JPS60231908A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To improve remarkably the traveling performance of a magnetic recording medium by exposing the surface of the thin magnetic metallic film on the nonmagnetic support to electric discharge and forming a lubricant layer on the exposed surface by vapor deposition. CONSTITUTION:The thin magnetic metallic film 2 of a ferromagnetic metallic material such as Co, Co-Ni or Co-Cr is formed on the nonmagnetic support 1 of polyethylene terephthalate, polyimide or the like by vapor deposition such as evaporation or sputtering, and the surface of the film 2 is exposed to electric discharge. A lubricant layer 3 of about 10-100Angstrom thickness is formed on the exposed surface of the film 2 by vapor deposition. Thus, a magnetic recording medium having a lubricating effect for a very long period is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic recording medium, and particularly to a metal thin film type magnetic recording medium.

[Prior art and its problems].

In recent years, with the progress of magnetic recording and reproducing devices, there has been a significant demand for higher density recording in magnetic recording media. Co, Co-Ni alloy, Co-C
A so-called metal thin film type magnetic recording medium has been proposed in which a magnetic thin film layer is formed by depositing or sputtering a ferromagnetic metal material such as r-alloy on a nonmagnetic substrate such as polyethylene terephthalate or polyimide.

However, since metal thin film magnetic recording media do not contain binder resin, lubricant, etc. in the magnetic thin film layer, the packing density of magnetic material is higher and is suitable for higher density. If the surface of the magnetic thin film layer of a magnetic recording medium is in contact with a magnetic head, drum, guide, etc. (while running), the magnetic thin film layer will be damaged and problems such as falling magnetic particles will occur.

Therefore, in order to eliminate such drawbacks as much as possible, attempts have been made to prevent damage to the magnetic thin film layer by providing a lubricant layer on the surface of the magnetic thin film layer to lower the friction coefficient of the surface.

However, in metal thin film magnetic recording media for which such measures have been taken, the lubricant is merely attached to the surface of the magnetic thin film layer, and is repeatedly applied to the magnetic head etc. When running in contact, the lubricant layer itself peels off within a short period of time, and the magnetic thin film layer is immediately damaged.

[Means for solving problems]

A lubricant layer is provided by paper deposition on the discharge-treated surface of the metal magnetic thin film on the nonmagnetic support.

〔Example〕

FIG. 1 is a cross-sectional explanatory diagram of one embodiment of a magnetic recording medium according to the present invention, FIG. 2 is a schematic explanatory diagram of a manufacturing apparatus for a magnetic recording medium according to the present invention, and FIG. 3 is a magnetic recording medium according to the present invention. It is a graph showing the characteristics of.

In the figure, 1 is a non-magnetic support such as polyethylene terephthalate or polyimide, and 2 is a ferromagnetic metal material such as Co, Co-Ni, Co-Cr, etc. deposited or deposited on the non-magnetic support 1. 3 is a metal magnetic thin film formed by a paper deposition method such as sputtering;
This is a lubricant layer with a thickness of about 10 to 100 Å formed on the discharge-treated surface of the metal magnetic thin film 2 by a paper deposition method.

The magnetic recording medium A having the above structure can be manufactured by using the apparatus shown in FIG. 2, for example.

That is, in an apparatus equipped with a supply roll 11, a take-up roll 12, a drum 13, an electrode 14, a vapor flow control mask 15, and an evaporation source container 16 in a vacuum chamber 10, a metal magnetic material having a thickness of about 150 OA is deposited by the vapor deposition method. When winding up the magnetic recording medium A', which has a thin film formed on a non-magnetic support with a thickness of about 12 μm, from the supply roll 11 to the take-up roll 12 via the drum 13, the inside of the vacuum chamber 10 is heated to about zero by the vacuum pump 17. .1 to ITorr, for example 0. ．． 5To
rr, and the discharge current is about 0.1 to 0.5A between the electrode 14 and the drum 13, for example, 01IA, and the discharge voltage is 100.
The surface activation treatment is carried out by subjecting the surface of the metal magnetic thin film layer to ion bombardment treatment by applying a voltage of ~500V, for example 100V.

Then, while performing the surface activation treatment on the surface of the metal magnetic thin film layer that has been subjected to an activation treatment such as ion bombardment treatment, fatty acid ester, such as butyl stearate, in the evaporation source container 16 is evaporated, and the metal magnetic thin film layer is Butyl stearate is deposited on the active surface of the surface to provide a lubricant layer, for example a butyl stearate layer approximately 30λ thick.

Also, since the ion bombardment process and the vapor deposition process are performed in almost the same process, the vapor deposition process can be performed even in a relatively low degree of vacuum, improving processing efficiency, and there is no need to prepare separate vacuum chambers. Manufacturing equipment can be simplified.

Measure the coefficient of friction μ of the magnetic tape constructed as described above (in a room at a temperature of 20°C and a humidity of 50%, a load of 50 g was applied to one end of the magnetic tape, and the magnetic tape was brought into contact with a SUS guide pin). This is as shown by the solid line when a load of Fg was applied to the other end of the tape and the running speed was 3.36 rIL/s. The dotted line indicates the change in the friction coefficient of the magnetic tape provided on the surface of the thin film layer, and the dotted line indicates the change in the friction coefficient of the magnetic tape without the vapor-deposited lubricant layer provided on the surface of the metal magnetic thin film layer.

According to this, a magnetic tape without a lubricant layer on its surface immediately increases its coefficient of friction and causes the magnetic tape to stick, which is out of the question.

In addition, with the magnetic tape with the characteristics shown by the dashed-dotted line, in which a lubricant layer is deposited on the surface of the metal magnetic thin film layer, the sticking phenomenon of the magnetic tape does not occur even after 100 repeated running tests, but the coefficient of friction after one running test is is 0.26, and 10
The coefficient of friction after 0 runs is 0°35,
The durability of the lubricant layer is poor, and problems remain if only the lubricant layer is provided.

On the other hand, in the magnetic tape according to the present invention, the friction coefficient after one run is 0.22. Even after 100 repeated running tests, the friction coefficient is only 0.23, that is, 1
Even after running 00 times, the friction coefficient was smaller than that of the magnetic tape having the characteristics shown by the dashed line after running once, and it can be seen that the durability of the lubricity effect is extremely excellent.

〔effect〕

The running properties of the magnetic recording medium are extremely good. In other words, even after repeated running, the increase in the coefficient of friction is extremely small.
The running properties are stable and good.

In addition, since the running properties are excellent over a long period of time, the metal magnetic thin film is less likely to be damaged, and therefore the recording and reproducing characteristics are also good.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional explanatory diagram of a magnetic recording medium according to the present invention, and FIG.
The figure is an explanatory diagram of the manufacturing apparatus, and FIG. 3 is a graph showing the characteristics of the friction coefficient. 1... Nonmagnetic support, 2... Metal magnetic thin film, 3...
・Lubricant layer. 72 countries of age 1

Claims (1)

[Claims] A magnetic recording medium characterized in that a lubricant layer is provided by paper deposition on the discharge-treated surface of a metal magnetic thin film on a non-magnetic support.