JPH01211217A - Magnetic memory medium - Google Patents

Abstract

PURPOSE:To improve adhesiveness by forming a silane coupling film between a mirror finished glass substrate and magnetic film. CONSTITUTION:After the mirror-finished glass plate is degreased, the silane coupling film is formed thereon by a treatment using a silane coupling agent dissolved in ion exchange water. The magnetic film is plated thereon. The compd. which forms the silane coupling film makes covalent bond or analogous bond with the Si compd. on one hand the makes the bond via electrons with an activated metal or plating metal on the other and, therefore, the glass substrate which is an insulator and the magnetic film which is a plating film are tightly bonded to each other. This bonding is additionally strengthened by heating. The adhesiveness is improved without roughening the substrate surface and the recording medium of a high recording density is obtd. according to this constitution.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a magnetic storage medium used in a magnetic disk device.

[Conventional technology]

In recent years, with the increase in storage capacity and miniaturization of computer systems, the importance of magnetic disk devices, which are one type of external storage devices, has increased, and magnetic storage media are required to have higher recording densities.

In order to achieve high recording density in magnetic storage media, it is necessary to increase the coercive force (He) of the magnetic film, make it thinner, and narrow the air gap (flying height) between the flying magnetic head and the magnetic storage medium. There is.

The surface roughness of magnetic storage media using glass as a substrate is better than those using aluminum or nickel phosphorus alloy as a substrate, so the magnetic storage medium and magnetic head do not collide, the flying height is kept low, and recording is possible. It is possible to increase the density. Therefore, it is attracting attention as a substrate for magnetic storage media. For example, like patent publication number 61-54018,
A magnetic storage medium is known in which a ferromagnetic metal film is plated on a glass substrate via a nickel-phosphorous alloy.

(Problem to be solved by the invention) However, with conventional electroless plating technology, it is difficult to deposit a plating film with good adhesion on glass because there is no bonding mechanism involving electrons, unlike plating on metal. This is difficult.As a result, magnetic storage media have the problem of deteriorating their durability.

Also, to deposit a plating film with good adhesion.

There is a dry method in which activated metals such as Pd, Au, Ni, etc. are evaporated and sputter-linked onto a glass substrate, but there is a problem in that the plating process becomes complicated.

Furthermore, roughening the glass substrate mechanically or by chemical etching is a relatively easy means of improving the adhesion between the plating film and the glass substrate. However, this causes a large change in the shape of the glass surface, resulting in surface roughness, resulting in the problem that the magnetic head cannot stably fly in the magnetic storage medium.

The present invention solves the above problems, and its purpose is to:
The object of the present invention is to increase the adhesion between a glass substrate and a magnetic film without using dry methods or mechanical or chemical surface roughening methods, thereby achieving higher recording density in magnetic storage media.

[Means to solve the problem]

The magnetic storage medium of the present invention is characterized in that a silane coupling film is formed as an intermediate film between a mirror-finished glass substrate and a magnetic film.

(Function) By forming the silane coupling film between the glass substrate and the magnetic film, it improves the adhesion between the two and does not roughen the surface of the glass substrate, thereby improving the durability of the magnetic storage medium. By improving the characteristics, it is possible to achieve a stable magnetic field and a low flying height. As a result, high recording density can be achieved.

In addition, the reason for the improved adhesion due to the silane coupling film is that the compound that forms the silane coupling film has a covalent bond or similar bond with the silicon compound, which is a product of glass, and Since the bond is made with the metal compound or the plated metal through electrons, the glass substrate, which is an insulator, and the magnetic film, which is the plating film, are bonded closely together.

Furthermore, the above-mentioned bond is strengthened by heating.

Hereinafter, this will be explained in detail using examples.

[Comparison example]

The mirror-finished glass substrate was degreased by a conventional method, and activation was performed by a conventional tin-palladium wet activation method. On top of that, the following nickel/phosphorus and cobalt/phosphorus were formed by electroless plating, each containing 500O and 1000.
A magnetic storage medium was manufactured.

The strength of the above-mentioned plating film was examined using a Brenner type ledger tester, and the strength was found to be 0.05 Kg/mm'.

Nickel/phosphorous plating solution (composition) Nickel sulfate 0.05 mol/standing hypophosphorous acid
0.2 mol/ml Citric acid 0.4 mol/Ammonium sulfate mol/Also <Conditions> pH 4,0 (ammonia) Plating temperature 80°C Cobalt/phosphorous plating solution <Composition> Cobalt sulfate 0.1 mol/hypophosphorous acid
0.2 mo1/1 citric acid 0.2
mol/text 0.5 mol/
<Conditions> pH 7°O (ammonia) Bath temperature 70°C (Example 1) After degreasing the same substrate as in the comparative example in the usual manner, a silane coupling treatment solution was used to form a silane coupling film. After washing with water, activate the same as in the comparative example, nickel phosphorus,
A magnetic storage medium was manufactured by forming a magnetic film using a cobalt-phosphorus electroless plating solution.

Silane coupling liquid (composition) Silane coupling agent 0.5ml/MS H60
20 (manufactured by Toshi Silicon) Ion exchange water 999.5 ml/Jl <Conditions> Temperature Room temperature treatment time 30 seconds to 10 minutes The tensile strength of the above plating film was measured in the same manner as in the comparative example, and the results were Shown in the table.

(Example 2) A substrate similar to that of the comparative example was degreased, and a silane cup link film was formed using the silane cup link solution of Example 1. After washing with water, the substrate was heated at a temperature of 50°C to 250°C for 1 minute or more. did. Thereon, a magnetic film was formed using the same activation, nickel-phosphorus, and cobalt-phosphorus electroless plating solution as in the comparative example to produce a magnetic storage medium.

The tensile strength of the above plated film was measured in the same manner as in the comparative example, and the results are shown in Table 2.

It can be seen that forming a silane coupling film between the glass substrate and the magnetic film as in the comparative examples and examples above has the effect of increasing the adhesion between the glass substrate and the magnetic film.

(Effects of the Invention) As described above, according to the present invention, the adhesion between the glass substrate and the magnetic film can be easily increased, which has a great effect on increasing the recording density of magnetic storage media.

that's all Applicant: Seiko Epson Corporation 〕now

Claims (1)

[Claims] A magnetic storage medium characterized in that a silane coupling film is formed as an intermediate film between a mirror-finished glass substrate and a magnetic film.