JP2597686B2 - Manufacturing method of magnetic recording medium - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a magnetic recording medium using a ferromagnetic metal thin film suitable for high-density magnetic recording as a magnetic recording layer.

2. Description of the Related Art Efforts to increase the recording density have been made continually in order to reduce the size and performance of recording and reproducing equipment, and it has recently been expected that a ferromagnetic metal thin film will be put to practical use as a magnetic recording layer. (IEEE TRANS-ACTIONS ON MAGNETICS V
ol, MAG-21, NO-3, PP1217-1220 (1985)]. Although many combinations of ferromagnetic metal thin films are conceivable as materials, few have shown realistic possibilities, such as Co-Cr
Perpendicular magnetization film [JP-B-58-91, JP-A-61-12]
No. 0331] and obliquely deposited films such as Co-Ni and Co-Ni-O and wet plating films [JP-B-41-19389, JP-A-53-420].
No. 10 gazette), and recently for practical purposes,
The development of a protective lubrication layer is central to the study. At present, a ferromagnetic metal thin film is placed on a polymer film such as a polyethylene terephthalate film directly or after applying an undercoat such as fine particles, and then a ferromagnetic metal thin film is deposited by an electron beam evaporation method or a sputtering method. A method in which a solution in which a lubricant such as polyether is dissolved is applied and dried [JP-A-57-179948, JP-A-61-178718], or a lubricant is disposed via an oxide film [ 61−
No. 151830) or a combination of a carbon film and a fluorocarbon system (Japanese Patent Application Laid-Open No. 61-142525) has been proposed,
Although a magnetic disk has a carbon film which is still thick, it has been partially put to practical use, and studies have been made on carbonaceous materials, and the usefulness of increasing the hardness (US Pat. No. 4,717,622) has been known.

Problems to be Solved by the Invention However, in the case where a lubricant is disposed on a carbonaceous protective film, the general durability is improved, but it is used in combination with an existing alloy coating type tape (hereinafter referred to as MP tape). Sometimes the envelope waveform of the MP tape was distorted and the S / N was reduced.

An object of the present invention is to solve such a problem, and an object of the present invention is to provide a durable high-density magnetic recording medium that is excellent in use with an MP tape and durable.

Means for Solving the Problems In order to solve the problems, the present invention is to ion-implant a part of a lubricant into a carbon film on a ferromagnetic metal thin film provided on a polymer film.

Action With this configuration, even if the lubricant of the magnetic recording medium made slides with the magnetic head at a high speed, it is difficult to remove the lubricant, and a good lubricating effect is maintained, and the protective effect of the carbon film is maintained. In addition, the front surface of the head does not cause abnormal deformation, and even when used together with the MP tape, both the MP tape and the tape according to the present invention can maintain a good envelope.

Embodiment Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

In the figure, 1 is polyethylene terephthalate, polyethylene naphthalate, polyetheretherketone,
Polymer films such as polyphenylene sulfide, polyamide, polyimide, etc., 2 are inorganic fine particles such as Al ₂ O ₃ , CaO, CaCO ₃ , TiO ₂ , carbon or organic fine particles such as polycarbonate, polyethylene, polyimide, etc. A fine particle coating layer formed by combining fine particles and earth-like irregularities, and is provided on the polymer film 1. 3 is Co, Co
-Fi, Co-Ni, Co-Ta, Co-Mo, Co-W, Co-Cr, Co-O, Co-N
Ferromagnetic metal thin film such as i-Cr, Co-Ni-O, Co-Cr-Nb, etc.
It is formed on the fine particle coating layer 2 by an electron beam evaporation method, an ion plating method, a sputtering method, or the like. 4 is a carbon film provided on the ferromagnetic metal thin film 3,
It is formed by a sputtering method, an ion beam deposition method, a plasma CVD method or the like, and may be any of graphite, diamond, and a mixture thereof. Numeral 5 is a lubricant partly ion-implanted and firmly bonded to the carbon film 4 and preferably has a polar group such as a fatty acid, a carboxylic acid, a higher alcohol or a sulfonate. The method of ionization is preferably thermal electron irradiation, but there is no particular limitation on the method of glow discharge, since if the conditions are limited by suppressing the power, the lubricant can be ionized with almost no decomposition. However, it can be said that thermionic irradiation has a wide control range and is suitable for being performed in a disk shape or a tape shape. Reference numeral 6 denotes a lubricant provided on the lubricant 5, which may be the same as that injected by ionization, or may be a known one such as another ester or a metal salt, and may be formed by a vacuum deposition method, a solution coating method, or the like. Distributed. The back coat layer may be provided as needed. In addition, it is preferable that the ion implantation is performed so that a part of the molecules of the lubricant composition is embedded in the carbon film 4, so that the degree of vacuum at the time of implantation is 10 ⁻² (Torr) or less and the acceleration voltage is 10 KV. ~ 20KV.

Hereinafter, specific examples will be described in comparison with comparative examples.

Example 1 10 μm thick polyethylene terephthalate with a diameter of 10 μm
10 ° / (μm) ² SiO ₂ fine particles of 0 ° are arranged, and the minimum incident angle is 40 degrees and the oxygen partial pressure is 4 × 10 ^{-5 along} a cylindrical can with a diameter of 1 m.
(Torr) Co-Ni (Co: 80wt%) is vapor-deposited by 1600 ° electron beam, and graphite is targeted on it with Ar + H ₂
= 0.08 (Torr), Ar: H ₂ = 1: 3, 13.56 (MHz), 1.1 (KW) by high frequency sputtering to form a diamond-like hard carbon film of 80 ° and 5 × 10 ^{−5 on it.} 150 at (Torr)
V, 1A electron beam irradiation area through stearic acid, 1
The carbon film was accelerated to 5 KV and deflected by a magnetic field to irradiate only the ionized stearic acid to the carbon film, and implantation was performed at 5 × 10 ⁶ ions / cm ² . Furthermore, 4 × 10 Ni salt of stearic acid
Vacuum evaporation was performed at ^-4 (Torr) to form a lubricant layer of about 20 mg / m ² , and a prototype was produced on an 8 mm tape.

Specific Example 2 15 pieces of Cr ₂ O ₃ fine particles having a diameter of 80 mm were applied on a 10 μm thick polyethylene terephthalate film at a rate of 15 / (μm) ² .
Along a cylindrical cylinder (can surface, 80 ° C.) with a diameter of 50 cm, Co—Cr (Cr: 21 wt%) is targeted and Ar: 5 × 10
^-2 (Torr), 13.56 (MHz), 1.4 (KW) high-frequency spattering to form a 1700 mm Co-Cr perpendicular magnetization film,
Methane gas is plasma-decomposed at 0.13 (Torr), 200 (MHz), and 500 (W), and a diamond-like hard carbon film is formed at an angle of 95 ° by acceleration at 500 V, and 1 × 10 ⁻⁶ (Torr) at 70 V,
Pass the 2A electron beam irradiation area through perfluoromyristate, accelerate to 18 KV, deflect the magnetic field, and irradiate the carbon film with only ionized perfluoromyristate, 6 × 10
^The injection was performed at ⁷ ions / cm ² . Further, “Fumbrin Z-25” manufactured by Montefluos commercially available as perfluoropolyether was dissolved in trichlorotrifluoroethylene, coated and dried, and a lubricant of 22 mg / m ² was disposed.
8 mm tape was used.

Comparative Example 1 The stearic acid was vacuum-deposited at 1 mg / m ² without performing the ion implantation in the specific example 1, and then 18 mg of the Ni salt of stearic acid was applied.
/ m ² except that vacuum deposited [degree of vacuum 2 × 10 ^-4 (Torr)] of a prototype 8 mm tape having the same structure as in example 1.

Comparative Example 2 The ion implantation in Example 2 was not performed, but perfluoromyristic acid was vapor-deposited in a vacuum of 1.5 mg / m ² and 5 × 10 ⁻⁴ (Torr). An 8 mm tape having the same configuration as in Example 2 except that 25 ″ was applied at 17.5 mg / m ² was prototyped.

Using each of the above tapes with a commercially available MP tape (60 minutes long, total thickness 12.9 μm) using an 8 mm video, the durability of each tape itself was examined by still characteristics. Each tape was run for 400 hours at 45 ° C. and 85% RH, and the magnetic heads used were a metal-in-gap type head having a 0.25 μm gap-length sendust sputter film disposed near the gap, and a laminated alloy type head. . In addition, two types of cylinder diameters, 40 mm and 26.7 mm, were evaluated. Adjust the running of the initial envelope so that the MP tape is in the best condition, and set the S / N in that condition to 0 (d
B) and relative comparison was made. The still characteristics were compared by the time required for the reproduction output to decrease by 3 (dB) in the still state. The initial S / N of Specific Examples 1 and 2 and Comparative Examples 1 and 2 was 3.9, respectively.
(DB), 3.3 (dB), 3.7 (dB), and 3.3 (dB). The results are summarized in the following table.

From the above table, it can be seen that both the output characteristics and the post-running stillness of the MP tape are significantly better in the specific example than in the comparative example.

Effects of the Invention As described above, according to the present invention, it is difficult for the lubricant of the magnetic recording medium to be removed even when the lubricant slides at a high speed with the magnetic head, and a good lubrication effect can be maintained. , The head front surface does not deform abnormally, and both the MP tape and the tape according to the present invention can maintain a good envelope even when used together with the MP tape. As a result, it is possible to provide a magnetic recording medium that is excellent in use with an MP tape and has excellent durability.

[Brief description of the drawings]

The drawing is an enlarged sectional view of a magnetic recording medium manufactured by a manufacturing method according to an embodiment of the present invention. 1 ... polymer film, 3 ... ferromagnetic metal thin film, 4 ...
Carbon film, 5: lubricant, 6: lubricant.

Claims (1)

(57) [Claims] 1. A method of manufacturing a magnetic recording medium, wherein a part of a lubricant is ion-implanted into a carbon film on a ferromagnetic metal film provided on a polymer film.