JPH0444636A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To improve the still durability and traveling durability in low-humidity environment by forming a plasma-polymerized film of hydrocarbon, a hard carbon film contg. fluorine atoms and a lubricant layer on a ferromagnetic metallic thin film. CONSTITUTION:The ferromagnetic metallic thin film 2 is formed atop a nonmagnetic substrate 1 and the plasma-polymerized film 3 of the hydrocarbon is formed on this ferromagnetic metallic thin film 2. The fluorine-contg. hard carbon film 4 is formed thereon and the lubricant layer 5 is superposed as the uppermost protective layer thereon. On the other, a back coat layer 6 is formed on the rear surface of the nonmagnetic substrate 1 to finish the magnetic recording medium.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a magnetic recording medium in which a ferromagnetic metal thin film is used as a magnetic recording layer. The present invention relates to a magnetic recording medium with significantly improved performance and running durability.

BACKGROUND OF THE INVENTION Conventionally, in magnetic recording media whose magnetic recording layer is a ferromagnetic metal thin film, corrosion resistance has been improved using various methods.

Still durability and running durability have continued to improve. For example, firstly, a carboxylic acid-based 5-phosphorus lubricant layer is provided on a ferromagnetic metal thin film, secondly, a non-magnetic metal protective film is similarly provided, and thirdly, an S+02 film is similarly provided. be. However, the current situation is that these protective films do not further improve running durability and corrosion resistance. Therefore, recently, consideration has been given to using a diamond-like carbon film as a protective film for thin-film magnetic recording media.

Problems to be Solved by the Invention Although the technology using the diamond-like carbon film described above has the effect of significantly improving running durability, the spacing loss due to its thickness makes it difficult to achieve high performance in short wavelength recording, which is a characteristic of thin-film magnetic recording media. This has a large negative impact on output, making it impractical. Specifically, in order to improve running durability with a diamond-like carbon film, 200 to 300 people are required to increase the film thickness, and for this reason, the Y-output of 5MHz, which is the standard for an 8m video tape recorder (VTR), is approximately 3. The output was reduced by 0 to 4.0 dB.

The present invention has been made to solve the above-mentioned problems, and aims to provide a high-output metal thin film type magnetic recording medium that reduces substrate loss and has excellent running durability and still durability in low-humidity environments. do.

Means for Solving the Problems In order to achieve the above objects, the present invention forms a ferromagnetic metal thin film on a non-magnetic substrate, forms a hydrocarbon plasma polymerized film on this ferromagnetic metal thin film, and A fluorine-containing hard carbon film is formed on a polymer film, and a lubricant layer is further formed as the uppermost protective layer.

As described above, the present invention forms a hydrocarbon plasma polymerized film on a ferromagnetic metal thin film, forms a hard carbon film containing fluorine 5F' atoms on top of this, and further forms a lubricant layer on top of this. By forming a protective film, the still durability and running durability in low humidity environments are improved, and the output decrease due to these protective films is reduced by approximately 1.
．． This can be suppressed to about 0 dB.

EXAMPLE Hereinafter, an example of the magnetic recording medium of the present invention will be described based on the drawings.

A ferromagnetic metal thin film 2 is formed on the upper surface of a non-magnetic substrate 1 made of a polyethylene terephthalate film or the like, a hydrocarbon plasma polymerized film 3 is formed on this ferromagnetic metal thin film 2, and a fluorine atom-containing film is further formed on the ferromagnetic metal thin film 2. A fluorine-containing hard carbon film 4 is formed, and a lubricant layer 5 is further formed thereon as an uppermost protective layer. On the other hand, a back coat layer 6 is formed on the lower surface of the nonmagnetic substrate 1 to form a magnetic recording medium. And the fluorine-containing hard carbon film 4
Argon and common hydrocarbons and fluorine-containing hydrocarbons, such as CH2F2CF□, C-C3F
6. CHF3. C, F6, etc. may be mixed and introduced as a mixed gas, or a fluorine-containing hard carbon film may be formed using only argon and a fluorine-containing hydrocarbon.

These fluorine-containing hard carbon films contain fluorine atoms within themselves, so they have good slipperiness, prevent the magnetic head material from adhering to the thin film media surface in low humidity environments, and improve running durability. It can improve the durability and still durability.

Therefore, it is possible to make the hard carbon film itself thinner,
Sufficient credibility can be obtained with a depth of 60 to 100 people.

This will be explained in detail below.

500- with controlled surface roughness without abnormally large protrusions
Medium temperature polyethylene terephthalate film, for example, maximum surface roughness 200-300, center line average roughness 25-300
50 people, the density of Yamabushi protrusions is 1, mn (10" to 1 per
．． After forming 2,000 ferromagnetic metal thin films 2 of Co(80) to Ni(20) on OQ nonmagnetic substrates 1 by vacuum evaporation method while introducing oxygen, vacuum was applied onto the ferromagnetic metal thin films 2. Ten people form a plasma polymerized film 3 using propane as a raw material under the conditions of 0.1 Torr, 15 KHz frequency, and 500 cm output.Next, a mixed gas of methane, perfluorocyclobutane, and argon is poured onto the plasma polymerized film 3. As a raw material, the internal pressure of the discharge tube was 0.3 Torr, the AC frequency of IKHz was used, the voltage was 2000 Port,
Plasma CVD by applying a DC voltage of +800 volts
A fluorine-containing hard carbon film 4 containing fluorine atoms was formed by 100 people using the method. The gas flow rate at this time varies from 80SCCM to 200SCCM. This is called sample A. As for other samples, B is a sample formed from a gas containing only argon and perfluorocyclobutane, and CH
CF4. Sample 01CH from argon gas
,,CH2F2. Sample D is from argon gas, and sample E is from C2F6 and argon gas.
And so.

For comparison, samples were also fabricated using a diamond-like carbon film that does not contain fluorine atoms as a protective film (-). Sample F was made from propane and argon gases, and sample F was made from methane and argon gases. It was designated as sample G.

A lubricant layer 5 was formed by applying a fluorine-containing carboxylic acid lubricant onto these samples (A-G) by 50 people using a well-known coating method such as mixing with a solvent and coating and drying or a vacuum deposition method. Formed, then 1/1 by slitter
Cut into 2 inch width. 1/2 created in this way
A metal thin film type magnetic tape for inch VTR was evaluated using MnVTR manufactured by Matsushita Electric Industrial ■.

The still durability was measured in an environment of 23° C.-10%, and the time until the output decreased by 3 dB compared to the initial state was expressed in minutes. The results are summarized in the following table as the effects of the fluorine-containing hard carbon film.

As is clear from Samples A to E in the above table, by forming hard carbon Iff (100 people) 4 containing fluorine atoms, - When using a diamond-like carbon film Since the still durability in a low humidity environment can be improved and the thickness of the protective film can be made thinner, a magnetic recording medium with higher output can be obtained.

Effects of the Invention As is clear from the above examples, according to the present invention, it is possible to obtain a metal thin film type magnetic recording medium with high still durability in a low humidity environment by minimizing the decrease in output due to the hard protective film. It is something.

[Brief explanation of drawings]

The figure is a schematic cross-sectional view of one embodiment of a magnetic recording medium according to the present invention. 1...Nonmagnetic substrate, 2...Ferromagnetic metal thin film, 3...Plasma polymerized film, 4...
Fluorine-containing hard carbon film, 5...Lubricant layer. Name of agent: Patent attorney Shigetaka Awano (1 person): fh
Hiiragi Fu Salvation 5T! '55 + ding total rent★-and f 7'ras ゛ma self ((5 rivers

Claims (1)

[Claims] A ferromagnetic metal thin film is formed on a non-magnetic substrate, a hydrocarbon plasma polymerized film is formed on this ferromagnetic metal thin film, a fluorine-containing hard carbon film is formed on this plasma polymerized film, and then a top protective layer is formed. A magnetic recording medium with a lubricant layer.