JPS63117311A - Magnetic disk - Google Patents

Abstract

PURPOSE:To assure satisfactory mechanical reliability as a disk side by coating aluminum oxide on a substrate and further coating perfluoropolyether having a hydroxyl group as a functional group, as a lubricating agent, on the aluminum oxide coating. CONSTITUTION:This magnetic disk is formed by coating the aluminum oxide on the substrate and further coating the perfluoropolyether having the hydroxyl group as the functional group, as the lubricating agent, thereon. The aluminum oxide is formed by magnetron sputtering and the film thickness is preferably 200-1,000Angstrom . The perfluoropolyether having OH groups at both ends of the molecules is used for the perfluoropolyether film to be formed on the aluminum oxide and the film thickness thereof is preferably about 30-150Angstrom . A dipping method, spraying method, spin coating method, etc., are applicable as a coating method. The coating is heated for 10-60min at 100-200 deg.C in an ordinary atmosphere after the coating of the perfluoropolyether. The stationary type magnetic disk having a magnetic metallic medium which is improved in the mechanical reliability such as wear resistance and lubricity with a miniature composite head and thin film head is thereby obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic disk used in a fixed magnetic storage device, and more particularly to a protective and lubricating film on a metal magnetic thin film of the magnetic disk.

[Conventional technology]

With the increase in recording density of magnetic disks used in fixed magnetic storage devices, there is a shift from conventional stone-coated disks coated with a magnetic medium to thin-film disks using a metal magnetic thin film as the medium. On the other hand, with the increase in recording density, the use of heads is shifting from conventional M, n-Zn ferrite heads to mini composite type heads or thin film heads, but mini composite heads and 8M
A part of the head slider is made of high-hardness ceramics such as calcium titanate, alumina, or titanium carbide. Therefore, the magnetic disk side is also required to be durable enough to withstand the aSS (contact start/stop) caused by these heads.

Conventionally, as a protective lubricant film for fixed magnetic disks that use a thin metal film as a magnetic medium, a sputtered carbon film or a sputtered or wet SiO□ film coated with a lubricant has been proposed. For example, a carbonaceous membrane is suitable for a mini-compositor head that uses calcium titanate (Hv 1500) as a slider. C-1-ν4 will wear out and cause a head crash.

In addition, alumina, titanium, and carbide with higher hardness (
B? -)-2000~! 5000), the above-mentioned phenomenon occurs more markedly.

On the other hand, since the Sin film is usually formed with Hv≦1000, even if a good lubricant is applied, its durability is unreliable, especially for thin film heads.

[Problem that the invention seeks to solve]

As described above, mini composite heads and thin film heads can be used to achieve even higher recording densities than conventional magnetic disks that have metal magnetic media with protective and lubricating films. The aSS, which is made of a hard slider material, has the problem of not being able to ensure sufficient wear resistance and lubricity on the disk side.

Therefore, the present invention is intended to solve such problems, and its purpose is to provide Hv=
A protective film made of a material with a hardness higher than the conventional protective film of about 1000 to 2000 is provided, and a lubricant that chemically bonds with the protective film and has excellent lubricity is applied on top of the protective film. Therefore, an object of the present invention is to provide a fixed magnetic disk having a metal magnetic medium with improved mechanical reliability such as wear resistance and lubricity for mini-composite heads and thin film heads.

[Means for solving problems]

The magnetic disk of the present invention is characterized in that a substrate is coated with aluminum oxide, and a perfluoropolyether having a hydroxyl group as a functional group is coated as a lubricant on the aluminum oxide coating6. The aluminum chloride film is formed by magnetron sputtering, and the film thickness is 200 to 10
00λ is desirable.Although the hardness cannot be accurately evaluated with the above film thickness, when a thick film is formed, there are at least two types of hardness that meet the purpose of the present invention, which correspond to hardnesses of approximately Hv+1500 and 1500. It has been found that this can be obtained by changing the sputtering conditions.

Next, the Super 70 Robolyether film formed on the aluminum oxide has OH groups at both ends of the molecule, and the film thickness is preferably 30 to 1soXg.The coating method is dipping, spraying, or spin coating. Laws etc. can be applied. Here is an important point when creating
100-200℃ after applying this par 70 roboliether
Heating is carried out in a normal atmosphere for 10 to 60 minutes at , -OH+ -OH-11 -〇-+ H,O↑A dehydration condensation reaction occurs.Therefore, even though this perfluoropolyether is liquid at room temperature, it is chemically strongly bonded and the rotation of the disk The excellent lubricity can be effectively exhibited without causing spin-off.

〔Example〕

Table 1. We created a prototype as shown in the figure below. The creation method will be explained below. Electroless N1-P nonmagnetic plating was formed to a thickness of about 20 μm on an Al4 + RAM disk substrate with a diameter of 95 cm, and polished to a thickness of about 15 μm.
The surface roughness was also processed to Rmawα03 μm or less.

Next, regarding the formation of a metal magnetic medium, in Examples 1 and 2, a 0o-Ni-P film was formed on the polished N1-P plating film by electroless plating. ooK was formed. Examples 3 and 4 were prepared using magnetron sputtering as the magnetic medium.
m%Or alloy 7001 was formed.

Subsequently, aluminum oxide protective films were formed using a magnetron sputtering device, with film thicknesses and hardnesses varied as shown in Table 1.

Furthermore, the Par 70 Robo-Rether lubricating film has a hydroxyl group-containing Par 70 Robo-Ether (7-on-purine ZDOL).
(manufactured by Nippon Montegilin Co., Ltd.) was dissolved in Daiflon 5-5 (manufactured by Daikin Industries) at a concentration of 1 W/V% and applied by dipping. The film thickness was controlled by the pulling speed.

Furthermore, the final heating and baking process was all carried out at 150°C for 30 minutes.

Table 1. Examples and Comparative Examples The quality of the above Examples and Comparative Examples was evaluated by an aSS test, and the appearance change of the deformed surface after 03'3, the static friction coefficient μ, and the output reduction rate were determined.

The results are shown in Table 2.

Table 2 Quality evaluation results (after 0.8135 million times) [Effects of the invention] As shown in Table 2, it is recognized that the effects of the present invention are remarkable, and this will help improve the density of future magnetic disk drives. Accordingly, even if a mini-composite head or a thin film head is used as the head side, sufficient mechanical reliability can be guaranteed as the disk side. In addition, a secondary effect of improving the corrosion resistance of the metal magnetic medium was also obtained by forming the aluminum oxide film. Furthermore, since aluminum oxide is inexpensive as a sputtering target, cost benefits can also be expected.

that's all

Claims (1)

[Claims] 1. A magnetic disk characterized in that a substrate is coated with aluminum oxide, and a perfluoropolyether having a hydroxyl group as a functional group is applied as a lubricant on the aluminum oxide coating.