JPS6154036A - Magnetic recording medium and its manufacture - Google Patents

Abstract

PURPOSE:To improve the durability and weather resistance by forming a protective layer having a mixed phase consisting of specified kinds of carbon. CONSTITUTION:Gaseous methane as a reactive gas is fed to a vacuum vessel 1 from a tank 3 and mixed with gaseous hydrogen as a carrier gas fed from a tank 2, and plasma discharge is caused in the gaseous mixture to form a protective layer 10 having a mixed phase consisting of diamondlike carbon 11 and amorphous carbon 12 on a recording layer 20 by plasma vapor deposition. By this structure, the durability and weather resistance of the resulting magnetic recording medium are remarkably improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic recording medium using a plastic substrate used in an external storage device of a computer.

[Conventional technology]

Among external storage devices for computers, the magnetic recording media of magnetic disk devices employing the CSS method, floppy disk devices and magnetic tape devices that utilize plastic substrates are subject to wear and damage due to magnetic heads. Furthermore, when a magnetic metal material is used for the recording medium, the recording medium may corrode. reducing wear and tear on these;
In other words, 5iOz and SiN are applied to the surface of the magnetic recording medium for the purpose of increasing durability and preventing corrosion, that is, strengthening weather resistance.
It formed a protective film such as

[Problem that the invention seeks to solve]

With the above-mentioned protective film, there was insufficient monitoring of durability, and if the thickness of the protective film was reduced in order to increase the density, the weather resistance would deteriorate.

It is an object of the present invention to solve these drawbacks and provide a magnetic recording medium with excellent durability and weather resistance, and a method for manufacturing the same.

[Means for solving problems]

The present invention is a magnetic recording medium that includes a substrate, a magnetic recording layer formed on the surface of the substrate, and a protective film formed on the surface of the magnetic recording layer, and is a means for solving the above-mentioned problems. The protective film is characterized in that it is a mixed phase of diamond-like carbon and amorphous carbon.

Further, in the method of manufacturing a magnetic recording medium, in which a protective film is formed on the surface of a magnetic recording layer formed on the surface of a substrate, the protective film is formed by a plasma deposition method.

Further, the plasma deposition method may be a method in which plasma discharge is performed in a mixed gas of a reactive gas and a carrier gas.

Further, the reaction gas may be methane gas, and the carrier gas may be hydrogen gas.

〔Effect of the invention〕

By forming a mixed phase of diamond-like carbon and amorphous carbon as a protective film of a magnetic recording medium, durability and weather resistance can be significantly improved.

Further, this protective film can be stably manufactured by low temperature and low pressure plasma deposition without degrading the magnetic properties of the recording film.

〔Example〕

First, the structure of an embodiment of the magnetic recording medium of the present invention will be explained based on the drawings.

FIG. 1 is a schematic diagram showing a cross section of this magnetic recording medium. As shown in the figure, there are six recording layers 20 on top of the substrate 30.
is deposited on the magnetic recording layer 20, and a protective film 10 is further deposited on the magnetic recording layer 20. The material of the substrate 30 is an aluminum alloy and a polyimide material. Aluminum alloys are used for stationary disks, and polyimide materials are used for floppy disks and tapes. The material of the magnetic recording layer 20 is a magnetic material.

Further, the protective film 10 is a mixed phase of diamond-like carbon 1) and amorphous carbon 12. The Pincus hardness of this diamond-like carbon 1) is approximately 8000 kg/mmz, and the Pincus hardness of the amorphous carbon 12 is approximately 80
0kIX/mm".

Next, a method for manufacturing this magnetic recording medium will be explained based on the drawings.

FIG. 2 is a schematic diagram showing an apparatus for manufacturing this magnetic recording medium. First, the pressure inside the vacuum container 1 is approximately 10-'T.
The inside of the vacuum container 1 is evacuated by the vacuum pump device 7 until the amount of
” is supplied into the vacuum container 1 from the methane gas tank 3 and the hydrogen gas tank 2 so that the internal pressure of the vacuum container 1 is approximately 0.1
It is filled up to Torr. Then r13.56
Plasma discharge is generated in the vacuum container by the high frequency power supply device 8 of J-cut 1z. On the other hand, the magnetic recording medium is placed on the heater 6 and heated by the heater 6 to 100°C or r300 JoC, and a mixed phase of diamond-like carbon and amorphous carbon is formed on the magnetic recording medium by plasma discharge. A protective film is formed. The growth rate of the formed protective film is adjusted to 5 to 20 people per second.

Next, evaluation results of Examples of the magnetic recording medium of the present invention will be explained. This embodiment is a fixed disk.

Further, the protective film of the comparative example was manufactured by a sputtering method.

First, the results of the durability test of the protective film using the scratch strength test method are shown in FIG. In this figure, wear ■ is 800 mm thick Si.
The wear amount of the O2 film is expressed as rloOJ%. Although the protective film of the magnetic recording medium of the present invention is IIIJ compared to the comparative example, the wear amount is about rl/2 compared to the comparative example.
J or "1/3".

Next, FIG. 4 shows the results of a durability test of the protective film using a low-speed sliding test method. In this test, Wenchester type C
The head is rotated at a rotation speed of 20 m and kept in constant contact with the test object, and the elapsed time until the head cracks or cracks occur is measured. As shown in the figure, the protective film of the magnetic recording medium of the present invention has an elapsed time of "10" compared to the comparative example.
” or rloOJ (miya.

Finally, the results of the weather resistance test of the protective film using the pure water adhesion test method are shown in FIG. In this test, pure water is deposited on a protective film that is a test object, and the number of occurrences of corrosion on a recording medium protected by this protective film is measured. Here, the adhesion time of pure water is rloo J time. As shown in the figure, although corrosion occurred frequently in the comparative example, no corrosion occurred in the protective film of the magnetic recording medium of the present invention.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the structure of the recording medium of the present invention. FIG. 2 is a schematic diagram showing the structure of an apparatus for manufacturing a recording medium of the present invention. FIG. 3 is a chart showing the scratch strength test results. Figure 4 is a chart showing the results of the low-speed sliding test. Figure 5 is a chart showing the results of the pure water adhesion test. ■...Vacuum container, 2...Hydrogen gas tank, 3...Hydrogen gas outlet, 4...Methane gas tank, 5...Methane gas outlet, 6...Heater, 7...Vacuum Pump, 8.
...High frequency power supply device, 10...Protective film, 1)...Diamond-like carbon, 12...Amorphous carbon, 2
0... Magnetic recording layer, 30... Substrate.

Claims (4)

[Claims] (1) A magnetic recording medium including a substrate, a magnetic recording layer formed on the surface of the substrate, and a protective film formed on the surface of the magnetic recording layer, in which the protective film is composed of diamond-like carbon and amorphous carbon. A magnetic recording medium characterized by having a mixed phase with carbon. (2) A method for manufacturing a magnetic recording medium in which a protective film is formed on the surface of a magnetic recording layer formed on the surface of a substrate, characterized in that the protective film is formed by a plasma deposition method. . (3) The method for manufacturing a magnetic recording medium according to claim (2), wherein the plasma deposition method is a method in which plasma discharge is performed in a mixed gas of a reactive gas and a carrier gas. (4) The method for manufacturing a magnetic recording medium according to claim (3), wherein the reactive gas is methane gas and the carrier gas is hydrogen gas.