JP3061984B2 - Magnetic storage - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic storage device used for a magnetic storage device such as a magnetic disk device and a magnetic drum device.

[0002]

2. Description of the Related Art In general, there are the following recording / reproducing methods for a magnetic storage device including a recording / reproducing magnetic head (hereinafter, referred to as a head) and a magnetic storage unit. That is, at the start of the operation, the head and the magnetic storage surface are set in contact with each other, and then the required rotation is given to the magnetic storage to create a space corresponding to an air layer between the head and the magnetic storage surface. (Contact start / stop method; hereinafter, referred to as CSS). In this method, the rotation of the magnetic storage body is stopped at the end of the operation, and at this time, the head and the surface of the magnetic storage body are in contact friction as in the start of the operation. The frictional force generated between the head and the magnetic storage body in these contact frictional states may cause the head and the magnetic storage body to wear, and eventually cause the head and the magnetic medium to be damaged. In the contact friction state,
A slight change in the attitude of the head causes the load applied to the head to be uneven, and may cause scratches on the head and the surface of the magnetic storage medium. A lubricant is applied to the surface of the magnetic storage medium in order to prevent wear of the magnetic storage body due to contact and sliding with the head.

[0003]

However, since the above-mentioned lubricant is generally used as a liquid oil,
The scattering of the lubricant due to the rotation of the magnetic storage body is a problem. That is, when the thickness of the lubricant decreases below the thickness at which the mechanical durability can be maintained due to the scattering of the lubricant, abrasion of the magnetic recording medium is accelerated and data loss is caused. The following techniques are focused on the surface shape of the disk medium to reduce the wear of the magnetic storage body. That is, JP-A-4
In JP-A-360017, JP-A-2-260126 or JP-A-3-54718, a magnetic disk substrate is subjected to a surface roughening treatment in order to prevent attraction between a head and a magnetic storage medium and reduce a friction coefficient. It has been disclosed. Further, Japanese Patent Application Laid-Open No. Hei 2-24821 discloses a magnetic storage body having an uneven layer provided on a protective film. Japanese Patent Laid-Open No. 5-2
Japanese Patent No. 739 describes that fine concavities and convexities (texture) are formed on concentric circles on a magnetic disk substrate, and the static friction or the dynamic friction coefficient is reduced. However, these irregularities or textures cannot solve the problem of lubricant scattering because they have no directivity or the guide grooves are formed concentrically. An object of the present invention is to provide a magnetic storage device that solves such a conventional problem.

[0004]

According to the present invention, there is provided a magnetic disk in which a substrate, a magnetic medium, a protective film and a lubricant are sequentially formed.
In click, the base member, a magnetic medium or the protective film surface, a groove
Tangent direction is almost constant in the radial direction of the magnetic disk
In angles become grooves formed in plurality, wherein the angle is 15 degrees or more, a magnetic disk, wherein at most 60 °
is there. Also, the plurality of formed grooves may intersect with each other.
Is a magnetic disk characterized by including the following.

As shown in the sectional view of FIG. 3, a magnetic storage medium according to the present invention has a base medium 9 covered with a magnetic medium 10, and a protective film 11 covered on the medium. A lubricant 12 is coated on the protective film 11. The surface of the underlayer, the magnetic medium, or the protective film is textured by forming a guide groove. As shown in FIG. 1, the guide groove has a groove angle (A) of not less than 15 degrees and not more than 60 degrees with respect to the radial direction.

[0006]

[0007]

[0008]

[0009]

As a result of experiments, it was found that when the groove angle A was between 15 degrees and 60 degrees , the rate of decrease in the film thickness of the lubricant was the smallest, and the mechanical durability of the magnetic memory could be maintained for a long time. Further, the groove angle A does not need to be a single value, and as shown in FIG.
May be crossed. Further, the guide groove 3 may be formed not only on the surface of the base body but also on the surface of a magnetic medium or a protective film.

The base used in the present invention is a metal such as aluminum alloy, titanium alloy, stainless steel, polyester, polyimide, polyamideimide, polyether sulfone, polysulfone, aromatic polyether, epoxy resin, urea resin, melamine resin. , Polycarbonate,
Plastics such as diallyl phthalate resin, acrylic resin, phenolic resin, polyphenylene sulfide, polyphenylene ether, polyacetal resin, polybutylene terephthalate, bismaleimide triazine resin, polyoxybenzylene resin, polyaminobismaleimide resin, polyphenylene oxide, polyphenylene sulfide, glass, Ceramics such as silicon, germanium, alumina, silica, diamond, amorphous carbon and graphite, anodized alumite-coated aluminum alloys, Ni-P plating films, metals such as Cr, FeNi, stainless steel, Mo and W are used.

Next, as the magnetic medium coated on the substrate, oxides such as Fe ₃ O ₄ , γ-Fe ₂ O _3, barium ferrite, CrO ₂ , nitrides such as Fe ₃ N ₄ , F
carbides such as e ₅ C ₂ , Co, CoNi, CoNiP, C
oMnP, CoMnNiP, CoRe, CoPt, Co
NiPt, CoCr, CoCrTa, CoNiRe, C
oMnReP, CoFeCr, CoV, CoRu, Co
Os, CoPtCr, CoPtV, CoRh, CoCr
Rh, CoNiMo, CoNiCr, CoNiW, Co
Metals containing cobalt such as Sm, FeNd, FeMg,
A metal containing iron such as FeNd, FeAg, FePd, and FeTb, and a metal containing manganese such as MnAl and MnCuAl are used. Alternatively, a resin in which fine particles of the above various magnetic substances are mixed and dispersed is used.

The protective film is made of SiO ₂ , Si ₃ N ₄ , Si
C or a silicon compound such as a silicate polymer, Al ₂ O ₃ , Co
O, Co ₃ O ₄ , Co ₂ O ₃ , α-Fe ₂ O ₃ , Cr ₂ O ₃ , C
rO ₃ , TiO ₂ , ZrO ₂ , ZnO, PbO, NiO,
Metal oxides such as MoO ₂ and SnO ₂ , TiN, ZrN,
Metal nitride such as CrN, TaN, BN, MoS ₂ , W
Metal sulfides such as S ₂ and TaS ₂ , TiC, ZrC, Cr
Metal carbides such as C and TaC, metal fluorides such as graphite fluoride, W, Cr, Ir, NiB, NiP, FeCr,
NiCr, Sn, Pb, Zn, Tl, Au, Ag, C
metals or alloys such as u, Ga, Ru, Rh, Mn, Mo, Os, Ta or alloys thereof, Si, Ge, B,
Semiconductors such as C (amorphous, diamond-like or a mixture thereof, or graphite-like or a mixture thereof);
Plastics such as polytetrafluoroethylene, phenol resin, and polyimide are used.

The type of the lubricant used in the present invention is not limited as long as it is a liquid within the operating temperature range. In general, perfluoropolyether represented by the following general formula is used. Lubricant A: GCF ₂ (OCF ₂ ) _p (OC ₂ F ₄ ) _q OCF ₂
G (where p and q are integers from 2 to 25, and G is -C
Functional groups such as OOH and -OH. Lubricant B: F (C ₃ F ₆ O) _n C ₂ F ₄ G (where n is 3
And G is a functional group such as -COOH and -OH. ) Lubricants _{C: F (CF (CF 3} ) CF 2 O) m CF 2 G ( wherein m is an integer from 3 to 25, G is -COOH, -O
H and other functional groups. )

[0015]

[0016]

The present invention will be described below with reference to examples. Example 1 A magnetic disk having a structure as shown in FIG. 3 was manufactured by the following method. The base body 9 having a nickel-phosphorous plating film coated on an aluminum alloy substrate is polished by 10 μm using a slurry polishing liquid and a polishing pad, and a groove angle (A) having a maximum roughness of 40 nm is 1 to 89. A groove having 5 degrees was formed, and a cobalt-chromium-platinum alloy as a magnetic medium 10 was coated on the base body 9 by sputtering to a thickness of 30 nm. Next, an amorphous carbon film is formed on the magnetic medium 10 as a protective film 11 by sputtering.
Then, a perfluorooctane solution of perfluoropolyether having a hydroxyl group (lubricant A, p = 13, q = 8) is spin-coated on the protective film 11 as a lubricant 12. To a thickness of 3 nm to produce a magnetic disk.

Embodiment 2 In the same manner as in Embodiment 1, except that the intersection angle 7 of 10 to 30 degrees is used.
(Φ in FIG. 2) was formed to form a magnetic disk.

Comparative Example 1 A magnetic disk was manufactured in the same manner as in Example 1 except that concentric grooves were formed.

FIG. 4 shows a magnetic disk substrate having an outer diameter of 130 mm and an inner diameter of 40 mm at 80 ° C. and 10,000 rpm counterclockwise using the magnetic disk of Example 1 in which the groove angle A was changed.
The reduction rate (ratio of the film thickness after the test to the initial film thickness) after 720 hours in the acceleration test in which the film is rotated around and the time change of the lubricant film thickness is measured is shown. According to the figure, A is 15 degrees and 60 degrees .
The degree of decrease decreased between degrees , and A exhibited a minimum value near 30 degrees. In the magnetic disk of the comparative example (corresponding to A = 90 degrees), the reduction rate was large, exceeding 50%. When the sliding with the magnetic head was repeated using the magnetic disk after the above acceleration test, the magnetic disk having A of 0 degree and 90 degree showed a scratch on the surface of the magnetic disk in 5000 times, but 3 degrees to 89 degrees. The sample during was intact. Similar results were obtained with the magnetic disk of Example 2.

[0020]

As described above in detail, the magnetic memory of the present invention can prevent the lubricant from scattering due to rotation, and can maintain the mechanical durability of the magnetic memory for a long period of time.

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of the shape of a groove of a magnetic storage body of the present invention.

FIG. 2 is a diagram showing another example of the shape of the groove of the magnetic storage body of the present invention.

FIG. 3 is a cross-sectional view of the magnetic storage body of the present invention.

FIG. 4 is a diagram showing a relationship between a reduction rate of a lubricant film thickness due to rotation of a magnetic storage body of the present invention and a groove angle A.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Magnetic disk 3 Guide groove 4 Centrifugal force 9 Base body 10 Magnetic medium 11 Protective film 12 Lubricant

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G11B 5/82

Claims (2)

(57) [Claims] In a magnetic disk in which a base, a magnetic medium, a protective film and a lubricant are sequentially formed, a tangential direction of a groove is formed on a surface of the base, magnetic medium or the protective film in a radial direction of the magnetic disk. Multiple grooves that always have a substantially constant angle
Is the angle of 15 degrees or more, a magnetic disk, wherein at most 60 degrees. 2. The plurality of formed grooves cross each other.
2. The magnetic disk according to claim 1, wherein
Disk.