JPS6226095B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a magnetic storage body used in a magnetic storage device such as a magnetic disk device or a magnetic drum device.

In general, there are the following methods for recording and reproducing a magnetic storage device comprising a recording and reproducing magnetic head (hereinafter referred to as a head) and a magnetic storage body. That is, after the head and the magnetic storage surface are set in contact at the start of operation, a space corresponding to an air layer is created between the head and the magnetic storage surface by giving the magnetic storage the required rotation, and this This is a method of recording and reproducing data in the current state (contact start/stop method; hereinafter referred to as the CSS method). In this method, at the end of the operation, the magnetic storage body stops rotating, and at this time the head and the magnetic storage body surface are in a frictional state of contact, as at the beginning of the operation.

The frictional force generated between the head and the magnetic storage material under these contact friction conditions may wear out the head and the magnetic storage material, and may eventually cause scratches on the head and the metal magnetic thin film medium. Further, in the contact friction state, a slight change in the posture of the head may cause the load applied to the head to become uneven, causing scratches on the surface of the head and the magnetic storage body.

Furthermore, during recording retrieval, the head suddenly comes into contact with the magnetic storage, creating a large frictional force between the head and the magnetic storage, often resulting in destruction of the head and the magnetic storage. In order to protect the head and the magnetic memory from such contact friction, contact wear and contact breakage between the head and the magnetic memory, it is necessary to coat the surface of the magnetic memory with a protective coating.

Various protective films have been proposed in the past, and polysilicic acid, which has high hardness and is easy to mass-produce, has already been proposed as a protective film that is effective against contact friction, contact wear, and contact fracture (Japanese Patent Application Laid-Open No. 52−20804
issue).

By irradiating the polysilicic acid with laser light and firing it, it is possible to increase the reliability against contact friction phenomenon without impairing the magnetic properties and mass productivity of the magnetic memory, but the reliability against mass production and contact friction phenomenon is The higher the value, the more desirable it is, and improvement is always desired.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for manufacturing a magnetic memory that further improves mass productivity without impairing the magnetic properties of the magnetic memory and the reliability with respect to contact friction phenomena.

That is, the method for manufacturing a magnetic memory according to the present invention is characterized in that polysilicate coated on a metal magnetic medium is irradiated with a laser beam while causing multiple reflections and fired.

Next, the present invention will be explained in detail with reference to the drawings.
FIG. 1 is a cross-sectional view of two magnetic storage bodies, showing a method of firing by arranging the storage surfaces of these magnetic storage bodies parallel to each other and causing multiple reflections of laser light between them.

FIG. 2 is a diagram illustrating a method of firing by arranging reflective mirrors parallel to the storage surface of a magnetic memory and causing multiple reflections of laser light between them.

In FIGS. 1 and 2, aluminum alloy is most often used as the base 1 of the magnetic memory because it is light, easy to work with, and inexpensive, but titanium alloy may be used in some cases. The base surface is finished by machining into a surface with small undulations (50 μm or less in the circumferential direction and 100 μm or less in the radial direction).

Next, a nickel-based alloy is plated onto this base 1 as a base body 2, and this base body 2
The surface has a surface roughness of 0.03μm by mechanical polishing.
Mirror finish is achieved below (Rmax).

Next, a cobalt-nickel-phosphorus alloy is coated on the mirror-polished surface of the base body 2 as a metal magnetic medium 3 by plating, and a protective film 4 is formed on the metal magnetic medium 3 as shown in Japanese Patent Laid-Open No. 52-20804. A polysilicic acid such as the one described above is coated by a spin coating method.

Next, the surface of the magnetic storage body coated with polysilicate is irradiated with carbon dioxide laser light having a wavelength of 9 μm to 11 μm by multiple reflections to bake the polysilicate film.

There are two methods for multiple reflection: one is between two magnetic storage bodies covered with polysilicic acid, as shown in Figure 1, and the other is between a reflecting mirror and a magnetic storage body, as shown in Figure 2. In this case, two sides of the magnetic memory can be fired at the same time, but the number of reflections that can be fired is limited due to attenuation of absorption of laser light by polysilicate. On the other hand, in the latter case, the number of reflections that can be fired increases because a high-reflectance reflecting mirror is used, but only one surface can be fired at a time. Multiple reflections can occur several dozen times in the case of FIG. 1, and can be sufficiently applied to magnetic storage bodies with a diameter of 14 inches or more. This is because the metal magnetic medium 3 in the magnetic memory has a high reflectance and the polysilicate film is thin (approximately 0.1 μm), so that the absorption attenuation of the laser beam per reflection is small. That is, the laser firing method using multiple reflections can be sufficiently effective in the magnetic memory of the present invention in which a metal magnetic medium is coated with polysilicic acid.

In both Figures 1 and 2, when firing polysilicic acid over a large area of the magnetic storage body, it is necessary to move the firing position sequentially, such as by rotating the magnetic storage body in the in-plane direction. Just do it.

Next, the method for manufacturing the magnetic storage body of the present invention will be explained in detail with reference to Examples and Comparative Examples.

Example 1 A base body 2 is placed on a disc-shaped aluminum alloy plate that has been finished with sufficiently small waviness (50 μm or less in the circumferential direction and 10 μm or less in the radial direction) by lathe processing and thermal straightening as the base 1. A nickel-phosphorus alloy is plated to a thickness of approximately 50μm, and this nickel-phosphorus plating film has a surface roughness of 0.02μm.
Mirror-polished to a thickness of 30 μm (Rmax). Next, on this nickel-phosphorus plating film, a cobalt-nickel-phosphorus alloy of 0.05 μm was applied as a magnetic medium 3.
It was plated to a thickness of m. On this cobalt-nylkel-phosphorus plating film, two layers of tetrahydroxysilane were applied.
% n-butyl alcohol solution was applied to a thickness of 0.1 μm and dried to form a polysilicic acid protective film.

Next, a pulse oscillation with an output of 50 MW and a beam diameter of 0.7 cm was generated at a 45-degree incident angle between two 14-inch diameter magnetic memory bodies whose memory surfaces (i.e., polysilicate coated surfaces) were placed parallel to each other with a 1 cm spacing. A carbon dioxide gas laser was applied to the two magnetic storage bodies, which were rotated and reflected 30 times, and fired to produce a magnetic disk. however,
The oscillation period of the carbon dioxide laser was 0.5 Hz, and the pulse time was 50+1 seconds.

Example 2 A magnetic disk was produced in the same manner as in Example 1, except that one of the magnetic storage bodies was replaced with a reflecting mirror having the same shape as the magnetic storage body, and the number of reflections was 60.

Comparative Example A magnetic disk was produced in the same manner as in Example 1, except that a carbon dioxide gas laser was irradiated by single reflection.

Regarding the magnetic disks shown in Examples 1 and 2 and Comparative Examples, the firing time per surface by laser irradiation was 30 minutes in Comparative Examples, but 4 minutes in Examples 1 and 2.

In addition, there was no change in the magnetic properties in Examples 1 and 2, and even after repeating CSS 30,000 times, no scratches were generated on the surface of the magnetic memory.

From the above, it was found that the magnetic disk manufactured by the method for manufacturing a magnetic storage body of the present invention has excellent reliability and excellent mass productivity.

[Brief explanation of the drawing]

FIG. 1 is a partial sectional view showing one embodiment, and FIG. 2 is a partial sectional view showing another embodiment. In the figure, 1 is a base, 2 is a base body, 3 is a metal magnetic medium, 4 is a protective film, 5 is a laser beam, and 6
represents a reflector.

Claims (1)

[Claims] 1. A metal magnetic medium is coated on a mirror-polished base body, polysilicic acid is coated on the medium, and then the polysilicic acid is irradiated with a laser beam with multiple reflections and fired. A method of manufacturing a magnetic memory body, characterized by: 2. The method of manufacturing a magnetic memory body according to claim 1, wherein laser light is multiple reflected between two magnetic memory bodies whose memory surfaces face each other in parallel. 3. The method of manufacturing a magnetic storage body according to claim 1, wherein a reflecting mirror is faced parallel to the storage surface of the magnetic storage body and the laser beam is multiple reflected between the magnetic storage body and the reflecting mirror.