JPS59201228A - Manufacture of magnetic recording medium - Google Patents

Abstract

PURPOSE:To reduce the coefficient of dynamic friction of a magnetic layer, and improve running performance and corrosion resistance by irradiating the surface of the magnetic layer opposite to a base with energy particles which contain oxygen during or/and after the formation of the surface part. CONSTITUTION:The surface part of the magnetic layer opposite to the base is irradiated with energy particles which contain >=10eV, specially, 10eV-10keV energy during and/or after the formation of the surface part. The energy particles contain normally 20at% oxygen. Ion gas is used for said irradiation. The ion gas makes the gas into plasma by cold cathode discharge, etc., and a gas component and an active neutral gas component which are ionized as mentioned above are extracted to strike the surface part. Thus, the coefficient of dynamic friction of the magnetic layer is decreased to improve running performance and corrosion resistance.

Description

DETAILED DESCRIPTION OF THE INVENTION 1. Background of the Invention Technical Field The present invention relates to a magnetic recording medium, and particularly to a magnetic recording medium having a continuous thin film type magnetic layer formed by a so-called oblique evaporation method.

Prior art and its problems As magnetic recording media for video, audio, etc., media having a continuous thin film type magnetic layer are being actively developed because of their continuous nature when wound into tapes.

Due to its characteristics, the magnetic layer of such a continuous thin film type medium is made of a Co-based, Co-Ni-based, etc. material formed by the so-called oblique evaporation method, in which the evaporation is performed at a predetermined angle to the normal to the substrate. Membranes are preferred.

However, such a medium has a disadvantage in that the dynamic friction coefficient of the surface of the magnetic layer is large and running properties are poor. Moreover, the corrosion resistance is also insufficient.

On the other hand, in order to improve runnability and corrosion resistance, various proposals have been made to form various top coat layers on the surface of the magnetic layer, but this increases the number of manufacturing steps, which is undesirable.

Furthermore, if the magnetic layer is formed in the presence of oxygen, oxygen is introduced to the surface of the magnetic layer, resulting in improved runnability and corrosion resistance, but these improvements are still insufficient. Moreover, it is difficult to control how to balance magnetic properties, runnability, and corrosion resistance. Furthermore, the introduction of oxygen causes problems in the operation of the apparatus and also causes the disadvantage that the molten metal oxidizes in the crucible.

On the other hand, when forming the magnetic layer on the surface opposite to the substrate,
It has been proposed to blow oxygen or, instead of, or in addition to this, to bring the film forming area into a discharge state.

At this time, inconveniences in the operation of the device are reduced, but improvements in running performance and corrosion resistance are insufficient.

Furthermore, it is known that various oxidation treatments are performed after the magnetic layer is formed, but this method is also insufficient in improving runnability and corrosion resistance, and has the disadvantage of increasing manufacturing costs due to the increased number of steps. be.

II. OBJECTS OF THE INVENTION The main object of the present invention is to provide a magnetic layer with a small dynamic friction coefficient;
It is an object of the present invention to provide a method for manufacturing a magnetic recording medium having a continuous thin film type magnetic layer, which has significantly improved runnability and corrosion resistance, and is free from various manufacturing inconveniences.

Such objects are achieved by the invention described below.

That is, in the case of forming a continuous thin-film type magnetic layer on a non-magnetic substrate, the present invention provides a method in which energetic particles containing oxygen are added to the surface of the magnetic layer on the side opposite to the substrate during and/or after formation. This is a method of manufacturing a magnetic recording medium characterized in that the magnetic recording medium is directed toward the surface portion.

■Specific structure of the invention Hereinafter, a specific configuration of the present invention will be explained in detail.

In the present invention, oxygen-containing energetic particles are directed to the surface of the magnetic layer opposite the substrate during and/or after formation.

In this case, even if conventional oxygen is introduced, the effects of the present invention will not be achieved unless oxygen is introduced as energetic particles.

In the present invention, 10 eV or more, especially 1 OeV to 1 O
It irradiates energetic particles with KeV energy.

The energetic particles contain oxygen.

Oxygen contained in energetic particles is oxygen ion (02
-, 02+, etc.).

Alternatively, neutral oxygen (02, active neutral oxygen 021, etc.)
It may be.

And these oxygens are usually present in energetic particles with 20
At% or more is contained. In addition, the energetic particles may contain argon, nitrogen, helium, ozone, etc. in addition to oxygen.

To irradiate energetic particles containing such oxygen ions, an ion gun can be used.
Gas is turned into plasma by cold cathode discharge or the like, and the ionized gas components and active neutral gas components are extracted and irradiated as a beam.

In this case, the energy of the particle is 1 (leV~10Ke
V, operating pressure is about 0.1 to 100 Pa, beam size is about 10 to 100 mm x 10 to 1000 mm,
The gun-substrate gap t may be about ±10 to 500 mm.

Then, from such ion gun irradiation, energetic particles containing oxygen ions and neutral oxygen are irradiated.

It is also possible to use a neutral particle gun.

A neutral particle gun irradiates gas by removing ionized components from the beam output when it turns gas into plasma and takes out a beam.

In this case, the particle energy is 1OeV to 1OKe
The operating pressure may be approximately 0 V, the operating pressure approximately 1-100 Pa, the beam size approximately 10-10100XIO-1000, and the gun-substrate gap to approximately 500 mm.

Then, by such neutral can irradiation, neutral active oxygen gas is irradiated.

The energetic particles containing oxygen are directed at the stage of forming the surface of the magnetic layer opposite to the substrate, or afterward, or both.

In this case, the stage of forming the surface portion of the magnetic layer opposite to the base body is 273, more preferably 33, the thickness of the magnetic layer.
It is preferable that the magnetic layer is formed to a thickness of /4.

The energetic particles may be irradiated at any time within the range of the film formation stage. It is preferable that the temperature be 1/mu.

Note that these energetic particles may be irradiated onto the surface of the magnetic layer after film formation, preferably immediately after film formation.

The magnetic layer in the present invention includes CO, Co-Ni, C
o-Cr, Co-Ti, Co-Mo, Co-
V, Co-W, Co-Re, C.

It may have various known compositions such as -Ru, Go-Mn, Co-Fe, Fe, etc., and can be formed by vapor deposition, ion blating, etc.

However, the effect of the present invention is most significant when a magnetic layer is formed on a substrate by a so-called oblique evaporation method, in which a magnetic layer having a composition mainly composed of CO, containing O, and further containing Ni and/or Cr as necessary. This is the second case.

That is, it may be made of CO alone, or it may be made of CO and Ni. If Ni is included, Co/N
The weight ratio of i is 1.5 or more.

Furthermore, the magnetic layer may contain Cr.

When Cr is contained, electromagnetic conversion characteristics are improved, output and S/N ratio are improved, and film strength is also improved.

In such cases, Cr/Co or Cr/(Co
The weight ratio of Ni) is preferably 0.001 to 0.1, more preferably 0.005 to 0.05.

Then, 0 is introduced into the magnetic layer by irradiation with the oxygen-containing energetic particles described above, or in addition to this, by performing vapor deposition in an oxygen-containing atmosphere as described later.

The amount of oxygen in the magnetic layer is O/(Co or Co+
Ni) atomic ratio, more preferably 0.5 or less, especially 0
．． It is preferable that it is 05-0.3.

V, Zr, Nb, Ta, Ti, Zn, Mo, WCu
etc. may be included.

The magnetic layer made of such components is preferably formed by an oblique vapor deposition method.

In this case, the minimum value of the incident angle of the vapor deposition substance with respect to the normal to the substrate is preferably 20° or more.

When the incident angle is less than 20', electromagnetic conversion characteristics deteriorate.

Note that there are no particular limitations on the vapor deposition conditions other than these.

That is, the vapor deposition atmosphere is an inert atmosphere such as argon, helium, vacuum, etc., or an atmosphere containing low-level oxygen gas, and the pressure is about 5 10 The structure, arrangement, etc. of the can and mask may be the same as known conditions.

In this case, oxygen can be contained in the vapor deposition atmosphere to improve electromagnetic conversion characteristics and corrosion resistance, but according to the present invention, the amount of oxygen at this time is 1O-3Pa.
As a result, there is no problem with the operation of the apparatus, and the oxidation of the vapor deposition material solution in the crucible is reduced.

By such an oblique vapor deposition method, a magnetic thin film consisting of an aggregate of columnar crystal grains mainly composed of Co is formed on the substrate.

In this case, the thickness of the magnetic thin film is 0.05 to 0.5 gm, preferably 0.07-0.3 JJ, m.

The columnar crystal grains have a length spanning almost the entire thickness direction of the thin film, and the longitudinal direction thereof is inclined at an angle of 10 to 70 degrees with respect to the normal to the main surface of the substrate. There is.

Further, the short axis of the crystal grains has a length of about 50 to 500 A.

The substrate on which such a magnetic thin film is formed is not particularly limited as long as it is non-magnetic, and is preferably a flexible substrate, especially one made of resin such as polyester or polyimide.

In addition, the thickness may be various, but especially 5.
It is preferable that it is 20 gm.

In this case, various known back coat layers may be formed on the back surface of the magnetic layer forming surface of the substrate.

Then, R of the surface roughness height of the back surface of the magnetic layer forming surface
It is preferable that the MS value is 0.05 JLm or more.

This improves electromagnetic conversion characteristics.

Note that various known underlayers may be interposed between the base and the magnetic layer, if necessary.

Note that, if necessary, the magnetic layer may be divided into a plurality of parts and a nonmagnetic layer may be interposed between them, or various top coat layers may be formed on the magnetic layer.

(2) Specific Effects of the Invention The magnetic recording medium according to the present invention is useful as a medium for video, audio, computers, various types of floppy disks, and perpendicular magnetization.

According to the present invention, the coefficient of dynamic friction on the surface of the magnetic layer is extremely low, and a medium with extremely good running properties is realized.

In addition, the medium has very good corrosion resistance.

Furthermore, since the process can be carried out in the same chamber without changing the film forming conditions during or immediately after film formation, manufacturing is extremely easy and there are no various inconveniences as in conventional methods.

(2) Specific Examples of the Invention Specific examples of the present invention will be shown below to explain the present invention in further detail.

Example 1 Using an alloy with a Co/Nt weight ratio of 4, 12
A magnetic layer with a thickness of 0.2 pm was formed on a polyethylene terephthalate film substrate with a thickness of IJ, m by an oblique vapor deposition method.

The substrate is continuously conveyed by a can, and the incident angle of the vapor deposition material is 90.
~40°. In addition, the vapor deposition atmosphere is P = 1
The pressure was set at 0-2 Pa.

Ar This sample for comparison is designated as AO.

Separately, the vapor deposition atmosphere was set to 2 P = 10 Pa, P = 3X10-2
A comparative sample A1 obtained as PaA r O2 was prepared.

In addition, while discharging with ACIKV on the film-forming area from the surface of the magnetic layer opposite to the base to a 0°03 gm thick part,
Comparative sample A2 was prepared in the same manner as sample AO by blowing oxygen gas at 50 m1/u+in.

On the other hand, according to the present invention, oxygen ions + neutral oxygen and neutral oxygen were irradiated with an ion gun and a neutral particle gun to the film-formed part from the surface of the magnetic layer opposite to the base to a 0.03 JLm thick part. .

The gun-substrate gap of the ion gun was 150 mm, the beam output was 100 mA, the acceleration voltage was IKV, and the oxygen sources were Ar and 02.

Further, the gun-substrate gap of the neutral particle gun was 100 mm, the beam output was 25 mA, the particle energy was 2 KeV, and the oxygen sources were Ar and O2.

Let these samples be B1, B2, B3, and B4.

Table 1 shows the dynamic friction coefficients of each of these samples before and after running 50 passes on the magnetic layer surface.

Further, each of these samples was subjected to a running test using a commercially available VH3 device.

The results are shown in Table 1 using O, Q, Δ, and ×.

Furthermore, each sample was stored at 50° C. and 90% relative humidity for 7 days, and the degree of deterioration of φm −Δφm (%) was measured.

The results are shown in Table 1.

From the results shown in Table 1, the effects of the present invention are clear.

Example 2 Co/Ni/Cr=65/30/
Using an alloy of 5 (weight ratio), 2 FA, = 10 Pa, P = 10-2 Pa
Sample A5 was obtained in the same manner as in Example 1 under the conditions of Example 2.

In addition, samples B5 and B6 were obtained using an ion gun and a neutral particle gun in the same manner.

These results are shown in Table 2.

Table 2 After initial pass (%) A 5 0.35 Unmeasurable ×30 (comparison) B5 0.25 0.25 ■
5 or less (ion can) B6 0.25 0.25 ■
5 or less (neutral particle gun) From the results shown in Table 2, the effects of the present invention are clear.

Applicant TDC Co., Ltd. Agent: Patent Attorney Yo Ishii -

Claims (1)

[Claims] 1. When forming a continuous thin film type magnetic layer on a non-magnetic substrate, energy containing oxygen is applied during and/or after the formation of the surface portion of the magnetic layer opposite to the substrate. A method for manufacturing a magnetic recording medium, characterized in that particles are directed toward the surface portion. 2. The method for manufacturing a magnetic recording medium according to claim 1, wherein the oxygen is an oxygen ion. 3. The method for manufacturing a magnetic recording medium according to claim 1 or 2, wherein the oxygen is neutral oxygen. 4. The time to direct the energetic particles is after the magnetic layer has been formed to 2/3 of the thickness of the magnetic layer, i.
4. The method of manufacturing a magnetic recording medium according to claim 1, wherein the method is performed immediately after the surface of the magnetic layer opposite to the substrate is formed. 5. The energy of energetic particles is 10eV to 10
The method for manufacturing a magnetic recording medium according to any one of claims 1 to 4, wherein the magnetic recording medium is KeV. 6. According to any one of claims 1 to 5, the magnetic layer is formed by evaporating the evaporation material by making it incident at an angle oblique to the normal to the magnetic layer forming surface of the substrate. A method of manufacturing a magnetic recording medium. 7. Does the magnetic layer consist of CO and O or CO, O and N?
7. The method for manufacturing a magnetic recording medium according to any one of claims 1 to 6, which comprises one or two of i and Cr. 8. The method for manufacturing a magnetic recording medium according to claim 7, wherein the magnetic layer contains Ni and the weight ratio of Co/Ni is 1.5 or more. 9. The magnetic layer contains Cr, Cr/(Co or Co+
The method for manufacturing a magnetic recording medium according to claim 7 or 8, wherein the weight ratio of Ni) is 0.001 to 0.1. 10. O/(Co or Co+Ni) in the magnetic layer
The method for manufacturing a magnetic recording medium according to any one of claims 7 to 9, wherein the atomic ratio of is 0.5 or less. Il, the thickness of the magnetic layer is 0.05 to 0.5 Bm
A method for manufacturing a magnetic recording medium according to any one of claims 1 to 10.