JPS62281120A - Magnetic recording medium and its production - Google Patents

Abstract

PURPOSE:To improve magnetic characteristics, durability and corrosion resis tance by forming a thin ferromagnetic metallic film layer in which the columnar particles of a ferromagnetic material deposited with a nonmagnetic metal having <=300 deg.C m.p. on the surface and an org. high-polymer compd. co-exist. CONSTITUTION:To thin ferromagnetic metallic film layer 18 in which the colum nar particles 16 of the ferromagnetic material segregated with the nonmagnetic metal 15 having <=300 deg.C m.p. and the org. high-polymer compd. 17 co-exist is provided on a substrate 4. The vapor flow of the ferromagnetic material is, therefore, directed from a ferromagnetic material evaporating source toward the substrate 4 in a vacuum atmosphere and at the same time, the gaseous monomer of an org. metallic compd. contg. the nonmagnetic low melting metal having <=300 deg.C is introduced into the atmosphere to make a glow discharge treatment. The magnetic characteristics, durability and corrosion resistance of the magnetic recording medium are thereby improved.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention [Field of Industrial Application] This invention relates to a magnetic recording medium having a ferromagnetic metal thin film layer as a magnetic recording layer and a method of manufacturing the same. The present invention relates to the above-mentioned magnetic recording medium having excellent durability and corrosion resistance, and a method for manufacturing the same.

[Conventional technology]

A magnetic recording medium whose magnetic recording layer is a ferromagnetic metal thin film layer is
Usually, ferromagnetic metals or their alloys are vacuum-deposited,
It is made by depositing it on a base film by sputtering or the like. (Unexamined Japanese Patent Publication No. 52-153407) [Problems to be Solved by the Invention] However, although this type of magnetic recording medium having a ferromagnetic metal thin film layer as a magnetic recording layer has characteristics suitable for high-density recording, It is still not completely satisfactory, and it has a large coefficient of friction with the magnetic head, making it easily susceptible to wear and damage (it also has the disadvantages of being poorly flexible and lacking stability in contact with the magnetic head). Another drawback is that if left in the air, it will corrode and its magnetic properties such as saturation magnetic flux density will deteriorate.

Means for Solving Problem C] This invention was made as a result of intensive research in view of the current situation, and it involves directing a vapor flow of a ferromagnetic material from a ferromagnetic material evaporation source to a substrate in a vacuum atmosphere. At the same time, a glow discharge treatment was performed by introducing a monomer gas of an organometallic compound containing a non-magnetic, low melting point metal with a melting point of 300°C or less, and the non-magnetic metal with a melting point of 300°C or less was segregated on the surface. By forming a ferromagnetic metal thin film layer in which columnar particles of a ferromagnetic material and an organic polymer compound coexist, we can improve the magnetic properties, durability, and corrosion resistance of a magnetic recording medium that uses the ferromagnetic metal thin film layer as a magnetic recording layer. This is a sufficient improvement.

In this invention, when a ferromagnetic metal thin film layer is formed by vacuum evaporation of a ferromagnetic material, the glow discharge treatment performed simultaneously is an organic metal compound containing a nonmagnetic, low melting point metal with a melting point of 300°C or less. It is preferable to use a monomer gas, and when glow discharge treatment is performed using such a monomer gas, the monomer gas of the organometallic compound decomposes and the nonmagnetic low-melting metal contained in the monomer gas is decomposed. The organic compound in the monomer gas of the organometallic compound is polymerized and becomes a polymer, and does not form a solid solution with the ferromagnetic material (segregates on the surface of the columnar particles of the ferromagnetic material). A ferromagnetic metal thin film layer is formed, which is deposited on the substrate so as to fill the gaps between the columnar particles, and in which columnar particles of ferromagnetic material with non-magnetic low melting point gold mud segregated on the surface coexist with an organic polymer compound. The columnar particles of ferromagnetic material with non-magnetic low melting point metal segregated on the surface become dispersed in the organic polymer compound, reducing the coefficient of friction with the magnetic head and increasing flexibility. In addition, the non-magnetic low melting point metal and organic polymer compound segregated on the surface of the columnar particles of the ferromagnetic material provide magnetic insulation between the columnar particles of the ferromagnetic material. Since the columnar particles of each ferromagnetic material have a single-domain particle-like structure and are made into fine particles, the magnetic properties are sufficiently improved and the corrosion resistance is also improved.

The present invention will be described below with reference to the drawings.

FIG. 1 shows a cross-sectional view of one example of a vacuum evaporation apparatus used in the present invention, and 1 is a vacuum chamber, and the inside of this vacuum chamber 1 is maintained at a predetermined vacuum level by an exhaust system 2. . 3 is a cylindrical can disposed in the center of the vacuum chamber 1, and a substrate 4 such as a polyester film is moved along the circumferential side of the cylindrical can 3 from a raw roll 5 via a guide roll 6. The take-up roll 8 is passed through the guide roll 7.
is wound up. During this time, the cylindrical can 3 inside the vacuum chamber 1
The vacuum chamber 1 is placed opposite the base 4 that moves along the circumferential side of
A ferromagnetic material 10 is heated and evaporated in a ferromagnetic material evaporation source 9 disposed below the substrate 4, and this vapor flow is directed toward the substrate 4 to perform vacuum evaporation. At the same time, monomer gas of an organometallic compound containing a low melting point non-magnetic metal is introduced from a gas introduction tube 12 connected to the glow discharge chamber 11 attached to the side wall of the vacuum chamber 1, and is wound around the glow discharge chamber 11. A high frequency is applied from the high frequency power supply 14 to the high frequency coil 13,
A glow discharge treatment is performed.

Here, the monomer gas of the organometallic compound to be subjected to the glow discharge treatment preferably contains a non-magnetic metal with a low melting point of 300°C or less. When discharge treatment is performed, the monomer gas decomposes and non-magnetic metals with low melting points are liberated. However, the ferromagnetic materials normally used have melting points of 700 °C or higher, and are less liberated than such ferromagnetic materials. Since the melting point of the nonmagnetic metal is very low, the free nonmagnetic metal with a low melting point does not form a solid solution with the ferromagnetic material and segregates on the surface of the columnar particles of the ferromagnetic material. Further, the organic compound in the monomer gas is polymerized and made into a polymer by glow discharge treatment using high frequency, and is deposited on the substrate so as to fill the gaps between the columnar particles of the ferromagnetic material. As shown in the enlarged cross-sectional view of the magnetic recording medium in FIG. The columnar particles 16 of the ferromagnetic material on which the metal thin film layer 18 is formed and the non-magnetic low melting point metal 15 segregated on the surface coexist in a dispersed state in the organic polymer compound 17, so that there is no interaction with the magnetic head. The friction coefficient is reduced, flexibility is improved, and durability is sufficiently improved. Furthermore, since the spaces between the columnar particles 16 of each ferromagnetic material are magnetically insulated by the non-magnetic low melting point metal 15 and the organic polymer compound 17 segregated on the surface of the columnar particles 16 of each ferromagnetic material, each ferromagnetic material The columnar grains 16 have a single-domain grain-like structure, are made into fine particles, and the magnetic properties are sufficiently improved, and the corrosion resistance is also improved.

Monomer gases of organometallic compounds used in such glow discharge treatment include, for example, trimethylbismuth, triethylbismuth, trimethylantimony, pentamethylantimony, tetramethyltin, tetramethoxytin, dimethylzinc, and dicyclopentadienyl. zinc,
A monomer gas containing a non-magnetic metal with a low melting point of 300° C. or lower, such as tetramethylzinc, is preferably used. If a non-magnetic metal contained in such a monomer gas is used with a melting point higher than 300°C, it will not be segregated on the surface of the columnar particles of a ferromagnetic material that has a melting point of 700°C or higher, which is usually used, and it will not be segregated into the ferromagnetic material. When solid solution occurs, the magnetic properties of the ferromagnetic metal thin film layer are deteriorated. In addition, if the non-magnetic gold mud contained in the monomer gas is not non-magnetic, it will segregate on the surface of the columnar particles of each ferromagnetic material, making it impossible to provide good magnetic insulation between the columnar particles of each ferromagnetic material. Magnetic properties and corrosion resistance cannot be sufficiently improved.

In this way, in the ferromagnetic metal thin film layer 18 formed by coexisting in a dispersed state in the finite polymer compound 17, the columnar particles 16 of the ferromagnetic material with the nonmagnetic low melting point metal 15 segregated on the surface coexist. , the nonmagnetic low melting point metal 15 segregated on the surface of the columnar particles 16 of the ferromagnetic material has a thickness of 80 to 10
The ferromagnetic material is segregated on the surface of the ferromagnetic material columnar particles 16 with an average diameter of 300 particles within the range of 0 particles, and the filling rate with respect to the total volume of the ferromagnetic metal thin film layer is within the range of 5 to 30% by volume. If the thickness of the low melting point metal 15 segregated on the surface of the columnar particles 16 of the ferromagnetic material is thinner than 80% or the filling rate is less than 5% by volume, the columnar particles of each ferromagnetic material Since it is not possible to sufficiently improve magnetic properties and corrosion resistance by providing good magnetic insulation between
If the thickness is more than 100 mm or the filling rate is more than 3-Ot%, the filling rate of the ferromagnetic metal becomes low and sufficient magnetic properties cannot be obtained. In addition, the ferromagnetic metal thin HIA layer 18
The filling rate of the organic polymer compound 17 is preferably within the range of 10 to 40% by volume based on the total volume of the ferromagnetic metal thin film layer, and the filling rate of the organic polymer compound 17 should not be too small. , it is not possible to sufficiently improve magnetic properties and corrosion resistance by providing good magnetic insulation between columnar particles of each ferromagnetic material.
If the amount is too high, the filling rate of the ferromagnetic metal will be low, and sufficient magnetic properties will not be obtained.

Glow discharge treatment of a monomer gas of an organometallic compound containing such a low melting point non-magnetic metal is usually performed using high frequency power,
13. Glow discharge is generated using direct current power, alternating current power, microwave power, etc., and it is relatively easy to handle.
RF power of 56 MHz is preferably used.

The ferromagnetic metal thin film layer may be formed by means such as sputtering and ion blasting in addition to the above-mentioned vacuum layer deposition. As the ferromagnetic material, CO1Ni SF
e, Co-Ni5Co-Cr.

Any ferromagnetic material that is normally used when forming a ferromagnetic metal thin film layer is suitable, such as metals and alloys such as Co-P and Co-Nt-P, and their oxides. Ru.

In addition, as magnetic recording media, polyester film,
Various types of structures that come into sliding contact with magnetic heads, such as magnetic tapes based on synthetic resin films such as polyimide films, magnetic disks and magnetic drums based on disks and drums made of synthetic resin films, aluminum plates, glass plates, etc. includes.

〔Example〕

Next, embodiments of the invention will be described.

Example 1 Using the vacuum thinning device shown in FIG. 1, a polyester film 4 with a thickness of 10 μm was moved from the original roll 5 through the guide roll 6 along the circumferential side of the cylindrical can 3, and then It is set so as to be wound onto a winding roll 8 via a guide roll 7.

I did it. Next, the inside of the vacuum chamber 1 is heated to about 1×1 O− by the exhaust system 2.
5) Evacuate the tube and remove the polyester film 4.
The ferromagnetic material evaporation source 9
cobalt-nickel alloy (weight ratio 80:
20) 10 was heated and evaporated.

At the same time, a gas introduction pipe 12 connected to the glow discharge treatment chamber 11
3Qsccm of trimethyl bismuth monomer gas from
13.56MH by the high frequency power supply 14.
Glow discharge treatment was performed by applying a high frequency wave of z at a power of 50W. Thereafter, the columnar particles 16 of a ferromagnetic material with a non-magnetic low melting point metal 15 segregated on the surface and the organic polymer compound 17 are placed on a polyester film 4 cut into a predetermined width as shown in FIG. A magnetic tape A was produced in which a ferromagnetic metal thin film layer 18 was formed. The ferromagnetic metal thin film layer thus formed is made of a composite of cobalt-nickel-bismuth-organic polymer compound, and has a thickness of 18
There were 00 people.

Example 2 Example 1 except that in the glow discharge treatment in Example 1, the same amount of dicyclopentagenyl zinc monomer gas was introduced instead of the trimethyl bismuth monomer gas.
A ferromagnetic metal thin film layer was formed in the same manner as above, and magnetic tape A was attached.The ferromagnetic metal thin film layer thus formed was made of a composite of cobalt-nickel-zinc-organic polymer compound. The film thickness was 1,900 people.

Comparative Example 1 Example 1 except that in the glow discharge treatment in Example 1, ethylene monomer gas was introduced at a flow rate of 20 seconds instead of trimethyl bismuth monomer gas.
A ferromagnetic metal thin film layer was formed in the same manner as described above, and a magnetic tape was made. The ferromagnetic metal thin film layer thus formed was made of a composite of cobalt-nickel-organic polymer compound, and had a thickness of 1,900 mm.

Comparative Example 2 A ferromagnetic metal thin film layer was formed in the same manner as in Example 1 except that the same amount of octacarbonyl cobalt monomer gas was introduced in place of the trimethyl bismuth monomer gas in the glow discharge treatment in Example 1. and created magnetic tape. The ferromagnetic metal thin film layer thus formed was made of a composite of cobalt-nickel-organic polymer compound and had a thickness of 1,700 mm.

Comparative Example 3 Same as Example 1 except that the glow discharge treatment of trimethyl bismuth monomer gas in Example 1 was omitted,
A magnetic tape was created by forming a ferromagnetic metal thin film layer. The ferromagnetic metal thin film layer thus formed was made of a cobalt-nickel alloy and had a thickness of 1,500 mm.

Regarding the magnetic tapes obtained in each example and comparative example,
The filling rate of the nonmagnetic low melting point metal in the ferromagnetic metal thin film layer, the thickness of the low melting point metal segregated on the surface of the columnar particles of the ferromagnetic material, and the filling rate of the organic polymer compound were measured.

Table 1 below shows the results.

Table 1 Also, for the magnetic tapes obtained in each example and comparative example, the coercive force was measured, and the room temperature still life was measured to examine the durability. The room-temperature still life was measured using a still life tester, and the time until the magnetic layer peeled off or its abrasion particles clogged the magnetic throat and output stopped. Furthermore, the obtained magnetic tape was
The saturation magnetic flux density after being left in a C190%RH atmosphere for several weeks was measured, and the deterioration rate from the saturation magnetic flux density before being left was calculated to examine the corrosion resistance.

Table 2 below shows the results.

Table 2 [Effects of the Invention] As is clear from Table 2 above, the magnetic tapes obtained by the present invention (Examples 1 and 2) are both comparable to conventional magnetic tapes (Comparative Examples 1 to 3). However, it has a high coercive force, a long still life, and a low rate of deterioration, which indicates that the magnetic recording medium obtained by the present invention has further improved magnetic properties, durability, and corrosion resistance.

[Brief explanation of drawings]

FIG. 1 is a schematic sectional view showing an example of vacuum deposition, and FIG. 2 is a partially enlarged sectional view of a magnetic tape obtained by the present invention. DESCRIPTION OF SYMBOLS 1... Vacuum chamber, 4... Polyester film (substrate), 10... Ferromagnetic material, 11... Glow discharge treatment chamber, 12... Gas introduction tube, 15... Non-magnetic low melting point Total bending, 16... Ferromagnetic material columnar particles, 17... Organic polymer compound, 18... Ferromagnetic metal thin film layer, A... Magnetic tape (magnetic recording medium)

Claims (1)

[Claims] 1. A ferromagnetic metal thin film layer in which columnar particles of a ferromagnetic material in which a nonmagnetic metal with a melting point of 300° C. or less is segregated on the surface and an organic polymer compound coexist is provided on a substrate. A magnetic recording medium 2 characterized in that, in a vacuum atmosphere, a vapor flow of a ferromagnetic material is directed to the substrate from a ferromagnetic material evaporation source, and at the same time, a non-magnetic material with a melting point of 30
A glow discharge treatment is performed by introducing a monomer gas of an organometallic compound containing a metal with a low melting point of 0°C or lower, and columnar particles of a ferromagnetic material with a nonmagnetic metal with a melting point of 300°C or lower segregated on the surface and an organic high A method for producing a magnetic recording medium characterized by forming a ferromagnetic metal thin film layer coexisting with a molecular compound.