JPS5860428A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To increase the strength of adhesion to a nonmagnetic substrate, and to improve wear resistance, head crushing resistance, etc., by allowing ionized vapor particles of a ferromagnetic material to strike a surface of the substrate at a high speed and at a specific angle of incidence under high vacuum, and thus forming two magnetic material layers. CONSTITUTION:A surface of a nonmagnetic substrate 1 is applied with a DC voltage under high vacuum while a filament 15 and a guard 16 are held negative, and thus the filament 15 is heated to vapor a vapor source material 14 in a crucible 13; and an ionization part 17 emits thermoelectrons by powering up a filament 18 to heat up, and accelerates the emitted thermoelectrons in an electric field by a mesh electrode 19 to ionize some of the vapor particles, and an acceleration electrode 10 is provided on the opposite side to the vapor-deposited surface of the substrate 1 to allow the ionized high-speed particles to strike the surface of the substrate 1, thus providing the 1st magnetic layer 4 of a ferromagnetic material at a 40-75 deg. angle of incidence to the normal line of the surface of the substrate 1. Then, the 2nd magnetic layer 5<=1/3 as thick as the layer 4 is formed on the layer 4 at a >=80 deg. angle of incidence. Thus, a magnetic recording medium which has excellent crystallinity, a uniform ratio of squareness, and uniform thin films 4 and 5 is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic recording medium formed by depositing a ferromagnetic metal onto a substrate surface.

Conventionally, magnetic recording media have been widely used in which diagonal magnetic powder or ultrafine powder of iron oxide, chromium oxide, etc. is dispersed in resin pine 1-goo and this is coated on a non-magnetic substrate. Ta. In these magnetic recording media, the frequency characteristics in the high range can be improved by increasing the coercive force, but if the coercive force is increased too much, the frequency characteristics in the low range tend to deteriorate. With regard to coating type magnetic recording media, it has not yet been possible to improve the frequency characteristics without increasing the coercive force. Recently, thin film deposition type magnetic recording media in which the magnetic layer is made of a ferromagnetic material and do not use any resin binder have been developed using thin film forming methods such as wet plating, vacuum evaporation method, S-Higashi tsuttering method, and ion plating method. have been actively researched and developed, and some of them have been put into practical use.

However, the magnetic recording media obtained by each of the above-mentioned thin film forming methods have their own drawbacks and have various practical problems.

That is, thin film magnetic recording media formed by wet plating have problems such as poor film quality due to non-uniformity of the solution, and irregularities and non-uniformity in magnetic properties.

In magnetic recording media formed by wet plating and vacuum evaporation, the adhesion strength between the t:l magnetic layer and the material is extremely low. It has the disadvantage that the layers tend to peel off and the magnetic field M JM il * is likely to occur, and good frequency exceptions have not been obtained compared to conventional coating-type magnetic recording media.

In addition, it is possible to use such a hectic ring and conventional 1#I! The coming ion blasting? Although the adhesion strength between the magnetic layer and the profiteer is improved by these methods, 10
Since the -C thin film is formed using J-discharge or high-frequency plasma in a low vacuum of -31-1,
Ferromagnetic material? The crystallinity of the %I film layer is adversely affected and the squareness ratio becomes small, which is disadvantageous in terms of magnetic properties.

=3 In addition, there were drawbacks such as non-uniformity in film quality and magnetic properties due to non-uniformity in the discharge state.

In view of the above-mentioned drawbacks of conventional magnetic recording media, the present invention has been made with the object of providing a thin film deposition type magnetic recording medium that has good adhesion strength against profiteering surfaces and excellent frequency characteristics. The gist is that ionized evaporated particles of ferromagnetic material are injected into the surface of a base material made of a non-magnetic material at an incident angle of 40 to 75 degrees with respect to the normal to the surface under high vacuum. A magnetic recording medium in which a ferromagnetic thin film is formed by bombarding the formed ferromagnetic thin film with ionized evaporated particles of ferromagnetic material at an incident angle of 1.80' or more relative to the normal. .

The materials made of non-magnetic materials conveniently used in the present invention include polyvinyl chloride, polyvinyl fluoride, cellulose acetate, polyethylene terephthalate, polybutylene terephthalate, polyethylene, polypropylene, polycarbonate, polyimide, and polyether. Polymer materials such as zulfon and polyparabanic acid, non-magnetic metal materials such as aluminum, copper, and copper-zinc alloys, and ceramic abrasives such as sintered bodies, porcelain, earthenware, and glass are used.

Zero shot +91 K at 10-4. The shape of the base material made of non-magnetic abrasive material may be determined as appropriate depending on the method of ejection of the magnetic recording medium, and may be, for example, in the shape of a magnetic recording medium, a recording medium, a film, a disk, a drum, or the like.

Further, as the ferromagnetic material in the wood grain, an alloy mixture containing 1 ml or more of iron, cobalt, nickel, or 4tIj14 of these materials is used.

The magnetic recording medium of the present invention and its manufacturing method will be explained below.

FIG. 1 is an explanatory diagram for explaining the angle of incidence at zero point 1, and shows the direction line 2 indicating the direction of incidence of ionized evaporated particles of ferromagnetic material incident on the surface of the base material l. The angle made with the normal 3 of the surface of 1 is indicated by θ.

Figure 2 is a cross-sectional view of a magnetic recording medium that generates zero
The first jliil was formed by bombarding the surface of the ferromagnetic material with ionized evaporated particles of ferromagnetic material at an incident angle of 40 to 75° with respect to the normal line of the surface under high vacuum.
A second layer formed by bombarding the i-th ferromagnetic thin film 4 and the surface of the thin film 40 with ionized evaporated particles of ferromagnetic material at an incident angle of 80° or more with respect to the normal under a sieve vacuum. A ferromagnetic thin film 5 is provided.

FIG. 3 is a schematic diagram showing an example of an apparatus for manufacturing a magnetic recording medium according to the present invention.

The inside of the vacuum chamber 6 can be evacuated to a high vacuum of up to 1X10-' Torr by an exhaust system device (consisting of an oil rotary pump, an oil diffusion pump, etc., not shown) connected to the exhaust lower. It is done like this.

Inside the vacuum chamber 6, a vapor deposition ion source 11, a supply roll 8 and a take-up roll 9 for the film-like substrate 1 (however, a roll drive device is not shown), and an ion accelerating electrode 10 are installed.

The vapor deposition ion source 11 includes a steam generation section 12 and a steam ionization section 17.

6- The steam generation section 12 includes an open J crucible 13, a filament for releasing thermionic electrons) +5, and a guard 16 for control by the city.
It consists of Z).

The steam ionization section 17 includes a heat exchanger discharger 18.
and a mesh electrode 19 that accelerates the emitted electrons.
and ``Sword for Awakening Control -+: 20''.

Furthermore, FIG. 3 shows power supplies 21 to 25 installed outside the vacuum chamber 6 and their circuits for operating and controlling the apparatus.

Next, we will explain the operation of a case where a non-explosion III magnetic recording medium is manufactured using two apparatuses.

First, as shown in FIG. 3, a supply roll 8 on which a non-magnetic group 4A1 such as a polyenalene terephthalate film is wound is installed, and the group 4711 is arranged so as to be wound around a take-up roll 9. .

A filler material 14 capable of forming a ferromagnetic thin film is supplied into a crucible 13 of a vapor deposition ion source 11 .

Next, the inside of the vacuum chamber 6 is evacuated from the exhaust lower to a high vacuum of 8X1G-)-1 to 10-1+)-1 (normally 10-')-1 to 10-6 Torr) by the exhaust system device from the exhaust lower. However, at this time, it is preferable to wind up and unwind in order to deaerate the air present on the surface of the fillet profit base 1, the kimono, and the air caught in the supply roll 8.

When the degree of vacuum in the vacuum chamber becomes constant, the power supply 21~
Enter 25.

To heat the crucible 13, the filament 15 is heated by the power source 22 to emit thermionic electrons, and a negative i&lit voltage is applied to the filament 15 and the guard 16 by @#21 to heat the crucible 13. By grounding, the emitted electrons are accelerated in an electric field and the crucible 13 is bombarded and heated.

The heated evaporation source material 14 evaporates at a vapor pressure corresponding to its heating temperature, and the evaporated particles reach the vapor ionization section 17.

In order to ionize the evaporated particles in the steam ionization section 17, the filament 18 is energized and heated by the source 23 to emit thermoelectrons, and a negative DC voltage is applied to the filament 18 and the guard 20 by the power source 24. is applied, and by grounding the net-like +lt pole 19, the emitter is accelerated by tb:W and collides with the evaporated particles, ionizing some of the evaporated particles.

Ionized evaporation particle t, 1 positive charge? Since it is in the lf state, it is connected to the ion accelerating electrode 1 by the power supply 25.
By applying a negative DC voltage to the crucible 13 which is grounded to 0, it is accelerated and given crystal kinetic energy.

The ionized evaporated particles thus accelerated by the electric field impinge on the surface of the base 61, forming a thin film.

Incidentally, the evaporated particles that have not been ionized in the vapor ionization section 17 are not accelerated by the electric field by the ion acceleration electrode 10, but they fly due to the kinetic energy given to them during evaporation and strike the surface of the profiteer 1. A thin film is formed by evaporation together with ionized evaporated particles.

Note that the operating conditions in the vapor ionization section 17 are as follows: The electron current required to ionize the evaporated particles is 30°C.
It is preferable that the current density be equal to or higher than mA, and it is preferable that the ion current density due to the ionized evaporation particles be set to be equal to or higher than lpAlt4.

Therefore, in the magnetic recording medium of the present invention, the incident angle of the ionized evaporated particles during the vapor deposition is 40 to 7
The first layer was deposited at an angle of 5°, and then the second layer was deposited at an angle of incidence of 80° or more with respect to the normal. By forming a magnetic thin film, the magnetic recording medium has excellent magnetic properties.

As for the thickness of the ferromagnetic thin films of the first layer and the second layer, it is preferable that the thickness of the second layer is less than % of the thickness of the first layer. The total thickness of these is 100
It is preferably 0 to 2500λ.

As described above, the magnetic recording medium of the present invention has a ferromagnetic thin film formed by bombarding ionized evaporated particles of ferromagnetic material at specific different incident angles. It has excellent frequency characteristics, especially low 1i! It has a characteristic that there is a slight difference in output between the d-wave region and the high-frequency region. In addition, it has a nuclear strength of 4m (+ thin film layer 1), which is formed by accelerating ionized evaporated particles under high vacuum with an electric field and making them collide with the base material, so the adhesion strength with the base material is high. , a% As a recording medium, it has excellent abrasion resistance (TL, head scratch resistance, etc.), and has a Fl-force I of 10-31·-1 or more by direct current glow discharge, high-frequency plasma method, etc.
The thin film Muku IC formed in a low vacuum at J is free from defects due to poor crystallinity due to the incorporation of residual gas and the contamination of impurities, and has excellent squareness and uniformity of the thin film.

Misfire 1 will be explained below based on an example.

Example 1 A high-purity cobalt metal ingot (purity 99.99%) 10y was placed in the crucible 13 of the high-vacuum insolating vapor deposition equipment shown in Fig. 3, and the nuclear device was activated to produce a A magnetic recording medium was prepared by depositing a cobalt thin film layer on a polyester 177 crate under the following conditions.

The measurement results of -C with respect to the frequency characteristics of the obtained magnetic recording medium are shown in curve 1 in FIG. Regarding the magnetic properties, the coercive force Hc = 7200e, the residual magnetic velocity density Br = 9300G, and the squareness ratio γ -092.

Comparative Example 1 The frequency characteristics of a commercially available product manufactured by vacuum evaporation and having a film thickness of approximately 2000X with each part being 7'r = 7 parts are as shown in Figure 4. It was as shown in the courtesy.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram explaining the incident angle in the present invention, a cross-sectional view showing an example of the second layer magnetic recording medium of the present invention, and FIG. A schematic diagram showing an example of a failure device, FIG. 4 is a diagram showing Example 1 and Comparative Example 1.
This shows the frequency characteristic curve measured at . 1... Base material, 2. Direction line indicating the incident direction, 3. Incident angle with respect to the normal line, 4... Ferromagnetic thin film of the eleventh noodle 1 [,
5... Second layer ferromagnetic thin film, 6... Vacuum chamber, 7
. . . Exhaust port, 8 . Crucible, 17
... Steam conversion department, 21-25 ... Power supply 13- Patent applicant Sekisui Chemical Co., Ltd. Representative Mototoshi Fujinuma ~ 14-

Claims (1)

[Claims] L: Under high vacuum, ionized evaporated particles of ferromagnetic material are made to impinge on the surface of a base material made of a non-magnetic material at an incident angle of 40 to 75 degrees with respect to the normal to the surface. A magnetic recording medium in which a ferromagnetic thin film is formed by bombarding the ferromagnetic thin film formed by ionized evaporated particles of ferromagnetic material at an incident angle of 80° or more with respect to the normal. 2. The magnetic material according to item 1, wherein the thickness of the thin film layer formed at an incident angle of 80° or more with respect to the normal is % or less of the thickness of the thin film layer formed at an incident angle of 40 to 75°. recoding media.