JPS6199926A - Magnetic storage medium - Google Patents

Abstract

PURPOSE:To obtain a magnetic storage medium having lubricating agents which have an excellent lubricating characteristic, decrease head attraction, have good adhesiveness to the surface of the magnetic storage medium and are hardly scattered by the rotation of a disk by coating a magnetic medium on a substrate and coating a mixture composed of low-viscosity and high-viscosity lubricating agents directly or via a protective film on said medium. CONSTITUTION:The magnetic medium 2 is coated on the substrate 1 having a specular surface and the mixture 4 composed of the low-viscosity and high- viscosity lubricating agents is coated directly or via the protective film 3 on the medium. The substrate 1 consists of a metal such as aluminum alloy or anodized alumite or glass plate and the iron oxide such as Fe3O4 or gamma-Fe2O3 or metal or alloy such as Co-Ni is coated thereon as the medium 2. The low- viscosity and high-viscosity liquid lubricating agents are exemplified by perfluoroalkyl polyether, perfluoroalkyl polyether having a functional group, silicone oil, silicone oil having a functional group, polytrifluoroethylene monochloride, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a magnetic storage body used in a magnetic storage device (such as a magnetic disk device or a magnetic drum device) and a method for manufacturing the same.

(Prior Art and its Problems) In general, there are the following methods for recording and reproducing a magnetic storage device that includes a recording and reproducing magnetic head (hereinafter referred to as a head) and a magnetic storage body. In other words, after setting the head and the magnetic storage surface in contact at the start of operation, the required rotation is given to the magnetic storage to create a space equivalent to an air layer between the head and the magnetic storage surface, and recording is performed in this state. The method of playback is the contact start-stop method.

(hereinafter referred to as the C8S method). In this method, the rotation of the magnetic storage body stops at the end of the operation, and at this time, the surface of the magnetic storage body and the magnetic storage body are in the same frictional state as at the beginning of the operation.

The frictional force generated between the head and the magnetic storage body in these contact friction states can wear out the head and the magnetic storage body, and may eventually cause damage to the head and the magnetic medium. Further, in the contact friction state, a slight change in the posture of the head may cause the load applied to the head to become uneven, causing scratches on the surface of the head and the magnetic storage body.

Further, the head and the magnetic storage body are attracted to each other due to contact for a long time, and become difficult to separate.

Furthermore, the lubricant coated on the surface may scatter due to the rotation of the disk.

In order to prevent the occurrence of scratches and scattering due to adsorption and rotation, various lubricants have been studied, including perfluoroalkyl polyethers such as FH352-49805. was removed and C8S was repeated many times, but it was not possible to prevent the occurrence of scratches on the magnetic storage body. Another disadvantage is that the removed lubricant is thickly localized on the contact sliding surface, causing adsorption with the head.

(Objective of the Invention) The object of the present invention is to provide a lubricant with excellent lubrication properties, less head adhesion, good adhesion to the magnetic storage surface (that is, no deterioration of the floating characteristics of the head), and less scattering due to disk rotation. An object of the present invention is to provide a magnetic memory having a magnetic agent.

(Structure of the Invention) That is, in the magnetic storage body of the present invention, a magnetic medium is coated on a base body having a mirror surface, and a mixture of low-viscosity and high-viscosity lubricants is coated on the medium directly or through a protective film. It is characterized by having a structure of

(Detailed explanation of configuration) Next, the present invention will be described in detail with reference to the drawings.

FIG. 1 is a partial sectional view of the magnetic storage body of the present invention, in which the base body 1
is an aluminum alloy, anodized alumite, N-neel plated film, aluminum alloy coated with Cr, FeNi, MO or W, or plastic such as polyester, polyimide, polyamideimide, polysulfone, aromatic polyether, or CR, P 'eNi.

It is a metal such as MO or W, or a glass plate. Next, a magnetic medium 2 of Fe, 0.0. , r-Fe,
Iron oxides such as O, or (0-Ni, Co-Nj-PC
o-Mn-P, CG-Ni-Mll-P, C
o-Re, co-yhn-Re-P, Co-Cr, C
o-V, Co-Pt, Co-Nj-pteCo-Pt-
Cr, Co-Pt-V, Co-Rh, C0-N1-Mo
Or coated with a metal or alloy such as Co-8m. Further, the magnetic medium 2 is coated with a lubricant M4 made of a mixture of a low viscosity liquid lubricant and a high viscosity liquid lubricant.

As shown in FIG. 3, the adsorption force acting between the head and the disk increases as the viscosity of the liquid lubricant increases, and the amount of lubricant splashed when the disk rotates at 3600 rpm decreases as the viscosity increases. Here, the relative amount of scattering R is expressed as (3600 rpm, film thickness after 100 hours)/(initial film thickness), and relative adsorption force F-(frictional force after 24 hours of standing)/(initial frictional force). expressed. In this case, in order to minimize both the adsorption force and the amount of scattering, it is necessary to use a lubricant with an appropriate viscosity (200 CSt in this case) as shown in FIG.

The mixture of low-viscosity and high-viscosity liquid lubricants of the present invention can further reduce the above-mentioned adsorption force and amount of scattering.

The reason for this is thought to be that in a mixture of low-viscosity and high-viscosity liquid lubricants, each lubricant molecule does not exist independently but interacts with each other, resulting in such a synergistic effect.

This is clear from the fact that this synergistic effect is not observed when low-viscosity and high-viscosity liquid lubricants are laminated without interaction, as will be described in the Effects of the Invention below. As shown in Figure 3, the viscosity of each of the low viscosity and high viscosity liquid lubricants is preferably less than 200C8t (kinematic viscosity (centistoke)) for the former, and more than zoocst for the latter.Also, as shown in Figure 4, low viscosity Difference Δη between the average viscosity ηa of the liquid lubricant (2) and the average viscosity ηb of the high-viscosity liquid lubricant (B)
It is desirable that the distance between the two is greater than the sum of the standard deviation values (σ and ah) of the respective viscosity distributions of the low-viscosity liquid lubricant (2) and the high-viscosity liquid lubricant (B).

1 of low viscosity and high viscosity liquid lubricants used in the present invention
Examples include perfluoroalkyl polyether, perfluoroalkyl polyether with functional groups, silicone oil, silicone oil with functional groups, polytrifluoromonochloroethylene, polyalkylene glycol, polyoxyethylene, neopentyl polyol ester. , polyphenyl ether, perfluoroalkyl, fluorosilicone oil, etc.

FIG. 2 is a partial cross-sectional view of another magnetic storage body of the present invention. In FIG. 2, the base body 1. and magnetic media 2. The lubricant layer 4 is the same as that shown in FIG. 1, but a protective film is coated between the magnetic medium 2 and the lubricant layer 4. The protective film 3 is
lo,, si, N,, sic or silicon compounds such as silicic acid polymers or C00°CJO4HCO20HHa-
Metal oxides such as Fe20s +Cr2O31cro31TiOt* or zro, or T:N.

Metal nitrides such as ZrN, CrN or TaN or
Metal carbides such as ZrC, CrC or TaC or W.

Metals or alloys such as Cr, IrtNiP+Ru, RhtMn, Mo*Os or Ta or alloys thereof are used. All of them react well with the lubricating oil 4 and can firmly hold the lubricating oil 4. In particular, nickel oxide, cobalt oxide, or sio has a remarkable effect.

Note that after coating with the lubricant layer 4, it may be baked at 100 to 300°C.

Next, the present invention will be explained in detail with reference to Examples.

Example 1 Murakel-phosphorus plating film is coated and the surface roughness is 0.02 μm
A cobalt-nickel-phosphorus alloy was plated to a thickness of 0.05 μm as a magnetic medium 2 on a mirror-finished base body 1. Next, the magnetic medium 2 is coated with polysilicic acid (silicic acid polymer) as a protective film 3 as disclosed in Japanese Patent Application Laid-Open No. 52-20804 by a spin coating method. Next, on top of this protection IX3, lubricate Itj4 with a viscosity of 2C8t and 500
0C3t low and high viscosity polydimethylsiloxane (
Magnetic disks were made by spin-coating a 0.1 weight sachet benzene solution of a 1:1 mixture of silicone oil.

When this magnetic disk was evaluated using the evaluation method described below, it was confirmed that it had excellent characteristics.

Example 2 Same as Example 1 except that lubrication/l=4 and viscosity 5
A magnetic disk was made using a 1:1 mixture of low viscosity and high viscosity polydimethylsiloxane (silicone oil) of 0C3t and 500C8t.

Example 3 A magnetic disk was produced in the same manner as in Example 1, except that a perfluoroalkyl polyether having the following structure was used as lubrication 1'; t4.

A magnetic disk was made using a 10:1 mixture of low and high viscosity polydimethylsiloxane (silicone oil) with a viscosity of o, 5cst and 2.5 million C8t.

Example 4 Same as Example 1 except that the lubricant layer 4 had a viscosity of 5ocs.
A magnetic disk was made using a 1:1 mixture of low viscosity and high viscosity polydimethylsiloxane (silicone oil) of 100,000 C8 t and 100,000 C8 t.

Example 5 Same as Example 1 except that the lubricant layer 4 had a viscosity of 18C8.
A magnetic disk was prepared by coating a 0.1% by weight trichlorotrifluoroethane (Freon) solution of a 1:1 mixture of low viscosity and high viscosity perfluoroalkyl polyethers of 495C8T and 495C8T by a spin coating method.

Example 6 Same as Example 1 except that the lubricant layer 4 had a viscosity of 30C8.
A magnetic disk was prepared by coating a 0.1% by weight trichlorotrifluoroethane (Freon) solution of a 1:1 mixture of low viscosity and high viscosity perfluoroalkyl polyethers of T and 2'50C8t by a spin coating method.

Example 7 Same as Example 1 except that the viscosity of the lubricant layer 4 was
(0.1% by weight of a 1:2 mixture of low and high viscosity neopentyl polyol fatty acid esters of T and ziocst)
A magnetic disk was made by coating a luene solution using a spin coating method.

Example 8 Same as Example 1 except that the lubrication jb was 4 and the viscosity was 5c.
Magnetic disks were prepared by coating with a 0.1'w/R% Freon solution of a 1:1 mixture of low viscosity and high viscosity polytrifluoromonochloride ethylene of st and 1500C8t by spin coating.

Example 9 Same as Example 1, but with the exception of lubrication. 4 as viscosity 10
A magnetic disk was prepared by coating a 0.1% by weight toluene solution of a 1:1 mixture of low-viscosity and high-viscosity fluorine-modified polysiloxanes (fluorosilicone) of 0C8t and 10000C8t by spin coating.

Example 10 Same as Example 1 except that the lubrication was 4 and the viscosity was 15C.
A magnetic disk was prepared by coating a 0.1% by weight Freon solution of a 1:1 mixture of a methyl diester of a low viscosity perfluoroalkyl polyether with a viscosity of 8t and a high viscosity perfluoroalkyl polyether with a viscosity of 200C by a spin coating method. Ta.

Example 11 Same as Example 1, except that the lubricant layer 4 had a viscosity of xocs.
t of low viscosity polyoxyethylene and two.

Magnetic disks were prepared by coating a 0.1% by weight luene solution of a 1:1 mixture of C8t high viscosity polyphenyl ether by spin coating.

Example 12 Same as Example 1 except that 50% NiP was used as the protective film 3.
0^ plating and then firing at 280°C to form NIO on the surface to produce a magnetic disk.

Example 13 As in Example 1, set 1 to 1, but set oio2 to 3 and oio2 to 2.
00^ A magnetic disk was made by coating by sputtering.

Example 14 In the same manner as in Example 1, except that the magnetic medium 2 was co(:r
The alloy is coated by sputtering and a protective film 3 is applied on top of it.
A magnetic disk was manufactured by coating the same lubricant layer as in Example 1 as a lubrication layer without providing a lubricant layer.

Example 15 Same as Example 14 except that r-Fe was used as the magnetic medium 2.
, O, was coated by sputtering to produce a magnetic disk.

Example 16 Same as Example 1 except that a 1:1 mixture of 2C8t low viscosity polydimethylsiloxane and 400C8t high viscosity polydimethylsiloxane with an average viscosity of about 2000St
．． Coating with 1% by weight benzene solution by spin coating method,
I made a magnetic diagonal.

Comparative Example 1 Same as Example 1 except that 0.1% by weight of low viscosity polydimethylsiloxane (silicone oil) with a viscosity of 2C3t
A magnetic disk was prepared by coating a benzene solution using a spin coating method.

Comparative Example 2 Same as Example 1 except that 0.1% of high viscosity polydimethylsiloxane (silicone oil) with a viscosity of 5000C8t was used.
A magnetic disk was prepared by coating a weight percent benzene solution by a spin coating method.

Comparative Example 3 Same as Example 1, except that 0.1% by weight of polydimethylsiloxane (silicone oil) with a viscosity of 200C8t
A magnetic disk was prepared by coating a benzene solution using a spin coating method.

Comparative Example 4 Same as Example 1 except that 400C was applied on low viscosity polydimethylsiloxane (silicone oil) with a viscosity of 2C8t.
A magnetic disk was made by applying 4 layers of 8t high viscosity polydimethylsiloxa.

Comparative Example 5 A magnetic disk was produced in the same manner as in Example 1, except that a low viscosity polydimethylsiloxane with a viscosity of 2C8t was overlaid on a high viscosity polydimethylsiloxane with a viscosity of 400C8t.

Load 1 was applied using the magnetic disks shown in the examples and comparative examples.
Using a head sliver with a 5f AttOs TiC core, we conducted many or several contact start/stop (C6S) cycles to determine the cause of varnish wear, the critical film thickness at which adsorption begins, and 3600rp for initial film thickness number
The ratio of the lubricant layer thickness on the magnetic disk (relative scattering amount (%)) when the magnetic disk is rotated for 100 hours at ) was measured and the results shown in the following table were obtained.

From the results shown in the table above, it was found that the rotational splattering rate of the single viscosity lubrication of Comparative Example 1.2.3 was significantly improved.

Implementation seconds 014.1 s is maintained! Since it does not have i-extension, its durability is worse than other Examples, but it has better durability than Comparative Examples. Also, regarding the critical film thickness, Comparative Example 1.2.3
The single viscosity lubricant of Comparative Example 4.5 and the laminated lubricant of high viscosity and low viscosity of Comparative Example 4.5 start adhering to the head even with a very small film thickness, but the mixture of high viscosity and low viscosity of Examples 1 to 16 It was found that the lubricant did not cause head adsorption up to a thicker film thickness of 110 to 300 A, and had a large margin. Furthermore, it can be seen that the rate of decrease in the lubricant layer thickness is smaller for the high-viscosity and low-viscosity mixed lubricant than for the single-viscosity lubricant of the comparative example.

As mentioned above, a mixed lubricant with low viscosity and high viscosity has excellent durability, is less likely to cause head adsorption, and has less decrease in lubricant layer thickness due to disk rotation, and can dramatically improve the reliability of magnetic disk drives. I found out that −′.

In the embodiments of the present invention, magnetic disks have been described, but it is clear that the present invention is also effective for floppy disks, magnetic tapes, and magnetic cards.

[Brief explanation of the drawing]

1 and 2 are partial cross-sectional views showing the present invention. DESCRIPTION OF SYMBOLS 1... Base body, 2... Magnetic medium, 3... Protective film,
4--Lubricating Layer FIG. 3 is a diagram showing the relationship between the relative scattering amount and the relative adsorption force with respect to the kinematic viscosity of the lubricant. FIG. 4 is a diagram showing the viscosity distribution of low-viscosity and high-viscosity lubricants. i ”- Agent ㅅr 二上 Uchihara Susumu\,: 71-3 Figure 1 102104106+08 Kinematic viscosity η [cs↑] 74 Figure η. ηb - Kinematic viscosity η

Claims (1)

[Claims] 1. A magnetic memory having a structure in which a magnetic medium is coated on a base body, and a mixture of low-viscosity and high-viscosity lubricants is further coated on the medium directly or through a protective film.