JPH02158917A - Method for manufacturing metal thin film 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 the Invention The present invention relates to a method for manufacturing a metal thin film magnetic recording medium that has high reliability and is excellent in mass production.

It is used in industrial fields such as video equipment and information equipment fields.

BACKGROUND OF THE INVENTION In recent years, the technological development of magnetic recording media has been remarkable, as seen in the improvement of magnetic recording density. γ-FeO powder is used in audio and video tape materials as an example of conventional magnetic recording media.

CrO powder, pure iron powder, etc. were coated on a polymer film together with a binder such as a resin. There are so-called coated magnetic recording media.

However, in order to improve the holding power, recording density, and electromagnetic characteristics compared to conventional coated tapes, Fe+
Metal thin film type magnetic recording media in which a magnetic metal such as Ni1 Cot Cr is deposited singly or as an alloy on a polymer film have been studied. Furthermore, as a ferromagnetic metal thin film type recording medium, an audio tape using an oblique evaporation method has already been put into practical use. The surface properties of ferromagnetic metal thin film tapes, as seen in vacuum evaporation methods and the like, are extremely superior to those of conventional coated tapes, with surface properties of several hundred amperes or less. For example, when a vapor-deposited tape is used as a video tape, high image quality with little noise can be obtained.

Next, a method for manufacturing a metal thin film tape using a conventional vacuum evaporation method will be described. FIG. 3 is a schematic process diagram of the vacuum evaporation apparatus, in which a polymer film 21 is set on a feed shaft 22, passes through a cooling drum, and is wound up on a winding shaft 24. At this time, the ferromagnetic metal 2B is melted and evaporated by an electron beam 25 from below and deposited on the surface of the polymer film 21. Unnecessary magnetic metal during vapor deposition is cut off by a shielding plate 27. This speed plate regulates the minimum incident angle θ during vapor deposition, and usually the minimum incident angle is 40 degrees or more, and vapor deposition is continuously performed from 90 degrees to 40 degrees on the polymer film.

Problems to be Solved by the Invention However, although the vapor-deposited tape manufactured by the above-mentioned manufacturing method can provide high image quality, it has drawbacks such as deterioration of image quality due to repeated running and formation of rust in high-temperature environments, which is poor in reliability. It had

The present invention was invented in view of the above-mentioned problems, and it is possible to obtain high image quality, and there is no deterioration of image quality due to repeated running, no occurrence of rust in high temperature and high humidity environments, and highly reliable metal. The purpose is to provide a thin film type recording medium.

Means for Solving the Problems In order to achieve the above object, the invention of claim 1 forms a metal oxide layer by spraying a reactive gas and an oxygen-based gas onto the surface of a magnetic metal formed on a polymer film. Preferably, in the invention according to claim 1, the metal thin film surface of the magnetic thin metal film is heated.

According to the present invention, by spraying a reactive gas containing excess oxygen onto the surface of a magnetic metal, the surface is modified to form a thicker, higher-order oxide layer than before, resulting in a stable surface with fewer defects. The presence of the protective wI layer eliminates the deterioration of image quality caused by repeated running and the occurrence of rust in high-temperature environments, increasing reliability.

EXAMPLES Hereinafter, examples of the present invention will be described with reference to the drawings.

Example 1 A first embodiment of the present invention will be described based on FIG.

As shown in the figure, a polyester film 1 is set on an unwinding roll 2, passes through a cooling rotating drum 3, and is wound up on a winding roll shaft 4. Ferromagnetic metal G.

-Ni alloy 6 is melted with an electron beam 5 and deposited on the polyester film 1 from below by method deposition.

After vapor deposition, the polyester film 1 passes over the shielding plate 7, and at this time, oxygen gas is introduced from the oxygen gas introduction nozzle 8.
And carbon monoxide gas is sprayed from the reactive gas introduction nozzle 9 toward the magnetic metal vapor flow at a ratio of 2:1.

Example 2 A second embodiment of the present invention will be described based on FIG.

A ferromagnetic metal thin film 9 produced by a conventional method is set on an unwinding roll 10, passed through a rotating drum 11 whose temperature can be raised, and then wound up with a take-up roll 12.

At this time, while heating the magnetic metal surface of the film 9 from below with a plurality of halogen lamps 13, oxygen gas and carbon oxide gas are sprayed from the gas nozzles 14 and 15 as in Example 1. The temperature on the surface of the heat-resistant film was set to approximately 200°C.

Example 3 In Example 2, a heatable rotating drum was used instead of the halogen lamp as the heat source, and a polymer film was attached to this drum, and oxygen gas and carbon monoxide gas were supplied thereto in the same manner as in Example 2. Spray.

The performance and effects of the metal thin film magnetic recording media according to Examples 1 to 3 as described above will be described.

To evaluate the metal thin film, a commercially available 8mm deck was modified for evaluation, and durability was investigated by conducting repeated running tests. Regarding the rust test, the changes over time were compared under a high temperature and high humidity environment of 60°C and 90%.

The results are shown in the table below.

In the above table, in this case, the value of the conventional example of the repeated durability test is assumed to be 1, and the relative values are shown. In addition, the evaluation method for the rust test was investigated by comparing the changes in appearance under a microscope before and after the test and the running condition on a deck.

As a result, in all of the examples of the present invention, the repeated running durability was improved by one order of magnitude compared to the conventional example, and the RF output was extremely stable.

On the other hand, the appearance of changes over time in the rust test shows that in the conventional example, spotty rust was generated and grew over time, but in the examples of the present invention, no rust was observed. Further, the sample after the rust test was run on an 8 mm deck, and in the conventional example, damage occurred on the tape, but in the example of the present invention, there was no problem.

Next, considering the effects of the embodiments of the present invention, the present invention has a thicker oxide layer on the surface of the magnetic metal thin film than the conventional example.
Auger and ES found that a high-order oxide layer was formed.
This was determined by CA spectroscopic analysis.

It is believed that by forming a high-order metal oxide layer on the surface of the metal thin film in this way, it is possible to form a strong protective layer and improve the durability and rust prevention effect. Of course, in this case, the thickness of the surface oxidation layer is important, and the thicker the protective layer, the better, but since the video characteristics will deteriorate, the optimum value is in the range of about 100 to 200 A.

The reason why the metal oxide layer of the present invention is high-order and uniform is that the heat of reaction between the reactive gas and excess oxygen gas on the magnetic metal surface is utilized, and the excess oxygen left over from the 9 reactions is used to modify the metal surface. This is because

Note that the present invention is not limited to the embodiments, and the same effect can be obtained even if other methods are used. For example, in the embodiments of the present invention, a method for manufacturing a metal thin film type magnetic recording medium by oblique vapor deposition has been described, but the same effect can be obtained for a thin film type perpendicular magnetic recording medium in which the incident angle component is centered around 0 degrees.

Also a halogen lamp to promote reactivity.

Although a heated rotating roller was used, other heating methods such as resistance heating are also possible, and heated gas may be sprayed directly onto the surface of the magnetic metal film. Regarding the type of gas to be sprayed, in addition to carbon monoxide gas, NOI N20 is also used as a reactive gas.
．． Nitrogen oxide cancers such as CN2. CH4, C2
A hydrocarbon gas such as H4, C3H 1, etc., or a reactive gas such as hydrogen gas may be used. Furthermore, the same effect can be obtained by using ozone gas instead of oxygen gas as the oxidizing gas.

Effects of the Invention According to the present invention, it is possible to mass-produce metal thin film type recording media that provide high image quality and are completely free from deterioration in image quality due to repeated running and no rust formation in high temperature and high humidity environments.

[Brief explanation of the drawing]

FIG. 1 is a schematic process diagram showing one embodiment of the present invention, FIG. 2 is a schematic process diagram showing another embodiment of the present invention, and FIG. 3 is a schematic process diagram showing a conventional method. 1... Polymer film, 6... Ferromagnetic metal Go-N
i alloy, 8...Oxygen gas introduction nozzle, 9...Reactive gas introduction nozzle. Name of agent: Patent attorney Shigetaka Awano and 1 other person!・-Reester Fill A 6--- N'fil lra *JA (::o-
Ni joint sac 8- Oxygen gas introduction nosule Q ---RK) Sho case nosule Fig. 1 Fig. 2 @ Fig. 3

Claims (2)

[Claims] (1) A method for manufacturing a metal thin film type recording medium, characterized in that a metal oxide layer is formed by spraying a reactive gas and an oxygen-based gas onto the surface of a magnetic metal formed on a polymer film. (2) The method for manufacturing a metal thin film type recording medium according to claim 1, wherein the metal thin film surface of the magnetic metal thin film is heated.