JPH0654539B2 - Magnetic memory - Google Patents

Description

The present invention relates to a magnetic memory used in a magnetic memory (such as a magnetic disk device or a magnetic drum device) and a method for manufacturing the same.

(Prior Art and Problems Thereof) There are the following methods for recording / reproducing in a magnetic storage device that generally includes a recording / reproducing magnetic head (hereinafter referred to as a head) and a magnetic storage body. That is, after the head and the magnetic memory surface are set in contact with each other at the start of the operation, a space corresponding to an air layer is created between the head and the magnetic memory surface by applying a required rotation to the magnetic memory, and recording is performed in this state. This is a method of reproducing (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 body in these contact frictional states may wear the head and the magnetic storage body and eventually cause damage to the head and the magnetic medium. Further, in the contact friction state, a slight change in the posture of the head may make the load applied to the head non-uniform, and may scratch the surface of the head and the magnetic memory.

Further, the head and the magnetic memory body for a long time are contacted with each other and are attracted to each other, and are hard to separate from each other. In order to prevent the generation of scratches and adsorption, various side chain perfluoroalkyl polyethers or straight chain perfluoroalkyl polyethers having the structures shown below as shown in JP-A-52-49805 have been conventionally used. The above lubricants have been proposed, but none of them have been able to prevent the generation of scratches on the magnetic memory body by repeating the CSS many times because the lubricant layer is gradually removed by CSS. Also, the removed lubricant is thickly localized on the contact sliding surface,
There is also a drawback that it causes adsorption to the head.

(Object of the Invention) An object of the present invention is to provide a magnetic memory device having a lubricant having excellent lubricating properties, less head adsorption, and good adhesion to the surface of the magnetic memory device (that is, not deteriorating the head floating characteristic). To provide.

(Structure of the Invention) In order to achieve the above-mentioned object, the present invention provides that a magnetic medium is coated on an underlayer, and a perfluoroalkyl polymer structure is molecularly formed on the magnetic medium directly or through a protective film. It has a structure formed by coating the silicone contained in the chain or the mixture of the silicone and the lubricant.

In order to achieve the above-mentioned object, the present invention provides that a magnetic medium is coated on a base material, and further, a perfluoroalkyl polymer structure and a silicone chain are formed on the magnetic medium directly or through a protective film. It has a structure formed by coating a silicone bound with a divalent functional group or a mixture of the silicone and a lubricant.

(Operation) 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. The base body 1 is made of aluminum alloy or anodized alumite, Ni-P plated film, Cr,
Aluminum alloy coated with FeNi, Mo or W, or plastic such as polyester, polyimide, polyamide-imide, polysulfone, aromatic polyether, or Cr, F
e Metal such as Ni, Mo, W, or glass plate. Next, iron oxide such as Fe ₂ O ₄ , γ-Fe ₂ O ₃ or Co-Ni, Co-Ni-P, Co-Mn-P, Co-Ni- is used as the magnetic medium 2 on the underlayer 1. Mn-P, C
o-Re, Co-Mn-Re-P, Co-Cr, Co-V, Co-Pt, Co-Ni-Pt, Co-Pt-C
Coating with a metal or alloy such as r, Co-Pt-V, Co-Rh, Co-Ni-Mo or Co-Sm. Further, a silicone containing one or more perfluoroalkyl polymer structures in the molecular chain on the magnetic medium 2 or a mixture of the silicone and a lubricant, or a silicone in which the perfluoroalkyl polymer and the silicone chain are bound by a divalent functional group. Alternatively, it is covered with a lubricating layer 4 made of a mixture of the silicone and the lubricant.

Examples of the silicone containing one or more perfluoroalkyl polymer structure used in the present invention in the molecular chain include compounds having a structure represented by the following formula.

Where R _f and R _f ^* are Clx _{2l + 1} (l is an integer of 1 or more, X is H, F, Cl, Br, I) m, m ′ or n is an integer of 1 or more R _f ′ is a fluorinated carbon. hydrogen _{-C h (C h F 2k +} 1) 2h-
(H is an integer of 1 or more, k is 0 or an integer of 1 or more.) M or n is an integer of 1 or more RR ^* is C _i X _{2i + 1} (i is an integer of 1 or more, X is H or F) Or Cl, Br, I) J is -O-, -S-, NHCO-, -NHCOO-, -NH-, Further, it is a divalent functional group such as or a combination of different kinds thereof.

An example of the silicone in which the perfluoroalkyl polymer used in the present invention and the silicone chain are bound by a divalent functional group has a structure represented by the following formula.

Each symbol is the same as that expressed by the formula. J ″ is a divalent functional group similar to J or J ′.

J'is the above-mentioned divalent functional group excluding the same divalent functional group as J.

Also, a functional group may be included in the formula.

Valid functional groups _{-NCO, -SH, -SO 3 H,} -SO 3 M (M is N
a, K, Li), (J is an integer of 1 or more), _- CiH 2 iOH (i is 0 or an integer of 1 or _{more), NH 2, -CH 2 =} CH 2, -Si
(ChH _{2 h + 1} ) gX ₃ −g (h is an integer of 1 or more, g is 0, 1 or 2, X is Cl or —OH or OC _f H _{2f + 1} (f
As with the integer of 1 or more)), or _{-A-Si (ChH 2 h +} 1) gX 3 = g (h, g, X is described above. The A is C, H, N, O, S
Of one or more elements).

For example And so on.

Since the functional group G in the above general formula reacts strongly and adheres to the magnetic medium 2 or the protective film 3 formed on the magnetic medium 2 as shown in FIG. 2, it is not removed by the sliding of the head. .

Among the functional groups, this effect is --Si (ChH _{2h + 1} ) gX _3-g (h
Is an integer of 1 or more, g is 0, 1 or 2, X is Cl or -OH
Alternatively, silane represented by OC _f H _{2f + 1} (f is an integer of 1 or more) is most effective.

Due to such strong fixing ability and bottom surface energy, the effect of sustaining the lubricity that prevents scratches against sliding with the head and the head
Two effects, that is, an effect of preventing accumulation of the lubricating layer between the disks and an attraction of the head and the disk, can be obtained at the same time. The viscosity of the silicone can be changed from 10 to 100,000 cst depending on the molecular chain length and the type of functional group.

~ As an example of the lubricant mixed with the silicon represented by the formula, And _{- (- CF 2 CF 2 -O} -) - (- CF 2 -O -) - perfluoroalkyl polyether consisting of polytetrafluoroethylene, polytetrafluoroethylene telomer perfluoro carboxylic acids, perfluoroalkyl alcohol, Perfluorocarboxylic acid ester, fatty acid ester of perfluoroalcohol, perfluoroalkylalkoxysilane, fluorosilicone, perfluoroalkylsulfonic acid, ammonium perfluoroalkylsulfonate, aliphatic alkylalkoxysilane, higher fatty acid, higher fatty acid alcohol, higher fatty acid Ester, higher fatty acid amide fatty amine, unsaturated higher fatty acid, long chain aliphatic hydrocarbon, polyalkylene glycol, silicone oil, polyoxyethylene, neopentyl polyol ester, polyphenyl ether, etc.

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 lubricating layer 4. The protective film 3 is made of SiO ₂ , S
Silicon compounds such as i ₃ N ₄ , SiC or silicic acid polymer or Co
O, Co ₃ O ₄ , Co ₂ O ₃ , α−Fe ₂ O ₃ , Cr ₂ O ₃ , CrO ₃ , TiO ₂ , or ZrO ₂
Or metal oxide such as TiN, ZrN, CrN or TaN or metal carbide such as TiC, ZrC, CrC or TaC or W, Cr, Ir, NiP, Ru, Rh, Mn, Mo, Os or Ta Alternatively, a metal or alloy such as an alloy thereof is used.

Both of them react well with the lubricant 4 and firmly adhere to the lubricant layer 4
Can hold. Particularly, nickel oxide, cobalt oxide, or SiO ₂ has a remarkable effect.

After coating the lubricating layer 4, it may be baked at 100 to 300 ° C.

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 .mu.m on a base body 1 which was coated with a nickel-phosphorus plating film and had a surface finish of 0.02 .mu.m and mirror-finished.
Next, a protective film 3 is formed on the magnetic medium 2 as a protective film 3 of JP-A-52-208.
The polysilicic acid (silicic acid polymer) as shown in Japanese Patent Publication No. 04 is coated by a spin coating method. Next, a silicone shown below as a lubricating layer 4 is formed on the protective film 3. Here, m = 10 and n = 10.

Was coated with a 0.1 wt% trifluorotrichloroethane (hereinafter referred to as Freon) solution by a spin coating method to prepare a magnetic disk. When this magnetic disk was evaluated by the evaluation method described below, it was confirmed that it had excellent durability.

Example 2 A magnetic disk was prepared in the same manner as in Example 1 except that the lubricating layer 4 was made of silicone having the following structure.

Here, m = 10 and n = 10.

Example 3 A magnetic disk was prepared in the same manner as in Example 1 except that the lubricating layer 4 was made of silicone having the following structure.

Here, m = 10 and n = 20.

Example 4 A magnetic disk was prepared in the same manner as in Example 1 except that the lubricating layer 4 was made of silicone having the following structure.

Here, m = 10 and n = 50.

Example 5 A magnetic disk was manufactured in the same manner as in Example 1 except that silicone having the following structure was used as the lubricating layer 4.

Here, m = 10 and n = 20.

Example 6 A magnetic disk was prepared in the same manner as in Example 1, except that 500 L of NiP was plated as the protective film 3 as the lubricating layer 4 and then baked at 280 ° C. to form NiO on the surface.

Example 7 Same as Example 3, except that SiO ₂ is 200Å as the protective film 3.
A magnetic disk was prepared by coating by sputtering.

Example 8 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 a lubricating layer similar to that in Example 7 was coated thereon as the lubricating layer 4.

Example 9 Same as Example 16 except that γ-Fe ₂ O ₃ was used as the magnetic medium 2.
Was coated by a sputtering method to prepare a magnetic disk.

Example 10 A magnetic disk was manufactured in the same manner as in Example 1 except that silicone having the following structure was used as the lubricating layer 4.

Here, m is 15.

Example 11 A magnetic disk was prepared in the same manner as in Example 1 except that silicone having the following structure was used as the lubricating layer 4.

Here, m is 10 Example 12 A magnetic disk was manufactured in the same manner as in Example 1 except that silicone having the following structure was used as the lubricating layer 4.

Here, m is 5.

Example 13 A magnetic disk was prepared in the same manner as in Example 1 except that the lubricating layer 4 was made of silicone having the following structure.

Example 14 A magnetic disk was manufactured in the same manner as in Example 1 except that the lubricating layer 4 was made of silicone having the following structure.

Comparative Example 1 A magnetic disk was prepared in the same manner as in Example 1 except that the protective film 3 was coated with perfluoroalkylpolyether having the following structure as the lubricating layer 4.

n = 30 to 50 Comparative Example 2 A magnetic disk was prepared in the same manner as in Example 1, except that the protective film 3 was coated with perfluoroalkyl polyether having the following structure as the lubricating layer 4.

_{F 3 CC 2 F 4 O m} CF 2 -O n CF 3 m = n = 20~30 Al 2 O 3 · TiC load 150g by using the magnetic disk shown in Examples 11-14 and Comparative Examples 1 and 2 Using a head slider having a core made of a material, a contact wear stop (CSS) repeated wear test was repeated many times, and the critical film thickness at which head adsorption started was measured. The results shown in the following table were obtained.

From the results in the above table, it was found that the durability of the silicones of Examples 1 to 14 was remarkably improved as compared with the perfluoroalkyl polyethers of Comparative Examples 1 and 2.

Since Examples 8 and 9 have no protective film, they have poorer durability than the other Examples, but they have better durability than the Comparative Examples, and the critical film thickness of the Comparative Examples Fluoroalkyl polyether starts head adsorption even with a very small film thickness, but the silicones of Examples 1 to 14 do not cause head adsorption up to a larger film thickness of 50 to 120Å, and have a large margin. I understand.

(Effects of the Invention) As described above, it has been found that the magnetic memory body of the present invention is excellent in durability, is less likely to cause head adsorption, and can dramatically improve the reliability of the magnetic disk device.

Although the magnetic disk is described in the embodiments of the present invention, it is obvious that the present invention is also effective for a floppy disk, a magnetic tape, and a magnetic card.

[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.

Claims (2)

[Claims] 1. A magnetic medium is coated on a substrate, and further,
A magnetic memory having a structure in which a silicone containing a perfluoroalkyl polymer structure in the molecular chain or a mixture of the silicone and a lubricant is coated on the magnetic medium directly or through a protective film. 2. A magnetic medium is coated on the underlayer, and further,
The magnetic medium has a structure in which a perfluoroalkyl polymer structure and a silicone chain bonded to a silicone chain with a divalent functional group or a mixture of the silicone and a lubricant is coated directly or through a protective film. Characteristic magnetic memory.