Patents

Abstract

PURPOSE:To form a secure magnetic gap without deteriorating a magnetic characteristic by providing a core formed of a low heat resistant material such as an amorphous magnetic material, providing a metallic layer on the inside surface of the core continuous with the cap surface by a vapor deposition method or the like and forming a glass layer on the surface of the metallic layer. CONSTITUTION:A winding groove 14 is formed to a core block A which is formed by sandwiching and joining a core 13 made of a magnetic amorphous material of low heat resistance such as Fe-Co-Si-B, Co-Nb, etc. with a pair of glass base plates 11, 12. Cr is sputtered to form a metallic Cr layer 5 on the inside surface (slope) of the core continuous with the gap surface 16 and the surface 16 is polished flat. The magnetic materials 11, 12 are kept at <=200 deg.C during sputtering if the base plates are thoroughly cooled. SiO2 is sputtered on the surface 16 and a gap spacer 17 is formed. A low melting glass rod 18 is disposed in a magnetic core window 14' and the right and left core blocks A, A' are joined by heating at about 480 deg.C. The temp. of the materials 11, 12 is thus maintained at the crystallization temp. or below by which the securely joined gap is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a magnetic head used in a magnetic recording/reproducing device.

Conventional Structure and Problems In order to ensure reliability, conventional magnetic heads use ferrite as the core material and use glass bonding technology to form a strong magnetic gap. For example, as shown in FIG. 1, the left and right core blocks 1.1 are butted together with the magnetic gap surface 3 flattened through the polished gap spacer 2, the glass rod 4 is placed in the magnetic core window 5, and the glass rod 4 is placed in the electric furnace. 700'''C・~800
℃, and the glass rod 4 was fused to form a ring-shaped magnetic head.

This glass bonding is performed at high temperatures (70°C as described above) in order to ensure that the viscosity of the bonded glass is sufficiently low so that the glass gets wet with the core and, as a result, develops adhesive strength sufficient to withstand machining.
The heat treatment was performed at M 00 "°C).

However, when using a material with poor heat resistance as the core material, such as an amorphous magnetic material, it is impossible to apply heat above the crystallization temperature of that material, and the current Fe
-Co-8iB system or Co-2r system or 4$, C
The crystallization temperature of o-Nb magnetic amorphous is 450℃
The lower limit of the softening point of low melting point high lead glass is about 350°C, and in order to obtain the low viscosity necessary for adhesion, heat treatment must be performed at 550°C or higher. However, at this temperature, the amorphous crystallizes and loses its magnetic properties, making it impossible to use glass bonding technology. In other words, when the core is made of a material with poor heat resistance, such as an amorphous magnetic material, there is a problem in that a strong magnetic gap cannot be formed.

OBJECTS OF THE INVENTION An object of the present invention is to provide a magnetic head that has a strong magnetic gap even when the core is made of a material with poor heat resistance such as an amorphous magnetic material.

Structure of the Invention The magnetic head of the present invention uses a core made of a low heat-resistant material such as an amorphous magnetic material, and has gold RN formed on the inner surface of the core that is connected to the gap surface of the core, and further has gold RN formed on the surface of the solid metal layer. A glass layer is formed.

In a preferred embodiment, the metal layer is preferably made of Cry Cut Ag+Ti t Al, and is formed by vapor deposition or sputtering. Also, as a constituent material of the glass layer, a low melting point glass containing lead as a main component is good.This glass has good wettability on the metal layer, and can be bonded to the glass in a relatively low viscosity state, that is, at a low melting point. Description of Embodiment 0 As shown in FIG. 2, a core 13 made of an amorphous magnetic material
A winding groove 14 is formed in the core block A, which is sandwiched and bonded between a pair of glass substrates 11 and 12, and chromium is formed on the inner surface (slanted surface) of the core connected to the gap surface 16 by spackle ring to a thickness of 1 μm. Then, a chromium layer (metal layer) 15 is formed. Thereafter, the gap surface 16 is polished flat. In this case, an amorphous magnetic material of Co8z-Nb13-Zr6 is used as the core 13, and a photosensitive glass containing lithium silicate as the main component is used as the glass substrate 11.12. The crystallization temperature of the amorphous magnetic material is 5501° C., and a decrease in saturation magnetic flux density is observed even when treated at a temperature lower than that, and heat treatment at 480° C. for 30 minutes seems to be the upper limit of the practical range. When forming the PM layer 15 by sputtering, if the substrate to be sputtered is sufficiently cooled, the temperature rise of the amorphous itself can be suppressed to 200''C or less.

Next, as shown in FIG. 3, desired gap spacers 17 were formed on one gap surface 16 by sputtering. The material was sputtered 5i02, and its thickness was 12ooi for each of the left and right core blocks A. At this time as well, if the substrate is sufficiently cooled as in the case of sputtering the chromium layer, the temperature rise of the amorphous itself can be suppressed to 200° C. or less. This gap spacer 17 is not formed on the chromium layer 15.

As shown in FIG. 3, the gap is formed by inserting the magnetic core window 14' into the
Place a low-melting graphite glass rod 18 (0.2 mm in diameter),
The left and right core blocks A and A were heated at 480°C for 3 minutes while being butted against each other. - This low melting point lead glass contains Pb084%, B
2O5: '10, Al, 033, 5to2a components.

The softening point of this glass is 365"C, and in order to obtain a viscosity of about 102 poise at the working point of the glass, it must be at least 500°C.
' ) temperature is required.0 To lower the softening point of this glass, for example, increasing the proportion of PbO can be considered,
As the amount of PbO increases, the softening point decreases, but
The glass becomes unstable, exhibits devitrification, or a significant decrease in glass strength, resulting in a glass that cannot withstand machining.

However, when the chromium layer 15 according to the present invention is formed on the magnetic core window 14, the glass flows sufficiently into the core blocks A and A at 480'C'', and the glass layer has good bendability and adhesive strength sufficient to withstand machining. I was able to obtain one with a sharp edge (see Figure 4). Incidentally, when glass bonding was performed at 480 t without forming the chromium layer 15, the glass did not wet the core block at all, but formed into a round ball with the surface tension of 1 glass, and could not be bonded.

The wettability of this low melting point glass was greatly improved because the base was chromium, and when we measured the wetting angle with the base when low melting point lead glass was used, as shown in Figure 5, we found that chromium, copper Improvement in wettability was observed for , silver, and titanium.

In this way, a metal layer 1 is formed on the inner surface of the core that is connected to the gap surface 16.
By forming 5 and bonding the glass at that part, an improvement has been made in the conventional case where there is no metal layer, the glass processing temperature becomes too high and glass bonding is impossible. A sufficiently strong and reliable magnetic gap was obtained.

Effects of the Invention According to this invention, since a metal layer is formed on the inner surface of the core connected to the gap surface and a glass layer is formed on top of the metal layer, the wettability of the glass is significantly improved compared to when the wetting object is the core itself. As a result, a magnetic head with a strong magnetic gap can be obtained while allowing the use of an amorphous magnetic material with poor heat resistance as a core.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing a conventional example, Fig. 2 is a perspective view of a core four according to an embodiment of the present invention, Fig. 3 is a perspective view of the glass bonded state, and Fig. 4 is a front view after glass bonding. FIG. 5 is a graph showing wetting angles of various materials. 11.12... Glass substrate, 13... Core, 15.
...Chromium layer (metal layer), 16...Gap surface, 18
'...Glass layer Figure 1 Figure 3 Figure 2 Figure 4 10 20 30 40 Angle (degrees) □ Figure 5

Claims (4)

[Claims] (1) A magnetic head that includes a core made of a low heat-resistant material such as an amorphous magnetic material, a metal layer formed on the inner surface of the core that connects to the gap surface, and a glass layer formed on the surface of this metal layer. (2) The magnetic head according to claim (1), wherein the constituent material of the metal layer is any one of chromium, copper, silver, and titanium. (3) The magnetic head according to claim 1 or 2, wherein the glass layer is made of low melting point high lead glass. (4) A magnetic head according to claim (1), wherein the core is sandwiched and bonded between a pair of glass substrates.