JP2550231B2 - Method of manufacturing magnetic recording medium - Google Patents

Description

Detailed Description of the Invention

[0001]

The present invention relates to a production how of the magnetic recording medium
To take suitable magnetic recording in particular to ensure a high cleanliness
The present invention relates to a method of manufacturing a medium .

[0002]

The magnetic disk apparatus of the Related Art In recent years, from the viewpoint of improving the recording density, high coercivity fine magnetic powder and a binder -
Or a thin film magnetic recording medium having a large residual magnetism.

The general structure of a magnetic disk using a coated medium is as follows. That is, on a non-magnetic substrate, a thin film coating of a magnetic coating composed of a magnetic powder, a binder-resin and a coating film reinforcing agent, after performing a magnetic field orientation treatment and curing treatment, the surface is processed, washed, A magnetic disk is formed by forming a lubricating film.

The general structure of a magnetic disk using a thin film magnetic recording medium is as follows. That is, a non-ferromagnetic metal layer is formed on a non-magnetic substrate, a magnetic film is further formed on the non-magnetic metal layer, a protective film is formed on the magnetic film, an appropriate surface protrusion treatment is performed, and then a lubricating film is formed if necessary. It is a structure that has formed. Here, the formation of the non-ferromagnetic metal layer may be omitted.

Prior arts relating to the present invention include Japanese Examined Patent Publication No. 60-42440 and Japanese Unexamined Patent Publication No. 61-14.
There are inventions disclosed in Japanese Patent Application Laid-Open No. 8398, Japanese Patent Application Laid-Open No. 61-500351 and Japanese Patent Application Laid-Open No. 62-95400.

[0006]

In situations where large capacity is required to Symbol recording apparatus [0005] The magnetic disk has to achieve a high recording density and high reliability. In order to achieve high recording density, it is necessary to improve the magnetic characteristics of the magnetic medium, and it is also necessary to reduce the flying height between the magnetic disk and the magnetic head.

Therefore, in the coating type medium, fine magnetic powder having a high coercive force tends to be used. When such a fine magnetic powder is used, the amount of shavings generated when the surface of the magnetic disk is polished is small and remains on the disk surface. On the other hand, in the thin-film magnetic recording medium, it became clear that the shavings generated in the step of removing the surface protrusions have high adhesiveness due to the smoothness of the medium itself and remain on the disk surface as well.

As a result, in the coated medium and the magnetic disk, the head starts contact / stop (c).
ontact start stop, hereafter CSS
Abbreviated. ), It was found that the shavings remaining on the surface of the recording medium adhered to the surface of the head slider of the magnetic head, causing a reliability problem. Therefore, it is necessary to ensure the cleanliness of the surface of the magnetic disk, but it has been clarified that the conventional cleaning technology cannot handle it because the particle size of the shavings remaining on the surface of the magnetic disk is small.

[0009] The present invention has been made in view of the problems of the prior art described above, onset Te manufacturing process smell of the magnetic disk
The grinding dust or small deposits adhering to the magnetic disk surface to live, magnetic recording, which make it possible to wash with a high degree of cleanliness
It is an object of the present invention to provide a method for manufacturing a recording medium .

[0010]

In order to remove the shavings (or simply particles) adhering to the surface of the magnetic recording medium , which is the object of the present invention, it is necessary to consider the characteristic behavior of the shavings. The reason why the shavings remain on the surface is that the surface attachment energy is high because the particle size is small. Furthermore, the magnetic medium itself
Because of the smoothness of the body, it has a high adsorption power. Therefore, in order to positively remove the shavings or particles adhering to the surface, fine particles are dispersed in a processing liquid such as a working grinding liquid or a cleaning liquid in advance, and the processing liquid is used.
Scrub bi ring magnetic medium material (scr ubb ing) Then, the bonding energy of the particles that are distributed - and by a high followability of the surface micro uneven portion, the dispersed microparticles in the processing solution, the magnetic recording medium of interest surface move the grinding dust or particles adhering to or adsorbed to itself, to disperse the deposit in the treatment liquid, the magnetic recording medium sheet surface or, et al., it is possible to eliminate.

[0011]

The shavings generated during the lapping process of the magnetic recording medium or the adhered substances adsorbed on the surface can be removed from the surface by rubbing with a cleaning liquid in which fine particles are dispersed.

[0012]

The present invention will be described in detail below with reference to examples in which the present invention is applied to the manufacture of magnetic disks.

Example 1 The following compositions were kneaded using a kneader and a ball mill.

Magnetic powder (Co-Fe ₂ O ₃ ) 100 parts by weight Alumina powder (α-Al ₂ O ₃ ) 10 parts by weight Epoxy resin 25 parts by weight Phenol resin 25 parts by weight Polyvinyl butyral resin 7 parts by weight Cyclohexanone 300 parts by weight Isophorone 150 parts by weight Dioxane 50 parts by weight The obtained magnetic paint was spin-coated on an aluminum substrate whose surface was previously cleaned, subjected to magnetic field orientation treatment, and heat-cured to 0.3 to 0. A magnetic film having a film thickness of 9 μm was formed. Next, the magnetic film is processed to obtain a finished film thickness of 0.2 to 0.
A 6 μm magnetic disk was prepared. At this time, the finishing process was performed by a wrapping tape. The magnetic disk processed by the above method was quickly washed and dried, and then a lubricating film was formed to complete the magnetic disk. This manufacturing method is the same as the conventional magnetic disk manufacturing method.

FIG. 1 is a partial cross-sectional view of the magnetic disk and the magnetic head formed as described above. In FIG. 1, 1 is an aluminum substrate, 2 is a magnetic film, 3 is alumina particles, 4 is a lubricating film, and 5 is a magnetic head.

As a result of performing a CSS test on the magnetic disk formed as described above, it was found that deposits were generated on the head slider surface of the magnetic head 5. As a result of elemental analysis of the deposit, a magnetic medium constituent was detected. Next, the surface of the magnetic disk is scanned with a high resolution scanning electron microscope (S
As a result of observation with EM), it was confirmed that shavings of tens to hundreds of nanometers adhered to the surface of the magnetic disk. FIG. 2 is a model of deposit formation, and in FIG.
1 is an aluminum substrate, 2 is a magnetic film, 3 is alumina powder, 7 is a wrapping tape, 8 is a rubber roller, 9 is shavings attached to a magnetic disk, and 10 is a film thickness after coating. As is apparent from FIG. 2, by rubbing the surface of the magnetic film 2 with a wrapping tape through the rubber roller 8, large powder adhering to the surface of the magnetic film 2 is removed. Adhere to the surface of the magnetic film 2.

Next, the case where the cleaning process of the present invention is applied to the magnetic disk manufactured by the above-mentioned conventional method to clean it to a high degree of cleanliness will be described.

FIG. 3 is a perspective view showing a magnetic disk finishing method. In FIG. 3, 6 is a magnetic disk, 7 is a wrapping tape (or cotton tape), 8 is a rubber roller, and 15 is a processing liquid supply pipe. Shows. For cleaning the surface after processing, a cotton tape was used in the same mechanism as in FIG. 2, and a liquid in which alumina powder having an average particle size of 0.4 μm was dispersed was supplied from the treatment liquid supply pipe 15 and scraped off. 4 and 5 show the deposit removing mechanism. 4 and 5,
Reference numeral 2 is a magnetic film, 9 is an adhering shaving, and 16 is a fine particle dispersed in the treatment liquid. As shown in the figure, the fine particles 16 dispersed in the treatment liquid are the shavings 9 attached to the surface of the magnetic film 2.
Is moved or the shavings 9 themselves are adsorbed and dispersed in the treatment liquid, whereby the shavings 9 are removed from the surface of the magnetic recording medium. Here, the above treatment will be referred to as fine particle cleaning.

The processing conditions are shown below.

Particle cleaning conditions Alumina concentration 10 wt% Treatment liquid supply amount 100 cc / min Cotton tape feed 100 mm / min Pressing load 0.2 kg Heavy disk rotation speed 300 rpm Processing time 20 sec At a magnification of 20,000 times for disk surface observation by SEM The amount of deposits present in the visual field was quantified. As a result, fine cleaning without ----- 6.3 / 24.3μm ² particles washed there ----- 0.4 / 24.3μm ² that results.

From these results, it has been clarified that the fine particle cleaning is effective in removing the submicron particles and the like adhering to the minute irregularities.

Example 2 A magnetic disk was manufactured in the same manner as in Example 1 except that the average particle diameter of alumina particles was 0.2, 0.4, 0.5 and 1.0 μm, and the disk surface was adhered by SEM. The physical quantity was evaluated. As a result, 0.2 μm −−−−− 0.28 / 24.3 μm ² 0.4 μm −−−− 0.44 / 24.3 μm ² 0.5 μm −−−−− 0.86 / 24.3 μm ² 1.0 μm −−−−− 2.6 / 24.3 μm ² No fine particle cleaning −−−− 6.3 / 24.3 μm ^{2 From these} results, it was found that the smaller the particle size, the higher the cleaning effect. . It was also confirmed that the effect was obtained even with 1.0 μm particles.

Example 3 A magnetic disk was manufactured in the same manner as in Example 1 except that alumina carbide (aluminum oxide), silicon carbide, cerium oxide, and silicon nitride were used.
The amount of deposits on the disk surface due to M was evaluated. Each particle had an average particle diameter of 0.5 μm. Consequently alumina particles ------ 0.86 / 24.3μm ² silicon carbide ------ 0.39 / 24.3μm ² cerium oxide ------ 0.57 / 24.3μm ² Silicon nitride -------- 0.48 / 24.3 [mu] m < ² > From these results, it was found that an effect other than alumina particles was also effective. It is easily conceivable that not only the materials used here but also oxides, carbides, and nitrides can be expected to be effective. Furthermore, it is conceivable that this effect can be expected for all particles.

(Embodiment 4) A nickel-phosphorus alloy is applied to a flatly finished aluminum substrate by electroless plating,
In order to obtain surface accuracy, polishing is performed using abrasive grains.
Hereinafter, this is referred to as a nickel-phosphorus substrate. This nickel-phosphorus substrate is subjected to texture processing to form processing grooves of substantially concentric circles. For texture processing, diamond particles were dispersed in a processing liquid, and the processing liquid was supplied and processed in the same manner as in Example 1 (see FIG. 3). This processing method is
It was found that the shavings can be removed from the disk surface at the same time as the processing, and as a result, scratches (defects) generated on the disk surface can be reduced. After washing and drying the texture-processed substrate by these treatments, a chromium underlayer film, a cobalt alloy magnetic film, a sputtering method,
After forming the protective film, the surface protrusions were scraped off and a lubricating film was formed to obtain a magnetic disk. If necessary, the fine particle cleaning described in Example 1 was performed to ensure high cleanliness of the magnetic disk surface. The magnetic disk using the thin film magnetic medium obtained by the above manufacturing method is
Due to the smoothness of the surface, a low flying height of the head could be achieved.

(Embodiment 5) FIG. 6 shows a schematic sectional view of a magnetic recording apparatus. In FIG. 6, the magnetic disk 6 is attached to a support 12 that is rotatable by a rotation drive mechanism 13. The magnetic head 5 is carried to a desired position on the magnetic disk 6 by the voice coil 14. These are stored in the case 11.

When the magnetic disk having the surface cleanliness obtained according to each of the above-mentioned embodiments is stored in this magnetic recording apparatus and operated under CSS conditions, the magnetic head slider portion, which is conventionally found, is not contaminated. I understood.

In each of the above embodiments, a magnetic disk was described as an example, but the present invention is not limited to this, and removal of minute foreign substances and minute removal of minute foreign particles required for electronic device parts and the like. It is clear that the present invention is also effective when applied to the removal of minute foreign matter existing on the uneven surface.

Although alumina particles, silicon carbide, cerium oxide, and silicon nitride are used as the fine particles dispersed in the treatment liquid in the above-mentioned embodiments, the present invention is not limited to this and, for example, silicon oxide is used. , Zirconium oxide,
Alternatively, a mixture of these may be used.

Further, in the above embodiment, the fine particles are dispersed in the cleaning liquid, but the same effect can be obtained by processing the fine particles dispersed in a working liquid such as lapping. Furthermore, by performing the cleaning of the present invention according to each stage of the manufacturing process of the magnetic recording medium, it becomes possible to manufacture a magnetic recording medium having higher reliability.

[0030]

According to the present invention, the surface of the magnetic film is lapped.
After rubbing with a tape, the average particle size is 0.2 to 1.0
While supplying the cleaning liquid in which μm particles are dispersed,
Since it has a step of rubbing the surface of the film,
Therefore, fine shavings generated on the surface or
Adhesive matter adsorbed on the surface can be removed from the surface
It becomes Noh. Therefore, there is an effect that a magnetic recording medium having a high recording density and high reliability and a high surface cleanliness can be obtained. Moreover, that it has a effect that it is possible to easily produce such magnetic recording medium.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view showing a magnetic disk and a magnetic head to which the present invention is applied.

FIG. 2 is a model diagram showing a state in which shavings adhere to the surface of a magnetic film during magnetic disk finishing.

FIG. 3 is a perspective view showing a magnetic disk finishing method.

FIG. 4 is a diagram showing a mechanism for removing shavings adhering to the magnetic film.

FIG. 5 is a diagram showing a mechanism for removing shavings adhering to the magnetic film.

FIG. 6 is a schematic cross-sectional view showing a state where the magnetic disk obtained in the example of the present invention is housed in a magnetic recording device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Al substrate 2 Magnetic film 3 Alumina powder 4 Lubrication film 5 Magnetic head 6 Magnetic disk 7 Lapping tape 8 Rubber roller 9 Adhering shavings 10 Film thickness after application 11 Case 12 Support tool 13 Rotation drive mechanism 14 Voice Coil 15 Treatment liquid supply pipe 16 Fine particles dispersed in treatment liquid

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Yoshiki Kato 2880, Kozu, Odawara-shi, Kanagawa Hitachi Ltd. Odawara factory (72) Masaki Oura 2880, Kozu, Odawara, Kanagawa Hitachi Ltd. Odawara factory ( 72) Inventor Mitsuyoshi Otake, 292 Yoshida-cho, Totsuka-ku, Yokohama, Kanagawa, Japan, Production Engineering Research Laboratory, Hitachi, Ltd. (72) Masahiro Watanabe, 292 Yoshida-cho, Totsuka-ku, Yokohama, Kanagawa, Hitachi, Ltd. (56) References JP-A 2-169078 (JP, A) JP-A 53-67706 (JP, A) JP-A 49-60305 (JP, A) JP-A 62-75400 (JP, A) JP 61-148398 (JP, A) Special table 61-500351 (JP, A) JP 60-42440 (JP, B2)

Claims (2)

(57) [Claims] 1. The surface of a magnetic film is rubbed with a wrapping tape.
After removing, remove fine shavings adhering to the surface of the magnetic film
In order to achieve the above, a method of manufacturing a magnetic recording medium, which comprises a step of rubbing the surface of the magnetic film while supplying a cleaning liquid in which fine particles having an average particle diameter of 0.2 to 1.0 μm are dispersed. 2. The fine particles are aluminum oxide,
Is silicon carbide, or silicon oxide, or cerium oxide, or
Or silicon nitride, or zirconium oxide, or these
2. A magnetic material according to claim 1, characterized in that a mixture of
Recording medium manufacturing method.