JPS6031010B2 - magnetic recording medium - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a protective layer for magnetic recording bodies such as magnetic drums and magnetic disks.

[Summary of the invention]

The present invention provides a first magnetic recording medium made of a non-magnetic material on a magnetic recording medium.
A protective layer and a second protective layer made of ruthenium are provided, and the thickness of both protective layers is 0.02 to 1 micron.

[Prior Art] Conventionally, materials commonly used as magnetic recording medium materials include iron oxides such as y-Fe203 and Fe304, and magnetic alloy powders such as Cr02.

However, as information has become more dense in recent years, magnetic recording media plated or vapor-deposited with magnetic metal have come to be used.These magnetic recording media are usually used under extreme conditions, and when starting up or stopping, Since it rotates in contact with the magnetic head, it wears out, its recording characteristics deteriorate, and it loses its function as a magnetic recording device. Furthermore, the surface of the magnetic medium often corrodes during long-term use.

Under these circumstances, most magnetic recording bodies are provided with a protective layer. In reality, the film thickness is about 2 to several microns (hereinafter referred to as "mountain"). [Problem and purpose to be solved by the invention]
However, if the protective layer is made thick as described above, it becomes difficult to read when writing, and when writing, the writing magnetic field is blocked and delayed by the eddy current effect, and reaches the magnetic medium rapidly. Therefore, it is desirable that the protective layer be as thin as possible. Also, to satisfy the above,
A hard coating with high wear resistance is required. Furthermore, the protective film must be non-magnetic since if it has magnetism, it will have an adverse effect on the magnetic recording characteristics. To explain in more detail, as the thickness of the protective layer increases, as shown in FIG. 1, the distance between the magnetic head and the magnetic medium increases.
Gap loss increases, reproduction output decreases, and resolution deteriorates. Therefore, high density recording is not possible. On the other hand, if the protective layer has a thickness of 1 or less, its influence is relatively small and the desired resolution can be obtained. However, in the thickness range of the protective layer, the hardness of the protective layer is required to have a Vickers hardness of 200 or more, probably from the viewpoint of durability of the magnetic recording body. As mentioned above, in order to obtain a certain level of protective layer hardness, the protective layer in the conventional technology requires a layer thickness of 2 microns or more, which reduces the reproduction output and deteriorates the resolution. To,
The drawback was that high-density recording was not possible. The present invention
This method overcomes the drawbacks of the conventional technology described above, and provides a magnetic recording medium with good durability and excellent magnetic recording characteristics by using a nonmagnetic layer of 1 micron or less and a ruthenium layer as a protective layer. purpose. [Means for Solving the Problems] The present invention provides a magnetic depository body in which a ferromagnetic layer is formed on a support substrate, in which a first protective layer made of a non-magnetic material and a ruthenium layer are provided on the ferromagnetic layer. A second protective layer is formed, and the total thickness of the first protective layer and the second protective layer is 0.
．． This magnetic recording medium is characterized by having a particle size of 0.02 to 1 micron.

〔Example〕

Corrosion-resistant aluminum 5052 was cut into a size of 2000 x 1 rib to create the original shape of a magnetic disk support.

This was further finished with a diamond bite to form a base. Then, it was degreased, pickled, and plated with zinc for about 2 hours using the zinc substitution method. Furthermore, one layer of sulfuric acid steel plating was applied using cyanide steel plating as a strike, and on top of this, a cobalt-nickel-phosphorus ferromagnetic layer of about 0.3 mm was applied. Further, on the magnetic layer, copper and ruthenium plating was applied as a protective layer at a thickness of 0.1 mm and 0.2 mm, respectively. (Copper plating) (Ruthenium plating) The obtained magnetic recording body was applied to a contact head type recording device.

When this was operated at a relative speed of 3 shoes/second, the impact of the ferrite head was applied with a pressure of about 3 k9/second.
I was able to endure 2 to 3 hours of writing information and presenting arguments without any problems. The above examples show a part of the present invention, and the effects of the present invention can be expected even if the type of protective layer film, component composition, and plating conditions are changed as long as the Vickers hardness is 200 or more.

Although the green plating method has been described in this embodiment, vapor phase plating methods such as vapor deposition and ion plating can also be used. The total thickness of the protective layer is 0.02
The magnetic recording body of the present invention can be obtained if the magnetic recording medium is 1 to 1 μm.

Further, the underlayer and magnetic layer can be changed as desired depending on the purpose. As described above, the present invention enables high-density recording by thinning the protective layer on the magnetic medium.

Furthermore, a magnetic recording medium with good durability can be produced. [Effect] In a magnetic recording body in which a ferromagnetic layer is formed on a support substrate, a first protective layer made of a non-magnetic material and a second protective layer made of ruthenium are formed on the ferromagnetic layer. ,
The total thickness of the first protective layer and the second protective layer is 0.02 to 1
Because it is structured to have a micron thickness, it is possible to obtain a very thin protective layer compared to conventional protective layers, and it also has high retention strength and
A magnetic recording medium capable of high-density recording is obtained.

Further, although ruthenium plating is normally performed using a strongly acidic liquid, the first nonmagnetic protective layer provides the effect that the ferromagnetic layer will not be damaged by the strong acidic liquid. Furthermore, the second ruthenium protective layer prevents damage to the upper surface of the magnetic recording medium by heads, etc., and maintains a highly hard surface with a Vickers hardness of 200 or more, resulting in a significant improvement in durability.

[Brief explanation of the drawing]

FIG. 1 is a characteristic diagram showing the dependence of the protective layer thickness on the reproduction output voltage. Many/Figures

Claims (1)

[Claims] 1. A magnetic recording body having a ferromagnetic layer formed on a support substrate, wherein a first protective layer made of a non-magnetic material and a second protective layer made of ruthenium are formed on the ferromagnetic layer, and the second protective layer made of ruthenium is formed on the ferromagnetic layer. The total thickness of the first protective layer and the second protective layer is 0.02
A magnetic recording medium characterized by a diameter of ~1 micron.