JPH0974014A - Magnetic recording medium and method of manufacturing the same - Google Patents

Abstract

(57) Abstract: To provide a magnetic recording medium having a large coercive force and capable of coping with high density recording. A Fe-based metal magnetic film containing N is provided on a support, wherein the Fe-based metal magnetic film has a CuKα characteristic X-ray (wavelength: 1.54050).
The peak of Bragg angle 2θ with respect to Å) is 41 degrees ± 0.9
And 43 degrees ± 0.9 degrees and at least 41 degrees
A magnetic recording medium having a maximum peak at either ± 0.9 degrees or 43 degrees ± 0.9 degrees.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a magnetic recording medium having an Fe-based metal magnetic film.

[0002]

A metal thin film type magnetic recording medium in which a magnetic film is formed by dry plating means such as vapor deposition or sputtering is widely known. There are various materials for forming the magnetic film. As such magnetic materials, Co-Ni and Co-Cr based magnetic alloys have been mainly used so far.

However, Co, Ni, Cr, etc. are expensive. There are also concerns about pollution problems. In view of the above problems, attention is paid to Fe. This Fe is low in price and rarely causes pollution problems. An Fe-N-based metal magnetic film has been proposed as the Fe-based metal magnetic film.

However, the Fe-based metal magnetic films proposed so far have not been sufficient in coercive force, which is essential for high-density recording. While working diligently on this point, I came across an unexpected result. That is, iron nitrides of Fe ₂ N and Fe ₃ N never showed excellent magnetic properties, but when they coexist, they showed excellent magnetic properties.

In particular, CuKα characteristic X-ray (wavelength 1.540
The peak of Bragg angle 2θ for 50 Å) is 41 degrees ±
A Fe-N-based metallic magnetic film having a maximum peak at 0.9 degrees and 43 degrees ± 0.9 degrees and having a maximum peak at at least 41 degrees ± 0.9 degrees and 43 degrees ± 0.9 degrees. The magnetic force Hc is extremely large (for example, 1000 to 2000O).
e) In addition, the saturation magnetic flux density Bs is also large (for example, 400
0 to 10000 G), and was also excellent in corrosion resistance.

The present invention has been achieved based on this finding, and an object of the present invention is to provide a magnetic recording medium having a large coercive force and capable of coping with high density recording.

[0007]

The object of the present invention is a magnetic recording medium comprising an Fe-based metal magnetic film containing N on a support, wherein the Fe-based metal magnetic film is C
Bragg angle 2θ peak for uKα characteristic X-ray (wavelength 1.54050Å) is 41 ° ± 0.9 ° and 43 ° ±
It is achieved by a magnetic recording medium characterized by having a maximum peak at 0.9 degree and at least one of 41 degrees ± 0.9 degrees and 43 degrees ± 0.9 degrees.

A magnetic recording medium comprising an Fe-based metal magnetic film containing N on a support, wherein
The base metal magnetic film is achieved by a magnetic recording medium containing Fe ₂ N and Fe ₃ N. A method of manufacturing a magnetic recording medium in which an Fe-based metal magnetic film containing N is provided on a support, the method comprising scattering and depositing an Fe-based material toward the support, and the deposited Fe-based material. And a step of irradiating the metal magnetic film with nitrogen ions by an ion gun.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The magnetic recording medium of the present invention is a magnetic recording medium in which an Fe-based metal magnetic film containing N is provided on a support, and the Fe-based metal magnetic film is CuK.
The peak of the Bragg angle 2θ for α characteristic X-ray (wavelength 1.54050Å) is 41 ° ± 0.9 ° and 43 ° ± 0.9.
And at least 41 degrees ± 0.9 degrees and 43 degrees
It has a maximum peak at any one of ± 0.9 degrees.

Alternatively, the magnetic recording medium comprises a Fe-based metal magnetic film containing N provided on a support, wherein the Fe-based metal magnetic film contains Fe ₂ N and Fe ₃ N. . In particular, a magnetic recording medium comprising an Fe-based metal magnetic film containing N on a support, wherein
The e-based metal magnetic film contains Fe ₂ N and Fe ₃ N as main components.

In the Fe-based metal magnetic film of the present invention, Fe: N is 65 to 95 at%: 5 to 35 at% (F
e + N = 100%) is preferred. More preferably 75
˜90 at%: 10 to 25 at%. Such a magnetic recording medium can be manufactured by using a PVD (physical vapor deposition) method such as vapor deposition or sputtering.
For example, a vapor deposition method with a high film formation rate will be described as follows. First, for example, Fe is 9 in all metal components.
5 to 98.5 wt% (so-called purity is 95 to 98.5 wt%
% Fe), Au, Pt, Ag total amount is 0 to 0.05
wt% (It is perfect that it is 0, but it may be contained as an unavoidable impurity to some extent. Even if it is contained, the total amount of Au, Pt, and Ag is as small as possible,
An Fe-based metal material containing, for example, 0.05 wt% or less) and the rest being other metal components (for example, Co, Ni, Mn, Cr, etc.) is put in the crucible of the oblique vapor deposition apparatus. The Fe material having such a purity (95 to 98.5 wt%) is used because it is much cheaper than the case of using high-purity Fe having a purity of 99.95 wt% or more. . Of course, high-purity F of 98.5 wt% or more
You may use e. Then, the inside of the oblique vapor deposition apparatus is evacuated to a predetermined degree of vacuum, and the Fe-based metal material is evaporated (scattered) by an electron gun or other means to deposit and deposit the Fe-based metal particles on the running support. At the time of this attachment / deposition, nitrogen ions are irradiated toward the Fe-based metal particle deposition surface. One of the features is that the dose of this nitrogen ion is much larger than in the past. That is, when the dose of nitrogen ions was small, the metal magnetic film having the features of the present invention could not be obtained. Incidentally, the amount of nitrogen gas supplied to the ion gun for irradiating nitrogen ions is about 5 to 10 times that of the conventional one (for example, 20 to 70 sccm, more preferably 25).
(~ 60 sccm) was required. Incidentally, the gas supply amount in the prior art is such that the flow rate is about 5 sccm while maintaining the degree of vacuum in the vacuum chamber at about 7 × 10 ⁻⁵ Torr.

The magnetic recording medium of the present invention is a method for producing a magnetic recording medium in which an Fe-based metallic magnetic film containing N is provided on a support, and the Fe-based material is directed toward the support. It is obtained by a manufacturing method including a step of scattering and depositing, and a step of irradiating the deposited Fe-based metal magnetic film with nitrogen ions with an ion gun. In particular, a method of manufacturing a magnetic recording medium in which an Fe-based metallic magnetic film containing N is provided on a support, which comprises a step of scattering and depositing an Fe-based material toward a support, and a deposited Fe-based material. And a step of irradiating the metal magnetic film with nitrogen ions with an ion gun, wherein the amount of nitrogen gas supplied to the ion gun is 20 to 70 sccm.

When the Fe-based metallic magnetic film having a thickness of 1500 to 2000Å is provided as described above, if necessary,
A protective film made of diamond-like carbon, boron carbide, silicon nitride or the like and having a thickness of about 50 to 200Å is provided on the Fe-based metal magnetic film. Further, a fluorine-based lubricant such as perfluoropolyether is provided with a thickness of about 20 to 70Å.

The magnetic recording medium configured as described above has a high coercive force and a high saturation magnetic flux density, and can be used for high density recording. Moreover, it was also excellent in corrosion resistance. Moreover, the magnetic material Fe is inexpensive and is unlikely to cause pollution problems. In particular, since it is not necessary to use high-purity Fe, the cost is lower.

[0015]

Embodiment 1 FIG. 1 is a schematic view of a magnetic recording medium manufacturing apparatus according to the present invention, and FIG. 2 is a schematic view of an ion gun. FIG.
Medium 1 is a non-magnetic support such as PET film, 2a
Is a PET film 1 supply side roll, 2b is a PET film 1 winding side roll, 3 is a cooling can roll, 4 is a shielding plate, 5 is a crucible, 6 is a Fe-based magnetic metal, 7 is an output 10
A kW electron gun, a vacuum chamber 8 and an ion gun 9. This ion gun 9 has the structure shown in FIG.
A current of 8 A is applied to the tungsten cathode 10 of φ,
500 between the anode 11 and the screen grid 12
A potential difference of V can be formed, and when nitrogen gas is supplied from the nozzle 13, nitrogen ions are emitted. Incidentally, 14 is a magnet.

The magnetic recording medium (magnetic tape) of this embodiment is obtained by using the oblique vapor deposition apparatus shown in FIG. That is, the PET film 1 having a thickness of 6.3 μm is passed between the supply side roll 2a and the winding side roll 2b,
It runs along the cooling can roll 3. After evacuation of the vacuum chamber 8 to a vacuum degree of about 10 ⁻⁴ to 10 ⁻⁶ Torr, for example, about 5 × 10 ⁻⁶ Torr, heating of the electron beam from the electron gun 7 causes the magnetic metal (purity of 99. 9 wt%
Fe) was melted and evaporated, and an Fe-based metal magnetic film having a thickness of 1500 to 2000Å, for example, 1830Å was provided on the PET film 1.

At the time of forming the Fe-based metal magnetic film, nitrogen gas was supplied from the nitrogen gas supply nozzle 13 at 40 sccm to irradiate the Fe-based metal magnetic film with nitrogen ions from the ion gun 9. On the back surface of the raw sheet having the Fe-N-based metal magnetic film thus obtained, carbon black having an average particle diameter of 40 nm and carbon black having an average particle diameter of 80 nm were mixed at a ratio of 2: 1 to prepare urethane. A back coat paint dispersed in a binder resin of a base resin and a vinyl chloride resin was applied by a die coating method to a dry film thickness of 0.5 μm and dried.

After this, perfluoropolyether (FO
MBLIN ZDOL Montecatini Co., Ltd.) was diluted with a fluorine-based inert liquid (Fluorinert FC-77 Sumitomo 3M Co., Ltd.) to a concentration of 0.05 wt%, and a dry film thickness of 20 Å was obtained by a die coating method. It was coated on a -N-based metal magnetic film and dried at 105 ° C.

After that, it was slit into a width of 8 mm and loaded into a cassette to obtain a magnetic tape for 8 mm VTR.

[0020]

Second Embodiment In the first embodiment, the potential difference between the anode 11 and the screen grid 12 is 300 V, and the nozzle 1 is
Example 3 was repeated except that the nitrogen gas supply amount from 3 was 25 sccm. The obtained Fe-based metallic magnetic film had a thickness of 1810Å.

[0021]

Example 3 The procedure of Example 1 was repeated except that the nitrogen gas supply rate from the nozzle 13 was changed to 60 sccm. The obtained Fe-based metal magnetic film has a thickness of 1800Å
Met.

[0022]

Comparative Example 1 The procedure of Example 1 was repeated except that the amount of nitrogen gas supplied from the nozzle 13 was changed to 6 sccm. The obtained Fe-based metallic magnetic film had a thickness of 1790Å.

[0023]

[Comparative Example 2] In Example 1, except that the ion gun 9 was not operated, and the nitrogen gas was irradiated to the Fe-based metal magnetic film at a rate of 5 sccm at the time of forming the Fe-based metal magnetic film. It carried out according to it. The obtained Fe-based metallic magnetic film had a thickness of 1820Å.

[0024]

[Characteristics] With respect to the Fe-based metal magnetic film obtained in each of the above examples, output 3 kW, target 1.54050 Å (Cu), acceleration voltage 50.0 kV, acceleration current 50.0 mA, sampling width 0.020 deg, sampling speed 2.000 d
The X-ray diffraction pattern was examined under the condition of eg / min, and the results are shown in FIGS. 3 to 7.

According to this, in the Fe-based metal magnetic film according to the present invention, the peak of the Bragg angle 2θ is 41.
It can be seen that it has a feature that it is in a range of ± 0.9 degrees and 43 degrees ± 0.9 degrees, and has a maximum peak at at least one of 41 degrees ± 0.9 degrees and 43 degrees ± 0.9 degrees.
The peaks at the positions of 41 ° ± 0.9 ° and 43 ° ± 0.9 ° are caused by Fe ₂ N and Fe ₃ N, and are 41 ° ± 0.9 ° and 48 ° ± 0.9 °. If peaks are present at both positions, it is due to Fe ₄ N.

On the other hand, Comparative Examples 1 and 2 did not exhibit the above characteristics. These peaks are summarized in Table-1. Table-1 X-ray diffraction strength Fe ₂ N and Fe ₃ N Fe ₄ N Fe Example 1 Peak confirmation No peak observed No peak observed Example 2 Peak confirmed Weak peak confirmed No peak confirmed Example 3 Peak confirmed No peak confirmed No peak is observed Comparative example 1 No peak is observed Weak peak is confirmed Peak confirmation Comparative example 2 No peak is observed No peak is observed Strong peak is confirmed Then, the magnetic properties (coercive force Hc, saturation magnetic flux density Bs) and corrosion resistance of the obtained magnetic tape are confirmed. Sex (20 ℃
The reduction rate ΔBs of the saturation magnetic flux density after immersion in 5 wt% saline for 1 week was examined, and the results are shown in Table-2.

Table-2 Coercive force Hc (Oe) Saturation magnetic flux density Bs (G) Corrosion resistance ΔBs (%) Example 1 1300 6500 1 Example 2 1000 7500 2 Example 3 1570 5800 1 Comparative Example 1 350 13000 7 Comparison Example 2 100 18000 48 According to this, according to the present invention, Hc is 1000 O
e or more and Bs is 4000 G or more, which means that high density recording can be supported.

It is also found that the corrosion resistance is excellent.

[0029]

Industrial Applicability A magnetic recording medium suitable for high density recording and having excellent corrosion resistance is obtained by using an inexpensive Fe-based material.

[Brief description of drawings]

FIG. 1 is a schematic view of an apparatus for manufacturing a magnetic recording medium of the present invention.

FIG. 2 is a schematic diagram of an ion gun.

FIG. 3 is an X-ray diffraction pattern diagram of the Fe—N-based metal magnetic film of Example 1.

FIG. 4 is an X-ray diffraction pattern diagram of the Fe—N-based metal magnetic film of Example 2.

FIG. 5 is an X-ray diffraction pattern diagram of the Fe—N-based metal magnetic film of Example 3.

FIG. 6 is an X-ray diffraction pattern diagram of the Fe—N-based metal magnetic film of Comparative Example 1.

FIG. 7 is an X-ray diffraction pattern diagram of a Fe—N-based metal magnetic film of Comparative Example 2.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Junko Ishikawa 2606 Akabane, Kai-cho, Haga-gun, Tochigi Prefecture Kao Corporation Company Information Science Laboratory

Claims (3)

[Claims] 1. A magnetic recording medium comprising an Fe-based metal magnetic film containing N provided on a support, wherein the Fe-based metal magnetic film is a Bragg film for CuKα characteristic X-rays (wavelength 1.54050Å). The peak of angle 2θ is 41 ° ± 0.9 ° and 43 ° ±
0.9 degrees and at least 41 degrees ± 0.9 degrees and 43 degrees ± 0.9 degrees
A magnetic recording medium having a maximum peak at any one of the degrees. 2. A magnetic recording medium comprising an Fe-containing metal magnetic film containing N provided on a support, wherein the Fe-containing metal magnetic film contains Fe ₂ N and Fe ₃ N. And a magnetic recording medium. 3. A method for manufacturing a magnetic recording medium comprising a Fe-based metallic magnetic film containing N on a support, the method comprising: scattering and depositing an Fe-based material toward the support; And a step of irradiating the Fe-based metal magnetic film with nitrogen ions with an ion gun.