JPS62159330A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To improve slipperiness and durability and to maintain the same for a long period of time by forming a silicon compd.-contg. layer on a thin ferromagnetic film provided on a nonmagnetic substrate and forming a higher aliphat. amine-contg. layer thereon. CONSTITUTION:This recording medium is formed by forming the silicon compd.- contg. layer 3 on the thin ferromagnetic film 2 and providing the higher aliphat. amine-contg. layer 4 thereon. the silicon compd. which can be used is silica.alumina or silica.nickel oxide. The ratio of the silica in the silica, alumina or silica.nickel oxide is preferably 40-90% silica in molar ratio and the compd. having such ratio adsorbs the higher aliphat. amine strongly. The film thickness of the silicon compd.-contg. layer 3 is adequately 5-40nm. Output is decreased by a spacing loss in the stage of reproducing signals if the film thickness is larger than 50nm and there is an easy tendency to pinholing if the film thickness is smaller than 5nm.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a high recording density magnetic recording medium used in the information industry and the like.

Conventional technology In place of conventional coating-type magnetic recording media, magnetic recording media in which a ferromagnetic metal thin film is provided on a non-magnetic substrate by methods such as plating, sputtering, vacuum evaporation, and ion blating are available. , is being researched as a magnetic recording medium for high recording density.

However, the magnetic recording medium using the ferromagnetic metal thin film produced by the method described above has problems in its wear resistance and running properties.

In the process of recording and reproducing magnetic signals, magnetic recording media
It is placed in high-speed relative motion with the magnetic head.

At this time, the magnetic recording medium must run smoothly and stably. Furthermore, wear and damage due to contact with the magnetic head must not occur.

However, the ferromagnetic metal thin film made by the method described above cannot withstand the harsh conditions of the magnetic recording and reproducing process, and the running becomes unstable due to the friction of the magnetic head, etc., and the ferromagnetic metal thin film made by the method described above cannot withstand the harsh conditions of the magnetic recording and reproducing process. In such cases, the output may be significantly reduced due to wear, damage, and generation of wear debris.

Therefore, it has been proposed to form a film made of a monolinear saturated alkylamine as a protective film on a ferromagnetic metal thin film (Japanese Patent Application Laid-Open No. 597119538).

Problems to be Solved by the Invention However, in this case, although the initial lubricity is slightly improved, the durability of the lubricity is lacking. This is because the bond between the monolinear saturated alkylamine and the magnetic film is weak, at the level of physical adsorption, and the monolinear saturated alkylamine is scraped off by a magnetic head or the like that moves while the vehicle is running.

The present invention has been made in view of these points, and an object of the present invention is to provide a magnetic recording medium with excellent slipperiness and durability.

Means for Solving the Problems A silicon compound-containing layer is formed on a ferromagnetic metal thin film provided on a non-magnetic substrate, and a higher aliphatic amine-containing layer is formed thereon.

Function Silicon compounds such as silica/alumina or silica/nickel oxide are strongly acidic compounds.

Therefore, higher aliphatic amines, which are basic compounds, are strongly chemically adsorbed onto the silicon compound. As a result, in magnetic recording media in which a silicon compound-containing layer is formed and a higher aliphatic amine-containing layer is formed on top of the layer, the higher aliphatic amine, which is a lubricant, is scraped off from the magnetic surface even when rubbed by a magnetic head, etc. Therefore, a magnetic recording medium with excellent slipperiness and durability can be obtained.

The embodiment diagram is a cross-sectional view of the magnetic recording medium of the present invention. In the figure, 1 is a nonmagnetic substrate, 2 is a ferromagnetic metal thin film, 3 is a silicon compound-containing layer, and 4 is a higher aliphatic amine-containing layer.

Examples of the nonmagnetic substrate 1 that can be used in the magnetic recording medium according to the present invention include polyvinyl chloride, cellulose acetate, polyethylene terephthalate, and polyethylene.

There are films, plates, etc. made of well-known materials such as polymeric materials such as polypropylene, polycarbonate, polyimide, and polyamide, nonmagnetic metal materials, and ceramic materials such as glass and porcelain.

Further, as the ferromagnetic material that can form the ferromagnetic metal thin film 2 that can be used in the magnetic recording medium of the present invention, any known material can be used, such as an alloy of one or more of iron, cobalt, and nickel, or an alloy of these. There are alloys made by combining metals with other metals such as manganese, chromium, titanium, phosphorous, samarium, bismuth, etc., and oxides of the above metals.

The ferromagnetic metal thin film 2 can be formed on the nonmagnetic substrate 1 by any known method such as vacuum evaporation, sputtering, ion blasting, or plating.

In the present invention, the key point is to form the silicon compound-containing layer 3 on the ferromagnetic metal thin film 2 as described above, and to provide the higher aliphatic amine-containing layer 4 thereon.

The vine silicon compound used in the present invention is Noriyoku/alumina or silica/nickel oxide.

The proportion of silica in silica/alumina and silica/nickel oxide is preferably 40% to 90% by molar ratio, and higher aliphatic amines are strongly adsorbed at this proportion.

Silica and alumina can be produced by mixing silica gel and alumina gel in a wet state, applying aluminum salt to silica gel by dipping, gelling silica and alumina simultaneously from an aqueous solution, and depositing alumina gel on silica gel. It is made by mixing silica powder and alumina powder, compressing it, and solidifying it.

Silica and nickel oxide are also produced in the same way as silica and alumina.

According to the present invention, the silicon compound-containing layer 3 can be formed on the ferromagnetic metal thin film 2 by a sputtering method.

When forming the silicon compound-containing layer 3 on the ferromagnetic metal thin film 2 according to the present invention, the film thickness is preferably 5 to 40 nm.

When the film thickness was greater than 5 onm, the output decreased due to spacing loss during signal reproduction.

Furthermore, as the SNM becomes smaller, pinholes tend to occur, and a combined effect with higher aliphatic amines cannot be expected.

According to the present invention, the higher aliphatic amine-containing layer 4 is provided on the silicon compound-containing layer 3 described above.

The higher aliphatic amine that can be used in the present invention has 12 to 2 carbon atoms.
It is a compound containing 6 hydrocarbon chains.

When the number of carbon atoms is 11 or less, sufficient lubricity cannot be obtained.

1. Aliphatic amines with a hydrocarbon chain of 27 or more carbon atoms do not improve lubricity any further and their durability deteriorates.

Higher aliphatic amines that can be used in the present invention include laurylamine, tetradecylamine, hexadecylamine, stearylamine, icosylamine, tocodylamine, tetradecylamine, hexaco/luamine, and the like.

The higher aliphatic amine-containing layer 4 can be formed on the silicon compound-containing layer 3 by a vacuum deposition method, a coating method, a Langmuir-Prodgett method, or the like.

When the higher aliphatic amine-containing layer 4 is formed on the silicon compound-containing layer 3 according to the present invention, the film thickness is 5 to 45 nm.
m is suitable, and 10 to 3 onm is preferable. However, the combined thickness of the silicon compound-containing layer 3 needs to be 50 nm or less.

If the wavelength is smaller than 5 Gnm, the output will decrease due to spacing loss during signal reproduction, which is not preferable. Furthermore, if the thickness of the higher aliphatic amine-containing layer 4 is less than 5 nm, the lubricity will be significantly reduced, which is not preferable.

The present invention will be explained below by giving specific examples.

〔Example〕

A 150 nm thick ferromagnetic metal thin film made of cobal (90%)-chromium (10%) was formed on a 20 μm thick polyimide film substrate by vacuum evaporation. A piece with a diameter of 76 rIrm was cut from the substrate on which this ferromagnetic metal thin film was formed, and argon gas was introduced onto the ferromagnetic metal thin film to form a film with a thickness of 10 nm by high-frequency sputtering.
A silicon compound-containing layer was formed. The argon gas pressure was 2×10 Torr, and seven recon compounds having the following compositions were used as targets.

Samples 1 to 37 silica/alumina (5i02:k1203:1:1 molar ratio) Samples 4 to 6 silica/nickel oxide (5in2:Ni0=2:1 molar ratio) Next, using a spinner, the following 1100pp higher aliphatic A solution of amine in ingropanol was coated onto the silicon compound layer.

Samples 1 and 4 Nilaurylamine Samples 2 and 5: Stearylamine Samples 3 and 6: Hexaconylamine 2 cc of the amine solution was applied at a rotation speed of 50 Orpm, and subsequently the rotation speed was increased to 11000 rl).
The solvent was dried. After vacuum drying the sample, the higher aliphatic amine layer formed on the silicon compound layer was measured with an ellipsometer and found to have a film thickness of 15 nm.

[Comparative example]

In the above embodiments, higher aliphatic amines were directly spin-coded under the same conditions without forming a silicon compound layer on top of the ferromagnetic metal thin film.

Sample 7: Laurylamine Sample 8: Stearylamine Sample s: Hexacosylamine The dynamic friction coefficients of Examples 1 to 6 and Comparative Examples 7 to 9 were measured with a dynamic friction coefficient needle (DFPM type, Kyowa Kagaku Seiya). . The head is a SUJ steel ball with a diameter of 12 mm, head load 1ooy, head running speed 1, Orran /
Measured at s. The results are shown below.

(Margins below) From the data in the table, it is clear that the magnetic recording media of Examples (Samples 1 to 6) according to the present invention have a low coefficient of dynamic friction not only at the initial stage but also after 200 reciprocations, and in terms of lubricity durability, compared to the comparative example (Samples 1 to 6). It can be seen that this sample is superior to samples 7 to 9).

Furthermore, when these magnetic recording media were run on a test machine with the same functionality as a commercially available floppy disk, all of the magnetic recording media of the examples ran stably even after 100 hours, and no wear scratches were observed. Ta. On the other hand, the magnetic recording medium of the comparative example ran unstable, and wear scratches were observed on the magnetic surface.

Note that although the above embodiments have been described with respect to magnetic disks,
It is clear that the magnetic recording medium of the present invention can also be applied to magnetic tapes, magnetic cards, etc.

Effects of the Invention The magnetic recording medium of the present invention has excellent slipperiness and durability and can maintain it for a long period of time.

[Brief explanation of drawings]

The figure is a sectional view of a magnetic recording medium in an embodiment of the present invention. DESCRIPTION OF SYMBOLS 1...Nonmagnetic substrate, 2...Ferromagnetic metal thin film, 3...Silicon compound containing layer, 4...
...Higher aliphatic amine-containing layer. Name of agent: Patent attorney Toshio Nakao and 1 other high school student
(Katsuzuki Kata Oya Amin Goyuta

Claims (4)

[Claims] (1) A magnetic recording medium in which a silicon compound-containing layer is formed on a ferromagnetic metal thin film provided on a non-magnetic substrate, and a higher aliphatic amine-containing layer is provided thereon. (2) The magnetic recording medium according to claim 1, wherein the silicon compound is silica/alumina or silica/nickel oxide. (3) The magnetic recording medium according to claim 1, wherein the silicon compound-containing layer has a thickness of 5 to 40 nm. (4) The magnetic recording medium according to claim 1, wherein the higher aliphatic amine contains a hydrocarbon chain having 12 to 26 carbon atoms.