JPS62102414A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To improve durability by mixing metallic or alloy particles with a ferromagnetic thin film being a magnetic film. CONSTITUTION:The ferromagnetic thin film 2 containing the metallic or alloy particles is installed on a nonmagnetic supporting body 1. Thus the particles spreading in the film 2 control the surface of the film 2. As a result a friction coefficient can be lower, thereby improving durability.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a so-called ferromagnetic metal thin film type, which is formed by forming a ferromagnetic thin film as a magnetic layer on a substrate by vacuum thin film forming techniques such as vapor deposition and sputtering. The present invention relates to a magnetic recording medium.

[Summary of the invention]

The present invention provides a magnetic recording medium in which a ferromagnetic VIT film is formed on a non-magnetic support, in which fine particles of metal or alloy are mixed in the ferromagnetic thin film that is the magnetic layer, thereby achieving durability without deteriorating the magnetic properties. This is an attempt to improve sexual quality.

[Conventional technology]

Conventionally, as a magnetic recording medium, rPeg containing rFezO++Co on a substrate made of a non-magnetic material has been used.
's.

Fe30a, r Fez containing Fe30t+Go
Bertolide compounds of O3 and Fezes, Bertolide compounds containing Go, oxide magnetic powders such as CrO□, or Fe, Co.

A magnetic layer is formed by dispersing powdered magnetic material such as alloy magnetic powder containing Ni etc. as the main component in an organic binder such as vinyl chloride-vinyl acetate copolymer, polyester resin, polyurethane resin, etc., coating it, and drying it. So-called coating-type magnetic recording media have been widely used.

In recent years, as the demand for high-density magnetic recording has increased, ferromagnetic metal thin films have been deposited directly onto substrates using vacuum thin film formation techniques such as vacuum evaporation, sputtering, and ion blating, as well as plating methods. The ferromagnetic metal thin film type magnetic recording medium created is attracting attention. This type of magnetic recording medium not only has high coercive force Hc and residual magnetic flux density Br, but also has extremely small thickness loss during recording demagnetization and reproduction because the thickness of the magnetic layer can be made extremely thin.
It has many advantages, such as the fact that it is not necessary to mix an organic binder, which is a non-magnetic material, into the magnetic layer, and the packing density of the magnetic material can be dramatically increased.

However, this ferromagnetic metal thin film type magnetic recording medium has many problems with running properties, durability, etc., which are important properties for practical use.
Improving this has become a major issue.

Conventionally, in order to improve the above-mentioned durability, for example, an underlayer having minute protrusions is provided on a non-magnetic support, and the surface properties of the ferromagnetic thin film, which is the magnetic layer, are controlled by the minute protrusions of this underlayer. A method is proposed.

However, although the above-mentioned method can improve durability such as still characteristics, it requires a special process for forming the underlayer LJ, which is not preferable in terms of productivity, manufacturing cost, etc. Further, when durability is improved by such a method, a slight decrease in magnetic properties is also observed.

[Problem that the invention seeks to solve]

The present invention has been proposed in view of the above-mentioned conventional circumstances, and is a magnetic recording medium that not only has excellent durability, runnability, electromagnetic conversion characteristics, etc., but also has good productivity and manufacturing cost. The purpose is to provide a medium.

[Means for solving problems]

In order to achieve the above objects, the present invention provides a magnetic recording medium in which a ferromagnetic thin film is formed on a non-magnetic support, wherein the ferromagnetic thin film contains fine particles made of a metal or an alloy. It is characterized by:

[Effect]

In the present invention, the surface properties of the ferromagnetic thin film are controlled by the action of fine particles dispersed in the ferromagnetic thin film. The fine particles are introduced into the ferromagnetic thin film at the same time as it is deposited.

〔Example〕

The present invention will be explained in detail below.

The magnetic recording medium according to the present invention, as shown in FIG.
Metal or alloy fine particles (3) are placed on a non-magnetic support (1).
) is provided as a magnetic layer, and the fine particles (3) control the surface properties of the ferromagnetic thin film (2), which is the magnetic layer, to reduce the coefficient of friction and improve durability. It was planned.

The fine particles (3) are the ferromagnetic bacteria 11! (2) can be mixed at the same time when depositing by a vacuum thin film forming technique such as vacuum evaporation.

For example, when producing a ferromagnetic thin film type magnetic recording medium (for example, when producing a vapor-deposited tape), in order to deposit a ferromagnetic thin film that will become a magnetic layer on a nonmagnetic support, the method shown in Fig. 2 is used. Use a device like the one shown below. Then, while running the non-magnetic support (1) such as a polymer film supplied from the unwinding roll (11) along the cylindrical can (12), the evaporated atoms from the evaporation source (13) are removed. A method is adopted in which the evaporated atoms are deposited on the non-magnetic support (1) at a predetermined angle of incidence, a continuous film of these evaporated atoms is formed as a magnetic layer, that is, a ferromagnetic thin film, and the film is wound up with a winding roll (14). There is.

At this time, near the continuously moving non-magnetic support (1),
For example, an introduction tube (step 5) for the fine particles (3) is provided on the high incident angle side of the incident angle of the evaporated atoms with respect to the non-magnetic support (1), and the fine particles are blown out together with the carrier gas from this introduction tube (15) for vapor deposition. If this is carried out, the fine particles (3) are introduced into the ferromagnetic thin film.

As shown in FIG. 3, the method for blowing out the fine particles (3) from the introduction pipe (15) is to insert the carrier gas supply pipe (17) into the reservoir (16) in which the fine particles (3) are stored. There is a method in which a carrier gas such as oxygen, nitrogen, argon, etc. is blown in and the lifted fine particles (3) are guided to the vapor deposition apparatus through an introduction pipe (15).

Examples of the fine particles (3) used include metal fine particles such as Go, Fe, Ni, and Heg, and alloy fine particles of Fe--Co alloy + Fe--Nt gold alloy. Among these, the use of ferromagnetic fine particles is effective in improving magnetic properties. The particle size of the fine particles (3) is 100 to 1,600 particles.

If the particle size is too small, the effect of improving durability cannot be expected.
On the other hand, if it is too large, the surface properties become too poor, resulting in deterioration of electromagnetic conversion characteristics.

The magnetic recording medium to which the present invention is applied is a so-called ferromagnetic metal thin film type magnetic recording medium, and the nonmagnetic support (1) serving as the base is a heat-resistant polymer film such as polyimide or polyamide. used. Also, its forms include tape and sheet.

It may be anything such as a disk, drum, card, etc. Alternatively, a so-called hard disk may be formed using a light alloy substrate such as an AI substrate, a glass substrate, a ceramic substrate, a highly rigid heat-resistant resin substrate, or the like.

In addition, the nonmagnetic support (1) has a center line average roughness R
A with a diameter of 0.001 to 0.08 μm is used,
Furthermore, one or more types of protrusions such as mountain-like protrusions or wrinkle-like protrusions may be formed on the surface to control the surface roughness.

The above-mentioned mountain-like protrusions have a particle size of 500 when forming a polymer film.
It is formed by internally adding ~3000 inorganic fine particles, and the height from the polymer film surface is 500~100.
0 people, density is lXl0'~1'0X10'pieces/m"
shall be. Inorganic fine particles used to form mountain-like protrusions include calcium carbonate (CaCOi), silica,
Alumina etc. are suitable.

The wrinkle-like protrusions are undulations formed by, for example, applying and drying a dilute solution of resin using a specific mixed solvent, and the height thereof is 0.01 to 10 μm, preferably 0.
．． 03-0.5μm, minimum distance between protrusions 0.1-20μm
Let it be m. Examples of resins used to form these wrinkle-like projections include saturated polyesters such as polyethylene terephthalate and polyethylene naphthalate, polyamides, polystyrene, polycarbonates, polyacrylates, polysulfones, polyethersulfones, polyvinyl chloride, polyvinylidene chloride, and polyvinyl butyral. A single substance, a mixture, or a copolymer of various resins such as polyphenylene oxide, phenoxy resin, etc., and those having a soluble solvent are suitable. Then, to a solution in which these resins were dissolved in the good solvent at a resin concentration of 1 to 11,000 ppp, a solvent that was a poor solvent for the resin and had a boiling point higher than the good solvent was added 10 to 100 times the amount of the resin. By applying the solution to the surface of a polymer film and drying it, a thin layer having very fine wrinkle-like irregularities can be obtained.

On the other hand, the ferromagnetic thin film (2) is formed as a magnetic layer by directly depositing a ferromagnetic metal material on the non-magnetic support (1).

The ferromagnetic metal material constituting this ferromagnetic thin film (2) includes metals such as Fe, Go, and Nt, or Fe-C.
o.

Fe-Ni+ Co-Ni 1Fe-Co-Ni+ F
e-Cu+ Go-Cu, Co-Au+ Co-Pt
+Mn-B1. Mn-AR+Fe-Cr, Go-Cr+
Ni-Cr+Fe-Co-Cr+Co-Ni-Cr, F
Examples include ferromagnetic alloys such as e-Co-Ni-Cr.

In addition, the means for depositing the ferromagnetic metal thin film is usually
Typical vacuum thin film forming techniques such as vacuum evaporation, ion blating, and sputtering are employed.

Here, in the vacuum evaporation method, the ferromagnetic metal material is evaporated under a vacuum of 10-' to 10-'' Torr by resistance heating, high-frequency heating, electron beam heating, etc., and the evaporated metal is deposited on the substrate. The ion blating method is also a type of vacuum evaporation method, and L O-4~10-'To
DC glow discharge and RF glow discharge are caused in an inert gas atmosphere of RR, and the ferromagnetic metal material is evaporated during the discharge. The sputtering method uses 10- to 1O-
ITOrr generates a glow discharge in an atmosphere whose main component is argon, and the generated argon ions knock out atoms on the target surface. , magnetron sputtering method using a magnetron, etc.

The thickness of the ferromagnetic thin film (2) thus formed is 0.05 to 1.5 μm.

In addition, when forming a ferromagnetic thin film by the above-mentioned method, an underlayer or an intermediate layer may be provided in order to improve the spring 1 adhesion between the substrate and the ferromagnetic \iJn', i, and to control the coercive force. good. These base layers or intermediate layers are A (1
, Si, Cr, Mn, Zn, Bi, Ti, Cu, In
, Ni+Co+Fe, or oxides and nitrides thereof.

Furthermore, on the ferromagnetic metal thin film mentioned above, in order to improve the corrosion resistance and runnability of this ferromagnetic metal thin film,
A protective film may also be formed. This protective film may be an inorganic protective film made of metals or their oxides or nitrides, etc. as mentioned in the previous base layer, fatty acids, metal soaps that are alkali metal salts or alkaline earth metal salts of fatty acids, or higher alcohols. .

Examples include organic protective films such as fatty acid esters, fluorine-containing compounds, and silicone oil.

The present inventors, according to the above-mentioned method, obtained particles with a particle size of 400-500.
Using human Coi particles, a magnetic recording medium in which CO fine particles were mixed in a ferromagnetic thin film (2) was fabricated as shown in FIG. The non-magnetic support (1) is a polyimide film, and the ferromagnetic thin film (2) is C at an incident angle of 50 to 90°.
A 00 ferromagnetic thin film with a film thickness of 2000 was obtained by color-depositing O.

This was taken as an example.

In addition, ferromagnetic bacteria [(2
) was made into a simple Co ferromagnetic thin film (thickness: 2000 mm) as Comparative Example 1. An underlayer having protrusions of 100 to 200 mm in height was formed, and fine particles were added on this underlayer in the same manner as in Comparative Example 1. Comparative Example 2 was prepared by forming a 00 ferromagnetic thin film containing no mixture of .

The magnetic properties and durability of each of the above Examples and Comparative Examples were measured. The results are shown in the table below. In addition, for the still characteristics in the table, a 4.2 MHz video signal was recorded on a tape, and the time until the playback output attenuated to 50% was measured.

In addition, the shuttle characteristics were examined by examining output fluctuations after running 100 times under conditions of 25° C. and 50% relative humidity.

From this table, it can be seen that in the formation of protrusions using the underlayer (Comparative Example 2), deterioration in the magnetic properties was observed, whereas in the example to which the present invention was applied, the magnetic recording medium did not deteriorate significantly in the magnetic properties. It was found that it is possible to create Furthermore, in this case, the step for forming the base layer could also be omitted.

〔Effect of the invention〕

As is clear from the above explanation, in the magnetic recording medium of the present invention, fine particles of metal or alloy are mixed in the ferromagnetic thin film that is the magnetic layer, so the surface properties of the magnetic layer are improved and the durability is improved. It is possible to significantly improve performance and running performance. In this case, since the fine particles can be introduced at the same time as the formation of the ferromagnetic thin film, no extra steps are required during manufacturing, which is advantageous in terms of productivity, manufacturing cost, etc.

Moreover, especially if a magnetic material is used as the fine particles, the magnetic properties of the ferromagnetic thin film layer will not be deteriorated.

[Brief explanation of drawings]

FIG. 1 is a schematic enlarged sectional view of essential parts showing the structure of a magnetic recording medium to which the present invention is applied. FIG. 2 is a schematic diagram showing the configuration of a vapor deposition apparatus for depositing a ferromagnetic thin film, and FIG. 3 is a schematic diagram showing an example of an apparatus for ejecting fine particles. 1...Nonmagnetic support 2...Ferromagnetic thin film 3...Fine particles

Claims (1)

[Scope of Claim] A magnetic recording medium comprising a ferromagnetic thin film formed on a non-magnetic support, wherein the ferromagnetic thin film contains fine particles made of metal or alloy.