JPH0287324A - magnetic recording medium - Google Patents

Abstract

PURPOSE:To increase sliding strength and to reduce sticking by specifying the mean diameter of solid particles contained in a liquid lubricant layer. CONSTITUTION:The particles 3 having 40nm or more mean particle size are incorporated into the liquid lubricant layer 4. The amount of particles 3 is preferably 0.5-50wt.% of the sum of particles and lubricant. The particles 3 in the liquid lubricant layer 4 keeps a distance between the magnetic head and the recording medium when the head and the medium interact. Namely, the particles prevent contact of the head to the medium through the lubricant 4 or increase of the contact area. Thus, sticking of a head can be avoided.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic recording medium, and particularly to a magnetic recording medium with excellent sliding strength.

[Conventional technology]

Conventionally, a lubricant has been applied to the surface of a magnetic recording medium in order to improve the sliding strength, which is the strength against contact of the magnetic recording medium with a magnetic head. However, there is a problem in that during use of the magnetic recording medium, the lubricant applied in advance dries up and the sliding strength deteriorates. In order to solve this problem, as described in Japanese Patent Application Laid-Open No. 62-283412, a coating film of a mixture of fine powder of metals, alloys, or their oxides, and a lubricant is formed as a protective layer on the surface of the magnetic recording medium. It is proposed to do so. In this magnetic recording medium, since the lubricant soaked between the fine particles is constantly supplied, the sliding strength does not deteriorate during use.

[Problem to be solved by the invention]

The above conventional technology does not take into account the phenomenon of adhesion between the magnetic recording medium and the magnetic head, and when the magnetic head that has adhered to the magnetic recording medium separates from the magnetic recording medium at startup, a sudden external force is applied to the magnetic head. However, there was a problem in that the magnetic head or magnetic recording medium was damaged. That is, in the prior art, the thickness of the protective layer is 0.003 to 0.
．． 3 μm, fine powder particle size o, ooos ~ 0.03 μm
In the example, the thickness of the protective layer is 200 mm, and the particle size of the fine powder is 10 to 80 mm.If the particle size of the fine powder is extremely smaller than the thickness of the protective layer, and the magnetic recording device is stopped for a long time, A magnetic recording medium and a magnetic head come into contact with each other via a lubricant. Also, when the magnetic recording device is in operation.

The protective layer is smoothed by contact wear with the magnetic head, causing an increase in the area of contact between the magnetic recording medium and the magnetic head via the lubricant. Therefore, when starting up the magnetic recording device, the above-mentioned problem of damage to the magnetic head or magnetic recording medium occurs.

SUMMARY OF THE INVENTION An object of the present invention is to provide a magnetic recording medium that has excellent sliding strength and reduces adhesion phenomena.

[Means to solve the problem]

The above object is (1) in a magnetic recording medium having a magnetic recording layer on a substrate and a liquid lubricant layer on the magnetic recording layer, the liquid lubricant layer is a solid with an average particle size of 40 nm or more. A magnetic recording medium characterized by containing particles of (
2) In a magnetic recording medium having a magnetic recording layer on a substrate and a liquid lubricant layer on the magnetic recording layer, the liquid lubricant layer has an average particle size larger than the film thickness of the liquid lubricant layer. A magnetic recording medium characterized by containing solid particles,
(3) In a magnetic recording medium that has a magnetic recording layer on a substrate and a liquid lubricant layer on the magnetic recording layer, the liquid lubricant layer has an average particle diameter that lies at the depth of the center line of the surface of the magnetic recording medium. This is achieved by a magnetic recording medium characterized by containing solid particles that are larger than the average size.

In the present invention, the magnetic recording layer may be formed directly on the substrate, or may be formed on the substrate via a base film or an intermediate layer for various purposes. Further, the lubricant layer may also be formed directly on the magnetic recording layer, or may be formed via a protective film or the like.

The thickness of the lubricant layer is preferably 20 nm or more and 500 nm or less. When the average particle size of the solid particles is greater than or equal to the film thickness of the lubricant layer, the average particle size is 20 nm or more;
It is preferable that the flying height is equal to or less than the flying height of the head. Generally, the average particle diameter is preferably 20 nm or more and 100 nm or less, more preferably 20 nm or more and 40 nm or less. In such a case, the thickness of the lubricant layer is equal to or less than the average particle diameter of the particles.

On the other hand, when the thickness of the lubricant layer exceeds the average particle size of the particles, it is preferable that the average particle size of the particles is 40 nm or more.
It is preferable that it is below m.

In either case, it is preferable to use particles having an average particle size larger than the centerline depth Rp of the surface of the magnetic recording medium.

The amount of particles is from 0.5 to the total amount of particles and lubricant.
It is preferably in the range of 50% by weight, and more preferably in the range of 1 to 10% by weight.

Furthermore, when a material having a hardness smaller than that of the magnetic recording medium and the magnetic head is used as the material for one particle, damage to the magnetic recording medium and the magnetic head is less likely to occur.

Furthermore, it is preferable that the particles have a more spherical shape.

Examples of particles include 1, for example AQ203. ZrO2゜Zn0
x (x=1.2), TiOx (x=1.2).

FexO"J ((X + 3')"(2t 3L (
3+ 4) LSin, MgO, etc. or a composite material thereof Co O・nAQ20. etc. are used. Also organic matter,
It may be a compound of organic and inorganic substances.

[Effect]

When the magnetic head and the magnetic recording medium come into contact, the particles contained in the liquid lubricant layer do not reduce the distance between the magnetic head and the magnetic recording medium, and the magnetic recording medium and the magnetic head come into contact via the lubricant. It is possible to prevent the contact area from increasing or increasing the contact area, thereby avoiding the sticking phenomenon.

In addition, since the particles can be easily moved through the liquid lubricant by external force, it has a bearing effect that not only disperses external force but also transfers an appropriate amount of lubricant to the magnetic head, which reduces the coefficient of friction to avoid sticking and provides lubrication. The effect can be maintained.

Furthermore, by making the particles smaller in diameter than the flying height of the magnetic head, stable flying and magnetic recording characteristics can be maintained without damaging the magnetic head and magnetic recording medium.

〔Example〕

An embodiment of the present invention will be described below with reference to FIG.

FIG. 1 is a longitudinal sectional view of a magnetic disk, which is one of the magnetic recording media of the present invention.

On the substrate 1, which is a polished aluminum alloy,
Magnetic recording layer 2 made of epoxy binder and magnetic powder
was arranged to a thickness of 0.4 μm, and a particle size of 50 nm was placed on top of it.
A liquid lubricant containing 2% by weight of zirconia particles 3 A solution of perfluoroalkyl polyether dissolved in trichlorotrifluoroethane was applied to form a liquid lubricant layer 4 with a thickness of 40 nm to obtain a magnetic recording medium. Ta. In addition,
The above solution is used by uniformly dispersing the particles using ultrasound,
Although the magnetic recording medium was immersed in the solution and pulled up, a spraying method may also be used. The coefficient of friction of the magnetic head against this magnetic recording medium was 0.6 times that of a conventional magnetic recording medium with a liquid lubricant layer that does not contain solids, making it possible to avoid sticking between the magnetic head and the magnetic recording medium. .

FIG. 2 is a diagram showing the relationship between particle diameter and friction coefficient according to another example. Figure 2 shows the coefficient of friction of a magnetic recording medium having a liquid lubricant layer containing particles of various sizes. The average linear depth I and ρ of this magnetic recording medium are 80 nm, and the thickness of the liquid lubricant layer is 70 nm.

As shown in the figure, when the liquid lubricant layer has a thickness greater than or equal to R1 or contains particles with a particle size greater than R1, the coefficient of friction is reduced. Note that the coefficient of friction of a magnetic recording medium having a liquid lubricant layer containing no particles is 0.2 to 0.3.

〔Effect of the invention〕

According to the present invention, since the particles contained in the liquid lubricant layer can easily move in the liquid lubricant layer, it has a bearing effect and also makes contact between the magnetic recording medium and the magnetic head via the lubricant. thing.

Alternatively, it prevents an increase in the contact area and reduces the friction coefficient between the magnetic head and magnetic recording medium to about 0.65% compared to conventional magnetic recording media.
It can be increased by ~0.8 times, and has the effect of avoiding adhesion between the magnetic head and the magnetic recording medium.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view of a magnetic disk according to an embodiment of the present invention;
FIG. 2 is a diagram showing the relationship between particle diameter and friction coefficient for explaining the present invention. 1...Substrate 2...Magnetic recording layer 3...
Particle 4...Liquid lubricant layer Figure 1 Attorney: Junnosuke Nakamura

Claims (1)

[Claims] 1. In a magnetic recording medium having a magnetic recording layer on a substrate and a liquid lubricant layer on the magnetic recording layer, the liquid lubricant layer has a solid state with an average particle size of 40 nm or more. A magnetic recording medium characterized by containing particles of. 2. In a magnetic recording medium having a magnetic recording layer on a substrate and a liquid lubricant layer on the magnetic recording layer, the liquid lubricant layer has an average particle size larger than the film thickness of the liquid lubricant layer. A magnetic recording medium characterized by containing solid particles. 3. In a magnetic recording medium having a magnetic recording layer on a substrate and a liquid lubricant layer on the magnetic recording layer, the liquid lubricant layer has an average particle size smaller than the center line depth of the surface of the magnetic recording medium. A magnetic recording medium characterized by containing large solid particles.