JPH09134523A - Protective film, magnetic recording medium and manufacture of magnetic recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a protective film which excels in durability by a simple means by making the maximum value of concentration of C exist in a temporal position delayed from the position showing the maximum value of concentration of F and both concentrations satisfy a specific relationship in an Auger profile. SOLUTION: This magnetic recording medium is a magnetic recording medium which is provided with a magnetic film on a supporting body and a protective film on the magnetic film. The protective film is observed by an Auger electronic spectro-chemical analysis, and in an Auger profile in which the concentration of F and the concentration of C are adopted as an axis of ordinates and time is adopted as an axis of abscissa, a peak showing the maximum value Cmax of the concentration of C is observed in a time position delayed from the position showing the maximum value Fmax of the concentration of F. Also, FO>CO, where FO and CO are the concentrations of F and C at the time when sputtering is started, is satisfied.

Description

Detailed Description of the Invention

[0001]

[0001] The present invention relates to a magnetic recording medium.

[0002]

In a magnetic recording medium such as a magnetic tape, due to the demand for high density recording, the magnetic film provided on the non-magnetic support is not a coating type using a binder resin. , A metal thin film type that does not use a binder resin has been proposed. That is, there has been proposed a magnetic recording medium having a magnetic film formed by a wet plating means or a dry plating means such as vacuum deposition, sputtering or ion plating. This kind of magnetic recording medium is suitable for high-density recording because of its high packing density of magnetic material.

This metal thin film type magnetic recording medium is provided with a protective film and a lubricant on its surface in order to improve running property and durability. However, it is possible to include a lubricant in the magnetic film, and therefore, compared to a coating type magnetic recording medium in which the lubricant is retained for a long period of time, the lubricant should be included in the protective film. The metal thin film type magnetic recording medium which cannot be stored easily loses the lubricant. For this reason, there is a problem that the traveling property is reduced in a short period of time.

Therefore, various proposals have been made. For example, a method of synthesizing and adhering a lubricant by performing gas phase polymerization on a protective film provided on a metal magnetic film has been proposed (JP-A-4-18652). However, this means of gas phase polymerization requires high technology and equipment. Therefore,
An object of the present invention is to provide a protective film having excellent durability by simple means.

[0005]

The object of the present invention is to observe the maximum F concentration in an Auger profile observed by Auger electron spectroscopic analysis, in which the vertical axis represents F concentration and C concentration, and the horizontal axis represents time. A peak showing the maximum C concentration Cmax is observed at a time position delayed from the position showing Fmax, and F0> C0 (where F0 and C0 are the F concentration and C concentration at the start of sputtering) is satisfied. It is achieved by a protective film which is characterized in that

Further, in the Auger profile observed by Auger electron spectroscopic analysis, in which the F and C concentrations are plotted on the ordinate and the time is plotted on the abscissa, C is placed at a time position delayed from the position showing the maximum F concentration Fmax. A protective film having a peak showing the maximum concentration Cmax and satisfying Fmax> Cmax F0> C0 (where F0 and C0 are the F amount and C amount at the start of sputtering). Achieved by

A magnetic recording medium having a magnetic film on a support and a protective film on the magnetic film, wherein the protective film is observed by Auger electron spectroscopy, and the vertical axis indicates the F concentration and C
In the Auger profile in which the abscissa represents the concentration, a peak showing the maximum C concentration Cmax was recognized at a time position delayed from the position showing the maximum F concentration Fmax.
Further, it is achieved by a magnetic recording medium characterized by satisfying F0> C0 (where F0 and C0 are F concentration and C concentration at the start of sputtering).

A magnetic recording medium having a magnetic film on a support and a protective film on the magnetic film, wherein the protective film is observed by Auger electron spectroscopy, and the vertical axis indicates F concentration and C
In the Auger profile in which the abscissa represents the concentration, a peak showing the maximum C concentration Cmax was recognized at a time position delayed from the position showing the maximum F concentration Fmax.
Further, it is achieved by a magnetic recording medium characterized by satisfying Fmax> Cmax F0> C0 (where F0 and C0 are the amount of F and the amount of C at the start of sputtering).

A method of manufacturing a magnetic recording medium comprising a magnetic film on a support and a protective film on the magnetic film, the method comprising: forming a magnetic film on the support; After the magnetic film forming step, a first CV for forming a protective film using a hydrocarbon-based compound by ECR microwave plasma CVD method
A magnetic recording comprising a step D and a second CVD step of forming a protective film by using an ECR microwave plasma CVD method using a compound of a fluorine-based hydrocarbon after the first CVD step. This is achieved by the method of manufacturing the medium.

Since the above-mentioned protective film is a carbon-based film having a large amount of F in the surface layer, particularly a diamond-like carbon film, it has an excellent sliding effect. In particular, it has excellent lubricity over a long period of time. Moreover, the protective film (diamond-like carbon film) having the above-mentioned excellent features is an ECR microwave plasma CV.
The film can be easily formed because it is obtained by the D method.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The protective film of the present invention is observed by Auger electron spectroscopy, and in the Auger profile in which the vertical axis shows F concentration and C concentration and the horizontal axis shows time, the maximum F concentration value Fmax is shown. A peak showing the maximum value Cmax of the C concentration is recognized at a time position delayed from the position shown, and F0> C0 (where F0 and C0 are the F concentration and C concentration at the start of sputtering). Also, in the Auger profile observed by Auger electron spectroscopic analysis and showing the F concentration and C concentration on the vertical axis and the time on the horizontal axis, the maximum C concentration is at a time position delayed from the position showing the maximum F concentration maximum Fmax. A peak showing a value Cmax is recognized, and Fmax> Cmax, F0> C0 (where F0,
C0 satisfies the F amount and C amount at the start of sputtering.

The magnetic recording medium of the present invention is a magnetic recording medium having a magnetic film on a support and a protective film on the magnetic film. The protective film is observed by Auger electron spectroscopy and the vertical axis indicates In the Auger profile in which the abscissa represents the F concentration and the C concentration, a peak showing the maximum C concentration Cmax was observed at a time position delayed from the position showing the maximum F concentration maximum Fmax, and F0> C0 (however, F0
, C0 satisfy the F concentration and C concentration at the start of sputtering. A magnetic recording medium having a magnetic film on a support and a protective film on the magnetic film, wherein the protective film is observed by Auger electron spectroscopy, and the ordinate indicates the F concentration and the C concentration. In the Auger profile with time, the peak showing the maximum C concentration Cmax is found at the time position delayed from the position showing the maximum F concentration Fmax, and Fmax> Cmax, F0> C0 (however, F0>
, C0 satisfy the F amount and C amount at the start of sputtering.

The relationship between F0 and C0 is F0> 2
Those satisfying C0 are more preferable. The method for producing a magnetic recording medium of the present invention is a method for producing a magnetic recording medium comprising a magnetic film on a support and a protective film on the magnetic film, wherein the magnetic film is formed on the support. A first CV for forming a protective film using a hydrocarbon-based compound by an ECR microwave plasma CVD method after the film forming step and the magnetic film forming step
After the first CVD step, a second CVD step of forming a protective film using a fluorine-based hydrocarbon compound by the ECR microwave plasma CVD method is provided.

The present invention is particularly applicable to a metal thin film type magnetic recording medium. The support in the magnetic recording medium may be magnetic or non-magnetic, but is generally non-magnetic. For example, polyester such as PET, polyamide, polyimide, polysulfone, polycarbonate, olefin resin such as polypropylene,
A polymer material such as a cellulose resin or a vinyl chloride resin is used. Further, ceramics or metal materials may be used. An undercoat layer for improving the adhesion of the magnetic film (metal magnetic film) is provided on the support, if necessary. That is, by appropriately roughening the surface roughness, for example, the adhesion of the magnetic film formed by the oblique deposition method is improved, and the surface roughness of the magnetic recording medium surface is moderated to improve the running property. Therefore, the undercoat layer is formed by providing a coating film containing particles such as SiO ₂ .

On this support, a metal thin film type magnetic film is provided by dry plating means such as vapor deposition or sputtering.
For example, in addition to metals such as Fe, Co and Ni, Co-Ni
Alloy, Co-Pt alloy, Co-Ni-Pt alloy, Fe-
Co alloy, Fe-Ni alloy, Fe-Co-Ni alloy, F
e-Co-B alloy, Co-Ni-Fe-B alloy, Co-
Use a magnetic metal such as Cr alloy, and set the inside of the vacuum chamber to 10 ^-4.
After evacuation to a vacuum degree of about 10 ^-6 Torr, for example, 2 × 10 ^-5 Torr, magnetic metal in the crucible is evaporated by resistance heating, high frequency heating, electron beam heating, etc.
A metal thin film type magnetic film is formed by obliquely vapor-depositing a magnetic metal having a thickness of 400 to 5000 Å, for example, 2000 Å on a support such as a film. During the oblique vapor deposition of the metal magnetic particles, a small amount of oxygen is blown from the oxygen gas supply nozzle. As a result, a magnetic column is formed on the metal magnetic film. The magnetic characteristics of the metal magnetic film thus obtained are excellent because the magnetic columns are magnetically separated by the oxide film. The film formation may be performed by means such as sputtering. As the magnetic film, in addition to the above, a nitride (for example, F
e-N, Fe-N-O) and carbides (for example, Fe-C,
Fe-C-O) etc. are also mentioned. Although it is basically a metal thin film type magnetic film, it does not exclude a coating type magnetic film.

A protective film is formed on the metal magnetic film in a range of 50 to 250.
Å Thickness is provided. The protective film may be an oxide-based film, a nitride-based film, a carbide-based film, or a composite film thereof, but is a carbon-based film, particularly a diamond-like carbon-based film. For example, the protective film is formed by using a CVD device, particularly an ECR microwave plasma CVD device. That is, the magnetic film, in particular the metallic magnetic film, is run on the support surface while the raw material of the magnetic recording medium is attached to a cooling can roll provided between the supply-side roll and the winding-side roll. A diamond-like carbon film is provided on the metal magnetic film by supplying a hydrocarbon-based gas to a first plasma reaction tube provided opposite to the cooling can roll and irradiating it with microwaves. Then, a second hydrocarbon-like film is provided on the first diamond-like carbon film by supplying a fluorine-based hydrocarbon gas to the second plasma reaction tube and irradiating it with microwaves. As a result, the protective film having the above characteristics is formed on the magnetic film.

Examples of the hydrocarbon-based gas (compound) used in the first CVD step include chain hydrocarbons such as methane, ethane and ethylene, and cyclic hydrocarbons such as benzene and cyclohexane. Examples of the fluorine-based hydrocarbon gas (compound) used in the second CVD step include monofluoromethane, difluoromethane, trifluoromethane, monofluoroethylene, difluoroethylene,
Trifluoroethylene, tetrafluoroethylene, monofluoroethane, difluorooroethane, trifluoroethane, tetrafluoroethane, pentafluoroethane, monofluoropropylene, difluoropropylene, trifluoropropylene, tetrafluoropropylene, pentafluoropropylene, hexafluoro Examples include propylene, monofluorobutadiene, difluorobutadiene, trifluorobutadiene, tetrafluorobutadiene, pentafluorobutadiene, hexafluorobutadiene and the like.

A so-called back coat film is provided on the surface of the support on which the metal magnetic film is not provided. The back coat film may be either a metal thin film type or a coating type, but a metal thin film type is preferred in the present invention.

[0019]

Example 1 A PET film having a thickness of 10 μm is used as a support, and a 2000 Å Co magnetic film is provided on the PET film by oblique vapor deposition means. This is an ECR microwave plasma CV with a vacuum degree of 10 mTorr.
Equipped with D equipment and ECR microwave plasma CVD
CH ₄ is supplied to the first plasma reaction tube of the apparatus, microwave (output 600 W, wavelength 2.45 GHz) is irradiated, and diamond-like carbon film is formed on the Co magnetic film on the PET film running at 10 m / min. Was set up. Then, CFH ₃ is supplied to the second plasma reaction tube provided in parallel with the first plasma reaction tube, and microwaves (output 600
W, wavelength 2.45 GHz) was applied to provide a diamond-like carbon film having F on the diamond-like carbon film, and an 8 mm VTR magnetic tape having a protective film with a total thickness of 100 Å was obtained.

[0020]

Example 2 In Example 1, C was used instead of CFH _3.
8 mm except that F ₂ H ₂ was used
A magnetic tape for VTR was obtained.

[0021]

Example 3 In Example 1, C was used instead of CFH _3.
Performed according to Example 1 except that F ₃ H was used, 8 mmV
A magnetic tape for TR was obtained.

[0022]

Comparative Example 1 According to Example 1, except that the F-containing amorphous carbon film was provided by the sputtering method using perfluoropolyether as a target instead of the diamond-like carbon film formed by ECR microwave plasma CVD. Then, a magnetic tape for 8 mm VTR was obtained.

The sputtering condition is 3 mTorr of Ar.
Gas, sputter voltage 430v, sputter power 3kw
It is.

[0024]

Comparative Example 2 A 10 μm PET film provided with a 2000 Å-thick Co magnetic film by oblique vapor deposition means was vacuumed to 1 degree.
It was loaded into an ECR microwave plasma CVD apparatus of 0 mTorr, and CH ₄ was supplied to the plasma reaction tube of the ECR microwave plasma CVD apparatus to generate microwaves (output 60
0 W, wavelength 2.45 GHz) and irradiate 10 m / min
100 on the Co magnetic film on the PET film
Å A thick diamond-like carbon film was provided. Subsequently, a fluorine-based lubricant was applied to the surface of the diamond-like carbon film using the vapor phase polymerization method described in JP-A-4-18652 to obtain an 8 mm VTR magnetic tape.

[0025]

[Comparative Example 3] A 10 μm PET film provided with a 2000 Å-thick Co magnetic film by oblique vapor deposition was used to obtain a vacuum degree of 1
It was loaded into an ECR microwave plasma CVD apparatus of 0 mTorr, and CH ₄ was supplied to the plasma reaction tube of the ECR microwave plasma CVD apparatus to generate microwaves (output 60
0 W, wavelength 2.45 GHz) and irradiate 10 m / min
100 on the Co magnetic film on the PET film
Å A thick diamond-like carbon film was provided. A fluorine-based lubricant (FOMBLIN AM2001) was applied to the surface of this diamond-like carbon film by a coating means to obtain an 8 mm VTR magnetic tape.

[0026]

[Characteristics] Fig. 1 shows Auger profiles (F amount + C amount + O amount + Co amount = 100 at.%) By Auger electron spectroscopy analysis for the magnetic tapes for 8 mm VTR in each of the above examples.
7 to FIG. According to this Auger profile, in the present embodiment, a peak showing the maximum C concentration Cmax is observed at a time position delayed from the position showing the maximum F concentration Fmax, and F0> C0, especially F0. > 2C0 (where F0 and C0 are the F concentration and C concentration at the start of sputtering), and further satisfy Fmax> Cmax.

On the other hand, in Comparative Example 1, C0>
F0, which does not satisfy the content of the present invention.
Further, in the case of Comparative Example 3, F is basically not detected. The Y-S / N, C- of the magnetic tapes of the above examples
The S / N and still durability were examined, and the results are shown in Table-1. Table-1 Y-S / N (dB) C-S / N (dB) Still durability (time) AM PM Example 1 +1.2 +1.0 +1.2 5.2 Example 2 +1.0 +1. 2 +0.8 6.4 Example 3 +1.2 +1.2 +1.0 7.0 Comparative example 1 -0.2 -0.2 0.0 1.0 Comparative example 2 +0.2 +0.4 +0. 2 1.8 Comparative Example 3 0 0 0 2.0 * Y-S / N and C-S / N are based on Comparative Example 3 (0 dB).

[0028]

The present invention is highly durable. When it is used as a protective film of a magnetic recording medium, it has not only excellent durability but also high reproduction output.

[Brief description of the drawings]

FIG. 1 is an Auger profile according to a first embodiment.

FIG. 2 is an enlarged Auger profile of the first embodiment.

FIG. 3 is an Auger profile according to the second embodiment.

FIG. 4 Auger profile of Example 3

5 is an Auger profile of Comparative Example 1. FIG.

FIG. 6 is an Auger profile of Comparative Example 2

FIG. 7 is an Auger profile of Comparative Example 3

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Katsumi Sasaki 2606, Akabane, Kai, Haga-gun, Tochigi Prefecture Kao Co., Ltd.Institute of Information Science Research Institute (72) Junko Ishikawa 2606, Akabane, Kai-cho, Haga-gun, Tochigi Kao Shikisha Institute of Information Science

Claims (5)

[Claims] 1. In an Auger profile observed by Auger electron spectroscopy, in which the vertical axis represents F concentration and C concentration and the horizontal axis represents time, the C position is delayed from the position showing the maximum F concentration maximum Fmax. A protective film having a peak showing the maximum concentration Cmax and satisfying F0> C0 (where F0 and C0 are the F concentration and C concentration at the start of sputtering). 2. In an Auger profile observed by Auger electron spectroscopic analysis and having the F concentration and the C concentration on the vertical axis and the time on the horizontal axis, the C at a time position delayed from the position showing the maximum F concentration maximum Fmax. A protective film having a peak showing the maximum concentration Cmax and satisfying Fmax> Cmax F0> C0 (where F0 and C0 are the F amount and C amount at the start of sputtering). . 3. A magnetic recording medium comprising a magnetic film on a support and a protective film on the magnetic film, wherein the protective film is observed by Auger electron spectroscopy, and the vertical axis indicates F concentration and C concentration. In the Auger profile with time on the horizontal axis, a peak showing the maximum C concentration Cmax is observed at a time position delayed from the position showing the maximum F concentration maximum Fmax, and F0> C0 (however, F0, A magnetic recording medium characterized in that C0 satisfies the F concentration and C concentration at the start of sputtering. 4. A magnetic recording medium comprising a magnetic film on a support and a protective film on the magnetic film, wherein the protective film is observed by Auger electron spectroscopy, and the vertical axis indicates F concentration and C concentration. In the Auger profile with time on the horizontal axis, a peak showing the maximum C concentration Cmax was found at a time position delayed from the position showing the maximum F concentration Fmax, and Fmax> Cmax F0> C0 (however, , F0, C0 satisfy the F amount and C amount at the start of sputtering. 5. A method of manufacturing a magnetic recording medium comprising a magnetic film on a support and a protective film on the magnetic film, comprising: a magnetic film forming step of forming a magnetic film on the support; After the magnetic film forming step, ECR microwave plasma C
A first CVD step of forming a protective film using a hydrocarbon-based compound by the VD method, and ECR microwave plasma C after the first CVD step.
A second CVD step of forming a protective film by using a fluorine-based hydrocarbon compound by the VD method, the method for producing a magnetic recording medium.