JPS63241717A - Magnetic recording body - Google Patents

Abstract

PURPOSE:To provide a magnetic recording medium having characteristics of high coercive force and high resolving power and to prevent the degradation in reproduction output and drop-out of recording by forming magnetic films having multi-layered structure consisting of a hard magnetic material contg. cobalt on a substrate. CONSTITUTION:A cured nonmagnetic underlying film 2 having a prescribed thickness is formed by nickel-phosphorus plating on the substrate 1 consisting of an aluminum alloy. Electroplating is thereafter executed under prescribed conditions by using a plating liquid having a prescribed soln. compsn. to form the magnetic films 3 having the multi-layered structure dividedly in 3 times at a prescribed thickness each. A protective film 4 consisting of chromium and carbon and a lubricating film 5 are then formed thereon. The magnetic film 3 having the multi-layered structure is formed of the hard magnetic material incorporated therein with the cobalt. Such films 3 are made into 2--5-layered structure. The coercive force and resolving power of the recording medium are improved and the residual noise is decreased, by which the density of the recording body is increased and the degradation in reproduction output and drop-out of recording are prevented.

Description

[Detailed description of the invention] Concerning limbs.

[Prior Art] For example, as shown in FIG. 3, a conventional magnetic recording body is made of a hardened M! (2), a magnetic till (3) of Co (cobalt) alloy, a protective film (4), and a lubricating film (S) are formed in this order.

Electroless plating methods and electroplating methods are generally widely used to form the Co--P (cobalt-phosphorous) hard magnetic film used as the magnetic film (3).

For example, Japanese Patent Application Laid-Open No. 48-67130 discloses a method for producing Cci magnetic alloy thin films with high coercive force and high residual magnetic flux density by electroless plating, and Japanese Patent Publication No. 55-14865 discloses a method for producing Cci magnetic alloy thin films with high coercive force and high residual magnetic flux density. A method for producing a magnetic recording medium is disclosed in which a Co-N1-P-based magnetic alloy thin film having magnetic force and good surface gloss is formed by electroless plating.

In addition, the aluminum alloy substrate (1) provided with the N1-P undercoat hardened film (2) was prepared using Co-N1-P as shown in Table 1.
A magnetic film several hundred thick is also formed by immersion in a plating solution.

Table 1 [Problems to be Solved by the Invention] However, in recent years, in order to satisfy the advanced magnetic properties and electromagnetic conversion properties required with the increase in the density of magnetic recording, the above-mentioned magnetic There is a limit to the improvement of magnetic properties and electromagnetic conversion properties in magnetic recording bodies provided with films. Furthermore, the plating process has the problem that it is difficult to avoid defects caused by a reduction in reproduction output or recording defects.

The present invention was made to solve the above-mentioned problems, and by forming a magnetic film (Co alloy magnetic film, etc.) into a multilayer structure, it is possible to improve Hc (coercive force), improve resolution,
The object of the present invention is to create a magnetic recording medium that can lower the S/N ratio (residual noise) and reduce defects.

[Means for Solving the Problems] The present invention relates to a magnetic recording body in which a multilayered magnetic film made of a hard magnetic material containing cobalt is provided on a substrate.

[Function] By configuring the magnetic film as described above, the HC (coercive force) of the magnetic recording medium is improved, and at the same time, the resolution is improved and the S
By lowering the /N ratio (residual noise), higher density of the magnetic recording medium can be achieved. Furthermore, defects caused by a reduction in reproduction output or recording defects can be reduced.

[Example] The magnetic recording body of the present invention has a base cured film, a magnetic film,
This can be achieved by sequentially forming a protective film and a lubricating film.

The substrate is not particularly limited, and includes those conventionally used in magnetic recording bodies, and specific examples include those made of aluminum alloy, glass substrate, ceramic substrate, plastic substrate, etc.

The base cured film is not particularly limited, and may include those conventionally used in magnetic recording media, such as old-P plating film, N1-Cu-P plating film, etc.
, N1-W-P, full v-1', formed on a substrate, and usually having a thickness of 1 to 50 mm.

The magnetic film of the magnetic recording body of the present invention is a multilayered plating film made of a hard magnetic material containing cobalt. Specific examples of such hard magnetic materials include Co-N1-P plating film, Co-Zn-P plating film, Co-P plating film,
Co-Re-P plating film, Co-Hn-P plating film, C
Examples include O-to-P plating films, but especially Go-N
An i-P plating film, a Co-P plating film, and a Co-Zn-P plating film are preferred. The CO content of the hard magnetic material is 50~
It is preferable that the P content is 100% (weight %, the same applies hereinafter), and the P content is preferably 30% or less.

The magnetic film is preferably a plated film made of the hard magnetic material with a thickness of 200 to 3000 layers and has a 2 to 5 layer structure.

If the magnetic film has less than two layers, Hc and resolution tend to decrease, and the S/N ratio tends to increase, and if it exceeds 5 ml, it tends to become difficult to control the film formation.

The method of forming the magnetic film is not particularly limited, and for example, electroless plating, electroplating, or the like can be used.

The protective film is not particularly limited, and may include those conventionally used in magnetic recording media. Specific examples include carbon sputtered films, 5102 sputtered films, TiN sputtered films, etc. It is formed on a film and is usually 100 to 1000 thick.

The lubricating film is not particularly limited, and may include those conventionally used in magnetic recording media, such as those made of perfluoroalkyl polyether, perfluoropolyether, stearic acid, fatty acids, etc. It is formed on a protective film, and usually has a thickness of 10~
200 people can be given.

The magnetic recording body of the present invention has excellent magnetic properties and electromagnetic conversion properties by forming the magnetic film into a multilayer structure as described above, and can reduce defects caused by a decrease in reproduction output and recording defects. This is possible.

Next, the magnetic recording medium of the present invention will be described with reference to more specific examples, but the present invention is not limited only to these examples.

Example 1 The magnetic recording body shown in FIG. 1 was produced as follows. FIG. 1 is a partial sectional view.

A nonmagnetic hardened base film (2) having a thickness of 15 layers was formed on a substrate (1) made of an aluminum alloy by N1-P plating. After that, electroless plating was performed using the plating solution and conditions shown in Table 2,
Multi-layered magnetic film (3) divided into 3 times of 200 layers each
was formed. Thereafter, a film of Cr (chromium) and C (carphone) caranal with a thickness of 400 mm (4) was formed by sputtering, and on top of that, a lubricating film (51e formed L'') with a thickness of 30A made of perfluoroalkyl polyether was formed.・
;-\ [hereinafter 'margin'] One! ' The second expressed coercive force of the magnetic recording medium is measured using a vibrating sample magnetometer (VS
H), and the resolution, S/N ratio, and defects were evaluated using a disk tester, and the average value of each 10 disks was determined. The results are shown in Table 3.

In addition, Fig. 2 shows the magnetic recording material of the present invention having a multi-layered magnetic film with 200 particles per layer (○) and the conventional magnetic recording material having a single layer magnetic film (△). It is a graph showing the relationship between film thickness and coercive force.

From FIG. 2, it can be seen that the magnetic recording material of the present invention exhibits a higher value of coercive force than the conventional magnetic recording material at the same film thickness.

Examples 2 to 3 Example 1 except that the magnetic film was changed as shown in Table 3.
A magnetic recording medium was produced in the same manner as above. The characteristics of the obtained magnetic recording medium were evaluated in the same manner as in Example 1. The results are shown in Table 3.

Comparative Example 1 A magnetic recording body was produced in the same manner as in Example 1, except that the magnetic film was changed to Co-N1-P plating II (single layer) with a thickness of 600 mm. The characteristics of the obtained magnetic recording medium were evaluated in the same manner as in Example 1. The results are shown in Table 3.

[Margin below] Table 3 From the results shown in Table 3, it was confirmed that the magnetic recording body of the present invention has excellent magnetic properties and electromagnetic conversion properties.

[Effects of the Invention] As described above, according to the present invention, by forming the magnetic film into a multilayer structure, it has a high coercive force and high resolution, and in addition, a magnetic film with fewer defects caused by a decrease in reproduction output and recording defects. You can wander around the recording body.

[Brief explanation of the drawing]

FIG. 1 is a partial sectional view showing an embodiment of the magnetic recording body of the present invention, and FIG. 2 is a relationship between the thickness of the magnetic film and the coercive force in the magnetic recording body of the present invention and the conventional magnetic recording body. FIG. 3 is a partial cross-sectional view of a conventional magnetic recording medium. (Main symbols in the drawings) (1) Two substrates (3): Magnetic film thickness Masu Oiwa 1 Figure 3 Figure 0: Multilayer magnetic film Δ: Single layer magnetic film thickness Cλ] Procedure Amendment (voluntary) Showa year month day

Claims (2)

[Claims] (1) A magnetic recording body in which a multilayered magnetic film made of a hard magnetic material containing cobalt is provided on a substrate. (2) The magnetic recording body according to claim (1), wherein the magnetic film has a 2-5 layer structure.