JPH02294922A - Magnetic memory medium and production thereof - Google Patents

Abstract

PURPOSE:To enhance the CSS durability with a hard magnetic head by forming microruggedness on a ferromagnetic metallic thin film medium formed on a nonmagnetic substrate and further forming a thin film consisting of an oxide, nitride, carbide or carbon thereon. CONSTITUTION:A mixture composed of liquefied carbon dioxide and dry nitrogen is injected under a high pressure onto the ferromagnetic metallic medium to form the microruggedness thereon. The surface thereof is further coated with the thin film consisting of at least one kind of materials selected from the oxide, nitride, carbide or carbon. The above-mentioned oxide, nitride and carbon have the function to relieve the impact of the magnetic head but are chipped by the CSS with the magnetic head having a high-hardness slider. The microruggedness is, thereupon, formed on the surface of the ferromagnetic metallic medium to enhance the adhesive strength to the oxide, nitride and carbon.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic storage medium comprising a ferromagnetic metal thin film provided on a non-magnetic substrate, and a method for manufacturing the same.

[Conventional technology]

It is essential for a magnetic storage medium having a metal medium to have sufficient mechanical reliability to withstand contact with a magnetic head. For magnetic storage media, contact start/stop (hereinafter referred to as CSS method) has been adopted to simplify the drive configuration, and in order to protect the magnetic recording surface, CSS is used in the same track in the shipping zone other than the magnetic recording surface.
is often done.

In addition, as magnetic recording density increases, magnetic heads change from ferrite mini-monolithic heads to composite heads and thin film heads, and as the hardness of slider materials increases, there is a need to improve the durability of the protective film of magnetic storage media. .

Conventionally, saturated fatty acids, etc. were coated on the surface of metal magnetic media. Method of providing an organic lubricating layer (Japanese Patent Publication No. 56-30609) Method of providing a mixed lubricating layer of fatty acid amide and phosphorus compound (Japanese Patent Publication No. 59-165238) Method of providing a mixed lubricating layer of higher fatty acids and fatty acid metal salts (Patent Publication No. 56-30609) 59-177728), etc., but CSS using a magnetic head having a slider with high hardness has problems of increased friction coefficient and crash.

Carbonaceous film exhibiting the characteristics of both a lubricating layer and a protective film layer (Japanese Patent Publication No. 54-33521) (Japanese Patent Publication No. 53-143206) (
Japanese Patent Application Laid-Open No. 56-41524) does not cause scratches during CSS and buffers the impact of the magnetic head, so no deterioration of magnetic properties is observed. There was a problem in that as the carbonaceous film increased, the carbonaceous film was scraped and the coefficient of friction increased.

In addition, in order to prevent the magnetic head and the magnetic storage medium from attracting each other and to prevent an increase in the coefficient of friction due to CSS, a method of processing a texture (microscopic irregularities) on a non-magnetic substrate has been used, but this method has not been sufficient.

[Problems and Objectives to be Solved by the Invention] As mentioned above, in the conventional technology, sufficient mechanical reliability cannot be obtained with CSS using a magnetic head having a slider with high hardness, and an increase in the coefficient of friction cannot be suppressed. Ta.

The present invention is intended to solve these problems, and its purpose is to avoid mechanical damage to the ferromagnetic metal medium even during CSS in a magnetic head with a highly hard slider, and to increase the coefficient of friction. The objective is to provide a magnetic storage medium that does not.

[Means to solve the problem]

The magnetic storage medium of the present invention is produced by injecting a mixture of liquefied carbon dioxide gas and dry nitrogen at high pressure onto a ferromagnetic metal medium formed on a non-magnetic substrate to form minute irregularities, and then forming fine irregularities on the ferromagnetic metal medium formed on a non-magnetic substrate. It is characterized by being coated with a thin film made of at least one substance selected from carbon, carbide, and carbon.

Oxides include S10x, TiO2, Cr20s, etc.
Nitride is TiN, Ta2N, AIN, Si3N4, etc. Carbide is SiC, TiC, etc. Carbon is diamond-like,
It may be either graphite or amorphous, and the film thickness is 150 to 800.

The above methods include vacuum evaporation method, sputtering method, and iodine method. It can be formed by any method such as a plating method or a C V'D method.

1 3 The roughness of the unevenness is measured by tower step and Ra is 0.
005 to 0.02 μm, Rma. x is 0.03 to 0.
The roughness is preferably 2 μm, and the more preferable roughness is Ra of 0.01.
~0.015μm, Rmax is 0.10~0.15μm
Met.

[Effect]

Oxides, nitrides, carbides, and carbon formed on the ferromagnetic metal medium have the function of buffering the impact of the magnetic head, but they will be scraped during CSS with a magnetic head having a highly hard slider. Therefore, minute irregularities are formed on the surface of the ferromagnetic metal medium to increase its adhesion to oxides, nitrides, carbides, and carbon.

When liquefied carbon dioxide is injected, it becomes soft dry ice particles about 1 mm in size. When this is blown onto the substrate together with nitrogen gas, minute irregularities are created on the substrate, and furthermore, the adhered particles on the substrate are removed.

Since dry ice is sprayed on the substrate, no thermal stress is applied to the substrate, and there is no change in magnetic properties.

Additionally, since this processing is done in a dry process, the substrate will not become contaminated during the process.

Next, a concrete explanation will be given in Examples.

1 4 [Example-1] Ni-P alloy plating of approximately 15 μm was applied as non-magnetic alloy plating to a mirror-finished disc-shaped aluminum alloy substrate.
After plating to a thickness of m, polishing to a thickness of lOμm and a surface roughness of 0.03μm or less, and further plated as a metal magnetic thin film.
An o-Ni-P alloy was plated to a thickness of about 0.06 μm.

Next, liquefied carbon dioxide gas and dry nitrogen were mixed at a weight ratio of 1:10 and sprayed over the entire surface for 60 seconds at a pressure of 2 kg/c+fl.

Furthermore, 300 people successively formed amorphous carbonaceous films using magnetron sputtering.

[Example 2] A disk having a metal medium was produced in the same manner as in Example 1.

Next, liquefied carbon dioxide gas and dry nitrogen were mixed at a weight ratio of 1:20 and sprayed over the entire surface at a pressure of 4 kg/ci for 120 seconds.

Next, 500 SiOx layers were formed using a magnetron scattering device.

[Example 3] A disk having a metal body was produced in the same manner as in Example 1.

Next, mix liquefied carbon dioxide gas and dry smoke nitrogen at a weight ratio of 1:2.4. It was sprayed over the entire surface for 6o seconds at a pressure of kg/cm.

Next, 800 pieces of graphite J-shaped carbon were formed using a magnetron sputtering device.

[Example 4] A disk having a metal medium was produced in the same manner as in Example 1.

Next, mix liquefied carbon dioxide and g'f=k nitrogen in a weight ratio of 1:2.
5 and sprayed on the entire surface for 120 seconds at a pressure of 2 kg/cm.

500 pieces of graphite-like carbon were formed using a magnetron sputtering device.

[Comparative Example-1] A sample was prepared in Example 1 without injecting liquefied carbon dioxide gas and nitrogen gas.

[Comparative Example-2] A sample was prepared in Example 2 without injecting liquefied carbon dioxide gas and nitrogen gas.

[Comparative Example-3] A sample was prepared in Example 3 without injecting liquefied carbon dioxide gas and nitrogen gas.

[Comparative Example-4] A sample was prepared in Example 4 without injecting liquefied carbon dioxide gas and nitrogen gas.

[Comparative Example-5] A sample was prepared by injecting only nitrogen gas over the entire surface for 120 seconds at a pressure of 2 kg/c+fl in Example 4.

The disks of the above Examples and Comparative Examples were subjected to a CSS test. C
In the SS test, the static friction coefficient was measured before CSS and after 320,000 times of CS using a thin film head made of alumina titanium carbide as a slider material with a flying height of 0.20 μm and Hvl of 200. The results are shown in Table 1.

〔Effect of the invention〕

As described above, according to the present invention, the durability of CSS is improved by forming minute irregularities on a ferromagnetic metal thin film medium formed on a nonmagnetic substrate using a dry process.

Furthermore, the durability of hard magnetic heads has been improved, making it possible to provide magnetic disks with high recording density.

Table 1 that's all Applicant: Seiko Epson Corporation Representative Patent Attorney Kisaburo Suzuki (and 1 other person)

Claims (4)

[Claims] (1) Fine irregularities are formed on a ferromagnetic metal thin film medium formed on a nonmagnetic substrate, and a thin film made of at least one substance selected from oxide, nitride, carbide, or carbon is further coated. A magnetic storage medium characterized by: (2) A first feature in which the minute irregularities are processed by spraying a mixture of liquefied carbon dioxide gas and dry nitrogen at high pressure.
Magnetic storage medium as described in section. (3) A step of forming minute irregularities on a ferromagnetic metal thin film medium formed on a non-magnetic substrate, and further forming at least one substance selected from oxides, nitrides, carbides, or carbon. A method of manufacturing a magnetic storage medium, characterized in that: (4) A third feature in which the minute irregularities are processed by spraying a mixture of liquefied carbon dioxide and dry nitrogen at high pressure.
A method for manufacturing a magnetic storage medium according to section 1.