JPS60127528A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To obtain a magnetic recording medium high in durability, output, and quality by forming a magnetic metal layer oxidized on the surface by a specified depth or less, on a base made of polyester or the like by the vapor deposition method, and then, forming a protective layer on this surface by the plasma polymn. method. CONSTITUTION:A thin magnetic metal film 2 made of a metallic magnetic material, such as Co, Ni, or Cr, is formed to about 150nm film thickness on a base 1 made of polyester or the like by the vapor deposition, ion plating, or sputtering method or the like. At that time, an amt. of O2 in a vacuum chamber is made less than the conventional method to form an oxide layer 3 of <=10nm film thickness. Then, a protective layer 4 is formed by the plasma polymn. method of a fluorinated compd., such as C4F8. The uniform layer 4 high in adhesion and free from pinholes, etc., can be formed, even if the layer 3 is made thinner than the conventional coating by forming the layer 4 by the plasma polymn. method. Moreover, the obtained magnetic recording medium is small in blocking and dropout, long in still life, high in output, and superior in durability.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a magnetic recording medium used in audio/video, floppy disks, and the like.

Conventional structure and its problems In recent years, magnetic recording and reproducing equipment has become smaller and lighter, and in response, magnetic recording media are required to be capable of high-density recording, high output, and high characteristics. In addition to coating methods in which a magnetic material is mixed and coated on a substrate, magnetic recording media in which a thin metal magnetic layer is provided on a substrate using a paper deposition method such as sputtering, ion blating, or vapor deposition have been studied. ing.

A conventional magnetic recording medium made by the paper deposition method will be described below.

FIG. 1 shows a cross-sectional view of a conventional magnetic recording medium, where 1 is a substrate made of polyester or the like, and 2 is Co.

This is a thin film-like metal magnetic layer made of a metal magnetic material such as Cr or Ni. 3 is an oxide layer on the surface of the thin metal magnetic layer, and 4 is a protective film.

A conventional magnetic recording medium configured as described above will be described below. In a vacuum chamber maintained at at least 5.0x10-"7orr or less, the substrate 1 is
A thin metal magnetic layer 2 made of a metal magnetic material such as Co, Ni, or Cr is formed on the surface of the substrate. At this time, 0.0% is in the vacuum chamber 7. is introduced to form an oxide layer 3 on the surface of the thin metal magnetic layer 2. The thickness of the oxide layer 3 is currently about 150 layers, and providing this oxide layer 3 will reduce the output of the magnetic recording medium.The reason for providing the oxide layer 3 even if the output of the magnetic recording medium is reduced is as follows. As shown in the figure, the thickness of the oxide layer 3 is 1
This is because if the thickness is less than 00 Å, the thin metal magnetic layer 2 is likely to be scratched when the magnetic recording medium slides on the magnetic head/guide post. This means that the thickness of the oxide layer 3 is 100
8 or less, when trying to create the protective film 4 by coating, not only will the adhesion strength between the thin metal magnetic layer 2 and the protective film 4 be significantly weakened, but depending on the material, the surface of the thin metal magnetic layer 2 may be damaged. This tendency is especially strong when trying to create the protective film 4 with a fluorine-containing organic material, which is thought to be due to the fact that it may repel and cannot be applied, and the protective film is incomplete. Since the film has a small coefficient of dynamic friction and good sliding properties, there is little sliding noise generated by sliding between the magnetic recording medium and the magnetic head, and a good magnetic recording medium can be obtained. However, the thickness of the oxide layer 3 If it is less than 1008, it cannot be applied.

As described above, Co is deposited on the substrate using the paper deposition method.
A magnetic recording medium provided with a thin metal magnetic layer made of a metal magnetic material such as , Ni, or Cr requires an oxide layer with a thickness of 150 μm or more on the surface of the thin metal magnetic layer from the viewpoint of durability.
The oxidized layer in No. 2 has the problem of causing a decrease in output (
It was 7.

Purpose of the Invention The present invention solves the above conventional problems by creating a protective film that does not reduce the adhesion strength with the thin metal magnetic layer even if the oxidation layer on the surface of the thin metal magnetic layer is reduced. The purpose is to provide durable, high-output, high-quality magnetic recording media.

Structure of the Invention The present invention has a surface oxidation layer formed on a substrate made of polyester or the like.
A magnetic recording medium comprising a thin metal magnetic layer made of a metal magnetic material such as Co, Ni, or Cr with a thickness of 00 Å or less, and a protective film on the thin metal magnetic layer, the protective film being created by a plasma polymerization method. By doing so, even if the thickness of the oxide layer on the surface of the thin metal magnetic layer is 100A or less, the adhesion strength between the thin metal magnetic layer and the protective film does not decrease, and a high-output, high-quality magnetic recording medium can be obtained. It is something.

Description of Examples At least 5. ○×1○ In a vacuum chamber maintained at a vacuum level of less than -5 Torr, a film made of a magnetic metal material such as Co, Ni, or Cr is approximately 16 mm thick on a substrate such as polyester.
The thickness of the oxide layer on the surface of the film-like metal magnetic layer is made to be 1° OA or less by vapor deposition. After this, the inside of the vacuum chamber is again maintained at a low vacuum of 1.0X10= or less, and then the monomer gas is pumped until the pressure inside the vacuum chamber is O, 1T.
Introduce it at a level where it becomes about orr. High frequency power (13.56 m) is applied to the vacuum chamber to generate a discharge, and a protective film is formed on the thin metal magnetic layer by plasma polymerization.

Pressure after monomer gas introduction is 0.01 to 2.0 Torr
The protective film formed by the plasma polymerization method is uniform and has no pinholes, has good durability, and has a high adhesion strength to the thin metal magnetic layer.

In the table above, we selected a fluorine-containing organic material as the protective film material, and changed the oxidation layer thickness and protective film creation method to avoid clogging and dropouts at the beak, and in a low-humidity environment that is harsh on wear such as a temperature of 23°C and a humidity of 10% RH. The results of a comparative study of still life are shown below. When the thickness of the oxide layer is changed from 1,508 to 60, clogging, dropouts, and still life in the environment deteriorate when the protective film is created by coating.

On the other hand, when the protective film is created using the plasma polymerization method (monomer gas: octafluorocyclobutane C-04F8: manufactured by Daikin), even if the oxide layer thickness is as small as 50, the conventional oxide layer thickness is 100, and the coating method Compared to the conventional method, it improves both eyelidness, dropout, and methyl lifespan in the environment. This is because when a protective film is created using a coating method on a thin metal magnetic layer with an oxide layer thickness of 5OA, it is repelled and is not applied uniformly, resulting in uneven coating, whereas when a protective film is created using a plasma polymerization method, This is thought to be due to the fact that a uniform protective film with high adhesion strength was obtained even with an oxide layer thickness of 6 mm when created. By reducing the thickness of the oxide layer from 1,508 to 60, the output of the magnetic recording medium itself increased by 2 db, and its durability and reliability improved.

As described above, according to this embodiment, the oxide layer on the surface of the thin metal magnetic layer has a thickness of 100 Å or less.Secondly, by creating a protective film by plasma polymerization, it is possible to achieve high output and A magnetic recording medium with high durability and reliability can be obtained.

Effects of the Invention The magnetic recording medium of the present invention has a structure in which the thickness of the oxide layer on the surface of the thin metal magnetic layer is set to 1008 or less, and a protective film is formed on the thin metal magnetic layer by plasma polymerization. Fluorine-containing organic materials can also be used as a protective film, and a magnetic recording medium with high output, low sliding noise, and high durability and reliability can be obtained, which has great practical effects.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a conventional magnetic recording medium, and FIG. 2 is a diagram for explaining the same magnetic recording medium. DESCRIPTION OF SYMBOLS 1...Substrate, 2...Thin film metal magnetic layer, 3
... Oxidation layer, 4... Protective layer.

Claims (2)

[Claims] (1) A thin metal magnetic layer made of a metal magnetic material such as Co, Ni, or Cr is provided on a substrate such as polyester by a paper deposition method such as vapor deposition, ion blating, or sputtering. The thickness of the oxide layer on the surface of the metal magnetic layer is 100% or less, and the metal magnetic layer is in the form of a thin film.
Second, a magnetic recording medium with a protective film provided by plasma polymerization. (2) The magnetic recording medium according to claim 1, wherein the protective film material is made of a fluorine-containing organic material.