JPS5960738A - Production of magnetic recording medium - Google Patents

Abstract

PURPOSE:To obtain a magnetic recording medium having excellent durability and high reliability by heating a substrate and intrducing ozone into vapor flow in the stage of forming a ferromagnetic layer on the substrate. CONSTITUTION:A magnetic metal 11 in a crucible 10 is melted by an electron beam 12 and sticks in the form of magnetic flow on the surface of a polymer film substrate 6. A film is formed in this case by introducing gaseous ozone 16 from an ozonizer 15 into the vapor flow of the magnetic metal. The generation of the gaseous ozone 16 is accomplished by the silent electric discharge of gaseous oxygen 19 by a water-cooled discharge tube 17. The oxidation condition on the surface of the vapor-deposited film in the case of using Co metal is such that the most of the magnetic layer consists of CoO in the prior art; whereas, in this embodiment the composite of the higher oxide such as stable Co3O4 and Co2O3 is formed as a protective film near the surface layer although the oxidation state of CoO is dominant in the internal layer of the magnetic metal. The oxidation by the gaseous ozone is much accelerated particularly when the substrate is kept heated during the vapor deposition. The heating temp. is preferably 40-150 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a magnetic recording medium product using a vacuum evaporation method.

Conventional Structures and Problems There has been remarkable technological development in magnetic recording media in recent years, as seen in the improvement in magnetic recording density. Representative examples of conventional magnetic recording media include γ-Fe203 powder and CrO.
There is a so-called coating type magnetic recording medium in which a polymer film is coated with powder, pure iron powder, etc. together with a binder. However, in order to increase the coercive force, other magnetic properties, and recording density of this coated type, recently, ferromagnetic metals such as Fe, Ni, Co, etc. have been used alone or in alloys using oblique incidence evaporation and ion blating methods. Vapor-deposited thin film magnetic recording media, which are vapor-deposited on molecular film substrates, have been studied.
A magnetic recording medium having high coercive force and high recording density has been obtained. However, vapor-deposited thin film magnetic recording media have a short history and have not yet been sufficiently studied from the viewpoint of mass production and industrial aspects compared to coated tapes. For example, the adhesion strength between a polymer film and a magnetic metal in a vacuum evaporation method, the non-uniformity of the deposited film due to the influence of outgas generated when depositing a magnetic metal, the reliability when used as a magnetic tape,
There is an urgent need to improve durability.

Purpose of the Invention The present invention has been made in view of the above-mentioned problems in the prior art.
The purpose is to easily obtain a highly reliable magnetic recording medium.

Structure of the Invention The present invention provides a method for forming a ferromagnetic layer on a substrate by directing a vapor flow of a ferromagnetic metal toward a substrate using a vacuum evaporation method.
It heats the substrate and introduces ozone into the vapor stream.

DESCRIPTION OF EMBODIMENTS Prior to a detailed description of the present invention, a conventional example will be specifically described to facilitate understanding.

FIG. 1 shows a manufacturing apparatus used in a conventional manufacturing method, including a vacuum evaporation apparatus main body 1, a film running system 2. Magnetic metal evaporation source 3. Vacuum exhaust system 4. and an introduction gas system 5. The polymer film substrate 6 has an unwinding shaft 7vrC
It is set, passed through the rotary can 8, taken up and unwound, and then wound up. Magnetic metals (Co, Ni, etc.), which are evaporation materials, are placed in a crucible 10 made of heat-resistant ceramic and placed at the bottom of the can 8.

(Fe, Cz, etc.) 11 is put in and melted with an electron beam 12 from an oblique direction. The evaporated magnetic metal is partially masked by a mask 13, and only the components necessary for forming the magnetic thin film are deposited. Then, during vapor deposition, oxygen gas 14 is introduced into the vapor flow of the magnetic metal to form a film having electromagnetic conversion characteristics necessary for a vapor deposition tape. The film substrate 6 deposited on the left side of the drawing is sent to the right and wound up on a winding shaft 9.

Now, a detailed description of the present invention will be entered.

An example of a manufacturing apparatus used in the manufacturing method according to the present invention is shown in FIG.

This manufacturing apparatus includes a vapor deposition apparatus main body 1, a film running system 2, a magnetic metal evaporation source 3, a vacuum exhaust system 4, and also has an ozone generator 15 connected to the vapor deposition apparatus main body 1. The magnetic metal 11 in the crucible 10 is melted by the electron beam 12 and becomes a vapor flow that adheres to the surface of the polymer film substrate 6. In this case, ozone gas 16 is introduced from the ozone generator 15 into the magnetic metal vapor flow. , to form a film. Ozone gas 16 is generated by a discharge tube 1 in which oxygen gas 19 is cooled with water.
This is done by silently discharging in step 7. Silent discharge power supply 1
8 used an ion transformer, and oxygen gas 19 was introduced by adjusting the pressure and controlling the flow rate from an ordinary gas cylinder.

It was also found that oxidation by ozone gas is more accelerated when the material is deposited in a state where it is evaporated. The temperature for heating and keeping warm is 40
℃~150℃ was suitable. The reason why the present invention has particularly excellent durability under high temperature and high humidity is that ozone gas is introduced into the vacuum chamber during vapor deposition to transform the magnetic metal into a protective film and modify it into a stable high-order oxide. . In addition to CO metal, Fe.

Even when Cr and Ni metals were used, although the oxidation states were different on the internal and external surfaces, they were modified to a higher oxidation state by introducing ozone gas, similar to the vapor deposition of CO gold metal.

In carrying out the present invention, the same effect can be obtained even if two or more types of magnetic metal alloys are deposited. A similar effect can be obtained by changing the method of generating and introducing ozone gas, or by mixing other gases with ozone gas.

Effects of the Invention According to the present invention, it is possible to easily obtain a highly reliable magnetic recording medium that has excellent durability in repeated running at high temperature and high humidity.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a manufacturing device used in the conventional method, and FIG. 2 is a diagram showing an example of the manufacturing device used in the method of the present invention. 1... Vacuum evaporation device main body, 3... Evaporation source, 6
...Polymer film substrate, 8 ... Rotating can, 15 ... Ozone generator. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure fOq Figure 2

Claims (1)

[Claims] When directing a vapor flow of a ferromagnetic metal toward a substrate by a vacuum evaporation method to form a ferromagnetic layer on the substrate, a magnetic method characterized by heating the substrate and introducing ozone into the vapor flow. A method for manufacturing a recording medium.