JPH02223008A - Magnetic recording medium and its production - Google Patents

Abstract

PURPOSE:To obtain a magnetic recording medium having a perpendicularly magnetized film suitable for high density recording by using such a perpendicular magnetic recording medium comprising an anodized aluminum layer having fine pores filled with magnetic metal essentially Fe and rendering the Fe particles crystallographically discontinuous. CONSTITUTION:The surface of the substrate is anodized to form an anodized aluminum layer with pores, which are filled with Fe-type ferromagnetic material containing P atoms. In the process of plating the substrate with Fe, a specific amt. of phosphit and/or hypophosphite is added into the Fe plating bath to make the Fe particles in the pores crystallographically discontinuous. When P is incorporated into Fe particles, the crystallographic continuity of the Fe particles disappears, the orientation deteriorates and fine structures appear. Thereby, coercive force of the perpendicularly magnetized film can be controlled at a desired value. The obtd. magnetic recording medium has excellent magnetic characteristics with high recording density.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to magnetic recording media. More specifically, the present invention relates to a perpendicular magnetic recording medium that can control coercive force to an appropriately low level and has excellent perpendicular magnetic anisotropy, and a method for manufacturing the same.

[Prior Art] A magnetic recording medium in which a ferromagnetic metal such as Fe is plated and filled into the fine pores of the alumite produced by anodizing Al or Al alloy has good perpendicular magnetic anisotropy due to its shape effect. It is expected to be used as a high-density magnetic recording medium.

[Problems to be Solved by the Invention] For example, Aλ or A, l! in an oxalic acid bath. When gold alloy is anodized (bath voltage ~40V), the cell diameter of the alumite formed is about 1000, and a cell with a diameter of 1000 is the minimum unit for recording. In a CoCr film, which is a typical perpendicular magnetization film, the column diameter in the film is 200 to 300 people, and the minimum unit during recording is considered to be ~300 people. Therefore, in order to achieve high-density recording comparable to that of a C0Cr film, in the case of an alumite-plated film, it is necessary to reduce the cell diameter. Alumite made using a sulfuric acid bath (bath voltage ~17V) has a small cell diameter of about 450, but a bore diameter of about 1.
50 people, and when Fe plating is performed in this state to deposit Fe in the micropores to form a perpendicularly magnetized film, the perpendicular coercive force shows a large value of 20,000e or more, making magnetic recording with a magnetic head impossible. A problem arises.

Furthermore, when the micropore diameter of the anodic oxide film is enlarged to about 350 mm and the coercive force is reduced to about 5000 e, the shape anisotropy of the perpendicularly magnetized film deteriorates and the distance between each Fe particle decreases. As a result, the magnetic separation between each Fe particle becomes insufficient, the magnetic film shifts from a perpendicularly magnetized film to an in-plane magnetized film, and the perpendicular magnetic anisotropy required for a high-density magnetic recording medium decreases. There was a problem. In addition, in the case of alumite made in the oxalic acid bath mentioned above, in order to control the coercive force to below 10,000e, which is magnetically recordable, the bore diameter must be set to 4
It was necessary to enlarge the area to 00 Å or more.

Therefore, an object of the present invention is to have a perpendicular magnetization film suitable for high-density recording, which has a saturation magnetization of 200 to 600 emu/cc and a perpendicular coercive force of 500 to 10,000 e, in an alumite or Fe-plated film. An object of the present invention is to provide a magnetic recording medium and a method for manufacturing the same.

[Means for solving the problem] In the present invention, as a means for achieving the L1 objective,
A perpendicular magnetic recording medium in which fine pores of alumite produced by anodizing Al or an Al alloy are filled with a magnetic metal mainly composed of Fe, in which the Fe particles are crystallographically discontinuous. Provide the medium.

An example of a method for making Fe particles filled in alumite micropores crystallographically discontinuous is to
The plated Fe is filled with phosphorus (P).
It consists of containing atoms.

In the present invention, in addition to the magnetic recording medium described above, the surface of the substrate made of Al or Al alloy is anodized to produce alumite, and the fine pores of the alumite are filled with Fe-based ferromagnetic material containing P atoms. A method for manufacturing a magnetic recording medium by forming a perpendicularly magnetized film using a Fe plating bath, characterized in that a predetermined amount of phosphite and/or hypophosphite is added to an Fe plating bath filled with Fe plating. A method of manufacturing a magnetic recording medium is also provided.

Alternatively, the surface of the substrate made of A, It or A, It alloy is anodized to produce alumite, and the fine pores are filled with Fe-based ferromagnetic material containing P atoms to form a perpendicularly magnetized film. In a method of manufacturing a magnetic recording medium by forming a Fe-P with a predetermined composition by adding a predetermined amount of hypophosphite and/or at least one compound of phosphites to an Fe plating bath, A plating bath is prepared, dissolved oxygen in the plating bath is removed, the anodized film is immersed in the Fe-P plating bath under an inert gas atmosphere, and the fine pores of the anodized film are electroplated. It is also possible to form a perpendicular magnetization film by precipitating and filling Fe containing a predetermined amount of P atoms.

[Operation] The magnetic properties of the perpendicularly magnetized film in which Fe is plated and filled into the fine pores of the core alumite are determined by considering the magnetic properties and recording/reproducing properties of a CoCr alloy film, which is a typical perpendicularly magnetized film, and the saturation magnetization is set at 200 to 800 emu/ cC, the vertical coercive force is 50
It is preferable to control it to 0 to 10,000e.

Regarding saturation magnetization, it can be adjusted by adjusting the porosity determined from the ratio of the bore diameter and the cell diameter, and can be kept within the above range. On the other hand, the vertical coercive force depends on the bore diameter. In order to control the vertical coercive force to below 10,000 e, which is capable of recording and reproducing, the bore diameter must be set to 4
00 people or more - It is necessary to set it to L. Therefore, the bore diameter is 40
An alumite film with a thickness of less than 0 Å was unsuitable as a recording medium in terms of perpendicular coercive force. Further, when the bore diameter is 400 Å or more, it is impossible to change the coercive force of the plating film without changing the bore diameter. If the bore diameter is increased unnecessarily, the mechanical strength of the cell will decrease and the vertical membrane will shift to an in-plane membrane, which is not preferable. Therefore, in order to obtain a magnetic recording medium with high mechanical strength, it is necessary to minimize the expansion of the bore diameter and control the perpendicular coercive force.

According to the present invention, even if the bore diameter is less than 400 Å, it is possible to control the vertical coercive force to 10,000 e or less by adding P atoms to Fe in the alumite micropores. Further, even if the bore diameter is 4oOÅ or more, it can be used for the purpose of lowering the vertical coercive force without changing the bore diameter.

As mentioned above, 0.28t% or more of P atoms are added to the micropores of the Al anodic oxide film with a bore diameter of less than 400mm.
By precipitating and filling Fe-based ferromagnetic material containing t% or less, the saturation magnetization is in the range of 200 to 600 emu/cc and the perpendicular coercive force is 500, while maintaining the characteristics of a perpendicularly magnetized film. It becomes possible to adjust and control within the range of ~10,000e.

The reason why the coercive force of the alumite-Fe plating film decreases due to the inclusion of phosphorus atoms (P) in Fe will be explained below.

FIGS. 1(a) and 1(b) show transmission electron microscope images of Fe particles taken out from alumite.

As shown in FIG. 1(a), it can be seen that a fine structure exists within the Fe particles when P is included at 12 at%. On the other hand, as shown in FIG. 1(b), when P is not contained, no fine structure is observed.

Figures 2 (a-a) and (b-i) show bright field images of Fe particles with and without P;
-portion) and (b-portion) show their electron diffraction patterns.

Regardless of the presence or absence of P, the diffraction from the (110) plane is the strongest <
, (110) of Fe determined from the diffraction spot of <ii
The o> direction coincided with the long sleeve direction of the Fe particles. However, as shown in FIG. 2 (a-portion), when P is included, (1
10) is wider in the circumferential direction compared to the case without P in Figure 2 (b-port), and the spot with P is more F
The (110) orientation of e-particles is poor.

FIGS. 3(a) and 3(b) show dark-field images formed from the (110) spot of Fe particles. In Figure 3(a), since the P content is 12 at%, the Fe particles are partially brightly imaged with a length of about 0.5 μm in the long sleeve direction, and the length of the single crystal is ~0°5 μm. Conceivable. On the other hand, in the case of FIG. 3(b) which does not contain P, Fe particles are brightly imaged with a length exceeding 2 μm in the long sleeve direction, and Fe exists as a single crystal in this range.

Figure 4 shows (
110) Shows a dark field image formed from a spot. It can be seen that the Fe particles are composed of finer Fe microcrystals than the Fe particles in FIG. 3(a) containing 12 at% P.

From the experimental results described below, when P is contained in Fe particles, the Fe particles lose their crystallographic continuity, their (110) orientation deteriorates, and they begin to have a fine structure inside. As a result, the anisotropy of the acicular Fe particles decreases, the magnetization reversal mechanism approaches buckling mode or fanning mode, and magnetization reversal occurs due to a weak external magnetic field. In other words, it is considered that the coercive force decreases.

A phosphorus compound soluble in the Fe plating bath is used as a source of P atoms added to Fe.

Examples of phosphorus compounds include phosphites and hypophosphites in which the valence of phosphorus is 3 or less, such as sodium phosphite (CNa2HPO3) and sodium hypophosphite (Na
PH202) etc. can be suitably used. Phosphites and hypophosphites can be used alone or in combination of two or more. P whose valence is higher than trivalence is not mixed into Fe. Therefore, phosphoric acid (Ha
Even if P04) is added to the Fe plating bath, it is not incorporated into the Fe in the alumite micropores. In this case, the valence of P is 15, and the electron arrangement of P is the same as that of Ne. Therefore, it is thought that this is related to the fact that 15-valent P is stabilized and does not exchange electrons during plating.

The content of atoms in Fe is preferably 25-0 at% or less; if the content of P atoms exceeds 25.0 at%, the perpendicular coercive force decreases to 5000e, deteriorating the magnetic properties. Undesirable. Regarding the lower limit of the content of P atoms in Fe, even a small amount of P atoms added to Fe is effective in reducing the coercive force, and it is from Ms200 to
Vertical coercive force is 500-10 at 600 emu/cC
It is sufficient if the P atom content can be controlled within the range of 000e, but as an indicator within the film, NO-2at%
It is preferable that it is above.

The content of PM particles in Fe can be controlled by changing the plating conditions such as the plating time, applied voltage, pH1 bath temperature, etc., as well as the concentration of the phosphorus compound added to the plating bath.

The phosphites and hypophosphites used in the production of the magnetic recording medium of the present invention are gradually oxidized by oxidizing species in the air or in the plating bath to become phosphates, which react with Fe in the plating bath. Iron phosphate [Fe3 (PO4)2
etc., resulting in precipitation.

At the same time, the P component in the FeP plating bath decreases, and the composition of the plating bath changes significantly. As a result, the P component contained in the Fe-P plating film also changes significantly in the direction of decreasing,
There is a problem in that the coercive force of the perpendicularly magnetized film that is formed increases, making it extremely difficult to control the coercive force to a preset low coercive force level.

In order to avoid this problem, for example, it is preferable to replace and remove oxidizing species (eg, oxygen) dissolved in the plating layer with an inert gas or the like. As a replacement method, for example, bubbling an inert gas into * (e.g., purified water, deionized water, pure water, etc.) used to prepare the Fe-P plating bath, or; -P is carried out by bubbling an inert gas into the plating bath. The Fe--P plating bath deoxidized as described above is placed in an inert gas atmosphere and electroplating is performed.

With this configuration, oxidation of hypophosphite or phosphite contained in the Fe-P plating bath can be prevented to the maximum, and the composition of the Fe-P plating bath can always be maintained within the set range. A magnetic recording medium having a perpendicular magnetization film that can be maintained constant and whose coercive force is controlled to a desired low level can be obtained.

Examples of inert gases that can be used in the present invention include N2, Art
Such as He or Kr. These gases alone
Alternatively, two or more types can be used in combination as a mixed gas. N2 gas is preferred in terms of availability and cost.

AJ2 or Al alloy can be formed into a film on the nonmagnetic substrate-L by a normal physical vapor deposition method. The physical vapor deposition method itself is well known to those skilled in the art and does not require any particular explanation. Furthermore, an underlayer such as Ti may be interposed between the nonmagnetic substrate and the A, It metal layer.

When a base layer is provided, the thickness of the base layer is not particularly limited. - The thickness within the membrane is preferably within the range of 0.01 μm to 10 μm.

The method of anodizing AJ or Al alloys itself is well known to those skilled in the art and will not be specifically described here.

In addition to aluminum substrates, polyimide may be used as the nonmagnetic substrate used in the magnetic recording medium of the present invention.

Polymer film such as polyethylene terephthalate.

There are Si single-crystal plates whose surfaces are thermally oxidized and the surfaces of metal plates such as glass, ceramics, anodized aluminum, and brass + Si single-crystal plates are subjected to thermal oxidation treatment.

Further, the magnetic recording medium of the present invention includes a magnetic tape or a magnetic disk based on a synthetic resin film such as a polyester film or a polyimide film, a disk or a drum made of a synthetic resin film, an aluminum plate, a glass plate, etc. as a base. It includes various forms of structures that come into sliding contact with a magnetic head, such as magnetic disks and magnetic drums.

[Example code] Hereinafter, the present invention will be explained in more detail with reference to Examples.

Real l[[[ Rolled AJ plate with purity of 99.99% (thickness: 65 μm).

20*mX20+gn) with 5vt% NaOH aqueous solution, washed with water,
Neutralized with 3 aqueous solution. Then 1 mol/λ H2S04
Anodic oxidation (counter electrode: carbon) was performed in an aqueous solution at a current density of I A / d m2 to remove the anodic oxide film.
．． A thickness of 45 μm was formed. The cell diameter and bore diameter at this time were 460 and 150, respectively.

Next, the anodic oxide film was immersed in a lvt% H3PO4 aqueous solution for 9 minutes at 30°C to enlarge the micropore diameter.
The bore diameter was expanded to 250 people. After this, Fe1o411
(NH4)280441E3H20 A mol/o*N
aPHz 02 ・B mol/Jl of H2O.

0.2 mol/Jl of H3BO3 and 2 m of glycerin
, l/J was used to perform electroplating of Fe-P. At this time, 5A+28=l.

While maintaining the relationship O, change B/A between 0 and 5,
The amount of sodium hypophosphite added during plating was adjusted. Add 2N H2SO4 to the plating bath and adjust the pH to 3.
．． 3, and the bath temperature was 22°C. The power supply used for plating was an AC 300Hz sine wave, 16Vp-p (18V on the alumite side.

18V on the counter electrode (carbon) side), 14Vp-p (-8V on the alumite side, 18V on the counter electrode side) and 15Vp
-p (-10V on the alumite side, 15V on the opposite electrode)
It is. Alumite-Fe plating films with different P contents were produced using a plating time of 30 seconds to 5 minutes.

Ura iti In Example 1, 30° C., lvt% H3po.

An alumite-Fe plating film was produced in the same manner as in Example 1, except that the bore diameter was expanded to 220 by immersion in an aqueous solution for 7 minutes.

Blood Type 1 An aluminium)-Fe plating film was prepared in the same manner as in Example 1, except that it was immersed in a 1 wt% H3PO4 aqueous solution at 30°C for 11 minutes and the bore diameter was expanded to 270 mm.

First implementation.

Rolled Al plate with purity 99.99% (thickness 85 ttm
*20ss
Neutralized with aqueous solution. After that, 1 mol/J! of H2SO4
Anodic oxidation (counter electrode: carbon) was performed in an aqueous solution at a current density of s I A / d m 2 to form an anodic oxide film of 0.45 μm. The cell diameter and bore diameter at this time were 460 and 150, respectively.

Next, the anodic oxide film was immersed in a 1wt% H3PO4 aqueous solution for 9 minutes at 30°C to enlarge the micropore diameter.
The bore diameter was expanded to 250 people. After this, Fe50+”
(NH4) 2804 life eH20 50g/λ, 8
3 BO3 15g/λ, glycerin 2m, It/J
Basic Fe plating bath containing Na2HPOa・5H2
0 is Og/λ, 0.28g/J.

0.55g/J! , 1.38g/J, respectively, F
Electroplating of e-P was performed to produce an alumite-Fe plating film, which has a higher P content. The power supply used for plating is A
C300Hz, 15Vp-p, -10 on the alumite side
DC so that 15V is applied to the V1 counter electrode (carbon) side.
Biased. The plating time was 10 to 25 seconds.

FIG. 5 shows the relationship between the P content (abundance ratio to Fe: at%) of the alumite-Fe plating films obtained in Examples 1 to 4 described above and the coercive force in the direction perpendicular to the film surface. In addition, P*
Quantification of Fe was performed using EPMA (wavelength dispersive X-ray microanalyzer), and coercive force measurement was performed using VSM (sample vibrating magnetometer).

As is clear from this figure, as the P content increases, the coercive force decreases. From the figure, the P content is 0.2~
By changing it to 25.0 at%, it becomes possible to freely control the coercive force within the range of 500 to 10,000 e even when the pore diameter is less than 400 Å.

FIG. 6 shows the relationship between the P content and the saturation magnetization of the plated film. In the case of not containing P, the saturation magnetization of the alumite-Fe plated film was 410 emu/in Examples 1 and 4.
cc (value calculated from porosity 0.25 is 430 emu
/cc), in Example 2, 320emu/cc (
The value calculated from the porosity of 0.20 is 340 emu/cc)
In Example 3, it was 470 emu/cc (the value calculated from the porosity of 0 and 285 was 490 emu/cc). In either case, it is approximately % lower than the value calculated from the porosity.
Although small, this is thought to be caused by iron oxide or disordered pores. As the P content increases, the saturation magnetization decreases, but does not fall below 200 emu/CC.
It is thought that this will not have a large effect on output reduction.

Immediately outside I 1 Rolled AJl plate with purity of 99.99% (thickness 658 m *
After the same pretreatment as in Example 1, anodic oxidation (counter electrode: carbon) was performed using a constant voltage of 40 V in a 3 vt% oxalic acid bath.
Anodized aluminum with a thickness of . The cell diameter and bore diameter at this time were 960 and 320, respectively. Next, 30
The above sample was immersed in a 1 wt % phosphoric acid aqueous solution at ℃ for 19 minutes, and the bore diameter was expanded to 500. After this, after this,
F e S 04・(NH4)2 SO4・6H20 at 50 g/J.

83 15g/J of Bo3 and 2mJ of glycerin! /
NaPH2O2/N20 in the basic Fe plating bath containing λ gold
Og/J! , 0.14g/J, 0.88g/J2.1
．． 35 g/λ was added to perform Fe-P plating. The I)H of the bath was adjusted to 3.0 with 2N H2SO4, and the bath temperature was 22°C.

Power supply using Mekkino! tAc500Hz, 15Vp-p
- 10V on the alumite side, 15V on the opposite electrode (carbon) side
A DC bias was applied so that V was applied. The plating time was 7 to 10 minutes.

FIG. 7 shows the relationship between the molar ratio of NaPHz 02 /Fe2 nions in the plating bath and the coercive force of the film. NaP820
When 2m is added, a coercive force of 8000e is exhibited, but as the molar ratio of NaPH2O2 in the plating bath increases, the coercive force decreases. In this way, even when the bore diameter is 400 Å or more, by including P in Fe, the coercive force can be controlled without increasing the bore diameter (in this example, the bore diameter is constant at 500 Å). becomes possible.

L five 1 Rolled AJ plate with purity of 99.99% (thickness: 85 μm).

Anodic oxidation (counter electrode: carbon) was performed in 2N sulfuric acid at a current density of I A / d m2 using a 0.45 μm thick aluminum anodic oxide film ( alumite) was formed. At this time, the cell diameter and bore diameter were 460 and 15, respectively.
There were 0 people. Next, at 30°C, lvt% phosphoric acid (83P
O4) The sample was immersed in an aqueous solution for 9 minutes to expand the bore diameter of the anodic oxide film to 0.025 μm.

In preparing the Fe-P plating bath, pure water (distilled water)
N2 gas was bubbled inside for about 1 hour to replace dissolved oxygen in the water with N2 gas. 50 g/J of Mohr's salt was added to the pure water that had been replaced with N2 gas.

Boric acid 1 g/J, glycerin 2 m J/J!
, 1.4 g/J of sodium hypophosphite was dissolved, 2N sulfuric acid was added, and the pH was adjusted to 3.0.

This Fe-P plating bath is placed in a plating tank, the entire plating tank is surrounded by a vinyl draft, and while N2 gas is continuously introduced into the draft from the outside at a flow rate of 150 mλ/min, the bore diameter of the anodic oxide coating is Fe--P plating was applied to the surface of the sample subjected to the enlargement treatment to produce a perpendicularly magnetized film having the cross-sectional structure shown in FIG. The power supply used for Fe-P plating was AC 300 Hz, 15 Vp-p, and a DC bias was applied so that -10 V was applied to the anodized film side and 15 V was applied to the counter electrode (carbon) side, and the plating time was 20 seconds. . Under these conditions, using the samples provided with the above-mentioned anodic oxide film, Fe-
When P plating was performed and the P content in the Fe-P plating film of each sample was investigated, the P content was 7.5 to 8.
．． It showed 0 at%.

The solid line a in FIG. 8 shows the relationship between the vertical coercive force (kOe) of the alumite/Fe-P plating film produced by the method of this example and the number of times the alumite/Fe-P plating film is formed. show. As is clear from the figure, according to the method of the present invention, it is possible to control the coercive force of the perpendicularly magnetized film to a nearly constant level of about 8000e even if the aluminium/Fe-P plating film is formed more than 50 times. I understand.

The inert gas used in Example 6 was changed from N2 gas to A.
r s Except for changing to He or Kr gas,
An alumite/Fe-P plating film was formed in the same manner as in Example 6. When the coercive force of the perpendicularly magnetized film thus formed was examined, results almost similar to those shown by the solid line in FIG. 8 were obtained.

Anonymous story 1 In Example 6, alumite/Fe was produced in the same manner as in Example 6, except for bubbling N2 gas into pure water and surrounding the plating bath with a draft of N2 gas atmosphere. - A P plating film was formed to produce a perpendicular magnetization film.

Coercive force of perpendicular magnetization film and alumite in this comparative example
The relationship between the number of times the F e -P plating film is formed is shown at point a in Figure 8.
Shown in b. As shown in the figure, in Comparative Example 1, in which the dissolved oxygen in the Fe-P plating bath was not removed and the plating bath was not surrounded with an inert gas, the The coercive force in the vertical direction starts to increase after the number of times the aluminium)/Fe-P plating film is formed, and increases to more than 13,000e when the number of times of formation is around 50, and the Fe-P plating bath in this comparative example is This indicates that the ability to control the coercive force to a set low level is lost.

[Effects of the Invention] As explained above, according to the present invention, Fe, etc. filled in the alumite micropores can be By incorporating P atoms into the ferromagnetic metal and adjusting the content, the perpendicular coercive force can be increased from 500 to 10,000 e at saturation magnetization within the range of 200 to 600 emu/cc.
can be freely controlled within the range of

In addition, by removing oxidizing species from the plating bath and plating atmosphere, oxidation of hypophosphite or phosphite in the Fe-P plating bath is effectively prevented, and the amount of P contained in Fe is can be held almost constant at any preset value.

As a result, it becomes possible to control the coercive force of the perpendicularly magnetized film to an arbitrary set value, and a perpendicular magnetic recording medium having excellent magnetic properties capable of achieving high-density recording by a magnetic head is obtained.

Needless to say, in addition to the adjustment of the P atom content according to the present invention, conventional adjustment of physical factors can also be used.

[Brief explanation of the drawing]

Figure 1(a) is a photograph showing a bright field image of Fe particles containing 12 wt% P by a transmission electron microscope, and Figure 1(b)
) is a photograph showing a bright field image of Fe particles that do not contain P, taken by a transmission electron microscope, and (a) in Figure 2 (a) is a photograph showing a bright field image of Fe particles containing 12 wt% P, taken by a transmission electron microscope. (b) in Figure 2(a) is a photograph showing the electron diffraction pattern, and (b) in Figure 2(b) is a photograph showing the electron diffraction pattern.
A) is a photograph showing a bright field image of Fe particles that do not contain P by a transmission electron microscope, FIG. a)
is a photograph showing a dark-field image of Fe particles containing 12 wt% P, FIG. 3(b) is a photograph showing a dark-field image of Fe particles containing no P, and FIG. 4 is a photograph showing a dark-field image of Fe particles containing 25 wt% P. F to do
This is a photograph showing a dark field image of e-particles, Figure 5 is a characteristic diagram showing the relationship between P content and perpendicular coercive force, and Figure 6 is a characteristic diagram showing the relationship between P content and saturation magnetization. Figure 7 is a characteristic diagram showing the relationship between the molar ratio of NaPHz 02 /F132+ ions and the perpendicular coercive force, and Figure 8 is a characteristic diagram showing the relationship between the number of times the alumite/Fe-P plating film is formed and the vertical coercive force of the perpendicularly magnetized film produced. 9 is a characteristic diagram showing the relationship with directional coercive force, and FIG. 9 is a schematic diagram showing a cross-sectional structure of a magnetic recording medium having a perpendicularly magnetized film manufactured in Example 6. 1...Aluminum substrate. 2...Anodic oxide film. 3...Fe-P plating film. 4...Alumite/F e-P plating membrane Patent distributor Hitachi Maxell Co., Ltd. Agent Patent attorney Kore Kajiyama

Claims (19)

[Claims] (1) A perpendicular magnetic recording medium in which alumite micropores formed by anodizing Al or an Al alloy are filled with a magnetic metal mainly composed of Fe, characterized in that the Fe particles are crystallographically discontinuous. magnetic recording media. (2) In a perpendicular magnetic recording medium in which alumite micropores formed by anodizing Al or Al alloy are filled with magnetic metal mainly composed of Fe, the plated F
2. The magnetic recording medium according to claim 1, wherein e contains a phosphorus (P) atom. (3) The magnetic recording medium according to claim 2, wherein the content of P in the Fe plated into the micropores is 0.2 at% or more and 25.0 at% or less. (4) Saturation magnetization of perpendicular magnetization film is 200 to 600 emu/
In the cc range, the vertical coercive force is 500 to 10
3. The magnetic recording medium according to claim 1, wherein the magnetic recording medium is within the range of 000e. (5) The magnetic recording medium according to claim 1 or 2, wherein the micropores have a diameter of less than 400 Å. (6) The magnetic recording medium according to claim 2, wherein the P atoms in the Fe plated into the micropores are derived from phosphite and/or hypophosphite. (7) Phosphite is sodium phosphite (Na_2HP
7. The magnetic recording medium according to claim 6, wherein the hypophosphite is sodium hypophosphite (NaPH_2O_2). (8) The surface of the substrate made of Al or Al alloy is anodized to produce alumite, and the fine pores are filled with Fe-based ferromagnetic material containing P atoms to form a perpendicularly magnetized film. In the method of manufacturing a recording medium, Fe
A method for producing a magnetic recording medium, comprising adding a predetermined amount of at least one compound of hypophosphite and/or phosphite to an Fe plating bath filled with plating. (9) Phosphite is sodium phosphite (Na_2HP
9. The method for manufacturing a magnetic recording medium according to claim 8, wherein the hypophosphite is sodium hypophosphite (NaPH_2O_2). (10) The method for manufacturing a magnetic recording medium according to claim 8, wherein the content of P in the Fe plated into the micropores is 0.2 at% or more and 25.0 at% or less. (11) Saturation magnetization of perpendicular magnetization film is 200 to 800 emu
/cc, the vertical coercive force is 500 to 1
9. The method of manufacturing a magnetic recording medium according to claim 8, wherein the magnetic recording medium is within a range of 000 Oe. (12) The method for manufacturing a magnetic recording medium according to claim 8 or 10, wherein the diameter of the micropores is less than 400 Å. (13) The surface of the substrate made of Al or Al alloy is anodized to produce alumite, and the fine pores are filled with Fe-based ferromagnetic material containing P atoms to form a perpendicularly magnetized film. In the method of manufacturing a recording medium, F
A Fe-P plating bath having a predetermined composition is prepared by adding a predetermined amount of hypophosphite and/or at least one type of phosphite compound to an e-plating bath, and dissolved oxygen in this plating bath is was removed, and the Fe-
The anodic oxide film is immersed in a P plating bath, and Fe containing a predetermined amount of P atoms is precipitated and filled into the fine pores of the anodic oxide film by electroplating to form a perpendicularly magnetized film. A method for manufacturing a magnetic recording medium. (14) The means for removing dissolved oxygen in the Fe-P plating bath includes bubbling an inert gas into the water used for preparing the Fe-P plating bath, or
14. The method of manufacturing a magnetic recording medium according to claim 13, further comprising bubbling an inert gas into the plating bath. (15) The method for manufacturing a magnetic recording medium according to claim 13 or 14, wherein the inert gas is at least one type of gas selected from the group consisting of N_2, Ar, He, and Kr. (16) Phosphite is sodium phosphite (Na_2H
14. The method for manufacturing a magnetic recording medium according to claim 13, wherein the hypophosphite is sodium hypophosphite (NaPH_2O_2). (17) The method for manufacturing a magnetic recording medium according to claim 13, wherein the content of P in the Fe plated into the micropores is 0.2 at% or more and 25.0 at% or less. (18) Saturation magnetization of perpendicular magnetization film is 200 to 600 emu
/cc, the vertical coercive force is 500 to 1
Claim 13 characterized in that it is within the range of 000 Oe.
A method of manufacturing the magnetic recording medium described above. (19) The method for manufacturing a magnetic recording medium according to claim 13 or 17, wherein the diameter of the micropores is less than 400 Å.