JPH05217155A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To enhance the lubricative property and the wear-resistant property of the title medium by a method wherein a carbon-based lubricative protective layer composed of two specific layers is laminated on a magnetic layer. CONSTITUTION:An intermediate layer 2 which is composed of a chromium alloy or the like and a magnetic layer which is composed of cobalt or its alloy are formed on a nonmagnetic substrate 1 which is composed of an aluminum alloy, a glass or the like. In addition, a carbon-based lubricative protective layer 4 composed of the following two layers is formed: a wear-resistant film 4a whose wear-resistant property is excellent and which contains nitrogen gas; and a lubricative film 4b whose lubricative characteristic is excellent. An organic lubricative layer 5 is formed on the uppermost layer. Thereby, a magnetic recording medium whose wear-resistant property and lubricative characteristic are excellent can be mass-produced at high yield and at low costs.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic disk or audio device used in computers, word processors, etc.
The present invention relates to a magnetic recording medium such as a magnetic tape used in video equipment and the like.

[0002]

2. Description of the Related Art In recent years, metal thin film disks have been used as magnetic recording media for high density recording. When performing recording / reproducing on such a magnetic recording medium, the CSS method (contact start / stop method) is generally used. In the above method, the magnetic head and the magnetic recording medium are in contact with each other when stopped, and by rotating the magnetic recording medium, a minute air layer is formed between the magnetic head and the magnetic recording medium to perform recording and reproduction. To do. In such a CSS system, the frictional force generated between the magnetic head and the magnetic recording medium is
In some cases, the magnetic layer may be damaged or the rotation of the magnetic recording medium may be hindered due to an adsorption phenomenon at the start of the operation. Therefore, a carbon-based protective film having abrasion resistance and lubricity is formed by a sputtering method, and an organic lubricant is applied on the carbon-based protective film to prevent an increase in the friction coefficient. Further, as the material of the magnetic head tends to be changed from ferrite to ceramic and hard materials such as Al.Ti.C for higher density, it is indispensable to improve the wear resistance performance for the magnetic recording medium. Furthermore, in order to save labor, the magnetic recording device itself has a function of automatically turning off the power when it is not used for a long time, and the number of times of CSS is increasing.

[0003]

However, in the structure of the conventional magnetic recording medium described above, the carbon-based protective film containing no nitrogen does not provide the necessary wear resistance, and the carbon-based protective film containing nitrogen does not have the necessary wear resistance. There is a problem that the friction coefficient is increased by the adsorption phenomenon with the magnetic head, and therefore, it has become essential to make the organic lubricating film as thin as possible.

The present invention solves the above-mentioned conventional problems, and an object of the present invention is to provide a magnetic recording medium excellent in lubricity and wear resistance.

[0005]

In order to achieve the above object, a magnetic recording medium of the present invention comprises a carbon-based lubrication protection composed of two layers of a wear resistant film and a lubricating film on a magnetic layer on a non-magnetic substrate. It is a stack of layers.

[0006]

According to the present invention, therefore, excellent wear resistance and lubricity can be obtained by dividing the carbon-based lubrication protective layer into two layers and comprising the wear resistant film and the lubricative film.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view of a magnetic recording medium according to an embodiment of the present invention. In the figure, 1 is a non-magnetic substrate such as an aluminum alloy or glass, 2 is an intermediate layer made of a chromium alloy or the like, 3 is a magnetic layer made of cobalt or an alloy thereof, 4 is a carbon-based lubrication protective layer, and has wear resistance. Two of the excellent wear resistance film 4a containing nitrogen gas and the excellent lubrication film 4b
It is composed of layers. Reference numeral 5 is an organic lubricating layer.

With the above structure, samples of the magnetic recording media of Examples and Comparative Examples were prepared as follows.

(Example 1) The abrasion resistant film 4a was formed in a mixed gas of argon gas containing 50% of nitrogen gas,
A lubricous film 4b was formed thereon in an argon gas containing no nitrogen gas to prepare a sample of the magnetic recording medium.

Example 2 A magnetic recording medium sample was prepared in the same manner as in Example 1 except that the abrasion resistant film 4a was formed in nitrogen gas instead of mixed gas.

(Embodiment 3) On the wear-resistant film 4a formed in a mixed gas of argon gas containing 50% or more of nitrogen gas, a lubricating film 4b is formed in argon gas containing no nitrogen gas.
Was formed into a film to prepare a sample of a magnetic recording medium.

(Comparative Example 1) Abrasion resistant film 4a was formed in argon gas containing no nitrogen gas, and lubricating film 4b was formed thereon in argon gas containing no nitrogen gas for magnetic recording. It was used as a sample of the medium (resultingly, it means that the carbon-based lubrication protective layer 4 is entirely composed of the lubricity film 4b).

(Comparative Example 2) The lubricating film 4b was replaced with nitrogen gas.
A magnetic recording medium sample was prepared in the same manner as in Example 3 except that the film was formed in a mixed gas containing 0% of argon gas. (As a result, it means that the carbon-based lubrication protective layer 4 is entirely composed of the abrasion resistant film 4a).

Comparative Example 3 Nitrogen gas 100 was used instead of the mixed gas in Comparative Example 2.
A magnetic recording medium sample was prepared in the same manner as in (Example 3) except that% was used. (As in (Comparative Example 2), it means that the carbon-based lubrication protective layer 4 is entirely composed of the wear resistant film 4a).

CSS characteristics, adsorption characteristics, and hardness of the examples and comparative examples configured as described above were measured. Table 1 shows the change in the friction coefficient and the effect on the magnetic layer after CSS was performed 20,000 times for (Examples 1 and 2) and (Comparative Example 1). The slider portion of the magnetic head used here is a composite type magnetic head whose main component is calcium titanate.

[0017]

[Table 1]

As is clear from Table 1 as well, when the abrasion resistant film 4a is formed in a mixed gas containing nitrogen or a nitrogen gas, the change in the friction coefficient is small and the appearance of the magnetic recording medium after the test is small. In the inspection, no damage was found on the magnetic layer 3. Next, (Table 2) shows the results of measuring the adsorption characteristics of (Example 3) and (Comparative Example 2) and (Comparative Example 3).
The initial torque was measured after allowing the magnetic disk to stand in the constant temperature and humidity layer of% RH for 24 hours without rotating it, and further allowing it to stand at room temperature and normal humidity for 24 hours. As the magnetic head for the test, a composite type magnetic head similar to the above was used.

[0019]

[Table 2]

As is clear from (Table 2), the adsorption characteristics are better when the lubricating film 4b formed in the argon gas containing no nitrogen gas is provided (Example 3), while the nitrogen is superior. Consisting of only the wear resistant film 4a formed in a mixed gas containing (Comparative Example 2) and (Comparative Example 3)
Has a high wettability with water, and the wettability does not decrease even when the water-repellent organic lubricating layer 5 is applied, and as a result, water is lost between the magnetic head and the magnetic recording medium under high humidity. Further, the lubricant is evenly present to cause an adsorption phenomenon, and the friction coefficient (μs) increases.

Table 3 shows the results of measuring the hardness of (Example 1) and (Example 2) and (Comparative Example 1). The hardness was measured using a diamond needle with a load of 0.5 g.

[0022]

[Table 3]

As is clear from (Table 3), it is clear that (Example 1) and (Example 2) have a hardness about 1.8 times or more that of (Comparative Example 1). . As described above, according to the above-described embodiment, the abrasion resistant film 4a is formed in a mixed gas of nitrogen gas and argon gas or nitrogen gas,
Since the lubricous film 4b is formed thereon in the argon gas, it is possible to improve wear resistance and lubricity. The wear-resistant film 4a formed in a mixed gas containing nitrogen gas or in nitrogen gas has a thickness of 20 to 25 nm, and the lubricating film 4b formed in argon gas containing no nitrogen. Has a thickness of 15 to 20 nm, and the total thickness of the carbon-based lubrication protective layer 4 including the abrasion resistant film 4a and the lubricating film 4b is preferably 40 nm or less.

[0024]

As is apparent from the above embodiments, according to the present invention, a carbon-based lubrication protective layer composed of two layers of an abrasion resistant film and a lubrication film is formed on a magnetic layer formed on a non-magnetic substrate. The magnetic recording medium having excellent wear resistance and lubrication characteristics can be mass-produced at a high yield and at a low cost.

[Brief description of drawings]

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

[Explanation of symbols]

 1 Non-Magnetic Substrate 2 Intermediate Layer 3 Magnetic Layer 4 Carbon-Based Lubrication Protective Layer 4a Abrasion Resistant Film 4b Lubricative Film

Claims (4)

[Claims] 1. A magnetic recording medium comprising an intermediate layer, a magnetic layer, and a carbon-based lubrication protective layer formed on a non-magnetic substrate, the carbon-based lubrication protective layer being a wear-resistant film and a lubrication film. Of 2
A magnetic recording medium composed of layers. 2. The magnetic recording medium according to claim 1, wherein the wear-resistant film is a wear-resistant film formed in a mixed gas of argon gas and nitrogen gas or a nitrogen gas as a sputtering gas. 3. The mixed gas contains nitrogen gas in an amount of 50 vol% or more,
The magnetic recording medium according to claim 2, which is a mixed gas containing less than 100 vol%. 4. The magnetic recording medium according to claim 1, wherein the lubricating film is a lubricating film formed in an argon gas.