JPH03183010A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To greatly improve still durability and corrosion resistance by providing a diamond-like hard carbon film on a ferromagnetic metallic thin film and forming this film as the film having the content distribution in which the content ratio of the fluoride at the beginning of the film formation is specific wt.% and the ratio at the end of the film formation is 0wt.%. CONSTITUTION:A film substrate 4 consists of polyethylene terephthalate, polyimide, etc., and the diamond-like hard carbon DLC film 2 contg. a carbon fluoride compd. is provided on the ferromagnetic metallic thin film 3 formed on this substrate 4. This DLC film 2 has the content distribution in which the content ratio of the fluoride at the beginning of the film formation is the max. content alphaM (where alphaM is in a 10 to 30wt.% range) and the ratio at the end of the film formation is 0wt.%. This DLC film 2 is formed by sputtering graphite as a target to form the film or utilizing the electric discharge sepn. of the gaseous hydrocarbon system contg. the fluorine compd. A lubricating layer 1 is thereafter formed and meanwhile, a back coat layer 5 is formed on the rear surface of the substrate 4, by which the magnetic recording medium is constituted.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a magnetic recording medium suitable for digital recording or high-density recording using a ferromagnetic metal thin film as a magnetic recording layer.

[Prior Art] Magnetic recording media are widely used as recording media such as magnetic tapes and magnetic disks.

Incidentally, in magnetic recording media whose recording layer is a metal thin film, improvements in still durability and corrosion resistance have been continued by various methods. For example, various methods described below have been proposed.

■ A carboxylic acid-based or phosphorus-based lubricating layer is provided on the magnetic layer.

■ Provide a protective film of non-magnetic metal.

■ Provide a SiO2 film.

■ Providing fine protrusions uniformly on the magnetic layer.

etc. can be raised.

[Problems to be Solved by the Invention] However, the current situation is that even with these conventional methods, still durability and corrosion resistance cannot be improved. , corrosion resistance is required.

In order to solve the above problems, the present invention provides magnetic recording with excellent still durability and corrosion resistance by providing a diamond-like hard carbon film containing a fluorocarbon compound having a specific content ratio on a ferromagnetic metal thin film. It provides a medium.

[Means for Solving the Problems] In order to solve the above problems, the present invention has the following configuration. That is, the present invention provides a magnetic recording medium in which a ferromagnetic metal thin film is provided on a substrate, in which a diamond-like hard carbon film containing a fluorocarbon compound is provided on the ferromagnetic metal thin film,
The fluoride content ratio of the diamond-like hard carbon film is at the maximum content αMwt% (however, αM is 10 to 30%) at the beginning of film formation.
The magnetic recording medium is characterized in that it is a film having a content distribution in which the film thickness is 0 wt %.

[Function] According to the present invention having the above configuration, a diamond-like hard carbon film containing a fluorocarbon compound (
Hereinafter referred to as DLC film. ), and the fluoride content ratio of the diamond-like hard carbon film reaches the maximum content αM at the beginning of film formation.
wt% (however, αM is in the range of 10 to 30), and by creating a film with a content distribution in which the film fluff is 0 wt%, it has an effective hardness when sliding with the head of a video deck, etc. is larger, and durability and corrosion resistance are improved compared to conventional magnetic recording media.

[Embodiments] Magnetic recording media according to embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a block diagram of an embodiment of a magnetic recording medium of the present invention. As shown in FIG. 1, 4 is a film substrate made of polyethylene terephthalate, polyethylene naphthalate, polyphenylene sulfide, polyimide, or the like. Then, a ferromagnetic metal thin film 3 is formed on this substrate, and a diamond-like hard carbon film 2 containing a fluorocarbon compound is provided on this ferromagnetic metal thin film 3. The film has a content ratio distribution in which the content ratio of the compound is the maximum content αM (however, αM is in the range of 10 to 30 wt%) at the beginning of film formation, and Owt% when the film is fluffy. The diamond-like hard carbon film 2 containing the fluorocarbon compound targets graphite,
The film is formed by sputtering or by using discharge separation of a hydrocarbon gas containing a fluorine compound. After forming a DLC film 2 containing a fluorine compound, a lubricating layer 1 is applied, and a back coat layer 5 is formed on the lower surface of the substrate 4 to construct a magnetic recording medium.

The above configuration is effective in sufficiently improving the required still durability and corrosion resistance.

Examples of the present invention will be described in more detail below.

20 Sio2 fine particles with a diameter of 150A were placed on a smooth polyethylene terephthalate film with a thickness of 10μm, and carbon dioxide was added onto the film while introducing oxygen using a vacuum evaporation method.
o (80)-Ni (20) ferromagnetic metal thin film
After the film was formed to a thickness of 1,000 mm, a back coat layer was coated with carbon black using a well-known coating method and used in each example.

Examples 1 to 2 As shown in FIG. 1, a mixed gas of Ar and H2 (Ar
: H2=1 : 3), degree of vacuum 0.1 to 10 (To
rr), frequency 13.56 (MHz), power 1. IK
During glow discharge of W, using 2 to 5 devices capable of injecting C2F4 gas, the content ratio of the fluorocarbon compound in the DLC film was set to 0 wt% in the surface layer, and the content ratio was changed in the film. The content ratio at the beginning of film formation is maximum αMwt% = 20w
t%. DLC film 2 is 5OA, 10
They were molded to a thickness of 0 and 150 mm, and perfluorocarbon was applied thereon to a thickness of 100 A as a lubricating layer 1, and cut into a width of 8 mm.

Moreover, αMwt% of the content ratio of the fluorine compound in the example is 2
Example 2 contained 0.30 wt%.

Comparative Example 1 A mixed gas of Ar and H2 (Ar: H2=1=3) was placed on a ferromagnetic metal thin film layer with graphite as a target.
, degree of vacuum 0.1 to 10 (Torr), frequency 13.56
(MHz), power 1. By glow discharge of IKW, a DLC film containing no fluorocarbon compound was formed at 5OA, 10
They were formed to a thickness of 0A and 150A, and perfluorocarbon was applied thereon to a thickness of 100A as a lubricating layer, and cut into 8-inch widths.

Comparative Example 2 CH4+CF (
CH4:C2F4=10:1), true 8 empty seat 0.1 (Torr), frequency 13.56 (Mi
(z) A DLC film (fluorine content ratio 20wt%) uniformly fluorinated by glow discharge with a power of 2.2KW was heated at 50A,
They were formed to a thickness of 100 mm and 150 mm respectively, and perfluorocarbon was applied thereon to a thickness of 10 OA as a lubricating layer, and cut into a width of 8 mm.

Comparative Example 3 Perfluorocarbon was applied as a lubricating layer to a thickness of 100 mm on a ferromagnetic metal thin film layer, and cut into a width of 8 mm.

Comparative Example 4 S was deposited on a ferromagnetic metal thin film layer using a sputtering method.
An iO2 film was formed to a thickness of 15OA, and perfluorocarbon was applied as a lubricating layer to a thickness of 100mm on top of it.
It was cut to a width of tIlI11.

The 8 mm video metal thin film tapes of the example and comparative example 1.
Evaluation was performed using MilliVideo (AV-300, manufactured by Sony ■). In order to accelerate the still durability evaluation, the tape tension was set to 20 g, and still playback was performed in a special environment of a temperature of 23° C. and a humidity of 10%, and the time at which the playback output decreased by 6 dB was measured. For corrosion resistance, temperature 60℃
, expresses the time it takes for rust to occur in an environment with 80% humidity.

The results are shown in Table 1.

As shown in Table 1, the still durability was 2 to 10 times higher in both Examples than in the Comparative Example.

As shown in Table 1, when comparing Examples and Comparative Examples 1 and 2, Examples 1 and 2 had durability 3 to 5 times higher.

In the case of Comparative Example 1, the hardness of the surface is high, but the hardness as a whole is high, so the adhesion strength with the magnetic layer is poor, and in the case of Comparative Example 2, the hardness of the surface is not sufficient. You can see that it is worse than the example. From the results of Comparative Examples 1 and 2, even if the hardness of the surface layer is the same, it is necessary to balance the hardness in the outermost layer and the adhesion strength with the magnetic layer, and the example is superior.

The corrosion resistance of the example was 1.1 to 4 times higher than that of the comparative example, confirming the excellent still durability and corrosion resistance of the example, and confirming that it is suitable for future high recording densities. did.

[Effects of the Invention] As described above, the magnetic recording medium obtained by the present invention has the following effects:
A DLC film is provided on a ferromagnetic metal thin film, and the fluoride content ratio of the diamond-like hard carbon film is set to a maximum content αMwt% (however, αM is in the range of 10 to 30) at the beginning of the film, and 0wt at the end of the film formation. %, it is possible to achieve the remarkable effects of significantly improving still durability and dramatically increasing corrosion resistance.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view of a magnetic recording medium according to the present invention. 1... Lubricating layer 2... DLC film 3 containing fluoride (0 to 20 wt%)
...Ferromagnetic metal thin film layer 4...Substrate 5...Back coat layer Fig. 1

Claims (1)

[Claims] (1) In a magnetic recording medium in which a ferromagnetic metal thin film is provided on a substrate, a diamond-like hard carbon film containing a fluorocarbon compound is provided on the ferromagnetic metal thin film, and the fluoride of the diamond-like hard carbon film is The content ratio is the maximum content αM at the beginning of film formation (however, αM is in the range of 10 to 30 wt%),
A magnetic recording medium characterized in that the film has a content distribution such that the end of film formation is 0 wt%.