Stock material or miscellaneous articles – Web or sheet containing structurally defined element or... – Physical dimension specified
Patent
1983-01-12
1987-09-29
Pianalto, Bernard D.
Stock material or miscellaneous articles
Web or sheet containing structurally defined element or...
Physical dimension specified
428457, 428469, 428693, 428694, 428900, G11B 566
Patent
active
046968628
DESCRIPTION:
BRIEF SUMMARY
DESCRIPTION
1. Technical Field
This invention relates to a magnetic recording medium and particularly to a so-called thin film magnetic recording medium having a metal magnetic layer formed on a nonmagnetic base and especially to improve the durability such as adhesion to the nonmagnetic base, wear-proof property and so on the metal magnetic layer.
2. Background Art
While it was previously proposed in this kind of a thin film magnetic recording medium tha a continuous film made of a metal such as Al, Ti and so on or organic substance should be interposed between a nonmagnetic base and a metal magnetic layer for the purpose of increasing the adhesion of the metal magnetic layer to the nonmagnetic base, this was far from satisfactory.
DISCLOSURE OF INVENTION
According to the invention, a metal layer at least the surface of which is oxidized, nitrogenated or carbonized is formed on one major surface of a nonmagnetic base on which a metal magnetic layer is further formed. According to this invention, the durability of the metal magnetic layer of the magnetic recording medium can be improved (from several times to ten-odds times as that of the prior art), resulting in a magnetic recording medium of high reliability.
BRIEF DESCRIPTION OF DRAWINGS
FIGS. 1 through 5 are cross-sectional diagrams each showing an example of a magnetic recording medium of this invention in the order of its manufacturing process.
BEST MODE FOR CARRYING OUT THE INVENTION
Referring to the drawings, a magnetic recording medium according to this invention will hereinafter be described in detail in conjunction with a manufacturing process thereof.
In the present invention, first, as shown in FIG. 1, there is prepared a nonmagnetic base, for example, a polyethylene telephthalate-base 1, and then one major surface 1A of the base 1 is subjected to activation treatment. This activation treatment is performed by disposing the nonmagnetic base in plasma of an atmosphere gas generated by corona discharge in an atmosphere containing low pressure oxygen, for example, vacuum degree of the atmosphere is from 10.sup.-1 to 10 torr. As an example of the atmosphere, there can be utilized atmosphere of a mixed gas of 70% of Ar with 30% of O.sub.2 in which the pressure of O.sub.2 gas is 10.sup.-3 torr (hereinafter, this atmosphere is called atmosphere a). But, the atmosphere gas for this activation treatment to be activated is not limited to gas containing oxygen, but any gas, for example, even argon gas alone makes the activation treatment possible.
Next, as shown in FIG. 2, on the activated major surface 1A of the base 1 is formed by a process such as vacuum deposition, sputtering or the like a discontinuous film, namely, island-shaped portions 2 made of metal or cobalt Co which the example of this invention utilizes. The island-shaped portions 2 have a mean film thickness of about 10 to 1000 .ANG. or about 300 .ANG. the example of this invention utilizes. For the metal which is utilized for the island-shaped portion 2, there can be employed Al, Ti and so on other than Co. Nonetheless, Co is most preferable, the reason of which is that since Co is the same as the component of a metal magnetic layer which will be formed later, only one evaporating source is enough, giving rise to improvement of productivity. As a manner of the vacuum deposition, while either of vertical and oblique evaporations can be utilized, the oblique evaporation rather allows the discontinuous island-shaped portions to rather easily be formed.
Next, as shown in FIG. 3, the oxidizing atmosphere (gas containing more than 20% of O.sub.2 gas (the remaining gas is inert gas)), nitrogenating atmosphere (gas containing N.sub.2) or carbonizing atmosphere (acetylene gas, ethylene gas and so on), is formed and applied with a DC voltage to this atmosphere gas to generate plasma of the atmosphere gas. Then, exposing the base film on which the metal layer was formed as the island-shape to this plasma, the surface of the island-shaped portions 2 or the overall inside thereof is formed as
REFERENCES:
patent: 3691032 (1972-09-01), Luborsky et al.
patent: 4239835 (1980-12-01), Iijima et al.
Kawana Takahiro
Yokoyama Norio
Pianalto Bernard D.
Sony Corporation
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