JPH07161036A - Production of magnetic recording medium - Google Patents

Abstract

PURPOSE:To produce a magnetic recording medium prevented from the deterioration in corrosion and wear resistances of the protective layer. CONSTITUTION:An intermediate layer 7 of Ni-P and an underlayer 8 of Cr, etc., are successively formed on a substrate 6 of a nonmagnetic Al alloy, etc., a ferromagnetic metallic thin film 9 of CoCr is formed on the underlayer 8 by sputtering or other method and a 1st buffer layer 10 of at least one of Cr and Si is formed on the thin film 9 by sputtering or other method. A 2nd buffer layer 11 is formed on the 1st buffer layer 10 by sputtering carbon with gaseous Ar and a carbon film 12 contg. 9 to <17% hydrogen is formed on the 2nd buffer layer 11 by DC magnetron sputtering with a gaseous hydrogen-Ar mixture.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a magnetic recording medium used in the information industry field and the like.

[0002]

2. Description of the Related Art In recent years, external recording devices for computers have been developed in accordance with the demands of the market for light, thin, short and small products. The magnetic recording medium used in such an external recording device includes
The metal thin film type in which the magnetic recording layer of the magnetic recording medium is a ferromagnetic metal thin film is suitable for high density magnetic recording because it has a larger magnetic flux density, is thinner, and has a larger coercive force than the coating type. By the way, in an external recording device using a magnetic recording medium, the magnetic head is in contact with the magnetic recording medium in a stopped state, and the magnetic head slides on the magnetic recording medium at the start and stop of rotation. The start / stop (hereinafter referred to as CSS) method is predominant. Therefore, in the metal thin film magnetic recording medium, a protective layer is provided on the surface of the ferromagnetic metal thin film so that the magnetic head does not slide directly on the ferromagnetic metal thin film.

A conventional magnetic recording medium will be described below. FIG. 2 is a sectional view of a conventional magnetic recording medium. In FIG. 2, 1 is a substrate of non-magnetic aluminum alloy or the like, 2 is an intermediate layer made of NiP provided on the substrate 1, 3 is a base film made of Cr provided on the intermediate layer 2, and 4 is CoNi or Co provided on the base film 3
The ferromagnetic metal thin film layers 5 made of Cr or the like are protective layers made of a carbon film provided on the ferromagnetic metal thin film layer 4.

[0004]

In the above conventional magnetic recording medium, the carbon film forming the protective layer 5 of the magnetic recording medium has a low friction coefficient and a good lubricity at the initial stage. However, if the ferromagnetic metal thin film layer 4 is used for a long time, the friction coefficient deteriorates, and a potential difference occurs between the ferromagnetic metal thin film layer 4 and the protective layer 5 under a dew condensation environment and a high temperature and high humidity environment, and thus the ferromagnetic metal thin film layer 4 The element Co is dissolved in the protective layer 5 and the lubricity of the protective layer 5 deteriorates. When the lubricity deteriorates in this way, the CSS operation by the magnetic head is repeated, so that the abrasion resistance of the protective layer 5 of the magnetic recording medium deteriorates and the protective layer 5 is destroyed.

The present invention solves the above problems,
An object of the present invention is to provide a method for manufacturing a magnetic recording medium in which the corrosion resistance and wear resistance of a protective layer are prevented from deteriorating.

[0006]

In order to achieve this object, the present invention provides a first method of forming at least one element of Cr and Si on a ferromagnetic metal thin film layer formed on a substrate. A buffer layer is formed, a second buffer layer is formed on the first buffer layer with a carbon film having a graphite structure, and a mixed gas of argon and hydrogen is formed on the second buffer layer by sputtering. The hydrogen-containing carbon film is formed by containing the hydrogen in an amount of 9% or more and less than 17%.

[0007]

With this structure, the adhesion force of the hydrogen-containing carbon film is equivalent to that of the carbon film, the corrosion resistance is improved, and the wear resistance can be improved.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A method of manufacturing a magnetic recording medium according to an embodiment of the present invention will be described below with reference to the drawings. Figure 1
FIG. 3 is a cross-sectional view of a magnetic recording medium according to an embodiment of the present invention. As shown in FIG. 1, an intermediate layer 7 made of Ni-P having a thickness of 20 μm is formed on a substrate 6 made of a non-magnetic aluminum alloy or the like formed in a disc shape with a thickness of 0.6 to 1.25 mm by plating or the like. Form to thickness. Further, a base film 8 made of Cr or the like is formed on the intermediate layer 7 by sputtering or the like.
It is formed to a thickness of about 00 nm. Further, CoCrTa, CoCrN are formed on the base film 8 by sputtering or the like.
i, CoCrPt, CoCrPtTa, CoCrPtB
A ferromagnetic metal thin film layer 9 made of a CoCr-based magnetic material is formed to a thickness of 40 to 60 nm.

Further, the first buffer layer 10 made of at least one element of Cr and Si is formed on the ferromagnetic metal thin film layer 9 by sputtering or the like to have a thickness of 5 to 15 nm.
To the thickness of. Further, 10 to 25n of the second buffer layer 11 is formed on the first buffer layer 10 by sputtering using carbon gas as a target and argon gas.
It is formed to a thickness of m. Further, the second buffer layer 11
By changing the flow rate ratio of the mixed gas of hydrogen and argon by DC magnetron sputtering, the sputtering gas pressure is 1 to 10 mTorr, the film formation power is 500 W, the film formation time is 150 sec, and the hydrogen-containing carbon film 12 is 20 to 35 nm.
To the thickness of.

A test of the magnetic recording medium in which the hydrogen-containing carbon film 12 is formed by changing the flow rate ratio of the mixed gas of hydrogen and argon will be described. First, the hydrogen-containing carbon film 12
Peel strength was measured. The equipment used was a scanning scratch SST101 manufactured by Shimadzu Corporation, and the measurement conditions were stylus curvature 15
μm, scratch speed 20 μm / s, amplitude 50 μ
m, stylus pressing speed is 1 μm / s.

Next, the measurement of the friction coefficient will be described.
An apparatus for testing CSS operation is used to measure the coefficient of friction. The thin film magnetic head used for the measurement has two rails on the air bearing surface, and each rail has a width of 380 μm.
m and the length is 4.0 mm. A dynamic friction coefficient meter is attached to the head support mechanism of this thin film magnetic head, and the air bearing surface of the thin film magnetic head is brought into contact with the magnetic recording medium while a load of 9.5 g is applied to the thin film magnetic head.
The friction coefficient in the initial state is measured by traveling at a speed of 3.6 mm / s.

Thereafter, CSS operation is tested. CSS
In the operation test, the air bearing surface is brought into contact with the magnetic recording medium with a load of 9.5 g applied to the thin film magnetic head. In this state, the thin film magnetic head floats in 5 seconds while rotating and sliding the magnetic recording medium. Ascended (peripheral speed 8.5m /
After the thin film magnetic head is held for 5 seconds in s), the rotation of the magnetic recording medium is reduced for 10 seconds, and the flying height of the thin film magnetic head that has floated decreases, and the thin film magnetic head comes into contact and stops while sliding. The coefficient of friction is measured after performing such CSS operation cycle 10,000 times and performing CSS operation 10,000 times in the same circumferential orbit of the magnetic recording medium. Furthermore, the appearance of the sliding surface is examined.

Next, the corrosion resistance in a dew condensation environment is tested. The test conditions were left for 60 hours in an environment of a temperature of 45 ° C. and a humidity of 95% RH, and the state of precipitation of Co on the hydrogen-containing carbon film 12 was examined by ESCA.

The test results of the magnetic recording medium of the present embodiment tested as described above and the test results of the conventional product are shown in comparison with each other (Table 1).

[0015]

[Table 1]

The following (Table 1) results will be described.
As is clear from (Table 1), regarding the peel strength, according to the magnetic recording medium of the present embodiment, the peel strength is 19 to 21 g.
f, and since the conventional magnetic recording medium also has 20 gf, the difference in peel strength is small. Next, regarding the friction coefficient, according to the magnetic recording medium of the present embodiment, the CSS operation is 1
Repeated 10,000 times, the coefficient of friction increases, but it does not lead to damage and is good. However, in the conventional magnetic recording medium, when the CSS operation was repeated 10,000 times, the protective layer 5 was deteriorated and destroyed, and the friction coefficient could not be measured. Next, in a corrosion resistance test under a dew condensation environment, there was no change in the magnetic recording medium of this example, and precipitation of Co was observed in the conventional magnetic recording medium.

[0017]

As described above, according to the present invention, the first buffer layer made of at least one element of Cr and Si is formed on the ferromagnetic metal thin film layer formed on the substrate, and Since the second buffer layer was formed by the carbon film having the graphite structure on the first buffer layer and the hydrogen-containing carbon film was formed on the second buffer layer, the ferromagnetic metal thin film layer and the buffer layer were formed. The present invention realizes a method of manufacturing a magnetic recording medium in which the potential difference between the two is reduced, the corrosion resistance is improved, and the abrasion resistance is improved.

[Brief description of drawings]

FIG. 1 is a sectional view of a magnetic recording medium according to an embodiment of the present invention.

FIG. 2 is a sectional view of a conventional magnetic recording medium.

[Explanation of symbols]

 6 Substrate 7 Intermediate layer 8 Underlayer film 9 Ferromagnetic metal thin film layer 10, 11 Buffer layer 12 Hydrogen-containing carbon film

Claims (2)

[Claims] 1. A first buffer layer made of at least one element of Cr and Si is formed on a ferromagnetic metal thin film layer formed on a substrate, and the first buffer layer is formed on the first buffer layer. A second buffer layer is formed of a carbon film having a graphite structure, and the mixed gas of argon and hydrogen is sputtered on the second buffer layer to contain the hydrogen in an amount of 9% or more and less than 17%. A method of manufacturing a magnetic recording medium, which comprises forming a film. 2. The method of manufacturing a magnetic recording medium according to claim 1, wherein the ferromagnetic metal thin film layer has a CoCr system.