JP2000311338A - Manufacturing device of magnetic recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the occurrence of cracks or fissures in an evaporating source such as a crucible or the like even in the initial heating stage of a magnetic material in the manufacturing device of a magnetic recording medium. SOLUTION: An inductively heated material 11b is provided between a refractory crucible 11a and a high-frequency induction heating coil 12 constituting an evaporation source composition 11. During heating by the high-frequency induction heating coil 12, the inductively heated material 11b is heated together with a magnetic material 10 in the crucible 11a. Thus, the crucible 11a is heated from both inside and outside, and the occurrence of cracks or fissures caused by a difference in thermal expansion is prevented.

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 for heating and melting a metal material, evaporating the metal material, and evaporating the vapor flow on a 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.

[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 increased, the coercive force has increased, the frequency characteristics have shifted to shorter wavelengths, or Improvements such as thinning of the layers 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 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. 7, a vacuum deposition apparatus 1 has a cylindrical outer shape inside a vacuum chamber 2 in a substantially vacuum state, and a non-woven fabric 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 magnetic material in the longitudinal direction is provided. The cooling can 4 rotates in the arrow Y direction to send out the base film 3 and take up the winding shaft 6 from the shaft 5 side. To the side.

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, which evaporate and rise, are continuously deposited as a magnetic layer on the surface of the base film 3 conveyed in the direction of arrow Y with the rotation of the cooling can 4.

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 diffusion prevention means 15.

When such a cylindrical vapor diffusion preventing 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, when the vapor diffusion preventing means 15 is provided above the electron beam 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.

[0011]

An apparatus for manufacturing a magnetic recording medium as described above contains a magnetic material in a refractory crucible and turns on the power of a high frequency induction heating means to heat the magnetic material in the crucible. It is. During this heating, the high-frequency induction current flows intensively around the outer periphery of the magnetic material in the crucible, so that only the outer periphery of the magnetic material is heated in the initial stage of heating. At this time, the refractory crucible containing the magnetic material is also heated, but only the inner wall of the crucible is heated, and heat is not sufficiently transmitted to the outer peripheral portion of the crucible at the initial stage of heating. A temperature difference occurs between the inner wall and the outer periphery of the crucible. Due to the temperature difference between the inner wall portion and the outer peripheral portion, a difference in thermal expansion occurs between the inner wall portion and the outer peripheral portion of the crucible, thereby causing cracks to occur in a portion of the crucible that has mechanical distortion or a portion where the material is uneven. In the worst case, the crucible may be broken.

In view of the above circumstances, it is an object of the present invention to provide an apparatus for manufacturing a magnetic recording medium in which cracks and cracks do not occur in an evaporation source such as a crucible even in the initial stage of heating a magnetic material. Things.

[0013]

According to the present invention, there is provided an apparatus for manufacturing a magnetic recording medium for heating an evaporation source containing a magnetic material as described above by high-frequency induction heating. A gap is provided at a predetermined interval between the heating means and the induction heating means, and an induction heating member is provided in the gap so as to surround the evaporation source.

In the above-described apparatus, it is preferable that a gap is provided between the evaporation source and the guided heating member, and the gap is filled with a filler.

Further, a gap may be provided between the guided heating member and the high-frequency induction heating means, and the gap may be filled with a filler.

The filler is preferably made of at least one of oxides, carbides, nitrides, and borides having a melting point of 1800 ° K or more and a maximum particle size of 3.0 mm or less.

Further, the induction-induced heating member has a melting point 21.
It is preferably made of a member having a temperature of at least 00 ° K and a resistivity of at most 1.0 × 10 ² Ωcm, and more preferably at least one of carbonaceous carbon, amorphous carbon and Cd.

[0018]

In the apparatus for manufacturing a magnetic recording medium according to the present invention, a predetermined gap is provided between the evaporation source and the high-frequency induction heating means, and a guided heating member is provided in the gap so as to surround the evaporation source. Thus, when performing high-frequency induction heating, the member to be induction-heated is heated together with the magnetic material in the evaporation source. For this reason, the evaporation source is heated simultaneously with its inner wall as well as its outer periphery, so that even at the initial stage of heating, the temperature difference between the inner wall and the outer periphery of the evaporation source is eliminated, and the difference in thermal expansion between the inner wall and the outer periphery is eliminated. . Therefore, generation and cracking of the evaporation source due to a difference in thermal expansion between the inner wall portion and the outer peripheral portion of the evaporation source can be prevented.

Further, by providing a gap between the evaporation source and the member to be induced and filling the gap with the filler,
Even if a crack occurs in the evaporation source, the molten magnetic material is absorbed by the filler, so that leakage of the magnetic material can be prevented.

Further, by providing a gap between the induction-induced heating member and the high-frequency induction heating means and filling the gap with a filler, the magnetic material and the evaporation source are generated in the vicinity of the high-frequency induction heating means by heating. It is possible to prevent a partial increase in pressure due to gas released from the magnetic material, and to prevent an abnormal discharge from occurring in the high-frequency induction heating means.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a magnetic recording medium manufacturing apparatus according to the present invention will be described below with reference to the drawings. FIG. 1 shows a schematic configuration of a vacuum evaporation apparatus 1 which is a magnetic recording medium manufacturing apparatus of the present invention.

The illustrated vacuum deposition apparatus 1 includes 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
It is applied by dissolving saturated polyester such as ET, phenoxy resin, polyamide, polyacrylate, etc.) and filler (silica, titania, alumina, calcium carbonate, etc.), has a thickness of 5 to 30 nm, and a density of 5 million. ~Ten
It has projections of 10 million / mm ² .

The base film 3 is further provided with a glow discharge treatment, an electron beam irradiation treatment, an ion irradiation treatment, a heat treatment,
Pretreatment of chemical treatment may be performed.

The base film 3 is wrapped around the take-up shaft 6 from the delivery shaft 5 through the cylindrical surface of the cooling can 4, and rotates 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 100 m / min, and is taken up on a take-up shaft 6. The cooling can 4 has a diameter
This is a cylindrical drum of 800 mm and width of 400 mm. The surface is hard chrome plated and mirror-polished to 0.2 S or less. Cooling water and other refrigerant (ethylene glycol) are circulated inside. For example, it is maintained at -35 to + 25 ° C.

The surface of the cooling can 4 is separated from the cooling can 4 by a distance of 5 mm, and cooling water of 20 ° C. is circulated therein.
Masks 13 and 14 whose main body is formed of SUS304 are provided. The maximum incident angle (θmax) is defined by the mask 13 located on the upstream side in the transport direction of the base film 3 and the minimum incident angle (θmin) is defined by the mask 14 located on the downstream side in the transport direction of the base film 3. The angle of incidence is based on the center of the circle of the melted surface in the refractory crucible 11a to be described later, and the line segment from the center of this circle to the edge of the mask 13 and the mask 14 and the normal line at each mask edge position on the cooling can 4. The maximum incident angle (θmax) regulated by the mask 13 was set to 90 °, and the minimum incident angle (θmin) regulated by the mask 14 was set to 45 °. Mask 13 and
The opening width of the mask opening 18 formed by 14 in the width direction (perpendicular to the transport direction of the base film 3) is 280 mm.
Set to.

The front surfaces of the masks 13 and 14 are curved along the masks 13 and 14, respectively.
Has a function of preventing the evaporated metal particles of the magnetic material 10 from adhering to the surface of the base material 3,
A movable shutter device in which cooling water of 18 ° C. is circulated and whose main body is formed of SUS304 is provided (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. The take-up chamber 8 and the vapor deposition chamber 9 are each provided with an exhaust system (not shown) for evacuating the vacuum, and the degree of vacuum in each chamber can be individually adjusted. In particular, since the oxidizing gas described later is introduced into the vapor deposition chamber 9 from outside the vacuum chamber 2, the degree of vacuum in the chamber and the partial pressure of various residual gases such as H ₂ O and O ₂ are constantly adjusted.

The winding film 8 contains the base film 3.
For example, a device for the pre- and post-treatment described above, such as a glow discharge treatment device, an electron beam irradiation treatment device, an ion irradiation treatment device, a heat treatment device, and a CVD treatment device may be provided. Further, the cooling can 4 is not limited to a cylindrical shape.
An endless belt-shaped metal plate that can form a predetermined slope with respect to the evaporation source assembly 11 may be used.

An evaporation source assembly 11 having a magnetic material 10 is disposed below the cooling can 4 in the evaporation chamber 9. The evaporation source assembly 11 includes a refractory crucible 11a for accommodating the magnetic material 10 and an inductive heating member 11 arranged outside the refractory crucible 11a so as to surround the refractory crucible 11a.
b, and a high-frequency induction heating coil 12 for heating the magnetic material 10 disposed around the guided heating member 11b. Further, a high-frequency power supply 20 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 to the high-frequency induction heating coil 12 are provided. The inside of the high-frequency induction heating coil 12 and the high-frequency power supply feeder 21 has a structure in which cooling water circulates.

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.

A magnetic material which is a component of the evaporation source assembly 11
The refractory crucible 11a for containing 10 is, 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 made of a Cu pipe having a diameter of φ12 mm through which cooling water circulates. The high-frequency induction heating coil 12 has five turns, an inner diameter of φ120 mm and a height h110 mm. Oscillation frequency 100 kHz, output 60 kW
The two high frequency power supplies 20 are installed outside the vacuum chamber 2 and connected to two high frequency induction heating coils 12 disposed inside the vacuum chamber 2 through a high frequency feeder 21 and a vacuum feedthrough (not shown). . 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 high-frequency induction heating coil 12
It is preferable that the shape is a shape corresponding to the side surface of the refractory crucible 11a.

Further, the evaporation chamber 9 is located between the cooling can 4 and the evaporation source assembly 11 having the magnetic material 10 and is provided with a magnetic material.
A cylindrical wall (hereinafter referred to as a vapor diffusion preventing wall) 15 is provided as a means for preventing the diffusion of the vapor so that the peripheral wall surrounds a path through which the vapor flow generated by evaporation of the vapor passes. In the vicinity of the mask 4 and in the vicinity of the masks 13 and 14, a first gas inlet 17 for injecting an acidified gas or a mixed gas of an oxidizing gas and an inert gas toward the base film 3 is provided. ing.

The gas introduction section 17 is located downstream with respect to the transport direction 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 that regulates the minimum incident angle (θmin). ing. The injection gas is O ₂
Gas was used. The injection direction of the gas injection slit 17a is substantially parallel to the tangent line on the cooling can 4 at the reference point on the cooling can 4 which defines the minimum incident angle (θmin). O ₂ gas is injected in a substantially oblique direction with respect to the scattering direction of the evaporating particles that have passed through the opening of the vapor diffusion preventing wall 15 described later by the O ₂ gas introduction from the gas introduction part 17, and a part of the evaporating metal particles To oxidize.

The inner peripheral wall surface of the vapor diffusion preventing wall 15 is formed of a high melting point metal, ceramics or the like, and has a refractory crucible 11a.
Are arranged so as to constitute an evaporative vapor flow path surrounded by a regulating surface extending in a substantially vertical direction in a substantially continuous state, and the lower surface and the upper surface allow passage of evaporative particles of the magnetic material 10 and the directivity thereof. It has a cylindrical shape that is open to enhance and has 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 is also square, rectangular, trapezoidal,
Any other shape may be used.

Further, the vapor diffusion preventing wall 15 is formed concentrically from the center of the opening toward the outside with the inner wall portion 15a and the outer peripheral portion.
15c.

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 preventing wall 15. The main body is made of Fe, Cu, Al, Ni, Ti, Mg, Z
A structure including a cooling structure formed of n, an alloy thereof, stainless steel, or the like can be employed.

The vapor diffusion preventing wall 15 is based on the center in the melt surface of the refractory crucible 11a. Evaporated particles of the magnetic material 10 which evaporate from the reference point and fly upward are subjected to the maximum incident It is configured so as not to prevent adhesion to a continuous range from the maximum incident angle θmax to the minimum incident angle θmin defined by the angle regulating mask 13 and the minimum incident angle regulating mask 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 assembly 11, and the base film 3 is transported in the width direction (in the plane of the base film 3). (In the direction perpendicular to the direction), the evaporation source assembly is set according to the width of the base film 3.
The shape of the evaporation source assembly 11 is changed (for example, when the horizontal cross-sectional shape of the evaporation source assembly 11 is elliptical and the width of the base film 3 is large, the long axis direction of the evaporation source assembly 11 is changed to the base film). 3), it is also possible to adopt a configuration in which a plurality of sets of evaporation source assemblies 11 are arranged corresponding to the width direction of the base film 3. In this case, a plurality of sets of the evaporation source assembly 11 (including the refractory crucible 11a), the high-frequency induction heating coil 12, the high-frequency power supply 20, and the high-frequency feeder 21 are independently arranged. Arranged, high frequency induction heating coil 12, high frequency power supply 20, high frequency feeder 21
Can be adopted.

Next, the operation of the magnetic recording medium manufacturing apparatus according to the present embodiment will be described.

First, the insides of the vapor deposition chamber 9 and the winding chamber 8 are evacuated by vacuum evacuation means (not shown), and the state of the interior of the vapor deposition chamber 9 and the winding chamber 8 is, for example, 5.0 × 10 ^−5.
A vacuum state of about 4.0 × 10 ⁻⁴ Torr is set. After the insides of the vapor deposition chamber 9 and the winding chamber 8 are made substantially vacuum as described above, electric power is supplied to the high-frequency induction heating coil 12 using the high-frequency power supply 20, whereby the magnetic material 10 of the evaporation source assembly 11 is discharged. Heat and evaporate.

The heating method of the magnetic material 10 is as follows: the conveying speed of the base film 3 is 80 m / min, and the oxygen introduction amount is 1000 cc / min.
Preliminary tests were conducted on the input power in a steady state sufficient to maintain the evaporation rate at which the film thickness was 800 angstrom under the above conditions and the holding time until the evaporation rate was obtained. The holding time means that after starting to supply a constant power, the temperature of the magnetic material 10 rises and melts, and until the entire evaporation source assembly 11 is heated sufficiently to reach a thermal equilibrium state until a constant evaporation rate can be maintained. Time.

After the elapse of the holding time, the base film 3 is transported from the delivery shaft 5 at a conveying speed of 80 m / min and a tension of 8.0 kgf / min.
The base film 3 is fed with O _{2 in a} pretreatment chamber (not shown).
After performing a glow discharge treatment using gas, the cooling can 4
Transport the top. Then, the shutter device is driven to the "open" state, and at the same time, the injection amount 1000
A Co—O magnetic thin film is formed on the base film 3 while injecting O ₂ gas at cc / min. After the formation of the metal magnetic thin film, the shutter device is set to the "closed" state, and at the same time, the injection of the O ₂ gas from the gas introduction unit 17 and the power supply from the high frequency power supply 20 are stopped to terminate the film formation.

After depositing a magnetic thin film on the base film 3, a mixture of a phosphoric acid-based lubricant + a perfluoropolyether lubricant and a rust inhibitor (benzotriazole) is dissolved and applied to the surface of the magnetic thin film. A non-magnetic powder containing carbon black as a main component, a mixed material of nitrocellulose, polyester, and polyurethane and an isocyanate curing agent are dissolved and dispersed on the back surface, and applied to a thickness of 0.5 μm. As described above, the thin film of the magnetic material is deposited on the base film 3.

In the apparatus as described above, the evaporation source assembly 11
Various changes were made in the above embodiment to evaluate the occurrence of cracks and cracks in the refractory crucible 11a.

In the first embodiment, an evaporation source assembly 11 comprising a refractory crucible 11a, an induction-heated member 11b and a high-frequency induction heating coil 12 shown in FIG. 2 is used.
And a refractory crucible 11a, an induction heating member 11b, and a high-frequency induction heating coil 12 shown in FIG.
The first filler is inserted into the gap between the induction heating member 11b and the induction heating member 11b.
What filled 11c was used. As a third embodiment, a refractory crucible 11a and an inductive heating member 11b shown in FIG.
And a high-frequency induction heating coil 12, and a first gap is provided between the refractory crucible 11a and the induction heating member 11b.
Of the induction heating member 11b
A material obtained by filling a second filler between the coil and the high-frequency induction heating coil 12 was used.

The material of the refractory crucible 11a is CaO
Stabilized ZrO ₂ (chemical component (wt%) ZrO ₂ ; 90.0%
998.0%, CaO; 2.0% to 7.0%). The shape is cup-shaped (inner diameter φ80 mm, outer diameter φ96 mm, height 100 mm, internal depth 90 mm). Co ₁₀₀ was used as the ferromagnetic material 10 for evaporation inside the refractory crucible 11a.

The induction heating member 11b is made of a carbon cylinder (inner diameter φ104 mm, outer diameter φ114 mm, height 100 mm) as a floor member.
11e is provided as a fixed base. Floor member 11e (outer diameter φ11
5 mm, thickness 6 mm) is disk-shaped, CaO-stabilized ZrO
₂ (Chemical component (wt%) ZrO ₂ ; 90.0% to 98.0%, C
aO; 2.0% to 7.0%).

The material of the first filler 11c is powder-like, and has a particle size of 0.3 mm to 1.0 mm CaO-stabilized ZrO.
₂ (Chemical component (wt%) ZrO ₂ ; 90.0% to 98.0%, C
aO; 2.0% to 7.0%). This was filled while squeezing lightly from the bottom.

The material of the second filler 11c is powder-like, and has a particle diameter of 0.3 mm to 1.0 mm.
₂ (Chemical component (wt%) ZrO ₂ ; 90.0% to 98.0%, C
aO; 2.0% to 7.0%). This was filled while squeezing lightly from the bottom.

Further, as a comparative example 1, as shown in FIG. 5, an evaporation source assembly 11 comprising a refractory crucible 11a and a high-frequency induction heating coil 12, and as a comparative example 2, a refractory crucible 11a shown in FIG. Heating coil 12 and refractory crucible 11
Filler filled between a and the high frequency induction heating coil 12
The evaporation source assembly 11 composed of 11f was used.

[0053] Evaluation method, the refractory crucible 11a, accommodates Co ₁₀₀ as a magnetic material 10, exhaust the vacuum chamber 5.0
The magnetic material 10 was melted and evaporated by supplying a constant power of 22 KW to the high-frequency induction heating coil 12 by the high-frequency power source 20 for 40 minutes while maintaining the pressure at × 10 ⁻⁵ Torr. Thereafter, the power supply was set to 0 kW, and the system was left for 20 minutes. This heating and standing operation was defined as one cycle, and heating and standing were repeated five times. After that, disassemble the evaporation source and refractory crucible
The state of crack occurrence and the outflow state of the magnetic material 10 were observed. The evaluation results are shown in Table 1 below.

Table 1 Evaluation Results Comparative Example-1 A remarkable crack (0.5
mm or more), and the insertion of the molten metal extends over the entire width in the thickness direction. There is evidence that the melt has leaked from that part and has solidified.

Comparative Example 2 Three remarkable cracks (0.5 mm or more) were formed in the longitudinal direction of the refractory crucible, and the molten metal was inserted over the entire width in the thickness direction. There is a leak of molten metal from that part, and it stops in the middle of the filler.

Example 1 Two small cracks (0.5 mm or less) were formed in the longitudinal direction of the refractory crucible, and insertion of molten metal was recognized. One of the cracks in the refractory crucible extends over the entire width in the thickness direction, and the molten metal leaks from that portion, and there is evidence of solidification. The amount of molten metal leakage is small.

During the test, abnormal discharge between the coils occurred (3
Times).

Example 2 One small crack (0.5 mm or less) was formed in the longitudinal direction of the refractory crucible, and insertion of molten metal was observed. The crack in the refractory crucible extends over the entire width in the thickness direction, and the molten metal from that portion stops in the middle of the leak filler. The amount of molten metal leakage is small.

During the test, occurrence of abnormal discharge between the coils (1
Times).

Example 3 One small crack (0.5 mm or less) was formed in the longitudinal direction of the refractory crucible, and insertion of molten metal was observed. The crack in the refractory crucible extends over the entire width in the thickness direction, and the molten metal leaks from that portion and stops halfway through the first filler. The amount of molten metal leakage is small.

No abnormal discharge occurs between the coils during the test.

As shown in Table 1, when the induction heating member 11b was provided between the refractory crucible 11a and the high-frequency induction heating coil 12, the state of occurrence of cracks and The leakage of the molten magnetic material from the crack is reduced. This is for the following reason. That is,
Since the induction heating member 11b is provided between the refractory crucible 11a and the high frequency induction heating coil 12, the induction heating member 11b is heated together with the magnetic material in the crucible 11a when performing the high frequency induction heating. Becomes For this reason, the crucible 11a is simultaneously heated not only at its inner wall but also at its outer peripheral portion, thereby eliminating the temperature difference between the inner wall portion and the outer peripheral portion of the crucible 11a even in the initial stage of heating, and the difference in thermal expansion between the inner wall portion and the outer peripheral portion. . Therefore, it is possible to prevent the generation and cracking of the crucible 11a due to the difference in thermal expansion between the inner wall portion and the outer peripheral portion of the crucible 11a.

In Table 1, when the filler 11c is filled between the refractory crucible 11a and the induction-heated member 11b, cracks occur in the crucible 11a. The presence of the filler 11c prevents the leakage from reaching the inductively heated member, thereby suppressing the spread of the leakage.

Further, in the case where the filler 11c is filled between the induction-induced heating member 11b and the high-frequency induction heating coil 12, the magnetic material 10 and the refractory crucible 11a are heated near the high-frequency induction heating coil 12. It is possible to prevent a partial increase in pressure due to generation of gas released from the magnetic material 10, and to prevent abnormal discharge from occurring.

[Brief description of the drawings]

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

FIG. 2 is a diagram showing a first embodiment of an evaporation source assembly.

FIG. 3 is a diagram showing a second embodiment of the evaporation source assembly.

FIG. 4 is a diagram showing a third embodiment of the evaporation source assembly.

FIG. 5 is a diagram illustrating a first comparative example of an evaporation source assembly.

FIG. 6 is a diagram illustrating a second comparative example of the evaporation source assembly.

FIG. 7 is a diagram illustrating a configuration of a conventional magnetic recording medium manufacturing apparatus.

[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 assembly 11a Refractory crucible 11b Induced heating member 11c 11d, 11f Filler material 11e Bottom plate 12 High frequency induction heating coil 13, 14 Mask 15 Vapor diffusion prevention wall 17 First gas introduction part 18 Mask opening

Claims (6)

[Claims] 1. A transport means for transporting a long substrate along a predetermined path in a vacuum atmosphere, an evaporation source of a magnetic material disposed below the predetermined path, and an outer side of the evaporation source. High-frequency induction heating means for evaporating the magnetic material by heating by high-frequency induction heating surrounding the evaporation source,
In a magnetic recording medium manufacturing apparatus for forming a magnetic thin film on the substrate by depositing the vapor flow on the substrate while transporting the substrate, a predetermined distance between the evaporation source and the high-frequency induction heating means. An apparatus for manufacturing a magnetic recording medium, wherein a gap is provided, and a guided heating member is provided in the gap so as to surround the evaporation source. 2. The magnetic recording medium manufacturing apparatus according to claim 1, wherein a gap is provided between the evaporation source and the induced heating member, and the gap is filled with a filler. 3. The method of manufacturing a magnetic recording medium according to claim 1, wherein a gap is provided between the induction-induced heating member and the high-frequency induction heating means, and the gap is filled with a filler. apparatus. 4. The filler according to claim 2, wherein the filler comprises at least one of oxides, carbides, nitrides, and borides having a melting point of 1800 ° K or more and a maximum particle size of 3.0 mm or less. Or a manufacturing apparatus for a magnetic recording medium according to 3. 5. The method according to claim 1, wherein the induction-induced heating member has a melting point of 2100 ° K.
5. The apparatus for manufacturing a magnetic recording medium according to claim 1, wherein the member has a specific resistance of 1.0 × 10 ² Ωcm or less. 6. The magnetic recording medium according to claim 1, wherein the induction heating member is made of at least one of carbonaceous carbon, amorphous carbon, and Cd. apparatus.