JPS6216452B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of 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 in the current state (contact start-stop method, hereinafter referred to as 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 can 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 on the head to become uneven, causing scratches on the surface of the head and the magnetic storage body.

Furthermore, during recording and reproducing, the head suddenly comes into contact with the magnetic storage body, and a large frictional force acts between the head and the magnetic storage body, often resulting in destruction of the head and the magnetic storage body. 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, among which polysilicic acid has already been proposed as a protective film that is effective against contact friction, contact wear, and contact fracture, has high hardness, and is excellent in mass production (Japanese Patent Laid-Open No. 52 −
No. 20804). Although this also protects the magnetic memory against the contact friction phenomenon, the higher the reliability against the contact friction phenomenon, the more desirable it is, and improvement in reliability is always desired.

An object of the present invention is to provide a method for manufacturing a magnetic memory body having a protective film that better protects a metal magnetic thin film medium against the above-mentioned contact friction phenomenon.

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 laser light and fired.

Next, the present invention will be explained in detail with reference to the drawings.

The figure is a partial cross-sectional view of a magnetic storage body.

In the figure, aluminum alloy is most often used as the base 1 of the magnetic memory body because it is light, easy to work with, and inexpensive, but titanium alloy may be used in some cases. The base surface is machined to create small waviness (less than 50μm in the circumferential direction and radial direction).
100μm or less).

Next, a nickel-phosphorus alloy is coated on this base 1 as a base body 2 by plating, 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 that 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 to harden the polysilicate film by baking. Polysilicic acid has a large absorption of light in the wavelength range of 4 μm to 50 μm, and according to the infrared absorption spectrum, especially in the wavelength range of 9 to 10 μm.
It can be seen that there is a large absorption in the range of , and that carbon dioxide laser with a wavelength of 9 to 11 μm is well absorbed.

The method of baking polysilicic acid using carbon dioxide laser light as a method for producing a magnetic memory according to the present invention is applicable to nickel-phosphorus used as the base material 2, in addition to thermal curing of polysilicic acid by absorption of laser light as described above. Another excellent feature is that it does not magnetize the alloy or impair the magnetic properties of the cobalt-nickel-phosphorus alloy used as the metal magnetic medium 3. That is, due to the high energy density of the laser beam, the laser light absorption characteristics of polysilicate, and the high laser light reflectance of the metal magnetic medium 3, a high temperature gradient is created between the polysilicate surface and the cobalt-nickel-phosphorus alloy or the nickel-phosphorus alloy. This can bring about the dual effects of curing the polysilicic acid and simultaneously preventing magnetization of the base and deterioration of the magnetic properties of the metal magnetic medium.

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 As the substrate 1, a disc-shaped aluminum alloy plate whose surface was finished with sufficiently small waviness (50 μm or less in the circumferential direction and 10 μm or less in the radial direction) by lathe machining and heat straightening was used as the base body 2. 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 coated as a magnetic medium 3.
It was plated to a thickness of m. On this cobalt-nickel-phosphorized film, two coats of tetrahydroxysilane were applied.
% n-butyl alcohol solution was applied to a thickness of 0.1 μm and dried to coat polysilicic acid. Then output
A magnetic disk was made by irradiating and baking a polysilicate surface with a continuous wave carbon dioxide gas laser of 250 W and a beam diameter of 1 cm for 30 seconds.

Example 2 The same procedure as in Example 1 was carried out, except that a pulse oscillation carbon dioxide laser with an output of 25 KW and a beam diameter of 1 cm was irradiated onto the polysilicate surface for 10 seconds to burn it, and a magnetic disk was attached.

Comparative Example 1 The same procedure as in Example 1 was carried out except that the magnetic disk coated with the polysilicate film was not irradiated with laser light for 200
A magnetic disk was produced by firing in a hot firing oven at ℃ for 2 hours.

Comparative Example 2 A magnetic disk was produced in the same manner as Comparative Example 1, except that it was fired in a hot firing oven at 350°C for 1 hour.

A scratch test with a 0.03R sapphire needle was performed using each of the magnetic disks shown in Examples 1 and 2 and Comparative Examples 1 and 2, and it was found that the surface of the polysilicate film was 20 g for Comparative Example 1 and 40 g for Comparative Example 2. However, in Examples 1 and 2, no scratches occurred up to 80 g. Furthermore, when the magnetic properties of each magnetic disk were investigated, there was no change in the magnetic properties in Examples 1 and 2 and Comparative Example 1, but in Comparative Example 2, the nickel-phosphorus film was magnetized and the output voltage from the head decreased by 50%. Diminished.

Further, in both Examples 1 and 2, CSS was repeated 30,000 times, but no scratches occurred.

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 superior reliability.

[Brief explanation of the drawing]

The figure is a partial sectional view of a magnetic memory body manufactured according to the present invention. In the figure, 1 is a base, 2 is a base body, 3 is a magnetic medium, and 4 is a protective film.

Claims (1)

[Claims] 1. A magnetic storage body characterized by coating a mirror-polished base body with a magnetic medium, coating the medium with polysilicic acid, and then firing the magnetic medium by irradiating it with laser light. manufacturing method. 2. The method for manufacturing a magnetic memory body according to claim 1, wherein the wavelength of the laser beam is in the range of 4 μm to 50 μm. 3. The method for manufacturing a magnetic memory according to claim 2, which uses a carbon dioxide laser as a laser light source.