JPS63117320A - Production of magnetic recording medium - Google Patents

Abstract

PURPOSE:To permit formation of a nitrided film having a uniform nitrogen concn. in a depth direction on a moving film substrate by forming nitrogen ions by plural pieces of ion sources and adjusting the ion current density from the ion sources in such a manner that the nitrogen concn. of a magnetic layer is kept constant in the depth direction. CONSTITUTION:The nitrogen ions are formed by plural pieces of the ion sources 11, 12, 13 arranged in the progressing direction of the moving nonmagnetic substrate 7 and the ion current densities from the ion sources 11, 12, 13 are individually so adjusted that the nitrogen concn. of the magnetic layer is kept constant in the depth direction in the case of producing a magnetic recording medium by forming the magnetic layer on the substrate by projecting a magnetic metal diagonally to the above-mentioned substrate 7 and projecting the nitrogen ions onto the substrate 7. Formation of the magnetic layer having the excellent characteristics, corrosion resistance and wear resistance even on the moving magnetic substrate is permitted by maintaining nearly the uniform nitrogen concn. of the magnetic layer in the depth direction.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Industrial Application Field The present invention relates to a method of manufacturing a magnetic recording medium such as a magnetic tape.

(1. Conventional technology) In recent years, as the demand for higher density magnetic recording has increased, magnetic recording media have been manufactured using thin film forming methods such as vacuum evaporation, sputtering, and ion blasting. The magnetic recording medium formed by method C2 has the following characteristics: 6) a high residual magnetic flux density; 2) a large coercive force; and 2) the ability to make the magnetic layer thinner.

Compared to the conventional coated magnetic recording medium C, high-density recording is possible.

Conventionally, l is used as a magnetic material for metal thin film magnetic recording media.
A Co--Ni alloy containing zo to 5 oat% of Ji is used as the main material. However, it is expensive because it contains 70 or more cod, and its corrosion resistance under high temperature and high humidity is not sufficient.

In order to improve the above-mentioned drawbacks, a method using iron nitride (FeN-based) as the magnetic material was proposed, as disclosed in Japanese Patent Application Laid-Open No. 60-59537 (IP G11 B5/85). has been done.

As shown in Figure 4C2 (: Fe (4) in the evaporation material container (3) is attached to the substrate (2) fixed in the vacuum chamber (1).
Simultaneously with electron beam evaporation, a FeN thin film was formed by irradiating with nitrogen ions (61) from the ion source (5) (r'/D method, process on analyte).
porDeposition method). The coercive force (He) and squareness ratio 131 of this FeN thin film are almost the same as those of the Qo-Ni thin film.

In this way, when forming an F15N thin film on a stationary substrate (;), if the deposition rate of Fe and the amount of ion current of nitrogen ions arriving at the substrate are controlled constant, the composition ratio of the FeN thin film will change depending on the depth. Direction C is almost uniform. Figure 6 shows the concentration distribution in the depth direction of the FeN film formed by this method.
This is a diagram showing the results of analysis using 50A (photoelectron spectroscopy), and as can be seen from this diagram, the concentration distribution is almost uniform from the film surface to the substrate interface.

On the other hand, when mass-producing the FeN film formed by IVD method 1 as a vapor deposition tape, as shown in FIG. l-G is the winding roller α (Ic transport).

On the circumferential surface of the cooling can (9), the polymer film substrate (71CF e (4)) was deposited with an electron beam and at the same time nitrogen ions (611) were irradiated to form a FeN thin film.

At that time, the oblique incidence angle and deposition rate of Fa were set as above substrate (7).
It changes moment by moment as the position of 1 changes.

That is, in FIG. 5C, F at each point A, B, and O
・The deposition rate of R(l, R41Bl, R(1
[01+! : Surt, the relationship 1R (ltAl>R11
iBl>R(LIC+. Therefore, nitrogen ion (6
) is uniform within the shaded area, then the degree of nitridation of the film at points A, B, 0 and C;
I, YIOI are respectively Y prisoner < Y (R1(Y (C1
The relationship is as follows, and the degree of nitridation decreases by # and a toward the film surface. Figure 7 is a diagram showing the results of analyzing the concentration distribution in the depth direction ζ2 of the FeN film formed by this method using B80A. I can see that

The magnetic properties of the FeN film formed using the apparatus shown in FIGS. 4 and 5 are as shown in the table below.

As can be seen from the above table, C is
Second, it is necessary to further increase the degree of nitridation.

However, as shown in FIG. 7, when the degree of nitridation is increased, the nitrogen concentration at the interface with the substrate increases significantly.

A problem arises in that the saturation magnetization (M8) decreases.

In addition, it was found that in the FeN film as described above, the nitrogen concentration on the film surface was reduced, and the wear resistance and corrosion resistance were deteriorated.

l/, l Problems to be Solved by the Invention The present invention has been made in view of the drawbacks of the conventional examples described above, and involves forming a nitride film having a uniform nitrogen concentration in the depth direction on a moving film substrate. The object of the present invention is to provide a method for manufacturing a magnetic recording medium that makes it possible to achieve the following.

2)) Means for solving the problem A magnetic metal is obliquely incident on a moving non-magnetic substrate, and at the same time, the substrate is irradiated with nitrogen ions to form a magnetic layer on the substrate (magnetic recording). In the method for producing a medium, the nitrogen ions are created using a plurality of ion sources, and the ion current density from the ion sources is adjusted so that the nitrogen concentration of the magnetic layer is constant in the depth direction: do.

(e)) Effect: According to the method described above, the magnitude of the ion current density irradiated on the substrate differs depending on the irradiated portion C2, and the deposition rate of magnetic metal in the irradiated portion (: Then, by adjusting the ion current density from the ion source, the nitrogen concentration in the irradiated part (1) is uniform in the depth direction. It becomes constant.

(F) Embodiment An embodiment of the present invention will be described in detail below with reference to one drawing.

FIG. 1 is a sectional view of the magnetic tape manufacturing apparatus of this embodiment.

Vacuum chamber (inside the unwinding roller (8) 1 winding roller f
iol.

cooling can (9), vapor deposition material storage container (3), and first
゜Second. Third ion sources aυfi21 (13) are arranged.

(7) is a polymer film substrate such as polyethylene terephthalate (PET) or polyimide;
) is sent from the unwinding roller (8) to the winding roller file via the cooling can (9).

A vapor deposition material (Fl (41) is placed in the vapor deposition material storage container (3), is placed facing the cooling can (9), and is heated by an electron beam from an electron beam generation source (not shown). The heated vapor deposition material (4) is
Tona 9. Film substrate (7) on the cooling can (9)
C adheres to the film substrate (7) due to the shielding plate 051.
) The incident angle of the vapor flow a4 reaching the top (the angle between the direction of the vapor flow α4 and the normal to the film substrate (7)) is at least 55
is regulated.

Said 1st. Second. The sixth ion source αUα 3 is a Kakufuman type ion source arranged along the traveling direction of the film substrate (7), and the ion source is connected to a gas introduction tube (not shown).
The introduced nitrogen gas is internally ionized, and an ionic current (161αDC18) made of the nitrogen ions is applied to the film substrate (7) at the same time as the 1Q vapor flow (14).

At the same time, magnetic material is deposited on the film substrate (7) by the vapor flow a4, and at the same time, the first ion source α1. Second ion source Q3. Ion current σe10n in the order of sixth ion source α3
+21. I 1on(3) to husband tz, rion(
1) (I on (2K I 1 on (3J) 1: From this, the non-uniform composition distribution as shown in FIG. 7-1 is improved.

Note that the degree of vacuum in the vacuum chamber (1) is kept constant during film formation by an exhaust device t19C.

Next, Example 1.2 in which a magnetic tape was created using the method described above.
I will explain about it.

(Example 1) A magnetic layer was prepared on a film substrate under the following conditions.

Evaporation material F e (99,99%) Electron beam power 10. OKW Film feed speed 78 m/min Oblique incidence angle of ion current First ion source (Ill 90 ~ 70° Second ion source a3 70 ~ 60° Sixth ion #fi3 60 ~ 55° Nitrogen ion current density First ion source ( lu 2mA/at second ion (
12120rnA/ai 6th ion source (13100mA
/- Under these conditions, a FeN film with a thickness of 0.2 μm was formed on a film substrate, and the concentration distribution of 7e and N in the depth direction of 1% FeN is shown in FIG. Looking at this second factor, the composition distribution in the depth direction of this FeN film is shown in Figure 7-1.
- It can be seen that the film is much more uniform than the conventional FeN film shown.

In addition, the magnetic properties of this F 8 N 11% are determined by the coercive force (
HO) Snow 1050 (oθ), squareness ratio (81-0, 80,
The saturation magnetization (M a ) was -250"u/CC, and almost the same result as the FeN film formed on the stop film substrate was obtained.Also, the wear resistance and corrosion resistance: The results were comparable to those of the FilN film formed in 1995.

(Example 2) Under the conditions of Example 1, in order to increase the degree of nitridation, the first.
Second. A magnetic layer was prepared on a film substrate by changing the sixth ion source αLlα2σ3 as follows.

Oblique incidence angle of ion current First ion source 1υ 80 to 65° Second ion source α21 65 to 58° Third ion 03 58 to 55° Nitrogen ion current source First ion source fill 2 mA/j Second ion source yf
fp, ri7J 10 mA/cd 51st on #113 150mA/j Under these conditions, the film thickness was 0.
A 2 μm FeN film is formed on a film substrate, and the FeN film is
FIG. 3 shows the concentration distribution of Fe and N in the depth direction C of the N film. Looking at FIG. 6, it can be seen that the degree of nitridation increases toward the film surface.

In addition, the magnetic properties of this FeN film are coercive force (HQ) -98
0 (Oe), squareness ratio -0.83, saturation magnetization (M s )
-350emu/ca, with high saturation magnetization (Ma
) was obtained. Also.

Both abrasion resistance and corrosion resistance exceeded FISN films formed on stop film substrates.

In this example, only the case where Fet was used as the evaporation material was described; however, the present invention is not limited to this, but a magnetic material mainly composed of
It is also effective when -Co, Fe-0r, Fe-N1, and alloys thereof are used as vapor deposition materials.

(G1) Effects of the Invention According to the present invention, by making the nitrogen concentration of the magnetic layer almost uniform in the depth direction (-), C on the moving non-magnetic substrate also has excellent magnetic properties, corrosion resistance, and wear resistance. A method for manufacturing a magnetic recording medium that makes it possible to form a magnetic layer can be provided.

[Brief explanation of the drawing]

1 to 6 relate to the present invention, FIG. 1 is a sectional view of a magnetic tape manufacturing apparatus, and FIGS. 2 and 3 are FIN
This is a factor that indicates the composition distribution in the depth direction of the film.
7 to 7 are conventional examples (-) FIGS. 4 and 5 are sectional views of a magnetic tape manufacturing apparatus, respectively, and FIGS. 6 and 7 are views showing the composition distribution of a FIN film, respectively. (4)...Magnetic material (Fe) (magnetic metal), (7
)...Film substrate (non-magnetic substrate), au'a (L
3... 1st. 2nd ° 3rd ion source, C161 (l addition a... ion current.

Claims (1)

[Claims] (1) A method for manufacturing a magnetic recording medium in which a magnetic layer is formed on a moving non-magnetic substrate by obliquely injecting a magnetic metal onto the substrate and irradiating the substrate with nitrogen ions, the method comprising: creating the nitrogen ions with a plurality of ion sources arranged along the direction of movement of the substrate;
A method of manufacturing a magnetic recording medium, characterized in that the ion current density from the ion source is individually adjusted so that the nitrogen concentration of the magnetic layer is constant in the depth direction.