JPS5939808B2 - Magnetic memory and its manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic storage body used in a magnetic storage device (magnetic disk device, magnetic drum device, etc.).

In general, there are two types of recording/reproducing methods for a magnetic storage device that includes a recording/reproducing magnetic head (hereinafter referred to as a head) and a magnetic storage body, as follows.

The first method is to set the head and the magnetic storage surface in contact at the start of operation, and then apply a required rotation to the magnetic storage to create an air space between the head and the magnetic storage surface. This is a method for recording and playing in this state. In this method, the rotation of the magnetic storage body stops at the end of the operation, and at this time the head and the surface of the magnetic storage body are in the same frictional state as at the start of the operation. The second method is to apply a required rotation to the magnetic storage body in advance, and then suddenly press the head onto the magnetic storage body surface to create a space equivalent to an air layer between the head and the magnetic storage body surface. This is a method of recording and playing back in the current state. Thus, in the first method, the head and the magnetic storage surface are in a frictional contact state at the beginning and end of the operation, and in the second method, the head and the magnetic storage surface are in a contact frictional state when the head is pressed against the magnetic storage surface. The frictional force generated between the head and the magnetic memory under these contact friction conditions can wear out the head and the magnetic memory and eventually cause damage to the head and the metal magnetic thin film medium. Furthermore, in the contact friction state, a slight change in the posture of the head may cause the load on the head to become uneven, causing scratches on the surface of the head and the magnetic storage body. Furthermore, during recording and reproduction, the head suddenly comes into contact with the magnetic storage body, and a large frictional force acts between the head and the magnetic storage body, which often causes the head and the magnetic storage body to be destroyed.

In order to protect the head and the magnetic memory from such contact friction, contact wear and contact breakage between the head and the magnetic memory, it is necessary to coat the surface of the magnetic memory with a protective coating. Conventionally, there is a method of coating a metal plated film (for example, Cr, Rh, Ni-P, etc.) as a protective film, or a method of forming an oxide by oxidizing the surface of a metal magnetic thin film medium to form a protective film. However, none of these methods is effective against the above-mentioned contact friction phenomenon. The present inventor has already proposed a protective coating made of polysilicic acid that eliminates these drawbacks (Japanese Patent Application No. 81201/1983). This protective film made of polysilicate sufficiently withstands the contact friction between the head and the magnetic memory, and also withstands sudden contact of the head with the magnetic memory, and also protects the metal magnetic thin film even under high temperature and high humidity conditions. The F! +
．． It has a state of

However, depending on the head, it is easy to draw dust between the head and the magnetic memory, and the dust acts as an abrasive and wears down the head and the magnetic memory, and the abrasion powder generated by this abrasion further damages the head and the magnetic memory. There are some things that wear out magnetic memory.

This phenomenon is more pronounced in heads with a tapered front. SUMMARY OF THE INVENTION An object of the present invention is to provide a magnetic memory having a protective coating that sufficiently protects a metal magnetic thin film medium even from the above-mentioned heads that tend to attract dust, and a method for manufacturing the same.

In the magnetic memory of the present invention, a mirror-polished non-magnetic disc-shaped substrate is coated with a metal magnetic thin film medium, and a silane coupling agent or a chromium-based coupling agent is coated on the metal magnetic thin film medium. A treatment layer is coated, and a polysilicate protective coating containing or not containing a silane coupling agent or a chromium-based coupling agent is coated thereon.

In the method for manufacturing a magnetic pupil of the present invention, a metal magnetic thin film medium is coated on a mirror-polished non-magnetic disc-shaped substrate;
Furthermore, an alcohol solution or aqueous solution of a silane coupling agent or a chromium-based coupling agent is applied thereon and dried to form a pretreatment layer. After performing such pretreatment, a solution containing a substance that can be polymerized to form a polysilicate film is applied thereon, and then the whole is heated to room temperature and the magnetic curvature of the metal magnetic thin film medium is heated. A magnetic memory body is manufactured by forming a polysilicate protective coating by firing at a temperature at which changes in the temperature do not affect recording and reproduction. in this case,
Examples of substances that can be polymerized to form a polysilicic acid film include tetraalkoxysilane, tetrahydroxysilane, a mixture thereof, silicon anlate, etc.
These are used in the form of an alcohol solution or the like.

The solution may also contain a silane coupling agent or a chromium-based coupling agent. Next, the present invention will be explained in detail with reference to the drawings.

The figure is a cross-sectional view showing one embodiment of the magnetic storage body of the present invention. In the figure, the magnetic storage body 6 of the present invention includes a non-magnetic disc-shaped base body composed of an alloy disc 1 and a non-magnetic alloy layer 2 coated thereon, and a polished surface of the non-magnetic alloy layer 2. a pretreatment layer 4 made of a silane coupling agent or a chromium-based coupling agent on the metal magnetic thin film medium 3, and a polysilicate or silane coupling agent formed thereon. Alternatively, it is composed of a protective coating 5 made of polysilicic acid containing a chromium-based coupling agent. The alloy disk 1 must have a surface with sufficiently small waviness (50 μm or less in the circumferential direction and 100 μm or less in the radial direction).

This is because if the waviness is large, the head floating above the magnetic storage body during recording and playback will not be able to follow the vertical movement of the magnetic storage body surface, and the distance between the head and the magnetic storage body will change, resulting in a change in the recording and playback area. Because it does. The non-magnetic field alloy layer coated on the alloy disk 1 by plating is mirror-finished to a surface roughness of 0.04 μm or less by mechanical polishing.
Note that if the alloy disk 1 is made of a metal that can be mirror-polished, the non-magnetic field alloy layer 2 will be unnecessary. A metal magnetic thin film medium 3 for high-density recording is coated on the non-magnetic field alloy layer 2 by plating. The protective coating 5, which sufficiently protects the metal magnetic thin film medium 3 from head contact or changes due to moisture or temperature, is made of polysilicic acid with or without a silane coupling agent or a chromium-based coupling agent. In order to improve the adhesion between the protective coating 5 made of silicic acid and the metal magnetic thin film medium 3, a very thin pretreatment layer 4 made of a silane coupling agent or a chromium-based coupling agent is provided between the two. It is a characteristic.

The pretreatment layer 4 is applied by discharging an aqueous or alcoholic solution of a silane coupling agent while rotating the base bodies 1, 2, and 3, and then dried for about 10 minutes to form a very thin layer (several 10 ) A uniform layer of silane coupling agent can be formed.

The silane coupling 1 mentioned here is represented by the following general formula. Represents a group having a functional group, such as CH2NH(CH2)2NH(CH2)3.

Examples of such silane coupling agents include the following: Vinyltrichlorosilane CH2-CHS
iCl3vinyltriethoxysilane CH2-CHSi
(0C2H5)3vinyl-tris(betamethoxyethoxy)silaneAlso, the exact chemical formula for this is not clear, but do;21゛'! ．． ′；．． 17. X'. γ-Funilinie Meng Z: Also includes polyaminosilanes that are roughly branched to form a matrix like the one shown below. Such a silane coupling agent layer firmly bonds to the underlying metal magnetic thin film 3 and the tetrahydroxysilane coated thereon, thereby tightly and tightly connecting the metal magnetic thin film 3 and the protective coating 5. I can do it.

Although silane-based coupling agents have been described above, chromium-based coupling agents also exist.

That is, it is a Werna type chromium complex with the following structure. 10→C(CI2) Here, R represents an organic compound having a functional group such as a methacrylic group, but any compound capable of reacting with the protective film may be used.

→ indicates coordination to chromium. Even in the case of a chromium-based coupling agent, the chromium and R portions can bond the metal magnetic field thin film 3 and the protective coating 5 with good adhesion. Examples of such chromium-based coupling agents include the following:

Such a chromium-based coupling agent can also be used to form a pretreatment layer in the same manner as the silane coupling agent described above.

Next, the present invention will be explained in detail by giving Examples and Comparative Examples.

Comparative Example Alloy Disk 1 had sufficiently small waviness (50 μm in each of the circumferential and radial directions) by lathe processing and thermal straightening.
A disk-shaped aluminum alloy base E finished with a surface having a surface of 100 μm or less) is plated with a nickel monophosphorus (Nip) alloy to a thickness of approximately 50 μm as the non-magnetic field alloy layer 2. The film was mechanically polished to a mirror finish with a surface roughness of 0.04 μm or less and a thickness of about 30 μm, and then a cobalt-nickel-monophosphorus (CO-Ni-P) alloy of about 0.0 mm was coated thereon as a metal magnetic thin film medium 3. 05μ
It was plated to a thickness of m.

Furthermore, this cobalt nickel monophosphorus (CO-Ni-P)
After thoroughly mixing a solution with the composition shown below on the alloy film, a coating of 500λ was applied using a spin coating method (rotation speed: 200 rpm).
A disc-shaped disc coated with a film thickness of
A magnetic disk was made by firing in an electric furnace for an hour. Example 1 In the same manner as in Comparative Example, a nickel to phosphorus film was coated on an aluminum alloy disc, and a cobalt-nickel phosphorus film was coated on the disc-shaped disc, and 0% of gasomaminopropyltrinitoxysilane was applied as a pretreatment liquid. .1% n-butyl alcohol solution is spin-coated and the spin is continued for 10 minutes to generate heat and dry the solvent to form a very thin pretreatment layer of gamma-aminopropyltriethoxysilane.

Thereafter, a polysilicic acid coating was formed to a thickness of about 500 mm on the gamma-aminopropyltriethoxysilane pretreatment layer in the same manner as in the comparative example, and a magnetic disk was prepared. Example 2 A pretreatment layer was formed in the same manner as in Example 1, except that a 01% n-butyl alcohol solution of polyaminosilane was used as the pretreatment liquid, and polysilicic acid was formed on it in the same manner as in the comparative example. A magnetic disk was prepared by forming a film with a thickness of 500 mm.

Example 3 A pretreatment layer was formed using the same method as in Example 1, except that a 0.1% aqueous solution of gamma glycidoxypropyltrimethoxysilane was used as the pretreatment liquid, and a pretreatment layer was formed on the pretreatment layer using the same method as in the comparative example. A magnetic disk was prepared by forming a polysilicate film with a thickness of 500 mm.

Example 4 A pretreatment layer was formed in the same manner as in Example 3, and the composition solution shown in the above was applied on the pretreatment layer in the same manner as in the conventional example to form a protective film with a thickness of 0.1 μm. The resulting product was used as a magnetic disk.

Example 5 A pretreatment layer was formed in the same manner as in Example 1, and the composition shown in the proviso was applied thereon in the same manner as in the conventional example. A magnetic disk was prepared by applying a liquid to form a protective film with a thickness of 0.1 μm.

Example 6 A pretreatment layer was formed in the same manner as in Example 1, except that a 0.1% n-bunal alcohol solution of methacrylate chromic chloride was used as the pretreatment liquid, and a pretreatment layer was formed thereon in the same manner as in the conventional example. However, the composition shown below? A magnetic disk was prepared by applying a liquid to form a protective film with a thickness of 0.1 μm.

Example 7 A pretreatment layer was formed in the same manner as in Example 6, and a protective film with a thickness of 0.1 μm was formed by applying the composition solution shown in the above in the same manner as in the conventional example. The resulting product was used as a magnetic disk.

'V'VJ-11tw [in
Rv = 3'V Using each of the magnetic disks shown in the comparative example and Examples 1 to 7, the recording and reproducing method in which the head and the magnetic disk surface are always in contact at the start and end of the operation, A repeated operation test was conducted 20,000 times using a head with a tapered front to easily pull in dirt, and it was found that about 30% of the friction marks on the head of the comparative magnetic disk had peeled off. In each of the magnetic disks of Examples 1 to 7, there was no peeling.

Moreover, for each of the magnetic disks of Examples 4, 5, 6, and 7, there was no peeling even after 25,000 repetitions. As shown in the comparative examples and Examples 1 to 7 above. A magnetic disk with a protective coating made of polysilicate with a pretreatment layer provided between it and the metal magnetic thin film medium has a wear-resistant enclosure for the head compared to a magnetic disk with a protective coating made of polysilicate without a pretreatment layer. It can be seen that this has improved.

In particular, it can be seen that the wear resistance of magnetic disks having a polysilicate protective coating containing a silane coupling agent or a chromium-based coupling agent on the pretreatment layer is further improved. In this way, it has been found that a pretreatment layer made of a silane coupling agent or a chromium-based coupling agent is very effective in improving the wear resistance of a protective coating made of polysilicic acid. It is clear that the same effect can be obtained even if a polymer compound other than polysilicic acid is used for the protective coating, as long as the polymer compound adheres sufficiently to the pretreatment layer.
Was the silane coupling agent or chromium-based coupling agent according to the present invention formed as a pretreatment layer? The wear resistance of polysilicate protective coatings with or without a silane coupling agent or chromium-based coupling agent formed thereon was improved compared to polysilicic acid protective coatings without this pretreatment, but other coatings did not. In other words, head crushing resistance,
There was no change in the lubrication enclosure, environmental resistance enclosure, magnetic enclosure of the underlying metal body, etc.

In addition, in the comparative examples and examples of the present invention, metal was used as the non-magnetic circle disk-shaped substrate, but it is clear that, for example, plastic or the like can also be used, and the type of the substrate does not matter.

[Brief explanation of drawings]

The figure is a sectional view of the magnetic storage body of the present invention. In the figure, 1 is an alloy disk. 2 is a mirror-finished non-magnetic alloy layer. 3 is a metal magnetic thin film medium. 4 is a pretreatment layer made of a silane coupling agent or a chromium-based coupling agent; 5 is a polysilicate protective coating containing or not containing a silane coupling agent or a chromium-based coupling agent; and 6 is a magnetic memory.

Claims (1)

[Claims] 1. A metal magnetic thin film medium is coated on a mirror-polished nonmagnetic disc-shaped substrate, a pretreatment layer is coated on the metal magnetic thin film medium, and a polysilicate protective layer is coated on the pretreatment layer. A magnetic memory body characterized by being coated with a film. 2. The magnetic memory according to claim 1, wherein the pretreatment layer is a silane coupling agent. 3. The magnetic memory according to claim 1, wherein the pretreatment layer is a chromium-based coupling agent. 4. The magnetic memory according to claim 1, which contains a silane coupling agent in the polysilicate protective coating coated on the pretreatment layer. 5. The magnetic memory according to claim 1, wherein the polysilicate protective coating coated on the pretreatment layer contains a chromium-based coupling agent. 6 A metal magnetic thin film medium is coated on a mirror-polished non-magnetic disk-shaped substrate, a pre-treatment agent solution is applied on top of this, and after this pre-treatment agent layer is dried, polymerization is subsequently applied on top of this. After applying a solution containing a substance capable of forming a polysilicate protective film, the whole is fired at a temperature above room temperature and at a temperature at which changes in the magnetic properties of the metal magnetic thin film medium do not affect recording and reproduction. A method for producing a magnetic memory, which comprises forming a polysilicate protective film. 7. The method for manufacturing a magnetic memory according to claim 6, wherein the pretreatment agent solution is a silane coupling agent solution. 8. The method for manufacturing a magnetic memory according to claim 6, wherein the pretreatment agent solution is a chromium-based coupling agent solution. 9. The method for manufacturing a magnetic memory according to claim 6, wherein the substance capable of forming the polysilicate protective film is tetraalkoxysilane, tetrahydroxysilane, or a mixture thereof. 10. The method for manufacturing a magnetic memory body according to claim 6, wherein the substance capable of forming the polysilicate protective film is silicon acylate. 11. The method for manufacturing a magnetic memory body according to claim 6, wherein the solution containing the substance capable of forming the polysilicate protective film contains a silane coupling agent. 12. The method of manufacturing a magnetic memory according to claim 6, wherein the solution containing the substance capable of forming the polysilicate protective film contains a chromium-based coupling agent.