JPS61162822A - Production of magnetic disk - Google Patents

Abstract

PURPOSE:To prevent the attraction of a magnetic head and the exfoliation of the lubricating film thereof by using a decomposed polymn. product of ammonium silicate to form an SiO2 film on a magnetic metallic recording medium provided on a substrate. CONSTITUTION:A nickel-phosphorus alloy is plated as a substratum layer 2 on a disk-shaped aluminum alloy substrate 1 and a cobalt-nickel-phosphorus alloy is plated as the magnetic metallic recording medium 3 thereon. A circular disk coated with about 10% ammonium silicate soln. by a spin coating method is further calcined onto such recording medium. The formation of the SiO2 film by the low temp. heat treatment is thus made possible, by which the attrac tion of the magnetic head to the surface of the magnetic disk is eliminated. The number of CSS is thus increased and the trouble by a head crash is de creased. The cost reduction by using an inexpensive raw material is made possible and the reliability is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of manufacturing a magnetic disk used in this BAt:f magnetic disk device.

[Conventional technology]

A thin metal film is used as the magnetic recording medium of a magnetic disk, but in order to prevent oxidation due to oxygen in the air and protect the magnetic recording medium from contact friction, contact wear, and contact destruction between the magnetic head and the magnetic recording medium. In addition, it is necessary to provide a protective film on the surface of the magnetic recording medium.

Conventionally, inorganic oxides have been used for this protective film, and these include amorphous metalloids commonly called glassy materials such as quartz glass, silicate glass, borosilicate glass, phosphate glass, and amorphous alumina. It shows polysilicic acid, which is a condensation polymer such as compound and tetodihydroxysilane. The former is mainly coated by a sputtering method, and the latter is mainly coated by a liquid coating method.
013, JP-A-53-10610, etc.).

[Problem that the invention seeks to solve]

The lubricating film made by conventional sputtering has a very good surface precision and has a mirror surface.9) The magnetic head is attracted to the surface of the magnetic disk, and even when the magnetic disk starts rotating, it does not stick to the magnetic head.
There were problems such as the card not being able to levitate and the magnetic head etc. being damaged (1.M, Ros+si et al., Journal
Op Applied Physics (J, Appl, Ph
ys, ), Vol. 55, No. 6, p. 2254).

In addition, even when a lubricating film is provided on the protective film, the surface precision of the protective film is good, so the lubricating film is easily peeled off, and the number of contact start/stop (CSS) times, which indicates the reliability of the magnetic disk, is reduced. A problem arose.

In addition, protective films formed by conventional coating liquid coating methods are disclosed in, for example, Japanese Patent Laid-Open No. 5J-76013 and Japanese Patent Laid-Open No. 53-4061 (N.
As described in Japanese Patent Application Laid-Open No. 54-15704, a solution is prepared using gold, silane coupling agents such as alkoxide, and tetrahydroxysilane as raw materials and alcohol as a solvent, and then applied to the surface of a magnetic disk. It is obtained by coating and heat-treating.

This method had the problem that the raw materials were very expensive. In addition, when the magnetic recording medium is metal, the heat treatment temperature must be kept below 200°C due to restrictions from the substrate and underlayer, and as specified in the above-mentioned patent publication, the protective film is simply a decomposition of the above-mentioned raw material. It is made of polysilicic acid, which is a polymer. However, for example, in the sol-gel method of synthesizing glass from metal alkoxides, which has been extensively studied, the heat treatment temperature required to vitrify the gel obtained by hydrolyzing metal alkoxides is 600 to 1000 °C, and the melting method It is said that the same properties as silica glass can be obtained when heat treated at 900 to 1000°C (Sakuhana Masao, "Science of Glass Amorphous", Uchida Rokaku (1983), 147- (p. 164), vitrification cannot be expected at all with low brocade heat treatment at about 200°C. That is, polysilicic acid, which is a monolytic polymer, is considerably inferior in hardness and strength to the so-called 5102 film, and the protective film of polysilicic acid formed by conventional methods is weak and easily peeled off.

This invention was made in order to solve the above-mentioned problems, and provides a highly reliable magnetic disk manufacturing method that prevents magnetic heads from adhering to each other and prevents the lubricating film from peeling off due to running over. The purpose is to obtain.

[Means for Solving the Problems] - In the method for manufacturing a magnetic disk of the present invention, 102Li is formed on a metal magnetic recording medium provided on a base material using a decomposed polymer of ammonium diammonium.

[For production]

The $102 film made of a decomposed polymer of ammonium silicate according to the present invention has a surface precision that is lower than that of a sputtered film, and can prevent magnetic heads from being attracted to it, and can also be made of S
Strong retention wf as it changes to iO2 film! A film can be formed, and peeling of a lubricating film is prevented when a lubricating film is used.

〔Example〕

Although the ammonium silicate used here does not exist as a commercially available reagent, it can be synthesized into a container by a method for producing ammonium silicate according to the prior art (Japanese Patent Application No. 6611, Japanese Patent Application No. 4729). The raw material is sodium silicate, etc., which is very cheap compared to metal alkoxides and silane coupling agents.

The drawing is a cross-sectional view of a magnetic disk obtained according to an embodiment of the present invention.
) is a 5102 film, and (5) is a butterfly lubricant film.

Hereinafter, this invention will be explained in more detail with reference to Examples.
This invention is not limited to this.

Example A base layer (2
) was plated with a nickel-phosphorus alloy to a thickness of about 50 μm. A cobalt-nickel-phosphorus alloy was plated thereon to a thickness of about 5 OA as a metal magnetic recording medium (3). Furthermore, a disk-shaped disc with a film thickness of 500 A coated with approximately 10 # of ammonium tissilicate liquid by a spin coating method (rotation speed 200 rpm) was coated on this recording medium for 2000 mm.
It was fired in an electric furnace at a temperature of 3 hours. According to the X-ray diffraction diagram of this protective film, no remarkable small-angle scattering was observed below 2θ-5e, and it was found that the film was a 5102 film with a structure similar to silica glass.

Although this protective film also has a lubricating role, a lubricating film (5) having an excellent lubricating effect may be provided. As the lubricating film (5), for example, PIDAX (trade name, manufactured by DuPont), Krytox (trade name, manufactured by DuPont), etc. are used.

In the magnetic disk obtained as described above, no phenomenon of magnetic head adsorption was observed, and when a lubricant film was used, the peeling was reduced. In the C8B test, the number of 088 cycles was approximately twice that of the case with a protective film made using the conventional manufacturing method. Also, when a lubricating film was used, the number of C88 cycles was approximately twice that of the conventional method.

In addition, although the case of the spin coating method was explained in the above-mentioned ′), ″ example, other methods such as a dipping method may be used, and the same effects as in the above-mentioned example can be obtained.

〔Effect of the invention〕

As described above, according to the present invention, since the SiO□ film is formed on the metal magnetic recording medium provided on the base material using a decomposed polymer of ammonium silicate, Si
A highly reliable magnetic disk that can form an O2 film, prevent the magnetic head from adhering to the surface of the magnetic disk, increase the number of O88s, reduce failures due to head crashes, and reduce costs by using inexpensive raw materials. This has the effect of providing a manufacturing method.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing a magnetic disk obtained according to an embodiment of the present invention.

Claims (1)

[Claims] A method for manufacturing a magnetic disk, characterized in that a SiO_2 film is formed from a decomposed polymer of ammonium silicate on a metal magnetic recording medium provided on a base material.