JPH01267824A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To improve corrosion resistance and CSS resistance characteristic by forming 3 layers; an amorphous carbon layer, intermediate chromium layer and amorphous carbon layer continuously as a protective film. CONSTITUTION:A Co alloy layer 4 is provided on a nonmagnetic substrate 1 and the 3 layers; the amorphous carbon layer 5, the intermediate chromium layer 6 and the amorphous carbon layer 5 are continuously formed as the protective film thereon. Namely, the recording medium has the amorphous carbon layer 5 which plays the role of the protective film as a lubricating agent on the extreme surface and has the intermediate chromium layer 6 for provision of corrosion resistance and adhesiveness thereunder; further, the amorphous carbon layer 5 for the contact start stop (CSS) characteristic is formed thereunder. The corrosion resistance and CSS resistance characteristic are thereby improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic recording medium such as a magnetic disk used in a magnetic recording device.

[Prior Art] The mainstream of magnetic recording media conventionally used in magnetic disk drives is coated magnetic recording media, which are made by coating an aluminum substrate with ferromagnetic oxide particles and an organic resin binder. In response to the increasing density of recording, metal thin film magnetic recording media using thin film formation methods such as plating and sputtering are beginning to be put into practical use. FIG. 2 shows an example of the layer structure of this metal thin film type magnetic recording medium. In the figure (7
) is a substrate, (8) is a hardened base layer, (9) is a nonmagnetic base layer, (g)) is a ferromagnetic metal thin film layer, and (II+ is a carbon thin film layer).

The magnetic recording medium configured as described above is used, for example, in a hard disk drive as an external storage device of a computer, and a floating head is placed on the surface of the magnetic recording medium, and the magnetic recording medium repeatedly rotates at high speed and stops. Therefore, a hard non-magnetic alloy layer is formed on the surface of the substrate +7, and then a ferromagnetic metal thin film layer (g) which plays a role in reading information is formed. -33
As shown in the 521 Mei In, etc., carbon 4 is coated as a protective film with lubricity and wear resistance.

[Problem to be solved by the invention] In magnetic recording, information is read and written using a combination of a magnetic recording medium and a floating head as described above. However, when a metal thin film medium is used, the metal magnetic till is exposed to high temperature and high humidity. It is easy to corrode in such a poor atmosphere, and it is difficult to ensure sufficient environmental resistance.

Therefore, in order to prevent corrosion of the magnetic layer, consideration has been given to forming a protective film such as a carbon film on the surface of the magnetic layer. record·
Considering the regeneration properties, the thickness of the protective film must be kept to about 0.1 mm or less. However, such a thin protective film (carbon film) that exhibits a good anticorrosion function is not known.

Furthermore, the characteristics required for the protective film of magnetic recording media are C
Durability and running performance during 3S (contact start/stop) are mentioned. In this regard, simply forming a carbon film is not sufficient, and further improvements are desired.

[Object of the Invention] The present invention was made in order to solve the above-mentioned problems, and an object of the present invention is to improve the corrosion resistance and durability of a magnetic disk, that is, to improve the reliability.

[Means for Solving the Problems] A magnetic recording medium according to the present invention includes a CO alloy layer on a nonmagnetic substrate, and further comprises successively forming an amorphous carbon layer, an intermediate chromium layer, and an amorphous carbon layer thereon. It is characterized by

[Function 1] In the magnetic recording medium of the present invention, the protective film has a three-layer structure of an amorphous carbon layer, an intermediate chromium layer, and an amorphous carbon layer. It has an amorphous carbon layer, and below that is an intermediate chromium layer for the purpose of further improving corrosion resistance and adhesion of the carbon layer.
By forming an amorphous carbon layer for the purpose of further improving S characteristics, corrosion resistance and C3S resistance are extremely high, and reliability is improved.

[Example] Hereinafter, an example of the present invention will be described based on the drawings. FIG. 1 is a partial cross-sectional view of one embodiment of the present invention. The magnetic recording medium according to the present invention has a hardened base layer (2), a chromium base layer (3), and an alloy magnetic layer (4) on a nonmagnetic substrate (1).
), an amorphous carbon layer (5), an intermediate chromium layer (6), and an amorphous carbon layer are formed in this order by sputtering, vapor deposition, ion blating, etc. Glass ceramics and aluminum alloys can be used as the substrate (1), and it is preferable to use AI-H () alloy. The base hardened layer (2 is N1-P, N
1-Cu-P and alumite can be used, N
Preferably, 1-P is used. The thickness of the base hardening layer (2) is preferably between 5 and 50 mm, especially between 10 and 50 mm.
Preferably between 20 letters. Base chrome layer (3
) is preferably Cr. Non-magnetic underlayer (
The thickness of 3) is preferably between 1,000 and 10,000 mm, particularly preferably between 1,000 and 3,000 Å. Co-Ni as the alloy magnetic layer (4)
and Co-Ni-Pt can be used, and Co-X
Preferably, l-Cr is used. The thickness of the alloy magnetic layer (4) is preferably between 300 and 1500.
In particular, it is preferable that the number of people be between 400 and 1000. The reason why the thicknesses of each of the hardened base layer (2), the nonmagnetic base layer (3), and the alloy magnetic layer (4) are limited as described above is to take recording/reproducing characteristics into consideration. It is preferable to use sputtering for the amorphous carbon layer (5). The thickness of the amorphous carbon layer (5) is preferably between 100 and 1000 layers in total,
In particular, it is preferable that the total number of people in the two layers be between 200 and 600. The reason why the thickness of the amorphous carbon M(5) is limited as described above is to prevent space loss, to not impair recording/reproducing characteristics, and to consider durability during C8S.

Preferably, the thickness of the intermediate chromium layer (6) is between 50 and 300 mm. This is to prevent space loss while maintaining corrosion resistance.

Example N1-P was applied as a hardened base layer (2) on the magnetic substrate (1).
The eyes were coated with 15 coats. Furthermore, after polishing this to a predetermined roughness, a base chromium layer (3) is formed, and then Co-
A 2ON1 alloy magnetic film (4) was formed. In this example,
By DC magnetron sputtering method, a chromium layer (3) was formed to a thickness of 2,000 layers and a Co-208i alloy layer (4) was subsequently formed to a thickness of 700 layers at an argon pressure of 5 mTOrr. Next, on top of this metal magnetic layer, an amorphous carbon layer (5) and an intermediate chromium layer (6) are formed in the same atmosphere.
A magnetic disk was prepared by successively forming a three-layer protective film consisting of an amorphous carbon layer (5) and an amorphous carbon layer (5). The thickness of each protective film was 200 layers for each amorphous carbon layer, 200 layers for the intermediate chromium layer, and a total thickness of 600 layers.

Comparative Example 1 Instead of having three layers: an amorphous carbon layer, an intermediate chromium layer, and an amorphous carbon layer, the amorphous carbon layer was
A magnetic disk was produced in the same manner as in the example except that the film was formed to a thickness of 0.0 mm.

Comparative Example 2 A magnetic disk was manufactured in the same manner as in the example except that instead of forming three layers: an amorphous carbon layer, an intermediate chromium layer, and an amorphous carbon layer, 300 layers of chromium layer and 300 layers of amorphous carbon layer were formed. Created.

Next, errors were verified using a disk tester using 10 of each of the three types of magnetic disks obtained. As a result, no errors were detected in any of the magnetic disks at the initial stage. Next, these magnetic disks were placed in a constant temperature and humidity chamber maintained at a temperature of 60°C and a relative humidity of 90%.
After leaving it for 0 days, errors were verified again using a disk tester. No errors were found in any of the magnetic disks of Example, but 3 to 10 out of 10 disks were found in Comparative Example 1. Ten errors occurred, and two to four errors occurred in two out of ten magnetic disks of Comparative Example 2.

Subsequently, C8S test 1000 was performed on these magnetic disks.
0 times, the magnetic disk of Comparative Example 1 had 10
Peeling of the carbon layer and head crash occurred in 4 of the disks, and scratches occurred on the surface of the magnetic disk in 2 out of 10 magnetic disks of Comparative Example 2. However, no abnormality was observed in the example magnetic disk.

[Effects of the Invention] As explained above, according to the present invention, the three layers of the amorphous carbon layer, the intermediate chromium layer, and the amorphous carbon layer are continuously formed as a protective film, so that the corrosion resistance is extremely high and the C8S resistance is achieved. The effect is that it is possible to provide a magnetic recording medium with extremely high performance.

[Brief explanation of the drawing]

FIG. 1 is a partial sectional view showing a magnetic recording medium according to an embodiment of the present invention, and FIG. 2 is a partial sectional view of a conventional magnetic recording medium. (Main symbols in the drawings) (1): Substrate (z: Hardened base layer (3): Non-magnetic base layer (41: Co alloy magnetic layer (5): Amorphous carbon layer (6): Intermediate chromium layer Iwa Masu male body 1
4th Second Kindergarten Procedures Amendment (Voluntary) 1. Indication of case Relationship with patent application No. 63-97859 3 and the case of the person making the amendment Patent applicant address 2-2-3 Marunouchi, Chiyoda-ku, Tokyo Name (601) Moriya Shiki, representative of Mitsubishi Electric Corporation 4. Agent 5. Subject of amendment (1) Detailed explanation of 1. invention in the specification" column 6. Contents of amendment (1) If powder particles in the 5th line from the bottom of page 1 of the specification are "oxide particles. ” he corrected. (2) l”Co-Ni and Co-N on page 5, line 13
i -Pt J is corrected to "Co-Ni alloy". (3) "Space loss" on page 6, line 6 is corrected to "spacing loss." (4) ``1 supes loss'' on page 6, lines 10-11 is corrected to ``spacing loss.'' (5) "RTA substrate" on page 6, line 13 of the same page is replaced with "non-magnetic curtain plate"
and correct it. that's all

Claims (1)

[Claims] (1) A magnetic recording medium comprising a Co alloy layer on a nonmagnetic substrate, and further comprising an amorphous carbon layer, an intermediate chromium layer, and an amorphous carbon layer successively formed thereon.