JPH10124868A - Apparatus for production of magnetic recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the crack of an inside part and the leakage of a magnetic material by forming a vapor diffusion control means of plural cylindrical layers laminated outward from the inside and specifying the porosity and coefft. of thermal expansion of the inside wall parts thereof to specific values. SOLUTION: The ferromagnetic material 10 for evaporation is packed into a cup-shaped refractory crucible 11a consisting of material MgO. A high-frequency induction heating coil 12 internally has a cooling water circulating pipe and is connected to the high-frequency power source on the outside of a vacuum chamber. This vapor diffusion control means consists of the plural cylindrical layers laminated outward from the inside and the inside wall parts are formed of the material having the porosity of 10 to 25% and the coefft. of thermal expansion of 0.8×10<-5> / deg.K to 1.4×10<-5> / deg.K. The deterioration in the innermost layer side by thermal impact is, therefore, eliminated and the penetration of the molten metal by crack is prevented. Further, the vapor flow diffusion control means is provided with an inside wall test piece 15d in the state of that this test piece is continuous with the crucible 11a in order to investigate the crack and the penetration. An outer peripheral part 15e of a cooling structural body is arranged on the rear surface thereof.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for manufacturing a magnetic recording medium, and more particularly, to a method of heating and melting a metal material, evaporating the metal material, and depositing the vapor stream on a flexible substrate such as a base film. The present invention relates to an apparatus for manufacturing a magnetic recording medium in which a magnetic recording layer is formed by performing the method.

[0002]

2. Description of the Related Art Conventionally, as a magnetic recording medium, γ-Fe
₂ O ₃ , Co-doped Fe ₃ O ₄ , γ-Fe ₂ O ₃
Magnetic material as a berthollide compound of Fe ₃ O _4, berthollide compound doped with Co, from CrO _3, Ba oxide magnetic material such as ferrite, or Fe, Co, an alloy magnetic material mainly composed of Ni or the like Particles are dispersed and mixed together with additives in an organic binder such as a vinyl chloride-vinyl acetate copolymer, a styrene-butadiene copolymer, an epoxy resin, a polyurethane resin, and the dispersion mixture is mixed with a polyester such as polyethylene terephthalate (PET). 2. Description of the Related Art A so-called coating type magnetic tape is widely known, which is manufactured by coating a base film (substrate) made of polyolefin such as polypropylene or polypropylene and then drying the base film.

On the other hand, in recent years, the demand for higher recording density has become stronger, and the density of the magnetic material in the magnetic layer of the magnetic recording medium has been increased, the coercive force has been improved, the magnetic layer has been made thinner, or the frequency characteristics have been shortened. Improvements such as shifting to the wavelength side have been made. However, in the coating type tape, since the binder remains in the magnetic layer, it is difficult to satisfy the above-described conditions required for high-density recording.

Accordingly, attention has been paid to a method of manufacturing a magnetic recording medium by a vapor deposition method such as vacuum deposition, sputtering, or ion plating, or a plating method such as electroplating or electroless plating, and various proposals have been made. According to these methods, the magnetic layer can be formed by depositing and growing a magnetic material directly on a substrate without using a binder, so that the packing density of the magnetic material in the magnetic layer is increased, and Can also be made thinner.

In addition, these vapor deposition methods and the like make it easy to control the adjustment of the film thickness formed on the base film, adjust the coating solution of the magnetic layer in the manufacturing process of the coating type tape, and perform drying after coating. This has practically useful advantages such as eliminating the need for processing steps associated with the formation of a magnetic layer.

In particular, the vapor deposition method has the advantages that the waste liquid treatment required in the plating method is unnecessary and that the growth rate of the deposited magnetic film is high.
A magnetic tape using a magnetic layer formed on a base film by such a vapor deposition method as a recording layer has a much higher reproduction output and a shorter frequency characteristic of a recording signal than a conventional coating type magnetic tape. It is useful as a high-density magnetic recording medium, for example, it is improved on the wavelength side.

The production of the magnetic recording medium by the vapor deposition method can be performed in detail by, for example, a vacuum vapor deposition apparatus 1 shown in FIG. As shown in FIG. 3, the vacuum evaporation apparatus 1 has a cylindrical shape and a non-magnetic material such as a polyester film, a polyamide film, a polyimide film, etc. A cooling can 4 for winding a long base film 3 made of a material in the longitudinal direction is provided. The cooling can 4 is rotated in the direction of arrow Y to send out the base film 3 and send the base film 3 from the shaft 5 side to the winding shaft 6 side. Conveyed to.

The inside of the vacuum chamber 2 is wound by a partition plate 7 into a winding chamber 8 for feeding and winding the base film 3.
And a deposition chamber 9 for depositing a magnetic material on the base film 3. In the vapor deposition chamber 9, Co, CoNi alloy, CoCr alloy, CoC
An evaporation source 11 provided with a magnetic material 10 such as an rNi alloy is provided, and the magnetic material 10 is heated and evaporated by heating means 12 such as electron gun heating, resistance heating, and high-frequency induction heating. The particles of the magnetic material 10 as a vapor flow that evaporate and rise (referred to as magnetic particles or evaporating particles) are formed as a magnetic layer on the surface of the base film 3 that is conveyed in the direction of arrow Y with the rotation of the cooling can 4. Deposit continuously.

Here, in order to efficiently deposit the evaporated magnetic material particles on the substrate to increase the vapor deposition efficiency, it is sufficient to prevent the evaporated particles from diffusing widely. According to the technology disclosed in Japanese Patent Application Laid-Open No. 2-56730, a cylindrical shape is provided between the evaporation source and the cooling can so that the peripheral wall surrounds a portion through which the evaporated particles pass. What is necessary is just to provide the vapor flow diffusion control means (sometimes simply called vapor diffusion control means) 15. The vapor diffusion control means 15 has an inner wall surface for re-evaporating or collecting and collecting the evaporated particles of the magnetic material 10 attached to the inner wall surface, or for combining re-evaporation and collecting and collecting. Means for heating or cooling the temperature.

When such a cylindrical vapor diffusion control means 15 is provided, it is difficult to use an electron gun heating means generally used as a heating means. In other words, in this case, it is necessary to secure the trajectory of the electron beam from the electron gun to the magnetic material 10 in the evaporation source 11.
This is because, if the vapor diffusion control means 15 is provided above 11, it is difficult to secure a passage trajectory of the electron beam. Therefore, high frequency induction heating means is usually used as the heating means.

On the other hand, the above-mentioned vapor diffusion control means prevents the diffusion of the vapor flow by its inner wall surface. On the other hand, the vapor flow contacts the inner wall surface, and the evaporated magnetic material adheres to the inner wall surface. There is a risk of solidification. When the magnetic material adheres and solidifies on the inner wall surface, the vapor flow distribution becomes different from the intended vapor flow distribution, and maintenance such as a recovery operation of the deposited magnetic material is required. Therefore, in the above method, a heating source is added to the vapor diffusion control means, the inner wall surface of this means is set to a temperature equal to or higher than the boiling point of the magnetic material, and the magnetic material which collides with the inner wall surface of the vapor diffusion control means and adheres to the inner wall surface Are re-evaporated so that they can merge with other vapor streams.

However, since the scattering direction of the magnetic material particles re-evaporated from the inner wall surface of the vapor diffusion control means is different from the scattering direction of the other magnetic material particles, the originally intended steam flow distribution cannot be obtained and the deposition efficiency is reduced. Was likely to be caused. On the other hand, a manufacturing process of a magnetic recording medium for forming a magnetic thin film on a flexible substrate as used in the present invention is generally called oblique deposition.

The purpose of the oblique deposition is to grow a magnetic crystal deposited on a flexible substrate at an oblique angle with respect to the vertical direction of the flexible substrate, and to improve magnetic properties such as coercive force. The point is to improve. Therefore, the re-evaporated magnetic material particles adhering to the flexible substrate at an arbitrary angle hinder stable crystal growth in oblique vapor deposition, and may cause instability of magnetic characteristics. .

Therefore, by adjusting the temperature of the inner wall surface of the vapor diffusion control means to a temperature higher than the melting point of the magnetic material constituting the steam flow and lower than the boiling point, the magnetic material adhering to the inner wall surface of the vapor diffusion control means is adjusted. Particles are liquefied without being re-evaporated and descend along the inner wall surface, whereby the vapor flow from the upper opening of the vapor diffusion control means contains particles of the magnetic material re-evaporated from the inner wall surface of the vapor diffusion control means. A method for manufacturing a magnetic recording medium has been proposed in which a high vapor deposition efficiency is maintained without disturbing the vapor flow distribution by the vapor flow of the re-evaporated magnetic material (see Japanese Patent Application Laid-Open No. HEI 9-64572). 2-56730).

On the other hand, in such a magnetic recording medium manufacturing apparatus, the vapor diffusion control means has a two-layer structure of an inner wall portion and an outer peripheral portion provided outside the inner wall portion, or an inner wall portion, an intermediate portion and an outer peripheral portion. A three-layer structure is known. For example, Japanese Patent Application Laid-Open No. 2-56730 discloses that an inner wall portion is formed of a ceramic material, an outer intermediate portion is formed of a heat conductive medium such as carbon fiber, and an outer peripheral portion of the outer wall portion is cooled. A steam diffusion control means having a three-layer structure constituted by a water-cooled cylinder as a cooling means is disclosed. There is also known an apparatus in which a heating means is provided instead of the cooling means to heat the inner wall to a desired temperature. Since the vapor diffusion control means has a two-layer or three-layer structure, the heat of the inner wall can be transmitted to the cooling means satisfactorily or the inner wall can be satisfactorily heated. It is said that the control of the magnetic material becomes easy, thereby preventing the re-evaporation of the magnetic material attached to the inner wall portion and improving the vapor deposition efficiency.

[0016]

However, in the above-described apparatus for manufacturing a magnetic recording medium, the magnetic material is heated from 2000 to 2500 degrees by high-frequency induction heating to evaporate it. The temperature of the inner wall becomes extremely high due to evaporation of the magnetic material. That is, the inner wall surface receives a thermal shock due to the latent heat of the evaporated particles of the magnetic material and the radiant heat from the molten metal surface,
When the magnetic material attached to the inner wall surface is redissolved, the molten metal and the inner wall surface come into contact at a high temperature, and an interfacial reaction occurs.
As a result, the inner wall portion is deteriorated, the strength is weakened, cracks may occur, or molten metal may be inserted, and the magnetic material may leak from the vapor diffusion control means.

The present invention has been made in view of the above circumstances, and has as its object to provide a magnetic recording medium manufacturing apparatus which does not cause cracks or leakage of a magnetic material in a vapor flow diffusion control means.

[0018]

According to the present invention, there is provided an apparatus for manufacturing a magnetic recording medium, comprising: transport means for transporting a long flexible substrate in a vacuum atmosphere; An evaporation source made of a magnetic material, an evaporation unit for heating and evaporating the evaporation source, and a diffusion direction of the vapor flow heated and evaporated by the evaporation unit, disposed between the evaporation unit and the flexible substrate. A magnetic recording medium for forming a magnetic thin film on the flexible substrate, comprising: a vapor flow diffusion control means for regulating and controlling; and an incident angle regulating means for regulating an incident angle of the vapor flow to the flexible substrate. Wherein the vapor flow diffusion control means comprises a plurality of cylindrical layers stacked from the inside to the outside of the means, of which the innermost layer is 10% to 25%. It has porosity and the coefficient of thermal expansion of the innermost layer is 0.8 × It is accomplished by a ^{10 -5 /°K~1.4 × 10 -5 / °} K.

The lower limit of the porosity is desirably 14%.

If the porosity is less than 10%, the layer structure becomes too dense to absorb thermal deformation, and if it exceeds 25%, the structure becomes brittle and the deterioration is apt to progress.

Further, the melting point of the innermost layer is desirably 2100K or more.

In order to satisfy these conditions, the innermost layer is formed by selecting at least one of particles consisting of oxide, carbide, nitride, boride, silicide and carbon, Is desirably provided by sintering, and among them, it is more desirable to select an oxide.

In the sintering step, these material particles are preferably mixed in the range of 3000 μm to 0.5 μm, and more preferably, 10% or more of the weight of the innermost layer is set to 3000 μm to 300 μm. It is desirable to do.

Here, the term "evaporation source" refers to an evaporation source formed of a magnetic material. In the present invention, for convenience of explanation, the evaporation source is referred to as an evaporation source including an evaporation container containing the magnetic material as the evaporation source. It is assumed that there is.

[0025]

The innermost layer of the vapor flow diffusion control means is always exposed to heat during vapor deposition, and is very susceptible to deterioration due to the thermal shock of the evaporated particles. The present applicant has investigated the degree of this deterioration using various materials in order to minimize the deterioration of the innermost layer, and as a result, the degree of deterioration was determined by the porosity of the material constituting the innermost layer. In contrast, the present inventors have found that when the porosity is 10% to 25%, the deterioration of the material is the least, and the present invention has been achieved.

That is, in the magnetic recording medium manufacturing apparatus according to the present invention, the vapor flow diffusion control means is constituted by a plurality of layers, and the innermost layer among the layers has a porosity of 10% to 25%. Therefore, deterioration of the innermost layer due to thermal shock is reduced. Thus, it is possible to prevent the innermost layer from being cracked or the molten metal from being inserted, thereby preventing the magnetic material from leaking from the vapor flow diffusion control means.

Further, the present applicant has found that the degree of deterioration of the material varies depending on the material of the innermost layer, the particle size of the particles constituting the layer, the coefficient of thermal expansion, and the melting point. That is, the material is at least one of an oxide, a carbide, a nitride, a boride, a silicide, and carbon;
at least one of oxides, carbides, nitrides, borides, silicides and carbon obtained by sintering particles having different particle diameters in a range from m to 0.5 μm, and occupying at least 10% of the total constituent weight. The particles having a particle size in the range of 3000 μm to 300 μm are made of sintered oxide, carbide, nitride, boride, silicide and / or carbon, and have a coefficient of thermal expansion of 0.8 × 10 ⁻⁵ / ° K. By setting the melting point to 1.4 × 10 ^-5 / ° K or a melting point of 2100 ° K or more, deterioration of the innermost layer due to thermal shock is reduced. Thus, it is possible to prevent the innermost layer from being cracked or the molten metal from being inserted, thereby preventing the magnetic material from leaking from the vapor flow diffusion control means.

[0028]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a magnetic recording medium manufacturing apparatus according to an embodiment of the present invention.
FIG. 1 shows a schematic configuration of an embodiment of a vacuum evaporation apparatus which is a magnetic recording medium manufacturing apparatus of the present invention.

The illustrated vacuum evaporation apparatus 1 has a cylindrical cooling can 4 inside a vacuum chamber 2, and a cylindrical film (outer peripheral surface) of the cooling can 4 has a base film 3 as a substrate of a magnetic recording medium. Is wound. The base film 3 is made of a polyester such as polyethylene terephthalate (PET) or polyethylene naphthalate, a polyolefin such as polypropylene, a cellulose dielectric such as cellulose triacetate or cellulose diacetate, a vinyl resin such as polyvinyl chloride,
It is formed by processing a plastic such as polycarbonate, polyamide, or polyphenylene sulfide into a long film, and the thickness thereof is, for example, 3 to 100 μm.

An undercoat is applied to the surface of the base film 3 if necessary. The undercoat is made of a binder (cellulose such as methylcellulose, P
Saturated polyesters such as ET, phenoxy resins, polyamides, polyacrylates, etc.) and fillers (silica, titania, alumina, calcium carbonate, etc.) are dissolved and applied. so,
It has protrusions with a density of 5 million to 100 million / mm ² . The height and density are appropriately selected depending on the required adhesion performance and the like.

Further, the base film 3 may be subjected to a pretreatment such as a glow discharge treatment, an ion irradiation treatment, a heat treatment, and a chemical treatment.

The base film 3 is wrapped around the take-up shaft 6 from the delivery shaft 5 via the cylindrical surface of the cooling can 4, and is rotated on the cylindrical surface of the cooling can 4 by rotating the cooling can 4 in the direction of arrow Y. For example, it is conveyed at a speed of 10 to 200 m / min, and is taken up by the take-up shaft 6. The cooling can 4 has a diameter
It is a cylindrical drum of 800 mm and width of 400 mm, the surface of which is hard chrome plated and mirror-polished to 0.2 S or less, and has a structure in which cooling water and other refrigerants (for example, ethylene glycol) are circulated inside. Is maintained at, for example, −35 to + 25 ° C.

On the surface of the cooling can 4, masks 13 and 14 whose main body is formed of SUS304 or the like are provided, and the cooling water or the coolant is circulated inside the cooling can 4 at a predetermined distance. This distance is between 2 and 15 mm, more preferably between 2 and 10 mm, most preferably between 3 and 5 mm. 2mm
If it is narrower, the space for installing the first gas blowing section described later cannot be secured, and if it is more than 15 mm, the vapor flow goes between the mask and the base film and adheres to the cooling can 4, causing contamination. Because. This is because the heat transfer coefficient between the can and the base film changes in the portion where the dirt is generated, or the base film is insufficiently adhered to the can, so that the can is easily damaged by heat. And base film 3
The maximum incident angle (θmax) is defined by the mask 13 located on the upstream side in the transport direction, and the minimum incident angle (θmin) is defined by the mask 14 located on the downstream side. The angle of incidence is based on the center of the circle of the melted surface in the refractory crucible 11a described later,
The maximum incident angle (θmax) defined by the angle between the line segment from the center of the circle to the edge of the mask 13 and the edge of the mask 14 and the normal line at the position of each mask edge on the cooling can 4 and regulated by the mask 13 Has an upper limit of 90 °, more preferably 87 °, most preferably an upper limit of 85 °, and the mask 14
It is desirable that the minimum incident angle (θmin) regulated by the above is set to a lower limit of 20 °, more preferably 25 °, and most preferably 30 °. This is because a desired holding power cannot be obtained if the above range is not satisfied. mask
The opening width of the mask opening 18 formed by 13 and 14 in the width direction (direction perpendicular to the transport direction of the base film 3) can be set arbitrarily.

On the front surfaces of the masks 13 and 14, the masks 13 and 14 are curved along the masks 13 and 14, respectively.
And has a function of preventing the evaporated metal particles of the magnetic material 10 from adhering to the surface of the base material 3, circulating cooling water inside, and a movable type having a main body formed of SUS304 or the like. (Not shown).

The vacuum chamber 2 includes a winding chamber 8 for feeding and winding the base film 3 by a partition plate 7,
The base film 3 is partitioned into a deposition chamber 9 for depositing a magnetic material. Each of the winding chamber 8 and the vapor deposition chamber 9 is provided with an exhaust system (not shown) for vacuuming, and the degree of vacuum in each chamber can be individually adjusted. In particular, since the oxidizing gas described below is introduced into the vapor deposition chamber 9 from outside the vacuum chamber 2, the degree of vacuum in the chamber and the partial pressures of various residual gases are constantly adjusted.

Further, the winding film 8 contains the base film 3.
For the pre- and post-treatments described above, for example, glow discharge treatment device, ion irradiation treatment device, heat treatment device, C
A VD processing device or the like may be provided. In addition, cooling can 4
Is not limited to a cylindrical shape, and may be an endless belt-shaped metal plate capable of forming a predetermined slope with respect to the evaporation source 11.

An evaporation source 11 having a magnetic material 10 is disposed below the cooling can 4 in the vapor deposition chamber 9. Around the evaporation source 11, an inside for heating the magnetic material 10 is provided. A high frequency induction heating coil 12 having a structure in which cooling water circulates is provided. Further, a high frequency power supply 13 for supplying high frequency power to the high frequency induction heating coil 12 and a high frequency power supply feeder 21 for transmitting high frequency power are provided.

The magnetic material 10 is made of, for example, Fe, Co, Ni,
CoNi, FeCo, FeCu, FeCr, CoCr,
CoCu, CoAu, CoPt, CoW, NiCr, C
oV, MnBi, MnAl, CoFeCr, CoNiC
r, CoRh, CoNiPt, CoNiFe, CoNi
It is appropriately selected from ferromagnetic metals and ferromagnetic alloys such as FeB, FeCoNiCr, and CiNiZn.

The refractory crucible 11a containing the magnetic material 10, which is a component of the evaporation source 11, is made of, for example, MgO, Zr
O ₂ , Al ₂ O ₃ , CaO, Y ₂ O ₃ , ThO ₂ , B
N, BeOCaO stabilized ZrO ₂ , Y ₂ O ₃ stabilized Zr
It is appropriately selected from ceramics such as O ₂ , carbon or a carbon compound, and other heat-resistant materials. The shape of the refractory crucible 11a is a container shape having a bottom, and the horizontal cross-sectional shape may be a true circle, an ellipse, an oval, a square, a rectangle, or any other shape, and the vertical cross-section may be a square. , Rectangular, trapezoidal, or any other shape. The high-frequency induction heating coil 12 is a refractory crucible 11.
Preferably, the shape corresponds to the side surface of a.

Further, the peripheral wall of the vapor deposition chamber 9 surrounds a path between the cooling can 4 and the evaporation source 11 having the magnetic material 10 and through which a vapor flow generated by evaporation of the magnetic material 10 passes. The vapor diffusion control means 15 is provided as described above, and an acidifying gas or an oxidizing gas and an inert gas (for example, N ₂ Ar gas) are provided near the cooling can 4 and near the masks 13 and 14.
And a first gas blowing unit 17 for blowing a mixed gas with the base film 3 toward the base film 3.

The gas blowing section 17 is located downstream with respect to the direction of transport of the base film 3 and is built in the surface of the mask 14 on the side of the cooling can 4 near the mask 14 which regulates the minimum incident angle (θmin). ing. The blowing direction of the gas blowing slit 17a is a cooling can 4 that defines the minimum incident angle (θmin).
The direction is substantially parallel to the tangent line on the cooling can 4 at the upper reference point. The oxidizing gas is blown from the gas blowing unit 17 so that the oxidizing gas is blown in a substantially oblique direction with respect to the scattering direction of the evaporated particles that have passed through the opening of the vapor diffusion control means 15 described later, and a part of the evaporated metal particles. To oxidize.

The inner peripheral wall surface of the vapor diffusion control means 15 is formed of, for example, MgO, ZrO ₂ , Al ₂ O ₃ , CaO, Y ₂ O ₃ , T
hO ₂ , BN, BeOCaO stabilized ZrO ₂ , Y ₂ O ₃
Evaporation steam flow path formed of ceramics such as stabilized ZrO ₂ , carbon or carbon compound, or other heat-resistant material and surrounded by a regulating surface extending substantially vertically in a state substantially continuous with the refractory crucible 11a The lower surface and the upper surface are opened to allow the passage of the evaporated particles of the magnetic material 10 and to improve the directivity thereof,
It is a cylindrical shape having only a peripheral wall, and the horizontal cross-sectional shape may be circular, elliptical, oval, square, rectangular, or any other shape. The vertical cross-section may also be square, rectangular, trapezoidal, or any other shape.

Further, the vapor diffusion control means 15 has a laminated structure composed of a plurality of members such as three layers of an inner wall portion 15a, an intermediate portion 15b, and an outer peripheral portion 15c concentrically from the center of the opening toward the outside. ing.

A heating structure including a heating source such as a resistance heater, a high-frequency induction heating coil or the like, or cooling water, liquid nitrogen, liquid helium, ethylene glycol is provided on the outer peripheral surface side of the vapor diffusion control means 15. Circulates refrigerant such as Fe, Cu, Al, Ni, Ti, Mg,
A configuration including a cooling structure formed of Zn, an alloy thereof, stainless steel, or the like can be employed.

The vapor diffusion control means 15 includes a refractory crucible 11a.
Evaporated particles of the magnetic material 10 that evaporate from the center point in the melt surface and fly upward from the point set as the reference point are used as a mask 13 for controlling the maximum incident angle and a mask for controlling the minimum incident angle, which will be described later. It is configured so as not to prevent adhesion in a continuous range from the maximum incident angle θmax to the minimum incident angle θmin defined by 14.

The refractory crucible 11a, the high-frequency induction heating coil 12, the high-frequency power supply 20, the high-frequency feeder 21 and the like are merely examples of the evaporation source, and the base film 3 extends in the width direction (perpendicular to the transport direction in the plane of the base film 3). When the width of the evaporation source 11 is large, the shape of the evaporation source 11 is changed according to the width of the base film 3 (for example, when the horizontal cross-sectional shape of the evaporation source 11 is elliptical and the width of the base film 3 is wide). The long axis direction of the elliptical shape of the evaporation source 11 is adjusted to the width direction of the base film 3), and a plurality of sets of the evaporation sources 11 arranged in the width direction of the base film 3 may be adopted. In this case, the evaporation source 11 (including the refractory crucible 11a), the high-frequency induction heating coil 12, the high-frequency power supply 20, the high-frequency feeder 21
Or a plurality of sets of the evaporation sources 11 are arranged independently, and a high-frequency induction heating coil 12, a high-frequency power supply 20,
It is also possible to adopt a configuration in which the high-frequency feeder 21 is shared.

[0047]

EXAMPLE The refractory crucible 11a of this example is cup-shaped (inner diameter φ80mm, outer diameter φ96mm, height 100mm, internal depth 92mm), and is made of MgO (chemical component: MgO; 98.0%, Al _2).
O ₃ ; 0.5%, SiO ₂ ; 0.5%, CaO; 0.2%, F
e ₂ O ₃ ; 0.2%). Co ₈₀ Ni ₂₀ was used as the ferromagnetic material 10 for evaporation inside the refractory crucible 11a.

The high-frequency induction heating coil 12 is made of a Cu pipe having a diameter of φ12 mm through which cooling water circulates. The high-frequency induction heating coil 12 has four turns, an inner diameter of φ120 mm, and a height h12.
0 mm. Two high-frequency power supplies 20 having an oscillation frequency of 50 kHz and an output of 30 kW are installed outside the vacuum chamber 2, and two high-frequency power sources provided inside the vacuum chamber 2 through a high-frequency feeder 21 and a vacuum feedthrough (not shown). Heating coil 12
Connected to. The high-frequency feeder 21 is made of a Cu plate, and the extended Cu pipe portions of the high-frequency induction heating coil 12 are each surrounded by an insulating tube made of Al ₂ O ₃ and are electrically insulated from each other.

The inner wall portion 15a of the vapor diffusion control means 15 is made of a material having a porosity of 10% to 25% and has a cylindrical shape (inner diameter φ80 mm, outer diameter φ102.0 mm, height h75 mm) as described later. The material was Al ₂ O ₃ . The intermediate portion 15b was cylindrical (inner diameter φ102.6 mm, outer diameter φ114 mm, height h75 mm), and was made of graphite carbon or BN.

The outer peripheral portion 15c has a cylindrical shape (inner diameter φ114 mm, outer diameter φ150 mm, height h75 mm), circulates cooling water at 18 ° C. inside, and forms a cooling structure whose main body is made of SUS304. Using.

Further, in order to investigate cracks due to a change in the porosity of the inner wall portion 15a and insertion of a molten metal in the present embodiment, the steam diffusion control means 15 is provided so as to be substantially perpendicular to the refractory crucible 11a in a substantially continuous state. Extending plate-shaped inner wall test piece 15
d (width 30 mm, thickness 5 mm, height h75 mm), and the back surface of the cooling structure outer peripheral portion 15e in contact with the test piece 15d
Was disposed, and the test piece 15d was held. Test piece
The material composition of 15d is ZrO ₂ , MgO, Al ₂ O ₃ , Z
A material containing rB ₂ , BN, ZrN, TiC, ZrC, and MoSi ₂ as main components and varying porosity, particle size, and particle size mixing ratio was used. For the outer peripheral portion 15e, a cooling structure having a main body made of SUS304 was used by circulating cooling water of 20 ° C. inside. This cooling structure has a width of 40 mm, a thickness of 30 mm, and a height of 10
It is a block of 0 mm.

The method of evaluating the material of the constituent layers of the vapor diffusion control means 15 is as follows. The evaporation source 11 on which the magnetic material 10 is set is installed in the vacuum chamber 2 and the vacuum chamber 2 is moved using a cryopump (not shown). Exhaust and maintain at 5.0 × 10 ^-5 Torr. Then, using the high-frequency power supply 20, a constant power of 15 KW was supplied to the high-frequency induction heating coil 12 for 180 minutes to melt and evaporate the magnetic material 10. The test piece 15d of the vapor diffusion control means 15 receives a thermal shock due to the latent heat of the evaporating particles and the radiant heat from the surface of the molten metal, and the interfacial reaction occurs due to the re-dissolution of the adhered particles on the inner wall surface and the contact with the molten metal at a high temperature. Heating, melting,
After the end of the evaporation test, the inner wall test piece 15d of the vapor diffusion control means 15 was disassembled, and the state of cracking and the thickness of the interface reaction layer (discoloration due to reduction action or penetration of dissolved metal) were observed and evaluated. Table 1 shows the results of the evaluation.

[0053]

[Table 1]

Rank S in cracked state Rank S: No cracks are visually observed at all, and there is no evidence that molten metal has been inserted.

A: There are one or two fine cracks, but there is no evidence that molten metal has been inserted.

(Width 0.5 mm or less) B: Three or less fine cracks, and insertion of molten metal was observed, but stopped in the thickness direction of the layer.

C: There are one or two remarkable cracks. Alternatively, the molten metal is inserted over the entire width of the layer (at least 0.5 mm in width) in the thickness direction.

D: There are three or more remarkable cracks, the insertion of the molten metal extends over the entire width in the layer thickness direction, and the leakage is large.

E: Those which were markedly cracked during the heating and dissolution tests, leading to structural destruction.

The ranks S, A and B in the cracked state can be used.

Incidentally, the main component of the material means a material which occupies 80% by weight as a whole. The porosity of the inner wall 15
a, Pressure during molding of test piece 15d (molding pressure: 3.0 kg)
f / cm ^{2 to} 10 kgf / cm ² , firing temperature; 1450 ° C. to 1600 ° C.).

As shown in Table 1, when the porosity is in the range of 10 to 25%, the ranks of the cracks are all S, A, and B. When the porosity is in this range, the test pieces 15d,
That is, it was found that the inner wall portion 15a was not cracked and the molten metal was not inserted, or that there was, but there was no problem in use.

Next, sample No. 8 (ZrO ₂ ,
For the porosity of 14.6% and the particle size range of 3000 μm to 0.5 μm), the above-described test was conducted by changing the mixing ratio of each particle size material.
The results are shown in Table 2 below.

[0064]

[Table 2]

As can be seen from Table 2, the particle size is 0.5 μm to
By mixing particles having a size in the range of 3000 μm, the ranks of the cracks are all S and A, and the test piece 15d, that is, the cracks in the inner wall portion 15a and the insertion of the molten metal does not occur or is used. I found that there was no problem.

Further, a particle size of 30% or more of the total constituent weight is 30%.
By making the particles different in the range of 0 to 3000 μm, it was found that the rank of the crack was S, that is, there was no crack and no molten metal was inserted.

Further, the above-described test was performed by changing the thermal expansion coefficient of the material. Table 3 shows the results.

[0068]

[Table 3]

Possible range 0.8 × 10 ^{-5 to} 1.4 × 10 ^-5 Desirable range 0.9 × 10 ^{-5 to} 1.4 × 10 ^{-5 As} shown in Table 3, the coefficient of thermal expansion is 0.8 × 10 ^{-5 to} 1.4 × 10 ^-5
When it is in the range of ^-5 , the crack ranks are S and A, and the test piece 15d, that is, the crack on the inner wall 15a,
It was found that there was no problem with the use of the molten metal, although it did not occur or occurred. Further, by setting the coefficient of thermal expansion to be in the range of 0.9 × 10 ^{−5 to} 1.4 × 10 ⁻⁵ , it was found that the rank of the crack was S, that is, the crack and the insertion of the molten metal did not occur at all.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an embodiment of a magnetic recording medium manufacturing apparatus according to the present invention.

FIG. 2 is a diagram showing details of a vapor diffusion control wall.

FIG. 3 is a diagram showing a conventional apparatus for manufacturing a magnetic recording medium.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Vacuum vapor deposition apparatus 2 Vacuum tank 3 Base film 4 Cooling can 5 Delivery axis 6 Winding axis 7 Partition plate 8 Winding chamber 9 Deposition chamber 10 Magnetic material 11 Evaporation source 11a Refractory crucible 12 High frequency induction heating coil 13,14 Mask 15 Vapor diffusion control means 15d Test piece 17 First gas spraying part 18 Mask opening

Claims (1)

[Claims] 1. A transport means for transporting a long flexible substrate in a vacuum atmosphere, an evaporation source made of a magnetic material disposed below which the substrate is transported, and heating and evaporating the evaporation source. An evaporating means, a vapor flow diffusion control means disposed between the evaporating means and the flexible substrate, for regulating and controlling a diffusion direction of a vapor flow heated and evaporated by the evaporating means, and An apparatus for manufacturing a magnetic recording medium for forming a magnetic thin film on the flexible substrate, comprising: an incident angle restricting means for restricting an incident angle to the flexible substrate; Consisting of a plurality of cylindrical layers laminated from the inside to the outside, of the plurality of layers, the innermost layer has a porosity of 10% to 25%,
And its thermal expansion coefficient is 0.8 × 10 ^{-5 /} ° K to 1.4 × 10 ^-5
/ ° K.