JPH01118217A - Production of magnetic disk - Google Patents

Abstract

PURPOSE:To obtain a high-reliability magnetic disk which has excellent contact start stop durability and small head attraction force by injecting fine particles to a substrate to form ruggedness on the surface thereof and forming a magnetic layer on such substrate. CONSTITUTION:An NiP underlying plating layer 2 is formed at 20mum thickness on the substrate (1.9mm thickness) 1 consisting of an Al-Mg alloy finished by lathing and the surface thereof is finished by polishing so as to have 15mum thickness and <=0.007mum surface roughness Ra. The fine particles of SiO2 (10mum average particle size) are injected onto the surface of such substrate by which the substrate 20 formed with the ruggedness is obtd. A Co-Ni film is formed to 0.08mum thickness by a high-frequency sputtering method as the magnetic layer 3 on the surface of the substrate formed with the ruggedness and further, a protective film consisting of SiO2 is formed to 0.04mum thickness thereon, on which a lubricating agent is spin-coated. The high-performance magnetic disk having the excellent contact start stop durability and the small head attraction force is thus obtd.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a magnetic disk, and in particular, a magnetic disk whose magnetic layer is a thin film has good durability against head sliding and has a contact start/stop (C
5S) The present invention relates to a method of manufacturing a magnetic disk with excellent characteristics.

[Conventional technology]

Substrates for thin-film magnetic deigns, in which magnetic thin films are formed by methods such as sputtering and vapor deposition, are made by forming a Ni alloy plating layer on an aluminum alloy substrate, or forming an anodic oxide film on an aluminum alloy substrate. Furthermore, after forming these base films, the surface is mirror-finished to a surface roughness of RaO, 005 μm or less by polishing methods such as polishing and flapping, and then used.

[Problem that the invention seeks to solve]

However, when a magnetic thin film is formed on this substrate, and a protective film and a lubricant layer are also provided, since both the magnetic disk surface and the magnetic head slider surface are mirror-finished, the lubricant or moisture in the air may be adsorbed. , C8S had the problem that disks were easily damaged when starting up. Also,
Since there is no place for the lubricant to stay, there is a problem in that the lubricant scatters due to sliding with the head, resulting in poor durability. In order to solve this problem, it is better to make the surface of the magnetic disk uneven without making it a mirror surface, and the appropriate surface roughness is Rmax 150 to 600A.

Therefore, a magnetic disk using a substrate on which fine concentric lines (texture) are formed using flipping tape or the like on the mirror substrate as described in Japanese Patent Application Laid-open No. 61-29418 J, A magnetic disk using a substrate having a fine particle coating layer on its surface as described in Japanese Patent No. 61-280618 has been proposed. However, in the former processing method using abrasive particles, large abrasive scratches caused by coarse abrasive particles or foreign matter tend to occur, causing signal loss. Furthermore, the latter method of providing a coating layer on the substrate surface has the problem that the coating layer lacks mechanical strength and adhesion, resulting in peeling from the coating layer during C8S.

In view of the above-mentioned problems, the present invention aims to improve the C8S characteristics and provide a highly reliable magnetic disk.

[Means for solving problems]

The method for manufacturing a magnetic decoupling according to the present invention involves spraying fine particles onto a substrate to form irregularities on its surface, thereby forming a magnetic layer on the substrate.

[Effect]

In the magnetic disk according to the present invention, since the surface of the substrate is uneven, the surface of the magnetic layer is also uneven, and even when the magnetic head contacts the magnetic disk, the frictional force can be reduced, so that the C8S characteristics are improved. Furthermore, since there is a gap between the head and the disk due to the unevenness, no adhesion occurs, so reliability can be improved. Furthermore, since the surface layer of the substrate is work-hardened by fine particle injection, durability can be improved.

Furthermore, since the unevenness is created by pounding rather than cutting, no shavings or abrasive particles remain. [Example] The method for manufacturing the magnetic decoy of the present invention will be described below with reference to Examples.

Example 1 FIG. 1 is a sectional view showing a magnetic disk obtained by an example of winding the present invention. In Fig. 1, (1) is a substrate, an Al-Mg alloy substrate (1) and an Al-Mg alloy substrate (1).
Like the N1-P base plating layer (2) formed thereon.

Ru. (3) is a magnetic layer formed on the 9Ni-P underplating layer (2) by the tsubata method.

First, an Al-Mg alloy substrate (thickness 1.
By forming a NiP base plating layer (2) with a thickness of zμm on (1) and polishing its surface, the thickness is finely μm and the surface roughness is Ra: 0.
It was finished to have a thickness of 0.007 μm or less. A substrate (1) with irregularities was obtained by spraying silica (SiOz) fine particles (average particle diameter of 7 particles: 10 μm) onto the surface of this substrate. A Co-Ni film with a thickness of 0.08 μm was formed as a magnetic layer on the uneven substrate surface by high-frequency sputtering, and a 5iOz protective film was further formed on the surface with a thickness of 0.04 μm, and Kryx AC was used as a lubricant. (Dupont Co., Ltd. product name) was spin-coded to obtain the magnetic disk shown in FIG.

The method of ejecting particles will be explained with reference to a schematic diagram of a particle injection device shown in FIG. (6) is a part of a hopper for storing fine particles 00, and (7) is a spray nozzle for spraying.

By sending compressed air for injection from the arrow (8), particles are supplied from the hopper part (6) through the particle transfer pipe (9), and from the injection nozzle (7) the magnetic deinuk substrate (
1) Fine particles 00 are sprayed onto the surface. The size and depth of the unevenness on the substrate surface can be controlled by the particle size, the pressure of the compressed air for injection, the hardness of the particles, etc. Note that the magnetic disk substrate of Example 1 had an average particle diameter of 10
This was obtained by injecting 3.8 kg/d of compressed air (ζ) with micron silica particles.

Fig. 8 shows a differential interference micrograph (magnification: 200x) of the surface of the magnetic decoy of Example 1 that has been molded in this way, and it shows that uniform irregularities are formed, and when the surface roughness is measured, it is Rmax. It was 0.028 μm.

Example 2 The surface of the substrate was made uneven by spraying micro water (H, O) particles (average particle size 5 μm) at a spray pressure of 3.2 kg/cut onto a 17 μm thick Ni-Mo-P underplated substrate. , on which a 0.15 μm thick γ-
Fete, a film is formed, and a protective film is formed with Sin, 0.
A magnetic disk was obtained by coating the magnetic disk with 0.085 μm lubricant Kryx 148AD (trade name of DuPont) with a thickness of 0.007 μm. The surface roughness of this magnetic disk is Rmax
It was 0.02.2 μm.

Comparative Example 1 NiP underplating substrate of Example 1 (finished to surface roughness Rmax Q, 007 μm by polishing)
The same magnetic layer, protection film, and lubricant layer as in Example 1 were formed thereon.

Comparative Example 2 The same Ni-MoP underplating substrate as in Example 2 was textured with #4000 white alumina wopping tape, and the same magnetic layer, protective film, and lubricant layer as in Example 2 were formed thereon. The surface roughness of this magnetic disk was 0.025 μm in Rmax.

With respect to the magnetic disks of Examples 1 and 2I and Comparative Example 1.2 thus prepared, a C
8S durability and head adsorption tests were conducted. As shown in Table 1, in terms of C8S durability, both the head and the disk showed no damage even after repeating C8S 25,000 times for both of the magnetic disks of Example 1.2. In addition, scratches were observed on the magnetic disk of Comparative Example 1 after 16,000 times, and scratches on the magnetic disk of Comparative Example 2 after 7,500 times. In the head adsorption test, the head was loaded with a load of 9.5
This was done by pressing the sample onto the first surface of Deinu with a pressure of 20" 0651 R, H and measuring the adsorption force after leaving it for 70 hours. Examples 1 and 2
2.8 g and 2.8 g for magnetic disks, respectively.
However, it was r in Comparative Example 1, and 3.7 in 99m Comparative Example 2.
It was g.

In the above embodiments, N1-P and Ni-Mo-P were used as the base plating, but other plating bases or alumite films may be used.

Moreover, Co-Ni and γ-Fe! Although an example of an Os sputtered film is shown, Co-Cr*Co-W
+Co-Ni-0.

It may also be a thin film of Co-Fe, Fe-N, or the like.

In addition, in the above example, a case was shown in which fine particles of silica and ice (N20) were injected, but other fine particles include Al2O8, TiO,, ZrO,, SiC, and Si3.
N.

Carbon, tetrafluoroethylene, PVC, NBR rubber.

and polyolefin.

Note that not only ice (H, O) but also other liquids that have been frozen can be applied. Further, mixed particles may be sprayed as necessary. Furthermore, the particle size of fine particles is 0.1 to 200.
A range of μm is desirable.

〔Effect of the invention〕

As described above, according to the present invention, fine particles are sprayed onto a substrate to make the surface uneven, and a magnetic layer is formed on the substrate. This has the effect of producing a high ri1ki disc.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a magnetic disk obtained according to an embodiment of the present invention, FIG. 2 is a schematic diagram showing a particle injection device according to an embodiment of the present invention, and FIG. 8 is a sectional view showing a magnetic disk obtained according to an embodiment of the present invention. This is a differential interference microscopic photograph of the surface state of the magnetic delinquent obtained by this method. In the figure, (3) is the magnetic layer, (7) is the injection nozzle, and a
o is a fine particle, and (1) is a substrate. In addition, in the figures, the same reference numerals indicate the same or corresponding parts.

Claims (2)

[Claims] (1) Spray fine particles onto the substrate to make the surface uneven;
A method of manufacturing a magnetic disk in which a magnetic layer is formed on the substrate. (2) Fine particles are SiO_2, Al_2O_3, H_2O
(ice), TiO_2, ZrO_2, SiC, Si_3N
The method for manufacturing a magnetic disk according to claim 1, wherein the magnetic disk is any one of _4, carbon, tetrafluoroethylene, vinyl chloride, NBR rubber, and polyolefin.