JPS6243824A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To obtain a magnetic recording medium having excellent durability against sliding with a magnetic head by forming a protective film into the structure consisting in dispersing a wear resisting agent into silicon oxide. CONSTITUTION:The protective film is made into the structure consisting in dispersion one or several among the wear-resisting agents including Al2O3, SiC, Si3N4, TiC, Cr2O3, Ta2O5, etc. into the silicon oxide having the compsn. SiOx (1<=x<=2) and is formed on a thin ferromagnetic metallic film by a method such as sputtering using a mixture composed of SiO2 and wear-resisting agents as a target, vacuum deposition using the mixture composed of SiO2 and wear- resisting agents as an evaporating source or co-vapor deposition using SiO2 and wear-resisting agents respectively as evaporating sources. The medium having the high durability can be obtd. even by coating a lubricating agent directly on the protective film but the much higher durability is obtd. by providing the surface treatment layer consisting of silane fluoride therebetween.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a metal thin film magnetic recording medium.

(Prior art) In recent years, various magnetic recording devices including flexible magnetic disk devices, audio magnetic tape devices, VTR magnetic tape devices, etc. are being improved in recording density and reliability. High recording density is mainly achieved by increasing the coercive force and thinning the magnetic layer of the magnetic recording medium (σ). Q) A Co-Ni alloy that is suitable for thin J1 heat and is easier to increase coercive force than a so-called grave magnetic recording medium with a structure in which Q) is coated on the medium.
Metal thin film magnetic recording media that use Co-Pt alloy evaporated films or S/(ivy films) are attracting attention.On the other hand, conventional longitudinal recording methods that record in the in-plane direction of such magnetic recording media In comparison, the perpendicular magnetic recording method, in which residual magnetization is formed in the thickness direction of the magnetic recording medium to record the six characters of the first word, has recently become the focus of attention because of its ability to obtain high recording density. -C As a recording medium, a deposited film or a sputtered film of a Co-Cr alloy is used. In order to put it into practical use as a magnetic recording medium, it is necessary to improve its mechanical durability.In general, in flexible magnetic disk devices and magnetic tape devices, there is a state of boundary friction between the magnetic recording medium and the magnetic head when recording and reproducing signals. This is a harsher operating condition than that of a rigid magnetic disk, in which the magnetic head is suspended above the medium by an air flow during signal o)6 recording and reproduction.For these reasons, reliability of the magnetic recording device is achieved. To achieve this, the magnetic recording medium is required to have mechanical durability against sliding with the magnetic head.

US%tFf3109741 The use of silicon monoxide vaporized film to improve the mechanical durability of magnetic recording media
No. i, same: (No. 353166, JP-A-50-80102
The number is 1) known.

(Problem to be solved by the invention) However, silicon [the chemical's retention is 1) in terms of machinability and durability.
U].

It turns out it's still not enough. It is also known that hydrolyzed products of alkoxysilanes can be used as protective agents (JP-A II <152-2 (184-1)).
but.

Silicon oxide has unreliable properties like 1), and must be coated as a bath liquid, so it is a good product. There is a IIJ flexible sulfur magnetic 6D recording medium using shellfish.

Furthermore, there is a method of forming an interlayer ('-) on the surface of the magnetic recording medium (Q) to increase mechanical durability. h b ,
Conventionally, there have been proposals for 7+1/1, perfluorinated alkyl polyetheryl or chlorinated wolfberry/oil, etc. θ) oils.

Although solid lubricants such as polytetranoroloethylene, polyester, carbon, or molybdenum disulfide are known, they have weak adhesion to the surface of the magnetic recording medium, so they do not adhere well to the head. There was a problem that the lubricant easily peeled off due to sliding, and sufficient durability could not be obtained. The same holds true when forming an agent.

An object of the present invention is to provide a metal thin film magnetic recording medium with excellent mechanical durability.

(Means for Solving the Problems) The magnetic recording medium of the present invention includes a ferromagnetic metal thin film formed on a nonmagnetic substrate, a protective film formed on the ferromagnetic metal thin film,
Furthermore, the magnetic recording medium having a lubricating layer on the protective film is characterized in that the protective film has a structure in which an anti-wear agent is dispersed in silicon oxide. Further, by providing a surface treatment layer containing fluorinated silane between the protective film and the lubricating layer, a magnetic recording medium with even higher durability can be obtained.

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

@Figure 1 is a partial cross-sectional view showing an example of the magnetic recording medium of the second invention, where l is a non-magnetic substrate, 2 is a ferromagnetic metal thin film,
3 is a protective film, 4 is a surface treatment layer made of fluorinated silane,
5 is a lubricating layer.

Non-magnetic substrates according to the invention include cellulose acetate, nitrocellulose, polyamide, polymethyl methacrylate, polytrifluoroethylene.

Polytrifluoroethylene, ethylene, propylene, etc.α
- Organic polymer films such as olefin polymers or copolymers, vinyl chloride polymers or copolymers, vinylidene chloride, polycarbonate, polyimide, polyethylene terephthalate, polyethylene naphthalate, etc. A/gold Alloy ceramics, SL glass, etc. are used. The ferromagnetic metal thin film according to the present invention is made of Pe,
Co, NisoQ]Other ferromagnetic metals, or)'e
-Co, Fe-Ni.

Co-Ni, Fe-Nd, re-Cr, Fe
-Si, Co-Cr, Co-V, Co-Sm,
Co-Pt, Co-P, Co-Ni-1),
Ferromagnetic alloys such as Fe-Cr-Co or additives are formed into thin films using vacuum evaporation, sputtering, ion blating, electroplating, electroless plating, or other methods. It is.

The thickness of the ferromagnetic metal thin film is preferably about 2 μm. The protective film is made of Al2O, 8iC, Si3N4, . T
ie, Cr20B.

It has a structure in which one or several of anti-wear agents such as Ta, O, etc. and the above anti-wear agent a
) Sputtering targeting the mixture, S10.
Vacuum deposition using a mixture of and the above-mentioned anti-wear agent as a deposition source, 8
i0. The protective film is formed on a ferromagnetic metal thin film by a method such as co-evaporation using each of the above anti-wear agents as an evaporation source.The anti-wear agent is eutectic in silicon oxide, and the anti-wear agent is dispersed. Because of its structure, it has excellent wear resistance and high sliding durability. The effect remains the same whether the protective film is amorphous or dermatome.

The thickness of the protective film is preferably in the range of IOX to 100OX.

Although a highly durable medium can be obtained by applying a lubricant directly onto the vk-retaining film, even higher durability can be obtained by providing a surface treatment layer that is more durable than fluorinated silane between the lubricants and the lubricant.

As a fluorinated silane, (cnF2n+1)msI(R)4-m... River, River, Old... 1lln is a positive integer from 1 to 30, m is a positive integer from 1 to 3. Integer (cn p 2 n+ 1(ci(2)m)z s
I(R), i-s・・・・・・・・・・-fill
n, m are positive type numbers from 1 to 30, l is a positive integer from 1 to 3 (CnF2n+, O(CH3)m), 5t(R)4. −
・・・・−・−flllln, m is a positive integer from 1 to 301] A compound that can be expressed by a general formula such as a positive integer from integer ast#il to 3 is suitable. Here, R is OCH3g OCt Hg HOC@ Hy r OC
Alkoxy group such as 4Hg t OCa Ht I or CH3*C! HI C3H? t C4H9+'4HI
It is an alkyl group such as +, or a hydrogen group such as F, C/, Br, I, etc.

The above fluorinated silane is directly applied to the surface of the protective film.
It is applied as a solution of U-alcohol, keto/ester, halogenated aliphatic hydrocarbon, etc. by a coating method such as a dipping method, a spray method, a roller coating method, or a spin cord method. At that time), the hydrogenated silane is hydrolyzed by moisture in the air or adsorbed water on the surface of the protective film, and reacts and bonds strongly with the surface of the protective film, resulting in excellent adhesion. Although this is observed to some extent even in the case of metals and compounds other than silicon oxide, when silicon oxide is included in the protective film, the reactivity is high because it is the same substance as the silane at the end of the fluorinated silane.

A strong bond is created, achieving significantly higher adhesion than other substrates.

On the other hand, the CnF2n+1 portion of the fluorinated silane is oriented on the surface of the magnetic recording medium, that is, the surface that rubs against the head.

As described above, a surface treatment layer is formed on the protective film that has strong adhesion to the base and has water repellency and lubricity specific to fluorocarbon. By further forming a lubricating layer on the film or surface treatment layer,
Sufficient durability can be obtained for practical use. As a lubricating layer, hydrocarbon lubricants such as fatty acids and metal soaps, lubricating oils such as silicone oil, 70-ro silicone oil, and per-70-ro alkyl polyether, tetrafluoroethylene low polymers, carbon, molybdenum disulfide, etc. A solid lubricant or a mixture thereof is applied directly or dissolved or dispersed in an appropriate solvent onto the surface treatment layer by a coating method such as a dipping method, a spray method, a vapor deposition method, a roller coating method, or a spin code method. Form.

The metal thin film magnetic recording medium with the above structure has a protective layer with high wear resistance, and a lubricating layer on top of it that has excellent adhesion to the substrate, so it is sufficient to withstand long-term sliding by the head. It has excellent durability.

Next, examples will be shown to further explain the present invention in detail.0 (Example) A CoCr ferromagnetic film with a thickness of 3000X was prepared by sputtering in Ar gas using a CoCr alloy as a target on a polyester film with a thickness of 50 μm. A thin metal film was formed. Next, a protective film shown in the table, a surface treatment layer using fluorinated silane, and a lubricating layer were formed on the protective film of Examples 1 to 7, respectively, using a composite target having the composition ratio shown in the table. It was fabricated by sputtering in Ar gas. The surface treatment layer was formed by applying 3 0.5% Isoprop+'ff Vyl alcohol common solution of the fluorinated silane shown in the table and drying. The lubricating layer is 0 for side chain polyperfluoropurkyl ether and linear polyperfluoropurkyl ether.
．． 0.05% for 1-line trifluorotrichloroethane solution, nato 2-fluoroethylene low polymer; 0.05% for trifluorotrichloroethane dispersion, monostearin.
A 1% toluene solution was applied onto each surface treatment layer and then dried. Next, Comparative Examples 1 and 2 were fabricated using S2O as a protective film using the same process.

Examples 1 to 7 above. Comparative example 1. 2 into the shape of a 51/4-inch diameter flexible disk (1) mounted on a 5'/4-inch flexible magnetic disk drive and rotated with the head loaded, causing scratches on the surface of the disk by the head. The durability of the discs was compared by measuring the number of rotations until this occurred. The results are shown in Table 1. According to Table 1, by adopting the structure of the present invention, the protective film thickness, fluorinated thinner, moisture ζ1h1[regardless of the type, only silicide U) protection) compared to 庚)%
It can be seen that 1a1) Kubo will be realized. In the retention film, even if the amount of 1) 1) abrasion 1 is more than the silicon oxide, the effect will not be affected, but if it increases too much, the adhesion with the treated J- or II 4 slipping layer will deteriorate. A hateful heart.

(Effects of the Invention) As described above, according to the present invention, a protective film formed on a ferromagnetic metal thin film formed on a non-magnetic substrate, and a protective film formed on the protective film. In a magnetic recording medium having a surface treatment layer containing fluorinated silane formed on the surface and a lubricant layer further formed on the surface treatment layer, the protective film has a structure in which an anti-wear agent is dispersed in silicon oxide. This has the effect that a magnetic recording medium with excellent durability against sliding with a magnetic head can be obtained.

[Brief explanation of the drawing]

Figure 1 is a partial sectional view of a magnetic recording medium according to the present invention. In the figure, 1 is a non-magnetic substrate, 2 is a ferromagnetic metal thin film, 3 is a protective film, and 4 is a surface treatment layer made of fluorinated silane. , 5 is a lubricating layer. Figure 1

Claims (2)

[Claims] (1) In a magnetic recording medium having a ferromagnetic metal thin film formed on a nonmagnetic substrate, a protective film formed on the ferromagnetic metal thin film, and a lubricant layer on the protective film layer, the protective film is oxidized. A magnetic recording medium characterized by a structure in which an anti-wear agent is dispersed in silicon. (2) A ferromagnetic metal thin film formed on a nonmagnetic substrate, a protective film formed on the ferromagnetic metal thin film, a surface treatment layer containing fluorinated silane formed on the protective film, and further the surface treatment. 1. A magnetic recording medium having a lubricating layer formed on the protective film, wherein the protective film has a structure in which an anti-wear agent is dispersed in silicon oxide.