JPH0612567B2 - Hard magnetic disk and manufacturing method thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a hard magnetic disk (hereinafter referred to as a “magnetic storage body”) used in a magnetic storage device (such as a magnetic disk device or a magnetic drum device), and The manufacturing method is related.

(Prior Art and Problems Thereof) There are the following methods for recording / reproducing methods of a magnetic storage device which generally comprises a recording / reproducing magnetic head (hereinafter referred to as a head) and a magnetic storage body. That is, after the head and the surface of the magnetic storage body are set in contact with each other at the start of the operation, a required rotation is applied to the magnetic storage body to create a space corresponding to an air layer between the head and the surface of the magnetic storage body so as to float. This is a method of recording / reproducing in a state (contact start / stop method; hereinafter referred to as CSS method). In this method, the rotation of the magnetic storage body is stopped at the end of the operation, and at this time, the head and the surface of the magnetic storage body are in the contact friction state as at the start of the operation.

The frictional force generated between the head and the magnetic storage medium in these contact frictional states may wear the head and the magnetic storage medium and eventually cause damage to the head and the magnetic medium. Also, in the above-mentioned floating state, a slight change in the posture of the head due to dust or the like may make the load applied to the head non-uniform and scratch the head and the surface of the magnetic memory body (hereinafter referred to as head crush).

Further, when the head and the magnetic memory body are in contact for a long time, the lubricant between the head and the magnetic memory body sticks to each other and makes it difficult to separate them. Various liquid lubricants have been proposed in order to prevent the generation and the adsorption of the scratches, but none of them has been able to prevent the generation of the scratches and the adsorption of the head and the disk at the same time.

(Object of the Invention) It is an object of the present invention to provide a magnetic memory body capable of preventing the occurrence of scratches due to CSS or head crash and at the same time preventing the adsorption of the head and the disk, and a manufacturing method thereof.

(Structure of the Invention) In order to achieve the above-mentioned object, the present invention comprises coating a magnetic medium on an underlayer, and further coating a lubricant on the magnetic medium directly or through a protective film, The film thickness of the lubricant is zero only in the sliding area of the head or thinner than other portions.

Further, in order to achieve the above object, the present invention covers a magnetic medium on the underlayer, and further coats a lubricant on the magnetic medium directly or through a protective film, thereby sliding the head. The film thickness of the lubricant is zero or thinner than other parts by wiping off only the part with the head.

Further, in order to achieve the above-mentioned object, the present invention covers a magnetic medium on the underlayer, and further coats a lubricant on the magnetic medium directly or through a protective film, thereby sliding the head. The lubricant is evaporated by irradiating electromagnetic waves only on the part to make the film thickness of the lubricant zero or thinner than other parts.

(Detailed Description of Configuration) Next, the present invention will be described in detail with reference to the drawings. FIG. 1 is a partial cross-sectional view of a magnetic memory body of the present invention, in which the base body 1 is made of aluminum alloy, anodized alumite, Ni-P plated film, C
Aluminum alloy coated with r, FeNi, Mo or W, or plastic such as polyester, polyimide, polyamide-imide, polysafone, aromatic polyether, or Cr,
It is a metal such as FeNi, Mo, W or a glass plate. Next, iron oxide such as Fe ₃ O ₄ , γ-Fe ₂ O ₃ or Co-Ni, CoNi-P, Co-Mn-P, Co- is used as the magnetic medium 2 on the underlayer 1.
Ni-Mn-P, Co-Re, Co-Mn-Re-P, Co-Cr, Co-
V, Co-Pt, Co-Ni-Pt, Co-Pt-Cr, Co-Pt-V, Co
Coat with a metal or alloy such as -Rh, Co-Ni-Mo or Co-Sm. Further, a lubricating layer 4 is coated on the magnetic medium 2.

The lubricating layer 4 used in the present invention is thickly coated from the inner circumference to the outer circumference of the magnetic disk as shown in FIG. 3, or
As shown in FIG. 4, only the sliding region 6 (CSS region) of the head has no lubricating layer or is thinner than other portions. Such a lubricating layer 4 is formed as follows. That is, a thick lubricant layer 4 is formed from the inner circumference to the outer circumference of the magnetic disk by applying a solvent diluted solution of a lubricant onto the magnetic medium 2 while rotating the magnetic disk. In this case, it is necessary to provide the sliding area 6 (CSS area) of the head on the inner peripheral side of the magnetic disk.

Further, the sliding area of the head can be provided at any place. That is, in addition to the spin coating method as described above, a spray method of applying a lubricant solution by spraying, an immersion method of immersing a magnetic disk in a lubricant solution, or a vapor deposition method in which a lubricant is heated and evaporated in a vacuum or in the atmosphere to be attached. After forming the lubricating layer 4 by the method, etc., the sliding area 6 (CSS area) of the head
Only the wiping head wipes off the lubrication layer to remove the lubrication layer at all or to a thin film thickness. A magnetic head may be used as the wiping head used here, but fibers such as cloth may also be used. Further, the wiping head can be efficiently wiped by including a solvent of the lubricant.

Further, by irradiating only the sliding area 6 (CSS area) of the head of the lubricating layer 4 with an electromagnetic wave from ultraviolet rays to infrared rays, the lubricating layer is decomposed or evaporated to completely remove the lubricating layer or to reduce the film thickness. Can be done.

A lamp may be used as the electromagnetic wave used here, but a laser beam can be used to more efficiently remove or thin the lubricating layer. In addition to electromagnetic waves, high-energy electromagnetic liquids such as electron beams, ion beams, particle beams, γ-rays, and X-rays can be used, but they are not common in terms of mass productivity and safety. Further, the lubricant used in the lubricating layer 4 used in the present invention is perfluoroalkyl polyether, silicone oil, fluorine modified, silicone oil (fluorosilicone), polyalkylene glycol, polytrifluoride, low ethylene monochloride polymer, polyoxy Liquid lubricants such as ethylene, neopentyl polyol fatty acid ester, long chain hydrocarbon, perfluoroalkyl polyether derivative, polyphenyl ether and the like can be used.

FIG. 2 is a partial sectional view of another magnetic memory body of the present invention.
In FIG. 2, the base 1, the magnetic medium 2, and the lubricating layer 4 are the same as those in FIG. 1, but a protective film is coated between the magnetic medium 2 and the polyether 4. The protective film 3 is Si
O _2, Si ₃ N _4, silicon compounds such as SiC or silicic acid polymer or _{CoO, Co 3 O 4, Co} 2 O 3, α-Fe 2 O 3, Cr 2 O 3, CrO 3, TiO
₂ , or metal oxide such as ZrO ₂ or TiN, ZrN, CrN or
Metal nitride such as TaN or TiC, ZrC, or CrC or TaC
Metal carbides such as or W, Cr, Ir, NiP, Ru, Rh, M
Metals or alloys such as n, Mo, Os or Ta or alloys thereof are used.

As described above, by making the thickness of the lubricating layer of the sliding portion of the head 0 or thinner than the others, it is possible to prevent the head / disk from adsorbing due to the contact of the head and to prevent the head crash in the flying area (data reading / writing area) of the head. Can be prevented. An appropriate film thickness of the lubricating layer on the sliding portion of the head is about 0 to 100Å depending on the lubricant used. Also, the film thickness of the lubrication layer in the flying area of the head is 50 to 1000Å from the distance between the head and the magnetic disk when reading and writing data.
The degree is appropriate.

Next, the present invention will be described in detail with reference to examples.

Example 1 A cobalt-nickel-phosphorus alloy as a magnetic medium 2 was plated to a thickness of 0.05 μm on a disk-shaped disk substrate 1 which was coated with a nickel-phosphorus plating film and mirror-finished to a surface roughness of 0.02 μm. . Next, a polysilicic acid (silicic acid polymer) as disclosed in JP-A-52-20804 is coated on the magnetic medium 2 as a protective film 3 by a spin coating method. Next, on this protective film 3, 0.1% of perfluoroalkylpolyether was formed.
A 1% by weight trifluorotrigloethane (Freon) solution was applied on a disk-shaped disk coated with the protective film 3 which was rotated at 400 rpm, and a lubricating layer 4 was coated to form a hard magnetic disk (hereinafter referred to as "magnetic field"). Disc.).

The thickness of the lubricating layer 4 was thicker from the inner circumference to the outer circumference as shown in FIG. 3, the sliding area (CSS area) of the head was 20Å, and the flying area of the head was 30 to 100Å.

Example 2 As Example 1, except that a 1% by weight Freon solution of perfluoroalkyl polyether was applied as the lubricating layer 4,
The sliding area of the head was slid by a magnetic head at 100 rpm for 30 seconds and wiped to produce a magnetic disk. As a result, the film thickness of the lubricating layer in the sliding area of the head was 30Å, but the flying area of the head was 100 to 500Å.

Example 3 A magnetic disk was prepared in the same manner as in Example 2, except that the head sliding area of the lubricating layer 4 was irradiated with a 200 W carbon dioxide laser beam on a disk-shaped disk rotating at 100 rPm for 1 minute.
As a result, the thickness of the lubricating layer in the sliding area of the head was 50Å, but the flying area of the head was 100 to 500Å.

Example 4 In the same manner as in Example 2, except that the sliding area of the head of the lubricating layer 4 was pressed against a disk-shaped disk rotating at 600 rpm with a cloth containing freon to remove the lubricating layer. As a result, the film thickness of the lubricating layer in the sliding area of the head was 0Å, but the flying area of the head was 100 to 500Å.

Example 5 Similar to Example 1, except that the disk-shaped disc having the protective film 3 was immersed in the solution, that is, one of the fluorine-modified silicone oil.
% Benzene solution and then pulled up and dried to coat the lubricating layer 4. Then, the sliding area of the head was pressed against a disk-shaped disk rotating at 100 rpm with a cloth containing benzene to remove the lubricating layer. As a result, the thickness of the lubricating layer in the sliding area of the head was 10Å, but the flying area of the head was 500
It was Å.

Example 6 In the same manner as in Example 1, except that 0.5% benzene solution of dimethylpolysiloxane (silicone oil) was spray-coated on the protective film 3 to coat the lubricating layer 4.

Then, the lubricating layer in the sliding area of the head was removed by the same method as in Example 5. As a result, the thickness of the lubricating layer in the sliding area of the head was 10Å, but the flying area of the head was 300 to 1000Å.
Met.

Example 7 In the same manner as in Example 1, except that the disc-shaped disk having the protective film 3 was treated with neopentyl polyol fatty acid ester at 10 ⁻³ to
The lubricating layer 4 was formed by leaving it in vapor evaporated by heating at 150 ° C. for 2 minutes.

Then, the lubricating layer in the sliding area of the head was removed by the same method as in Example 5. As a result, the thickness of the lubricating layer in the sliding area of the head was 100Å, but the flying area of the head was 1000Å.

Example 8 A magnetic disk was prepared in the same manner as in Example 1, except that 500 P of NiP was plated as the protective film 3 and then baked at 280 ° C. to form NiO on the surface.

Example 9 Same as Example 1, except that SiO ₂ is 200Å as the protective film 3.
A magnetic disk was prepared by coating by sputtering.

Example 10 A magnetic disk was prepared in the same manner as in Example 1, except that a CoCr alloy was coated as the magnetic medium 2 by the sputtering method and the lubricating layer 4 was coated thereon in the same manner as in Example 5.

Example 11 Same as Example 10, except that the magnetic medium 2 was γ-Fe.
_2o3 was coated by a sputtering method to make a magnetic disk.

Comparative Example 1 Similar to Example 1, except that the lubricating layer 4 in the sliding area of the head was used.
Made a magnetic disk without removing.

Comparative Example 2 A magnetic disk was prepared in the same manner as in Example 5, except that it was immersed in a 0.001% benzene solution of fluorine-modified silicone oil, then pulled up and dried to form a lubricating layer. In this case, the thickness of the lubricating layer was 5Å both in the head sliding area and the head floating area.

Using the magnetic disks shown in Examples 1 to 11 and Comparative Examples 1 and 2, a magnetic head having an Al ₂ O ₃ TiC core with a load of 15 g was used to form the magnetic disk and the magnetic head at 70% humidity.
The adsorption force in the disk rotation direction between the magnetic disk and the magnetic head was measured after the head was brought into contact with the head sliding area in a static state at a temperature of 40 ° C. and left for 20 hours. In addition, the magnetic disk was rotated at 3600 rpm, the magnetic head was levitated at 0.2 μm in the head flying area (read / write area), and was levitated for a long time in a class 1 million dust atmosphere, and the time when the head crash occurred was measured. . The impact of a head crush was measured by applying a shock to a floating magnetic head with a small hammer considering the load, and the results shown in the following table were obtained.

From the results in the above table, the comparative example in which the thickness of the lubricating layer in the sliding region was large generated a large attraction force and caused the plastic deformation of the gimbal spring supporting the head. A magnetic disk with a thin lubricating layer had a small adsorption force. Further, in the comparative example in which the lubricating layer in the head flying region was thin, head crush occurred in a short time or at a low load, but Examples 1 to 11
It was found that the magnetic disk with a thick lubricating layer in the floating area of the disk can withstand head crush for a long time or under high load.

(Effects of the Invention) As described above, the magnetic disk having a thin lubricating layer in the sliding area of the head and a thick lubricating layer in the floating area of the head shown in Examples 1 to 11 has a strong resistance to head crash and at the same time as a head. It was found that the adsorption of the disk is unlikely to occur and the reliability of the magnetic disk device can be dramatically improved.

[Brief description of drawings]

1 and 2 are partial sectional views showing the present invention. 1 ... Substrate, 2 ... Magnetic medium, 3 ... Protective film, 4 ...
It is a lubricating layer. 3 and 4 are views showing an example of the present invention. 4 ... Lubrication layer, 5 ... Magnetic head, 6 ... Head stop area, 7 ... Head floating area, 8 ... Disk disk, 9
The center of rotation.

Claims (4)

[Claims] 1. A magnetic medium is coated on a substrate, and further,
A hard magnetic disk characterized in that a lubricant is coated on the magnetic medium directly or via a protective film, and the film thickness of the lubricant is zero only in a sliding region of the head or thinner than other portions. 2. The hard magnetic disk according to claim 1, wherein the sliding area of the head is located inside. 3. A magnetic medium is coated on the underlayer, and a lubricant is further coated on the magnetic medium directly or through a protective film, and only the sliding portion of the head is wiped off by the head for lubrication. A method for manufacturing a hard magnetic disk, wherein the film thickness of the agent is zero or thinner than other portions. 4. A magnetic medium is coated on the underlayer, and a lubricant is further coated on the magnetic medium directly or through a protective film, and only the sliding portion of the head is irradiated with electromagnetic waves for lubrication. A method for manufacturing a hard magnetic disk, characterized in that the lubricant is evaporated to make the film thickness of the lubricant zero or thinner than other portions.