JPH04278218A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To enhance abrasion resistance of a protection film and reduce the damage of a projected part with regard to a magnetic record medium. CONSTITUTION:A projected part 3 on the surface of a magnetic recording medium is formed of group III and group VI metal oxides, group IVa, group Va, and group VIa metal oxides listed in Periodic Table. A heard metal oxide- made projected part installed on the surface of the magnetic recording medium prevents the damage inducted by the crash of the magnetic head and minimizes crash-induced abrasion. This construction makes it possible to prolong the life of the magnetic recording medium and enhance the reliability.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording medium, and more particularly to a magnetic disk having island-like protrusions for surface protection.

0002

[Prior Art] In conventional CSS (Contact Start Stop) type magnetic disk drives, the magnetic head comes into contact with the disk when the disk is stopped, and also slides when starting and stopping rotation, easily damaging the disk surface. Therefore, as shown in the partial sectional view of FIG. 2, an amorphous hard carbon film 4, a lubricating film 5, etc. were provided on the surface of the disk substrate 1 provided with the magnetic film 2.

Furthermore, if the surface smoothness is too good, friction will increase and the magnetic head will stick, inhibiting rotation and damaging the magnetic head suspension. I tried to create unevenness.

For this reason, in Japanese Patent Laid-Open No. 1-134720, island-shaped metal protrusions are formed on the surface of the magnetic disk, and a protective film is formed thereon.

Furthermore, in Japanese Patent Application Laid-Open No. 1-211236, fine particles are charged and attached to the surface of a magnetic disk, and a protective film is formed thereon.

[0006]

[Problems to be Solved by the Invention] In the conventional magnetic disk shown in FIG. 2, the protrusions on the surface are easily worn out by contact with the head, so the coefficient of friction with the head gradually increases in the CSS test. There was a problem. Furthermore, there is also the problem that when the amorphous hard carbon film 4 is worn down, the magnetic film 2 is exposed and a crash occurs.

The magnetic disk disclosed in Japanese Patent Application Laid-Open No. 1-134720 has poor wear resistance, and
The magnetic disk disclosed in Publication No. 236 had a problem in that the adhesion between the surface of the magnetic disk and the fine particles was low and they were likely to peel off.

An object of the present invention is to provide a magnetic recording medium that can improve the abrasion resistance of the protective film and reduce damage to the protrusions.

[0009]

[Means for Solving the Problems] In order to solve the above-mentioned problems, the present invention provides that the projections on the surface of the magnetic disk are made of aluminum.
, Si, Ge, etc., Group IIIb of the periodic table, and IVb
Group metal oxides, and Ti, Zr, Hf, V, Nb,
It is made of hard metal oxides of metals from groups IVa, Va, and VIa of the periodic table, such as Ta, W, Mo, and Cr.

Furthermore, the metal oxide protrusions are formed by plasma CVD or ion plating.

[0011]

[Function] In the magnetic recording medium such as a magnetic disk according to the present invention constructed as described above, the hard metal oxide protrusions provided on the surface prevent damage to the magnetic disk surface due to a crash of the magnetic head. Furthermore, wear of the projections due to repeated crashes is reduced.

0012

Embodiment FIG. 1 is a partial sectional view of a magnetic disk according to the present invention, in which metal oxide protrusions 3 are provided on the surface of a magnetic film 2 on a disk substrate 1, and an amorphous hard carbon film is provided on the surface of the magnetic film 2. 4 and a lubricating film 5 are provided.

Such a cross-sectional structure is similar to that of the conventional magnetic disk described above, but whereas in the conventional technology the protrusion was made of a relatively soft metal material, in the present invention it is made of a hard metal material. The difference is that metal oxides are used.

In FIG. 1, conventional materials are used for the substrate 1, the magnetic film 2, the amorphous hard carbide film 4, and the lubricating layer 5. For example, the substrate 1 is made of aluminum with NiP coated on the surface to a thickness of approximately 10 μm. An aluminum substrate plated and mirror-polished, an aluminum substrate heat-treated to provide an alumite layer, or a tempered glass or ceramic with a surface roughness Ra of about 5 nm coated with Cr or other alloyed non-magnetic metal or An ordinary substrate provided with a base film of ceramic or the like is used.

Further, the magnetic film 2 may contain, for example, Co or Co.
oxides, alloys such as CoNi and CoCr, or T in these
A composite metal containing some of i, Mo, Zr, V, PtSi, Nb, W, etc. is used. In addition, Fe, γ-Fe2O3
, iron nitride-based materials may be used.

The magnetic film 2 of the embodiment of the present invention shown in FIG.
A laminated film of CoCrTa with a thickness of r and 0.05 μm was used.

The metal oxide protrusions 3 of the present invention are produced by (1) a plasma CVD method in which a heated and evaporated metal oxide is exposed to low temperature plasma containing oxygen to form it on the magnetic film 2; (2) an organometallic compound; Alternatively, metal compound fine particles generated by plasma containing metal hydride and oxygen as main components are transferred to the magnetic film 2.
(3) Ion plating method that generates by spraying on
Method for producing metal oxide by large current sputtering (4) It can be produced by arranging metal oxides pulverized to a particle size of 0.05 μm or less on the magnetic film 2, or the like.

In the embodiment of the present invention shown in FIG. 1, high-speed ultrafine particles of Si produced by electron beam evaporation are exposed to low-temperature plasma of oxygen gas to form SiO2, which is then deposited on a magnetic film to form metal oxide. Object protrusion 3 was generated.

The metal oxide protrusions 3 are grown to occupy 0.01 to 30% of the total surface area of the magnetic film 2, and their height is on average 0.001 to 0.05 μm above the surface of the magnetic film 2.
However, it is desirable to keep it within the range of 0.02 to 0.05 μm.

In principle, all metal oxides can be used for the metal oxide protrusion 3 of the present invention, but among them, group IIIb of the periodic table such as B, Al, Si, Ge, etc.
and oxides of metals belonging to group IVb, Ti, Zr,
Oxides of metals belonging to groups IVa, Va, and VIa of the periodic table, such as Hf, V, Nb, Ta, W, Mo, and Cr, are relatively hard and have a hard surface between them and the amorphous hard carbide film 4. This is particularly suitable because metal carbide is formed on the surface of the material and the adhesion is improved.

After the metal oxide projections 3 are formed, an amorphous hard carbide film 4 is formed on the surface.

[0022] The amorphous hard carbonized film 4 is coated with a micro Vickers film of 100% by sputtering using graphite as a target, CVD using high-frequency plasma of a hydrocarbon gas, or ion acceleration method of a hydrocarbon gas.
Use one produced to a hardness of 0 Hv or higher.

If this amorphous hard carbonized film 4 is too thick, the distance between the magnetic film 2 and the magnetic head will become too large, so the thickness is 50 nm.
Although it is necessary to keep the thickness below, in the present invention, it is set within a range of 5 nm to 20 nm in order to prevent an increase in the contact area due to wear.

The amorphous hard carbide film 4 has excellent adhesion to the metal oxide protrusions 3 because metal carbides such as Al4C3, SiC, and WC are formed at the interface thereof. The ratio of metal to oxygen in the metal oxide protrusion 3 is 1 from a stoichiometric perspective.
:1 or slightly less oxygen provides better adhesion.

A lubricating layer 5 of a linear organic polymer is provided on the surface of the amorphous hard carbonized film 4 to improve the sliding properties.

This lubricating layer 5 includes, for example, perfluoropolyester or perfluoroalkyl whose main chain has at least one end substituted with an ether group, hydroxyl group, carbonyl group, amino group, amide group, etc. and has a molecular weight of 1000 to 10000.
Appropriate for those with a certain degree. In addition, saturated fatty acids, derivatives thereof, higher alcohols, derivatives thereof, etc. can also be used.

The magnetic disk prototyped in this way was
When SS tests were carried out, no crash occurred up to 30k cycles, and the increase in the coefficient of friction between the head and the magnetic disk was negligible.

Further, after coating perfluoropolyester with an average molecular weight of 2,000, in which the end of the main chain is substituted with a hydroxyl group, as a lubricating film 5 on the surface of the above-mentioned prototype magnetic disk, by a wet method,
When a CSS test was conducted in the same manner, no crash occurred up to 100k cycles, and the head was less contaminated than in the case without this lubricant film 5.

In addition, a disk substrate provided with an underlayer and a magnetic film similar to those of the above-mentioned prototype magnetic disk was attached to a rotating jig, and
A mixed plasma of SiH4 and O2 is generated using a high-frequency plasma torch to form metal oxide protrusions 3 on the magnetic film 2, and amorphous hard carbonization with a thickness of approximately 20 nm is performed on the protrusions 3 by sputtering using graphite as a target. Film 4 was formed and a magnetic disk was prototyped.

When this magnetic disk was subjected to a CSS test, the increase in the coefficient of friction was less than 1 g even after 30k cycles, there were no scratches on the disk, and almost no staining on the head was observed.

[0031]

According to the present invention, hard metal oxide protrusions provided on the surface of a magnetic recording medium such as a magnetic disk prevent damage to the surface of the magnetic disk due to a crash of the magnetic head, and Since the magnetic recording medium is less likely to be worn out by the magnetic recording medium, the magnetic recording medium has a long service life and its reliability is increased.

[Brief explanation of the drawing]

FIG. 1 is a partial cross-sectional view of a magnetic disk according to the present invention.

[Figure 2
] Partial cross-sectional view of a conventional magnetic disk

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1...Substrate, 2...Magnetic film, 3...Metal oxide projections, 4...Amorphous hard carbonized film, 5...Lubricating film.

Claims (5)

[Claims] 1. A magnetic recording medium characterized in that metal oxide protrusions are provided on a magnetic film of a magnetic recording medium substrate. 2. In claim 1, the protrusion is made of Al, S.
1. A magnetic recording medium comprising an oxide of a group IIIb or group IVb metal of the periodic table, such as i, Ge, etc. 3. In claim 1, the protrusion is made of Ti, Z
1. A magnetic recording medium comprising an oxide of a metal of group IVa, group Va, or group VIa of the periodic table, such as r, Hf, V, Nb, Ta, W, Mo, or Cr. 4. According to claim 1, the protrusions of the metal oxide are formed by plasma CVD (Chemical VaporDeposition).
1. A magnetic recording medium characterized in that it is formed by a chemical vapor deposition method. 5. The magnetic recording medium according to claim 1, wherein the protrusions of the metal oxide are formed by an ion plating method.