JP2003343976A - Heat treating device in magnetic field - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat treating device in a magnetic field capable of improving characteristic of a disclike member to be treated such as a magnetic disc uniformly in the circumferential direction, saving energy, and controlling temperature with high precision. <P>SOLUTION: This heat treating device in a magnetic field performs heat treatment in a vacuum vessel by generating a radial magnetic field in the radial direction of the member to be treated by a pair of coils arranged opposingly and symmetrically on the same upper and lower shaft of the disclike member to be treated. Two pairs of coils are inserted and fixed into 9a and 9b up and down of a cylindrical heat block 6 having non-magnetism and high heat conduction property. These pairs of coils are excited in a reverse phase to generate a radial magnetic field at a position of a sample chamber 10 in which the member to be treated is inserted. Heating of the member to be treated is performed by Joule heat and a heater coil wound in a non-inducing manner around outer periphery of the heat block. Coil pressing flanges 8a, 8b are replaced with flanges in which a spiral thin channel for refluxing a medium for cooling is buried to control temperature with high precision in processes of heating and removing heat. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a depressurized container,
In particular, it relates to a heat treatment apparatus in a magnetic field for performing heat treatment while applying a magnetic field to a member to be treated placed in a vacuum container.

[0002]

2. Description of the Related Art A magnetic field heat treatment apparatus of this type is used, for example, in a "magnetic field heat treatment method for a silicon steel sheet" (Patent 3019705) for improving the characteristics of a silicon steel sheet, or in a manufacturing process of a magnetoresistive head. The “heat treatment apparatus in magnetic field” (Japanese Patent Laid-Open No. 2001-102121) is known.

[0003]

The heat treatment apparatus in a magnetic field as described above uses a normal conduction solenoid coil or a superconducting solenoid coil as the magnetic field generating means, and the magnetic field generated by them is a strong component in the axial direction of the solenoid coil. The distribution has. When heat treatment is applied to a rotating body such as a magnetic disk in such a magnetic field, there is a problem that improvement in characteristics such as imparting magnetic anisotropy cannot be secured uniformly in the circumferential direction.

Further, the magnetic field heat treatment apparatus as described above uses an independent heating heater to heat the member to be processed. In the apparatus using the normal conduction coil, the heat generated by the Joule heat of the solenoid coil is cooled. It is released to the outside with water, etc., and is not actively used for heating the processed material. Further, in the device using the superconducting solenoid coil, the solenoid coil is cooled with liquid helium to be in a superconducting state so as to suppress the generation of Joule heat itself. There was a problem from the viewpoint of saving.

SUMMARY OF THE INVENTION An object of the present invention is to provide a magnetic field heat treatment apparatus capable of uniformly improving the characteristics of a disk-shaped member to be processed such as a magnetic disk in the circumferential direction.

Another object of the present invention is to provide a heat treatment apparatus in a magnetic field equipped with a heating device capable of realizing energy saving.

Still another object of the present invention is to provide a magnetic field heat treatment apparatus capable of controlling the heating temperature of a disk-shaped member to be processed with high accuracy.

[0008]

According to the present invention, in a magnetic field heat treatment apparatus for performing heat treatment while applying a magnetic field to a disk-shaped member to be processed arranged in a depressurized container, the disk-shaped member to be processed is provided. Magnetic field generating means for generating a radial magnetic field in the radial direction of the disk-shaped member to be processed by opposing coil pairs that are symmetrically arranged on the same vertical axis, and the coil pair in heating the disk-shaped member to be processed. An apparatus for heat treatment in a magnetic field is provided, which has a heating means that uses both the heat generation of the above and the heat generated from a heater arranged in the vicinity of the coil pair, and further has a cooling means for adjusting the temperature if necessary. it can.

According to a preferred first aspect of the present invention, the outer radius of the coil pair has a shape that reduces continuously or stepwise toward the point of symmetry of the coil pair, and the disk-shaped object to be treated. It is possible to provide a magnetic field generating means that can uniformly apply a radial magnetic field consisting of radial components to most of the region except the central part of the member.

According to a preferred second aspect of the present invention, the cylindrical coil case for tightly storing the coil pair also serves as a heat block made of a non-magnetic and highly heat-conductive member, and the heat block is A heater coil for heating is closely wound around the outer periphery of the heat block, and a space for accommodating and arranging the disk-shaped member to be processed is provided at a central position in the axial direction of the heat block cylinder relative to the axis of the coil pair. It is possible to provide a heat treatment apparatus in a magnetic field provided with a heat block that is provided in a vertical plane and that holds the disk-shaped member to be processed in a fixed position and can efficiently heat the disk-shaped member to be processed.

In the second aspect, further, if necessary, a flange formed by burying spiral narrow grooves for circulating a cooling medium in the upper and lower surfaces of the heat block cylinder can be installed, and the disk-shaped object to be treated can be installed. It is possible to provide a heating device that can precisely control the heating temperature of members.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The basic part of the present invention will be described with reference to FIG. This device is mainly used for magnetic disks, and in particular, it has a high coercive force recording layer with perpendicular magnetic anisotropy and an in-plane difference for reducing the demagnetization of the recording layer and improving the operating efficiency of the recording head and the reproducing head. It is applied to the so-called double-layered perpendicular magnetic disk manufacturing process, which basically has an underlayer with a low coercive force. FIG. 1 shows coil pairs 1a and 1b arranged on the z-axis with the origin of the cylindrical coordinate system (radial direction coordinate r, cylindrical axis direction coordinate z) as the symmetry point, and the z-axis at the center of the coil pair. A cross-sectional view of a magnetic disk 2, which is a disk-shaped member to be processed, is arranged on a plane perpendicular to. The coils 1a and 1b are excited so that their axial magnetic fields have opposite phases, and as a result, the plane of the magnetic disk 2 placed at the center of the coil pair is
A radial magnetic field is applied. Coil 1a and coil 1b
If the symmetry of is kept good, the magnetic field applied to the magnetic disk 2 has only a radial component without an axial component. Further, by appropriately designing the inner and outer shapes of the coils 1a and 1b, the r-direction component magnetic field (hereinafter referred to as the radial magnetic field) having sufficient uniformity for heat treatment in the region where the recording layer of the magnetic disk 2 is used. ) Can be generated.

The first embodiment of the radial magnetic field generating means of the present invention will be described with reference to FIG. This embodiment is designed to generate a radial magnetic field as uniform as possible using two pairs of solenoids. In this embodiment, a rectangular wire made of oxygen-free copper having a size of 2 mm × 2 mm is used as the winding wire, and the coils 3a and 3b are wound 9 times with an inner diameter of 5 mm, an outer diameter of 107.22 mm, and a winding interval of 0.22 mm. Each of 4a and 4b had an inner diameter of 2 mm, an outer diameter of 19.78 mm, and a winding interval of 0.22 mm, and was wound 32 times. These coil pairs are 3a and 4a, and 3b
And 4b have the same phase, 3a and 3b, and 4a, respectively.
And 4b were connected so that they had opposite phases, and a direct current of 32 A was applied. FIG. 3 shows the distribution of the r-direction component magnetic field Hr, which is the radial magnetic field in the plane of z = 0 when the inner gap Gap of the coil pair 3a, 3b is set to 4, 6, 8 mm. When Gap = 6 mm, the diameter shown in FIG. 2 is about 65 m.
The recording area of the magnetic disk 2 of m is r = 5 mm to r
In the region of = 32 mm, the radial magnetic field of 16,000 A / m necessary for the heat treatment in the magnetic field can be realized with an accuracy of ± 5%. FIG. 4 shows how the radial magnetic field when Gap = 6 mm in FIG. 3 is combined by the coil pair 3 and the coil pair 4. Coil pair 4 contributes to the radial magnetic field in the central portion, and coil pair 3 contributes to the radial magnetic field in the portion away from the center. As can be easily inferred from this figure, the distribution of the radial magnetic field in the required area of the magnetic disk can be designed more uniformly by the preferable shapes of the coil pair 3 and the coil pair 4. Furthermore, if the third coil pair is arranged between the coil pair 3 and the coil pair 4,
It can be easily inferred that the uniformity of the radial magnetic field distribution will be further improved. The magnetic field that a magnetic disk receives is only the r-direction component as long as the magnetic disk is located at the center of the coil pair, but if it deviates from the center position, it also receives the axial component magnetic field. FIG. 5 shows z = 0 on the z-axis,
The distribution of the axial component magnetic field Hz at 0.2 and 0.5 mm is shown. In the present embodiment, the axial component magnetic field becomes larger as it gets closer to the z-axis when it deviates from the center position.
Even on a plane of = 0.2 mm, the magnitude is at most 935 A / m at the position of r = 5 mm, which is only 6.3% of the r-direction component magnetic field at that point.

A second embodiment of the radial magnetic field generating means of the present invention will be described with reference to FIGS. 6 and 7. In FIG. 6, in order to further improve the uniformity of the radial magnetic field, the same rectangular wire made of 2 mm × 2 mm oxygen-free copper as used in the first embodiment is used, and the thickness is 2 mm, the inner diameter is 2 mm, and the outer diameter is 2 mm. 12 layers of coil pairs with different numbers of turns are formed, and 12 layers are laminated with a layer interval of 2.22 mm. The outer diameter and the number of turns of the first to twelfth layers are such that the outer diameter of the first layer and the second layer is 1
0.89 mm, the number of windings 2, the third to sixth layers have an outer diameter of 15.
33mm, the number of turns 3, the 7th layer has an outer diameter of 19.78mm, the number of turns 4, the 8th and 9th layers has an outer diameter of 24.22mm, the number of turns 5, 10th layer has an outer diameter of 37.56mm, the number of turns 8th, 11th The layer has an outer diameter of 68.67 mm, the number of turns is 15, and the twelfth layer has an outer diameter of 144.2.
The number of turns is 2 mm and the number of turns is 32. The total number of turns of each of the coil 5a and the coil 5b, which are stacked in 12 stages, is 85 turns. With the coil gap Gap = 6 mm, the coil 5a and the coil 5 are
Fig. 7 shows the distribution of the radial magnetic field when an antiphase current 72A is applied to b. The radial magnetic field strength in the required area r = 5 to 32 mm is average value = 16,114 A / m, maximum value = 1.
6,387 A / m (+ 1.6%), minimum value = 15,74
It was 7 A / m (-2.3%), and a very uniform radial magnetic field distribution was obtained.

Next, the first embodiment of the heating means of the present invention will be described with reference to FIG. The heat block 6 of FIG. 8 is a cylindrical shape made of oxygen-free copper and having a diameter of 130 mm and a height of 72 mm, and the upper and lower surfaces of the heat block 6 shown in FIG. 2 explained as the first embodiment of the radial magnetic field generating means of the present invention. The dugouts 9a and 9b for tightly storing the pair of coils are formed. In order to store the magnetic disk that is the disk-shaped member to be processed, the width of 65m in the plane perpendicular to the axis at the center position on the cylinder axis
A sample chamber 10 having a height of 6 m and a height of 6 mm is provided. Further, a heater coil 7 for heating is wound around the center of the heat block 6 without induction. After the coil pair is stored in the heat block, it is closely fixed to the heat block by the flanges 8a and 8b. One of the features of the present invention is that the Joule heat generated by the magnetic field generating coil is positively used for heating the member to be processed. When the coil pair shown in FIG. 2 is excited by a current of 32 A, the amount of heat generated by the coil is 44
It becomes 0W. The heat block can be heated up to about 350 degrees Celsius within 90 minutes using only the coil pair. Furthermore, a maximum current of 7 A is applied to the heater wound outside the heat block to obtain a heat generation amount of 700 W, and the heat block is heated to 50 degrees Celsius.
Can be heated above 0 degrees.

FIG. 9 shows a second embodiment in the case where more accurate temperature control is required in the heating and heat removal process than the first embodiment of the heating means. In this embodiment,
The flanges 11a and 11b in which the upper and lower flanges of the heat block in FIG. 8 are embedded with spiral fine grooves for circulating the cooling medium.
This is achieved by replacing The narrow groove has a structure in which a spiral groove excavated at a depth of 3 mm, a width of 3 mm, and a pitch of 4 mm in flanges 11a and 11b made of oxygen-free copper and having a depth of 3 mm is sealed from above, and a cooling medium injection port is provided. 12a and 12b and outlets 13a and 13b are connected. The cooling flanges 11a and 11b are used by closely fixing to the heat block 6 in which the magnetic field generating coil is already stored. Nitrogen gas is used as a cooling medium,
By supplying a maximum of 30 liters per minute through an external heat converter, the temperature of the heat block can be accurately controlled to any value between room temperature and 500 degrees Celsius.

Referring to FIG. 10, the first embodiment of the disk-shaped member to be treated in the magnetic field heat treatment apparatus of the present invention will be described. The magnetic disk 16 having a diameter of 65 mm, which is a disk-shaped member to be processed, has a width of 70 mm, a length of 150 mm, and a thickness of 1.
Place it on the sample table 14 consisting of a 365 mm quartz plate,
The magnetic disk is inserted into the sample chamber 10 shown in FIG. 8 so that the center of the magnetic disk coincides with the center of the sample chamber. 53 mm from the tip, 10 mm in diameter in the width center, and height of 2.
There is a circular projection 15 of 635 mm, and after fitting the magnetic disk into this circular projection, an upper lid 17 made of a quartz plate having the same shape as the magnetic disk and having a thickness of 2 mm is fitted and fixed thereon. By such an installation means, the radial magnetic field shown in FIG. 4 is uniformly applied to the entire surface of the recording area where the magnetic disk as the disk-shaped member to be processed is required.

The magnetic field heat treatment apparatus of the present invention described above is installed inside a vacuum chamber equipped with an evacuation means such as a rotary pump, and one magnetic disk is heat treated in the magnetic field by one evacuation of the vacuum apparatus. Do. When the effect of the axial magnetic field component on the effect of heat treatment in a magnetic field is negligible as a characteristic of a magnetic disk. The circular protrusion 10 shown in FIG.
It is easy to design the system so that the height is higher and multiple magnetic disks are stacked and loaded.

Another embodiment of the present invention in which a plurality of disk-shaped members to be processed are heat-treated in a magnetic field will be described with reference to FIG. When using the magnetic field heat treatment apparatus of the present invention in the development process or the production process, it is more preferable that the magnetic disk heat treatment can be performed on a plurality of magnetic disks by a single evacuation of the vacuum device without being affected by the axial magnetic field component. It may be preferable. The embodiment described here solves this problem. The base block 19 shown in FIG. 11 has the same basic coil configuration as that shown in FIG. 2, and by stacking the additional block 18 on top of it, a total of 10
A disk-shaped member to be processed can be heat-treated in a magnetic field. If the additional blocks 18a to 18i are described using the same-shaped additional block 18, the additional block 18 is the coil 3 shown in FIG.
a, 4a, 4b and the same coils 21a, 21b, 21c, and the disk-shaped processed member 20 includes coils 21b and 21c.
It is installed between. Further, the coil corresponding to the coil 3b shown in FIG.
a is also used. In the additional block 18a, the upper coil of the base block 19 also serves as this. That is, in the form of batch heat treatment of a plurality of sheets of the present invention, the intermediate coil is omitted, the size reduction of the apparatus and the improvement of energy efficiency are realized, and a plurality of disk-shaped processed members are collectively subjected to a magnetic field. Medium heat treatment is possible.

Although the present invention has been described with reference to the preferred embodiment in which a magnetic disk having a diameter of 65 mm is heat-treated in a magnetic field, the present invention can be easily applied to a heat treatment in a radial magnetic field of a magnetic disk having another size. Needless to say, the present invention is not limited to heat treatment in a magnetic field of a magnetic disk, but can be applied to all material processes in which heat treatment is preferably performed while applying a radial magnetic field.

[0021]

As described above, according to the present invention, for a disk-shaped member to be processed such as a magnetic disk,
Radial magnetic field that can perform heat treatment in a magnetic field that can achieve uniform property improvement in the circumferential direction and that has a heating device that can save energy and that can control the heating temperature of a disk-shaped member to be processed with high accuracy. We can provide medium heat treatment equipment.

[Brief description of drawings]

FIG. 1 is a conceptual cross-sectional view of a coil pair that uniformly generates a radial magnetic field on a member to be processed according to the present invention.

FIG. 2 is a schematic configuration sectional view showing a first embodiment of a radial magnetic field generating means used in a magnetic field heat treatment apparatus according to the present invention.

FIG. 3 is a graph showing a distribution of a radial magnetic field according to the first embodiment of the radial magnetic field generating means shown in FIG.

FIG. 4 is a graph showing how the radial magnetic fields are synthesized by the first embodiment of the radial magnetic field generating means shown in FIG.

5 is a graph showing a distribution of an axial magnetic field according to the first embodiment of the radial magnetic field generating means shown in FIG.

FIG. 6 is a schematic configuration sectional view showing a second embodiment of a radial magnetic field generating means used in a magnetic field heat treatment apparatus according to the present invention.

FIG. 7 is a graph showing the distribution of the radial magnetic field according to the second embodiment of the radial magnetic field generating means shown in FIG.

FIG. 8 is a schematic configuration sectional view (left) and a schematic view (right) showing a first embodiment of a heating means according to the present invention.

FIG. 9: Second heating means with cooling means according to the invention
FIG. 2 is a schematic cross-sectional view showing an embodiment of FIG.

FIG. 10 is a schematic configuration diagram showing a first setting means for a disk-shaped processed member according to the present invention.

FIG. 11 is a schematic configuration diagram showing an embodiment of heat treating a plurality of disk-shaped members to be processed in a collective magnetic field according to the present invention.

[Explanation of symbols]

1a, 1b, 3a, 3b, 4a, 4b, 5a, 5b
Coil 2, 20 Disk-shaped processed member 6 Heat block 7 Heating heater coil 8a, 8b Flange 9a, 9b Coil storage digging 10 Sample chamber 11a, 11b Cooling flange 12a, 12b Cooling medium inlet 13a, 13b Cooling Medium discharge port 14 Sample stage 15 Protrusion 16 Disc-shaped processed member 17 Upper lid 18, 18a to 8i Additional block 19 Base block 21a, 21b, 21c Coil

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hitoshi Mori             1-1-1, Ipponsugi-cho, Wakabayashi-ku, Sendai City, Miyagi Prefecture             Daiichi Lease Building No. 402 F-term (reference) 4K061 AA01 DA05 FA04 FA12                 5D112 AA24 DD08 FB29 GB01 GB10

Claims (3)

[Claims] 1. In a magnetic field heat treatment apparatus for performing heat treatment while applying a magnetic field to a disk-shaped member to be processed arranged in a depressurized container, the disk-shaped member to be processed is symmetrically arranged on the same vertical axis. Magnetic field generating means for generating a radial magnetic field in the radial direction of the disk-shaped member to be processed by the opposed coil pairs, and heat generation of the coil pair in heating the disk-shaped member to be processed and arrangement in the vicinity of the coil pair. An apparatus for heat treatment in a magnetic field, characterized by having a heating means which also uses heat generated from the above-mentioned heater, and further having a cooling means for temperature adjustment, if necessary. 2. The magnetic field heat treatment apparatus according to claim 1, wherein the outer radius of the coil pair has a shape that continuously or stepwise decreases toward a symmetry point of the coil pair, A heat treatment apparatus in a magnetic field characterized in that a radial magnetic field consisting of a radial component can be uniformly applied to most of the region except the central part of the processing member. 3. The heat treatment apparatus in a magnetic field according to claim 1, wherein the cylindrical coil case for tightly storing the coil pair also functions as a heat block made of a non-magnetic and highly heat-conductive member. A heater coil for heating is closely adhered to the outer periphery of the coil and is non-inductively wound, and
A space for accommodating and arranging the disk-shaped member to be processed is provided at a central position in the axial direction of the heat block in a plane perpendicular to the axis of the coil pair, and further, if necessary,
A heat treatment apparatus in a magnetic field, wherein a flange formed by burying spiral fine grooves for circulating a cooling medium on the upper and lower surfaces of the heat block cylinder can be installed.