JPS63220422A - Production of magnetic recording medium - Google Patents

Abstract

PURPOSE:To obtain a durable magnetic recording medium having superior characteristics at high temp., superior corrosion resistance and surface lubricity by forming a carbon film on the surface of a thin ferromagnetic metallic film by plasma vapor phase synthesis with a gaseous hydrocarbon-Ar mixture and by further forming a thin film of a polar solid lubricant on the carbon film. CONSTITUTION:A thin ferromagnetic metallic film 3 of a Co alloy is formed on an Al-Mg alloy plate as a substrate 1 by plating with an Ni-P layer 2 in-between. The substrate 1 is set at the center of a reactor contg. a pair of electrodes for electric discharge and the electrodes are arranged on both sides of the substrate 1 at equal intervals. A plasma-polymerized carbon film 4 of about 400Angstrom thickness is formed on the surface of the film 3 by plasma vapor deposition. The film 4 is then treated with triacontanol (polar solid lubricant) diluted with a solvent such as benzene or ether by means of a spin coater to form a thin lubricant film 5 of about 80Angstrom thickness. Thus, a durable magnetic recording medium having superior characteristics at high temp., superior corrosion resistance and surface lubricity is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for producing a magnetic recording medium having surface lubrication performance with excellent durability, high-temperature properties, and anti-corrosion properties.

(Prior art) The surface of a magnetic recording medium must be smooth and lubricated in order to allow the magnetic head to fly, and since the magnetic head repeats contact start and stop, it must be durable and corrosion-resistant. It also requires a surface. For this reason, in conventional coating-type magnetic recording media, methods have been used in which Al2O5 or the like is mixed into the adhesive for bonding the magnetic material, or a lubricant is included. However, in recent years, the density of magnetic recording media has increased and metal thin film media have come to be used, making it no longer possible to use conventional coated media, and it has become necessary to create a media surface that can replace this. ing.

(Structure of the Invention) In view of this, the present invention has been made for the purpose of obtaining a magnetic recording medium having surface lubrication performance with excellent durability, high-temperature properties, and corrosion resistance properties, and the gist thereof is that Ni-P After forming a ferromagnetic metal thin film on a nonmagnetic substrate having a plating layer, a carbon film is formed on the surface of the metal thin film using a plasma vapor phase synthesis method from a mixed gas of hydrocarbon and argon, and then the carbon film is A method for manufacturing a magnetic recording medium, comprising forming a thin film of a polar solid lubricant thereon.

As a result of various studies on manufacturing methods for the intended magnetic recording medium, the inventors of the present invention found that the surface of a magnetic recording medium formed on a conventionally known non-magnetic substrate was made by plasma vapor phase synthesis using a mixed gas of hydrocarbon and argon. If a film is coated and then a polar solid lubricant is coated on top of that, the chemical bond will be strengthened because the metal thin film and carbon film are each new solids, and at the same time, chemical bonds will be formed between the carbon film and the solid lubricant layer. It was found that the adhesion between each film for the purpose of effective bonding was improved, and durability was also obtained. In addition, carbon films formed by plasma vapor phase synthesis do not have defects such as pinholes, so they provide corrosion resistance to metal thin film media, and they themselves have good high-temperature properties. We discovered that the high-temperature properties of the entire medium were improved, and by coating this carbon film with a polar solid lubricant, we achieved surface lubrication performance that synergized the lubricity of the polar solid lubricant itself with that of the carbon film. The present invention was completed by confirming that a magnetic recording medium having the following characteristics could be obtained. The non-magnetic substrate used in the method of the present invention may be a conventionally known one, and examples include plates of metals such as Ni-P plated Al-Mg alloy, alumite-treated Al-Mg alloy, plastics, ceramics, and glass plates. Ru. Examples of the ferromagnetic metal thin film include Co-based alloys, Fe2O8 and other metals or metal oxide thin films produced by sputtering or plating.

If the thickness of the carbon film coated on this substrate is 50λ or more, it will be too thin and the reliability will be poor, and if it is 500λ or more, the spacing between the medium and the magnetic head will become too large. 100-200
It is preferable to set it within the range of ＾.

In addition, examples of polar solid lubricants coated on the carbon film include triacontanol and triacontyltrimethoxysilane, but if the thickness is less than 30 Å, it is too thin and unreliable; In this case, the spacing between the medium and the magnetic head becomes too large, so 4
A range of 0 to 180 people, preferably 50 to 80 people is suitable.

In the method of the present invention, a mixed gas of hydrocarbon and argon is used for plasma treatment, and a carbon film obtained by plasma vapor phase synthesis is deposited on a metal thin film. In this case, the plasma vapor phase synthesis method involves installing a substrate in a reactor using a conventional method, introducing a mixed gas of hydrocarbon and argon into the reactor, and then increasing the atmospheric pressure in the reactor by 0.1 to 0.2 torr. and then heat the substrate to a temperature in the range of 80 to 170°C, preferably 1
Plasma may be generated in the system by applying high frequency power of 1 to 30 MHz while heating in the range of 00 to 130°C. In this case, the content of hydrocarbons in the mixed gas is 0.1
-10%, preferably 1-5%. As a result, the hydrocarbon and argon mixture comes into contact with the plasma flame, and the carbon generated by the thermal decomposition is coated on the substrate as a plasma polymerized film of a desired thickness in the form of a uniform plate.

Note that examples of hydrocarbons used here include methane, ethane, propane, ethylene, and acetylene.

FIG. 1 shows a magnetic recording medium according to the present invention obtained in this way. For example, the surface of the magnetic recording medium is formed by applying a ferromagnetic metal thin film 3 to a non-magnetic alloy substrate 1 having a Ni-P underplating layer 2. The structure includes a carbon film 4 and a thin film 5 of polar solid lubricant covering the carbon film 4.

Next, examples of the present invention will be given.

Example A substrate with a ferromagnetic metal thin film of Co-based alloy applied by plating on an Al-Mg alloy plate with NL-P applied to the surface was installed in the center of a reactor having a pair of discharge electrodes inside. Electrodes were placed at equal intervals on both sides. Next, the pressure inside this reactor was evacuated to 5X10-2 torr, then methane and argon were introduced there, and the pressure inside the reactor was adjusted to 0.2 torr under gas flow. 13.5 between
A glow discharge was generated by applying a 6 MHz high frequency power (30 W), and a gas phase deposition reaction was caused by this plasma, and a plasma polymerized carbon film of about 40 OA was formed on the surface of the ferromagnetic metal thin film.

Next, after taking this substrate out of the container, it is treated with triacontanol (polar solid lubricant) diluted with a solvent such as benzene or ether using a spin coater, and then coated with approximately 80%
Formed a human lubricant. When this board was inspected for CSS characteristics, friction coefficient, and moisture resistance characteristics, the CSS characteristics were 30.0.
It was confirmed that the results of the moisture resistance test at 00 times or more, friction coefficient 0, 2.40°C, 85% RH were satisfactory. This shows that according to the method of the present invention, a magnetic recording medium can be obtained which has durability, high-temperature properties and corrosion resistance similar to or better than conventional products, and has excellent surface lubrication performance.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing one example of a magnetic recording medium obtained by the method of the present invention. DESCRIPTION OF SYMBOLS 1...Nonmagnetic alloy substrate, 2...Ni-P base plating layer, 3...Ferromagnetic metal thin film, 4...Carbon film, 5...Polar solid lubricant film.

Claims (1)

[Claims] After forming a ferromagnetic metal thin film on a nonmagnetic substrate having a Ni-P plating layer, a carbon film is formed on the surface of the metal thin film using a plasma vapor phase synthesis method from a mixed gas of hydrocarbon and argon, and then A method for manufacturing a magnetic recording medium, comprising forming a thin film of a polar solid lubricant on the carbon film.