JPH06231450A - Magnetic recording medium and its production - Google Patents

Abstract

PURPOSE:To improve the retentivity of a lubricant layer and to improve the frictional wear resistance and head crash resistance of a magnetic recording medium. CONSTITUTION:An underlayer 2 of an Ni-P alloy, an underlayer 3 of Cr and a magnetic film 4 of a Co-Cr-Ta alloy are successively formed on an Al substrate 1. A protective film 5a of, carbon is then formed on the magnetic film 4 by sputtering. The surface layer of the protective film 5a is made of a protective film 5b of carbon contg. 7-30% oxygen. A layer 6 of a lubricant having at least one polar group is stuck on the protective film 5b. The retentivity of the lubricant layer 6 is improved.

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 having a carbon protective film and a lubricant layer and a method for manufacturing the same.

[0002]

2. Description of the Related Art A magnetic recording medium is provided with a protective film and a lubricant layer in order to protect the magnetic film from friction and wear due to contact and sliding with a magnetic head. Generally, carbon is used as the material of the protective film, and it is formed by a sputtering method using argon gas as a reaction gas. Also,
Perfluoroalkyl polyether is used as the lubricant.

[0003]

In the case of a carbon protective film obtained by using only argon gas as the reaction gas at the time of sputtering, the retention of the perfluoroalkyl polyether, which is a lubricant, is poor, and the carbon protective film is used in a magnetic recording device. There is a drawback that the lubricant layer decreases during mounting and use, resulting in increased friction and wear, leading to head crash.

[0004]

The magnetic recording medium of the present invention is formed on the surface of a magnetic film on a substrate and has a surface layer of 7 to 30%.
And a carbon protective film containing oxygen and a lubricant layer deposited on the carbon protective film and having at least one polar group.

Further, the method of manufacturing a magnetic recording medium of the present invention comprises a first step of forming a carbon protective film on the surface of a magnetic film on a substrate by a sputtering method, and oxygen as a reaction gas after the end of the first step. And a third step of depositing a lubricant having at least one polar group on the carbon protective film.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings. FIG. 1 is a sectional view showing an embodiment of the present invention. A nickel-phosphorus alloy underlayer film 2 is formed on an aluminum substrate 1 by plating, and then a chromium underlayer film 3, a Gobartochrome tantalum alloy magnetic film 4, and a carbon protective film 5 are sequentially formed by a sputtering method.

In the step of forming the carbon protective film 5, a carbon protective film 5a having a thickness of 27 nm was formed by using only argon gas as a reaction gas, and then 10% of oxygen gas was added as a reaction gas to obtain an oxygen content of 7%. % Of oxygen-containing carbon film protection 5b was formed to a thickness of 3 nm. further,
On top of this, as a lubricant layer 6, a product made by Montefluos (I) F
omblin Z-DOL (structural formula: HOH ₂ C-CF
_{2 - (OCF 2 CF 2)} p - (OCF 2) q -OCF 2
The -CH ₂ OH) was 3nm deposited.

Next, as a comparative example, up to the magnetic film was the same as in the example, a carbon protective film using only argon gas as a reaction gas was formed thereon to a thickness of 30 nm, and Fomblin Z-DOL was applied to a thickness of 3 nm as a lubricant layer. did.

FIG. 2 shows changes in the film thickness of the lubricant layer when the present example and the comparative example were rotated at 15000 rpm for 250 and 500 hours in an atmosphere of 80 ° C. According to this, it can be seen that the oxygen-containing carbon protective film of the present example has less decrease in the lubricant layer and is better in retaining and holding in the lubricated state than the carbon protective film of the comparative example. Further, FIG. 3 shows changes in the coefficient of static friction when a contact start stop test (CSS test) using a magnetic head was performed on both of them. According to this, it can be seen that the oxygen-containing carbon protective film of the present example has less increase in static friction coefficient and is excellent in durability as compared with the carbon protective film of the comparative example.

Next, a carbon protective film containing oxygen was added
The flow rate of oxygen gas when forming the oxygen protective film is changed to 0 to 15%, and the oxygen-containing carbon protective film has an oxygen content of 0 to 8.
Fomblin Z-DOL is applied to the magnetic recording medium with 5%.
FIG. 4 shows the residual film thickness ratio with respect to the initial film thickness of the lubricant layer 6 after applying 3 nm of each of them and ultrasonically cleaning them in a Fluorinert solution. According to this, when the oxygen content is 7% or more, the residual rate of the lubricating film thickness is improved as compared with when the oxygen content is less than 7%. If the oxygen content of the oxygen-containing carbon protective film 5b is 30% or more, the characteristics of the carbon protective film are deteriorated, so the range of 7 to 30% is desirable.

[0011]

As described above, in the magnetic recording medium of the present invention, oxygen is contained in the surface layer of the carbon protective film, and perfluoroalkyl polyether having at least one polar group is deposited thereon. The polar group of the lubricant layer and oxygen of the surface layer of the carbon protective film chemically bond to each other, so that the retention of the lubricant can be improved, and the friction and wear resistance and the head crush resistance can be improved.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is a diagram showing changes in the film thickness of a lubricant layer when the magnetic recording medium of this example and the conventional magnetic recording medium were rotated at 15000 rpm for 500 hours in an atmosphere of 80 ° C.

FIG. 3 is a diagram showing the CS of this example and a conventional magnetic recording medium.
It is a figure which shows the change of a static friction coefficient when S test is implemented.

FIG. 4 is a diagram showing a residual ratio of a lubricating film thickness after cleaning a lubricant layer deposited on the surface of the oxygen-containing carbon protective film of the magnetic recording medium.

[Explanation of symbols]

 1 Aluminum Substrate 2 Nickel-Phosphorus Alloy Underlayer Film 3 Chromium Underlayer Film 4 Cobalt-Chromium-Tantalum Alloy Magnetic Film 5a Carbon Protective Film 5b Oxygen-Containing Carbon Protective Film 6 Lubricant Layer

Claims (3)

[Claims] 1. A carbon protective film formed on the surface of a magnetic film on a substrate and containing oxygen only in the surface layer, and a lubricant layer deposited on the carbon protective film and having at least one polar group. A magnetic recording medium characterized by: 2. The magnetic recording medium according to claim 1, wherein the surface layer of the carbon protective film has an oxygen content of 7 to 30%. 3. A method of manufacturing a magnetic recording medium according to claim 1, wherein the first step of forming a carbon protective film on the surface of the magnetic film on the substrate by a sputtering method, A magnetic recording medium comprising a second step of adding oxygen as a reaction gas after the final stage and a third step of depositing a lubricant having at least one polar group on the carbon protective film. Production method.