JPS59144048A - Production of magnetic recording medium - Google Patents

Abstract

PURPOSE:To improve a reaction factor with oxygen as well as a vapor deposition factor to secure a high coercive force by ejecting gaseous oxygen in parallel to the traveling direction of a base material set at a position where a magnetic metal (alloy) is vapor deposited with ejection onto the base material at a minimum incident angle or directly to the base material. CONSTITUTION:A magnetic metal 6 of Co, etc. is vapor deposited to a nonmagnetic base material 2 from a vapor source 7 while moving the material 2 to a take-up roll 5 from a feed roll 3 along a guide roll 4 within a vacuum tank 1. In this case, the gaseous oxygen is ejected to the position where the minimum incident angle theta of vapor deposition is set in parallel to the traveling direction (an arrow mark) of the material 2 or toward the material 2. The high coercive force is obtained when the gaseous oxygen ejection direction is set at an angle alpha=0 deg. in oppositely parallel to the traveling direction of the material 2 or at a plus angle alpha=0-60 deg. toward the material 2. In particular, the highest coercive force is obtained to the flow rate of gaseous oxygen at 0 deg. angle.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a magnetic recording medium, and more specifically, the present invention relates to a method for manufacturing a magnetic recording medium, and more specifically, a method for producing a magnetic recording medium by depositing a deposition material such as a suitable magnetic metal or alloy on a non-magnetic base material in an oxygen atmosphere. This invention relates to a method for manufacturing the resulting thin-film magnetic recording medium, and is particularly aimed at improving the coercive force of the magnetic recording medium.

Conventionally, the coercive force of the resulting magnetic tape is improved by depositing a magnetic metal or alloy onto a non-magnetic base material in an oxygen atmosphere in which the partial pressure of oxygen in a deposition apparatus is higher than that of other gases. There are reports that this is possible. However, this method has the disadvantage that when the partial pressure of oxygen is increased, the free path of the deposited material becomes shorter, resulting in insufficient deposition efficiency or no deposition at all. Further, the directions in which the vapor deposited material is scattered by oxygen are also random, which is disadvantageous. Furthermore, this method is not practical in oblique evaporation because the angle of incidence of the evaporation substance is small and therefore oxygen cannot be preferentially introduced into regions where the evaporation rate is high.

Therefore, the present invention provides a method that can greatly improve the shortcomings of the conventional methods, and in particular, a method that can obtain a magnetic recording medium with significantly improved coercive force compared to the conventional methods. This is what we provide.

According to the present invention, a method for manufacturing a magnetic recording medium includes (2) forming a ferromagnetic thin film by spraying and depositing a deposition substance onto a non-magnetic substrate at an incident angle within a certain range in an oxygen atmosphere; A method comprising:
In a region where the vapor deposition substance is sprayed onto the non-magnetic substrate to be vapor-deposited, oxygen gas is introduced parallel to the running direction of the substrate or toward the substrate at a position where the vapor deposition substance is vapor-deposited onto the substrate at the lowest incident angle. The process consists of performing vapor deposition.

The deposition material used in the present invention may be any material that can form a ferromagnetic thin film of a magnetic recording medium, such as metals such as Fe5Co and Nl, Fe-Co alloy, Fe-N1 alloy, Co -Ni-
Examples include ferromagnetic materials made of alloys such as Fe-B alloys. The deposition material is heated and evaporated using a heating wire, an electron beam, or the like, and then deposited on the nonmagnetic substrate. The incident angle for vapor depositing this vapor deposition material onto a non-magnetic substrate (any incident angle that allows for oblique vapor deposition is sufficient, preferably approximately 60° to 90°. It is preferable that the substance is first deposited on a non-magnetic substrate in a region where the incident angle is large, and then deposited in a region where the incident angle decreases as the substrate moves. Any material conventionally used for manufacturing magnetic recording media can be used. Examples of such non-magnetic substrates include polyesters such as polyethylene terephthalate, polyolefins such as polypropylene, cellulose triacetate, and cellulose diacetate. Examples include cellulose derivatives such as acetate, and polymeric substances such as polycarbonate, polyvinyl chloride, and polyimide.

In this invention, the area where the vapor deposition substance is vapor deposited on the non-magnetic base material (hereinafter referred to as the "evaporation area") is defined as a certain range of incidence angle (θ)l that allows oblique vapor deposition, and thus A deposited material is deposited on a non-magnetic substrate to form a ferromagnetic thin film in a region where = lh poison→礪→壬 means. According to the present invention, in this region, oxygen gas is introduced parallel to the running direction of the substrate or toward the substrate at a position where the vapor deposition substance is deposited onto the substrate at the lowest incident angle. As a method for introducing oxygen gas, in the evaporation region, at a position where the evaporation substance is evaporated onto the base material at the lowest incident angle,
It is only necessary to provide a position that does not prevent the deposition substance from adhering to the base material and an oxygen gas blowing mechanism. This oxygen gas blowing mechanism is preferably configured such that the gas blowing port can be adjusted so that the direction of the oxygen gas flow is parallel to the traveling direction of the substrate or directed toward the substrate. In this specification, the direction of the oxygen gas flow (angle α) is preferably parallel to the running direction of the substrate (α=0°) or at an angle of up to 60° toward the substrate.

According to the method of the present invention, it is possible to increase the vapor deposition efficiency while preferentially increasing the oxygen partial pressure in the vapor deposition region on the non-magnetic substrate without shortening the free path of the evaporated particles of the vapor deposition material. Can be done. In addition, in oblique evaporation, the amount of oxygen can be increased as the amount of evaporated particles of the evaporated material moves from a part with fewer evaporated particles to an area with more. The coercive force is thought to be significantly improved due to the crystal anisotropy as the size of the crystal becomes smaller. Furthermore, it is also conceivable that the appearance of evaporated particles whose actual angle of incidence is larger than the apparent angle of incidence contributes to the improvement of the coercive force.

Hereinafter, the present invention will be explained with reference to the drawings.

FIG. 1 shows an example of an apparatus for carrying out the invention. 1 for a given vacuum e.g. about 1x 10"-5
A non-magnetic base material (2) on which a deposition substance is to be deposited is wound onto a take-up roller (5) from a feeding roller (3) via a guide roller (4) in a vacuum chamber (1) whose temperature is below Thrr. It is located in 6 installed at the bottom of the vacuum chamber (1)
A ferromagnetic thin film is formed by heating and evaporating the vapor deposition substance (6) with a heating means (7) such as a heating wire or an electron beam, and depositing it on the surface of the non-magnetic base material (2) at a predetermined angle of incidence. The vacuum chamber (1) is maintained at a predetermined degree of vacuum by the exhaust system Uυ.In addition, in order to ensure a predetermined angle of incidence, a shielding part (8) is provided to prevent non-magnetic The evaporated particles of the evaporated substance are prevented from directly entering unnecessary parts on the surface of the base material.In addition, the pipe 11 having the nozzle (9)
is arranged in a vacuum chamber (1), and is configured to introduce oxygen gas parallel to the running direction of the substrate or in the direction of the substrate at a position where the vapor deposition substance is deposited onto the substrate at the lowest incident angle. There is. In this specification, as mentioned above, the direction of the oxygen gas flow (angle α) is α = 0° when it is parallel to and opposite to the running direction of the base material, and when the direction facing the base material is an angle of 10. Yes, the direction opposite to the rough board base material is the - angle.

This invention will be explained below with reference to Examples.

Using a vacuum chamber as shown in Figure 1 maintained at a vacuum level of 5 x 10'' Thrr, a vapor deposited layer is deposited on a polyethylene terephthalate film at an incident angle θ of 50° to 90° to a thickness of 800 to 900 A. G was deposited in the same way. In this case, the oxygen gas flow is applied from a nozzle as shown in Figure 1 at various rates between 100crrL3/min and 400crrL5/min, parallel to the running direction of the substrate at the position where 0 is deposited at the lowest angle of incidence. A magnetic tape was prepared by introducing the magnetic tape in the opposite direction (α = 0°) or at an angle of α = 90°. I made a tape.

In addition, as another comparative example, a magnetic tape was prepared in the same manner as in the actual ceramic example, except that no oxygen gas flow was introduced.

The results obtained by measuring the coercive force of these magnetic tapes are shown in FIG. As is clear from this figure, α
A magnetic tape with a high coercive force is obtained when the oxygen gas flow is introduced in the direction of = 01 to 60°, and especially when α = 0'', the highest coercive force is obtained for each oxygen gas flow rate. The angle where α is −

[Brief explanation of the drawing]

Fig. 1 is a schematic sectional view showing an example of a device applicable to the present invention, Fig. 2 is an explanatory diagram of the angle showing the direction of introduction of the oxygen gas flow, and Fig. 6 is an illustration of the introduction angle of the oxygen gas flow and the oxygen gas flow. 3 is a graph showing the coercive force of the magnetic tape obtained when the flow rate of the magnetic tape is changed. In addition, in the symbols used in the drawings, (1)...
・・・・・・・・・・・・Vacuum chamber (2)・・・・・・
......Nonmagnetic base material (6)...
・・・・・・Vapour-deposited substance (8)・・・・・・・・・・・・
・・・・Shielding part (9)・・・・・・・・・・・・・・・
Nozzle θ ・・・・・・・・・・・・Incidence angle α
・・・・・・・・・・・・・・・ Direction of oxygen gas flow (
angle). Agent Masaru Ueya Yoshio Tsuneko Toshiki Sugiura Figure 1

Claims (1)

[Claims] A method for producing a magnetic recording medium comprising forming a ferromagnetic thin film by spraying and depositing a vapor deposited material onto a non-magnetic base material at an incident angle within a certain range in an oxygen atmosphere, the method comprising: Magnetic recording characterized by introducing oxygen gas parallel to the traveling direction of the substrate or toward the substrate at a position where the vapor deposition substance is vapor-deposited onto the substrate at the lowest incident angle in a region where the vapor deposition substance is sprayed onto the substrate. Method of manufacturing media.