JPH033115A - Magnetic recording medium - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic recording medium using synthetic resin as a base.

[Prior Art] Conventionally, as a magnetic recording medium with improved adhesion between a base formed of synthetic resin and a recording layer, Japanese Patent Application Laid-Open No. 60-529
A magnetic recording medium technically disclosed in Publication No. 23 has been known. In this method, a synthetic resin substrate is surface-treated by irradiation with active gas ions, and then a recording film is formed on this substrate.

It is necessary to improve the adhesion between the synthetic resin substrate and the recording film. If the adhesion is poor, cracks will occur and the signal characteristics will deteriorate, or the recording film will deteriorate due to oxidation, resulting in insufficient reliability. This is because they cannot get sex.

[Problems to be Solved by the Invention] However, although the above-mentioned conventional techniques can improve adhesion to some extent, it is not sufficient, and the effect of preventing crack generation is also insufficient.

In addition, since synthetic resin substrates have low surface conductivity, it is necessary to take measures to increase this when using synthetic resin substrates, but the conventional technology described above does not improve the conductivity of synthetic resin substrates. I couldn't. For this reason, the surface of the substrate is easily charged, and minute dust is likely to adhere to the surface of the substrate, causing signal defects.

An object of the present invention is to provide a highly reliable magnetic recording medium that simultaneously improves both the prevention of crack generation and the prevention of electrification on the substrate surface, which have been difficult to solve with the above conventional methods.

[Means for Solving the Problems] The gist of the present invention is that a metal carbide film is formed on the surface of a base formed of a synthetic resin by implanting metal ions into the surface of the base, and that a metal carbide film is formed on the metal carbide film. A magnetic recording medium is characterized in that a chromium film is formed on the magnetic recording medium, and at least a recording film is formed on the chromium film.

Hereinafter, the configuration of the present invention will be explained in detail.

(Synthetic Resin Substrate) As the synthetic resin forming the substrate, for example, polyetherimide, polyether sulfone, polyphenylene sulfide, polyarylate, polycarbonate, etc. can be used. Furthermore, potassium titanate whiskers, carbon fibers, glass fibers, metal fibers, glass beads, ceramic powder, carbon particles, etc. may be added as appropriate.

(Metal ion implantation) Examples of metal ions to be ion-implanted in the present invention include An゜, Cr""St"Ta", Ti
”, V”, Zr+, etc. can be used.

Ion implantation is the process of implanting the element to be added into a high vacuum (10
This refers to a method in which the compound is ionized in a medium (approximately Pa), accelerated in an electric field of several + kV to several hundred kV, and added to a solid substrate.

(Chromium@) The present invention does not particularly limit the method of forming the chromium film, the film thickness, etc. As a forming method, for example, a sputtering method can be used.

(Recording Film) The present invention does not particularly limit the forming material, forming method, film thickness, etc. of the recording film. For example, Co-Cr, Co-N
i-Cr etc. can be used.

Note that another thin film may be formed on the recording film. For example, even if a protective film or a lubricating film is provided on the recording film, the effects of the present invention will not be affected in any way.

[Function] According to the present invention, a metal carbide film is formed on the surface of the synthetic resin substrate, a chromium film is formed on the metal carbide film, and a recording film is further formed on the chromium film. Adhesion between the substrate and the recording film can be improved, and therefore cracks can be prevented from occurring.

In addition, by forming a metal carbide film on the surface, the conductivity can be significantly improved compared to synthetic resin, so it is possible to prevent the surface of the substrate from being charged, and therefore to prevent the adsorption of minute dust. can.

[Example] Hereinafter, an example of the present invention will be described with reference to FIG. In this embodiment, a magnetic disk will be described as an example of a magnetic recording medium.

In this example, magnetic disks of the 7fff1 type, which differ only in the metal ions to be ion-implanted, were prepared as Example Samples 1 to 7, and the occurrence of cracks and signal characteristics were evaluated. Each magnetic disk had a layered structure as shown in FIG. In FIG. 1, 1 is a carbon film as a protective layer, 2 is a cobalt alloy film as a self-recording layer, 3 is a chromium film as an underlayer, 4 is a metal carbide layer formed by implanting metal ions, and 5 is a carbon film as a protective layer. is polyetherimide as a synthetic resin substrate.

First, a method of manufacturing each magnetic disk will be explained.

■By injection molding using polyetherimide resin,
A donut-shaped substrate having a thickness of 1.9 mm, an outer diameter of 130 mm, and an inner diameter of 40 mm was molded.

(2) Metal ions as shown in Table 1 were implanted into the surface of this substrate. Ion implantation was performed by ionizing the metal using a hot cathode ion source and adjusting the current so that the substrate would not be thermally deformed. The ion implantation amount is lX1, respectively.
015 ions/am2.

■On the metal carbide film formed by this ion implantation,
Using DC magnetron sputtering, a chromium film, a cobalt alloy film, and a carbon film were formed to a thickness of 2,000, 800, and 300, respectively, to complete the magnetic disk.

For comparison, a chromium film, a cobalt alloy film, and a carbon film were formed directly on the surface of a synthetic resin substrate without implanting metal ions onto the surface (the film thickness was the same as above for winter clothes). ) was created.

The surface of the magnetic disk produced as described above was observed using a scanning electron microscope at a magnification of up to 50,000 times.

The results are shown in Table 1.

Table 1 As seen from Table 1, the magnetic disk according to this example was able to completely prevent the occurrence of cranking.

Further, the number of signal defects was measured for each of these magnetic disks using a 3370 type head (gear width 25 μm). The results are shown in Table 2.

Table 2 As seen from Table 2, the magnetic disk according to this example was able to significantly reduce signal defects.

Next, these disks were placed in a constant temperature and humidity chamber at 80° C. and 80% RH, and after 1000 hours, the magnetic properties and signal characteristics were evaluated.

As a result, the magnetic disk of the comparative example showed changes in magnetic properties such as an increase in Hc and a decrease in squareness ratio, as well as a decrease in S/N ratio. No changes were observed in any of the characteristics.

Although the case of an En-air disk has been described above as an example of a magnetic recording medium, similar results could be obtained with other magnetic recording media.

[Effects] As explained above, according to the present invention, it is possible to prevent the occurrence of cracks in a magnetic recording medium using a synthetic resin as a substrate. Therefore, it is possible to prevent the magnetic layer of the magnetic recording medium from being oxidized, so that it is possible to provide a magnetic recording medium with high reliability over the long term.

Furthermore, since the surface conductivity of the synthetic resin substrate can be increased, an excellent magnetic recording medium without signal defects can be provided.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view showing the structure of a magnetic disk according to an embodiment of the present invention. (Explanation of symbols) 1... Carbon film, 2... Cobalt alloy film, 3...
-Chromium film, 4...Metal carbide film, 5...Synthetic resin substrate.

Claims (2)

[Claims] (1) A metal carbide film is formed on the surface of the base by injecting metal ions into the surface of the base formed of synthetic resin, and a chromium film is formed on the metal carbide film, and A magnetic recording medium comprising at least a recording film formed thereon. (2) The metal ions are Al^+, Cr^+, Si
2. The magnetic recording medium according to claim 1, wherein the magnetic recording medium is one of ^+, Ta^+, Ti^+, V^+, and Zr^+.