JPS5857631A - Production of magnetic recording medium - Google Patents

Abstract

PURPOSE:To improve both the wear resistance and the corrosion resistance of a magnetic recording medium, by forming a thin film of silicon oxide on the magnetic surface of a ferromagnetic metal with a specific process. CONSTITUTION:A base material 4 containing a magnetic metal layer is shifted to a take-up roll 6 from a supply roll 5 in a vacuum tank 1 and along a base material cooling plate 7 serving also as an ion accelerating electrode. At the same time, the oxygen gas fed from an oxygen gas cylinder 21 via an oxygen gas supply pipe 23 and the vapor particles obtained by heating SiO of an evaporating source material 13 by an electronic gun 11 are ionized by an ionizing device 10. These electric fields are applied and accelerated to be injected to the surface of the above-mentioned magnetic metallic layer. Thus a thin film of silicon oxide is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a magnetic recording medium using a ferromagnetic metal thin film layer as a magnetic recording layer.

Conventionally, I Fe2031 Co has been used as a magnetic recording medium.
rFe2O3+ doped with Fe,O,iCr 0
Magnetic recording media in which acicular magnetic powder such as No. 2 or ultrafine ferromagnetic alloy powder is dispersed in a resin binder and coated on a non-magnetic substrate have been widely used.

On the other hand, in recent years, the demand for higher information density has become stronger for magnetic recording media, and in order to meet this demand for high-density recording, magnetic recording layers are made of ferromagnetic metal thin film layers without using resin binders. Magnetic recording media have been actively developed using thin film forming methods such as wet plating, vacuum evaporation, sintering, and ion blating, and some of them have been put into practical use.

However, the ferromagnetic thin film layer has a fatal defect as a recording storage medium in that it is easily oxidized even when left unused, and its magnetic performance deteriorates over time. Furthermore, even if the surface is touched with fingers, the portion will rapidly corrode.

Furthermore, the %# film layer is easily peeled off and worn out due to the contact scanning of the recording head L during recording and reproduction, and is easily damaged.
This will cause a head crash phenomenon.

In order to improve the above-mentioned defects, various types of retentive layers have been applied on the surface of the ferromagnetic metal thin film. Forming a reactive film, forming a metal thin film by mixed plating methods such as electrolytic plating and electroless plating, or forming an oxide film on the surface of the ferromagnetic metal thin film by heating the recording medium at high temperature in an oxidizing atmosphere. Although many methods have been proposed, such as using a protective layer with sufficient performance, it has not yet been possible to obtain a protective layer with sufficient performance, and there are various problems that need to be solved in the method of forming it. I have a lot of In other words, in the method of forming a polymer film by coating, coating]-
In addition, large auxiliary equipment is required to prevent solvent recovery and pollution, and a film thickness of 2 or more is required to provide sufficient corrosion resistance, which reduces the recording density. This had the disadvantage of causing a decrease in Furthermore, the method of forming a film by treatment with chromic acid has the same drawbacks as mentioned above in treating wastewater from Vi6-valent qualichromium poison. In the formation method using the 鉦弐METSUGI method, the resulting coating has low wear resistance and is easily damaged. Furthermore, the method of forming an oxide film by heat-treating the recording medium at high temperature in an oxidizing atmosphere has the disadvantage that recording media whose base material is a polymeric material produces a hot love shape. However, attempts have been made to oxidize and form a film using a vacuum evaporation method, but the film formed by this method has disadvantages such as changes in the crystal structure, etc., and changes in the magnetic properties. has the disadvantage of insufficient wear resistance.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for manufacturing a magnetic recording medium having excellent wear resistance and corrosion resistance by eliminating the drawbacks of the above-mentioned conventional methods.

That is, the gist of the present invention is that vapor particles obtained by vaporizing SiO by heating in a high vacuum of 8 x 10') or less,
Magnetism is characterized in that a thin film of silicon oxide is formed on the surface by bombarding the surface of a magnetic layer of ferromagnetic metal formed on an electromagnetic base material with oxygen gas introduced into the system. It consists in the manufacturing method of the recording medium.

Materials for the non-magnetic base material used in the present invention include polyvinyl walling, polyvinyl heptadide, cellulose acetate, polyethylene terephthalate, polyethylene ethylene terephthalate, polyethylene, polypropylene, polycarbonate, polyside, and polyether. Polymer materials such as carbon dioxide, boric acid, etc., non-magnetic metal materials such as aluminum, copper, and copper-curved lead alloys, and ceramic materials such as sintered bodies, porcelain, earthenware, and glass are used. The shape of the base material may be determined as appropriate depending on the use of the magnetic recording medium, and for example, the shape of a tape, film, disk, drum, etc. is adopted.

Further, in the present invention, the ferromagnetic material used for vapor deposition on the above-mentioned substrate includes iron, cobalt and nickel, and alloys containing one or more of these metals and one or more of these metals and other elements. A mixture with 5- can also be used. However, alloys of iron include alloys of iron with cobalt, nickel, manganese, chromium, copper, gold, titanium, etc., and alloys of cobalt include cobalt and phosphorus, chromium, copper, nickel, manganese, gold, titanium, etc. , Yztrium, Samaritum, Bismuth,
Natoto alloys and nickel alloys include alloys of nickel with copper, zinc, manganese, etc.

In addition, as a mixture of iron, cobalt or nickel and other elements, there are those in which the other elements are phosphorus, chromium, copper, zinc, titanium, yttrium, samaritum, bismuth, etc. Vi2i or more may be selectively used.

The present invention will be explained in more detail below with reference to the drawings.

FIG. 1 is a schematic diagram showing an example of an apparatus used in the method of manufacturing a magnetic recording medium of the present invention.

The inside of the vacuum chamber 1 is connected to the exhaust port 2! The IP air thread device 61 (consisting of an oil rotary pump, an oil diffusion pump, etc., but not shown) is capable of exhausting the air at lXl0'toll1.

Inside the vacuum chamber 1 are a vapor deposition ion source 3, a non-magnetic base material (long polymer film) 4 on whose surface a magnetic layer of ferromagnetic metal has been deposited in advance, and a supply tube 5. %Dt
) Roll 6 ((111, roll drive device + a ii not shown) and ion acceleration electrode/substrate cooling plate 7
is installed. A pipe 8 through which the entire cooling medium passes is attached to the cooling plate 7Vc for heat exchange.

The evaporation ion source 3 #-1 is composed of an E gun evaporation source 9 and an ionization device 10. E gun evaporation source 9ti270
° Deflection E gun 11. Water-cooled copper hearth 12 and evaporation source material 1
It consists of 3. (However, the power supply etc. are not shown) The steam ionization device 1O is composed of a filament 14 for emitting thermionic electrons, a reticular electric field 1i15 for accelerating the emitted electrons with an electric field, and a guard 16 for the electric field III#. . Furthermore, in FIG.
Power supplies 24 and 25 for operating the ion generators 24 and 25, and power supplies 26 and their circuits for applying a negative DC voltage to the cooling plate 7 in order to accelerate the generated ions with an electric field are shown.

Further, the oxygen gas supply cap 20 includes an oxygen cylinder 21, a slow leak pulp 22, and a loop-shaped oxygen introduction pipe 2 having small holes.
It consists of 3.

To manufacture a magnetic recording medium according to the present invention, the inside of the vacuum chamber 1 is evacuated from the exhaust port 2 using an oil rotary pump, an oil diffusion pump, etc. to create a high vacuum of about 10-5 to io' Torr, and then oxygen Introduce oxygen from cylinder 21 to 8X10~l
Xl0)-, preferably 5×10 to lXl0)-
Create an oxygen atmosphere in the vacuum chamber and increase the pressure in the vacuum chamber to 8 x 10'
The E-gun evaporation source 9 is operated to heat and evaporate SiO', and the ionizer 1o is operated to fully ionize some of it together with oxygen gas. The ionized particles and ionized oxygen are accelerated in an electric field by the applied ion accelerating electrode and substrate cooling plate 7, and are made to impinge on the surface of the magnetic layer formed on the substrate 4 to form a thin film of silicon oxide on the surface. Let it happen.

Note that oxygen may be introduced into the vacuum 41 from any position, but oxygen is introduced between the E gun evaporation source 9, which is an SiO evaporation source, and the ionization device ff1lO for ionization.
Since the introduced oxygen can be effectively ionized, 9I'! Therefore, it is preferable to use a loop-shaped oxygen introduction tube.

Unlike the silicon oxide represented by the acid IIZ silicon # film ViSIO thus formed, sho is formed by colliding with ionized oxygen gas by being accelerated by an electric field. It is thought to have the chemical formula represented by 2), and the silicon oxide protective layer has a large hardness and excellent surface lubricity.

The magnetic recording medium obtained by forming a silicon oxide thin film according to the present invention can be obtained by depositing SIO or 5i02 as a deposition material using a vacuum deposition method, an ion spooling method, or the like. It has been confirmed that this material has superior practical characteristics required for magnetic recording media such as magnetic tape, such as wear resistance and corrosion resistance, compared to magnetic recording media on which a SiO storage layer or SIO□ protective layer is formed. It was done.

As described above, the method of the present invention eliminates the drawbacks of conventional ferromagnetic metal thin film magnetic recording media, and produces magnetic recording media that have excellent practical properties such as wear resistance and corrosion resistance, and also have excellent magnetic recording media properties. It is possible to manufacture recording media.

The present invention will be explained below with reference to Examples.

Example 1 Using the apparatus shown in FIG. 1, a cobalt lump (purity 99.99%) 10y was supplied to the E-gun evaporation source 9 to a thickness of 14)t.
Using polyethylene terephthalate film as the base material,
Vapor deposition was carried out under the conditions shown in Table 1 A to a thickness of α2. It
A magnetic thin film layer was formed.

Next, a 5 inch (purity 99°99%) 5
Oxidized rice (SiOx +1
<x<2) A film layer was formed.

When the adhesion strength of the obtained magnetic recording medium to the base material was examined by peeling with cellophane tape, no peeling of the magnetic layer or the 5iOxt'l layer was observed. Furthermore, a magnetic layer abrasion test was conducted on the magnetic recording medium in the form of an endless tape using a commercially available reel-to-reel tape recorder at a running speed of 9.5 km/h, and the head was worn 500 times. No peeling or falling off was observed even after repeated pass regeneration.

Further, a corrosion resistance test (hk) was conducted at a temperature of 60° C. and a degree of corrosion of 90%, and the results are shown in Table 2.

(Margin below) Table 1 Table 2

[Brief explanation of the drawing]

Figure vJ1 is a schematic diagram showing an example of an apparatus used in the method of the present invention. 1... Vacuum chamber, 2... Exhaust port, 3... Evaporation ion source, 4... Base material on which magnetic layer is formed, 5... U (supply roll, 6... Winding Roll, 7... Ion acceleration electrode/substrate cooling plate, 9... E gun evaporator, 1o... Ionization device, 20... Oxygen gas supply unit, 21... Oxygen cylinder, 23...・・Oxygen introduction pipe, 24.25.26・
・・Power supply patent applicant Sekisui Chemical Co., Ltd. Representative Itk Mototoshi 13-

Claims (1)

[Claims] L 8X10-4 Torr or less in a high vacuum, vapor particles obtained by vaporizing SiO by heating and oxygen gas introduced into the system are ionized by electron impact, and ionized vaporized particles are obtained. A thin film of silicon oxide is formed on the surface of the ferromagnetic metal magnetic layer formed on the non-magnetic base material by accelerating the oxygen gas by applying an electric field. A method for manufacturing a magnetic recording medium. 2. The manufacturing method according to item 1, wherein oxygen gas is introduced between the evaporation source of S]0 and the ionization device for performing ionization.