JPS61123016A - Magnetic disk - Google Patents

Abstract

PURPOSE:To improve the uniformity of the characteristics of a thin magnetic metallic film layer and to realize good durability by providing an activated plating layer into which fine particles are dispersed on an underlying plating layer. CONSTITUTION:A substrate 1 is subjected to underlying plating. The surface of the formed underlying plating layer 2 is then smoothed by polishing and is degreased and thereafter the surface is subjected to a pretreatment such as sensitizing and activating if necessary. The pretreated surface is subjected to Ni-P plating, etc. so that the activated plating layer 3 is formed thereon. The fine particles 4- are preliminarily dispersed into the plating bath, by which the particles 4- are incorporated into the layer 3. The surface is then subjected as quickly as possible to Co-Ni-P plating, etc. to form the thin magnetic metallic film layer 5.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a magnetic disk using a magnetic metal thin film layer as a recording medium, in which the uniformity of the characteristics of the magnetic wire mesh thin film layer is improved and good electromagnetic properties are achieved. It is designed to have a high durability and even better durability.

[Prior art and its problems]

As a magnetic disk that uses a magnetic metal thin film layer as a recording medium,
There is one in which a base plating I- is formed by Higashi-P plating or the like on a substrate made of an aluminum alloy or the like, and a magnetic metal thin film is formed on this base plating layer by Ni-Co-P plating or the like. After applying base plating on the substrate, this base plating layer has a surface roughness of approximately Rm.
a x Q, polished to 1 μm or less,
It is fabricated by forming a magnetic metal film layer.

By the way, with such conventional magnetic disks,
Processing distortion caused by polishing sometimes remained on the polished base plating layer.

Further, after polishing, an oxide film was sometimes formed on the surface due to contact with the atmosphere. If processing strain or oxide film remains in this way, the surface activity of the base plating layer will be non-uniform, so if a magnetic metal thin film layer is formed on such a base plating layer, this magnetic metal thin film layer has non-uniform magnetic properties, and the resulting magnetic disk is
This results in poor electromagnetic characteristics, such as large signal modulation. For this reason, conventional magnetic disks have been dissatisfied with the inability to produce disks with excellent electromagnetic properties at a high yield.

[Means for solving problems]

Therefore, in the present invention, the disadvantages of conventional magnetic disks are solved and good electromagnetic characteristics can be obtained by providing an activated plating layer in which fine particles are dispersed on the base plating layer.

〔Example〕

FIG. 1 shows an example of a magnetic disk of the present invention, and the number 1 in the figure is a board. This substrate 1 is made of an aluminum alloy plate, a ceramic plate, or the like, and is processed to have less waviness on the surface. This board 1
A base plating layer 2 is formed on top. The base metal key 2 is for smoothing minute irregularities on the surface of the substrate 1, and is formed by applying N1-P plating or the like to a thickness of about 10 to 30 μm by electroless plating, for example.

The surface of this base plating layer 20 is polished to a surface roughness ζ (Rmax) of approximately 0.1 μm using K such as super polish.

An activated plating layer 3 is formed on this base plating 1-2. This activated plating layer 3 is for making the surface activity uniform. This activated plating layer 3 is
It has a film thickness α of 1 μm to 1.0 pm, and is formed by N1-P plating or the like by a plating method such as electroless plating. The film thickness of this activated plating layer 3 is α1μ
If it is less than m, the surface activity cannot be made uniform enough, and if the film thickness exceeds 1.0 μm, the surface smoothness obtained by polishing the base plating layer 2 will deteriorate, and any The case is also unfavorable.

Further, in the magnetic disk of this example, fine particles 4 are dispersed in the activated plating layer 3.

These fine particles 4 are for reinforcing the disk surface and improving the contact start/stop (CSS) characteristics of the magnetic disk. The fine particles 4 preferably have a particle size of about 0.1 to 2.0 μm.

This consists of the active plating layer 3 and the magnetic gold supplementary thin film 1-, which will be described later.
This is because if the film thickness is smaller than the sum of the film thicknesses of 5 and 5, a sufficient reinforcing effect cannot be obtained. In addition, the fine particles 4 include alumina (A
＾0. ), silicon carbide (SIC), silicon nitride (s i
, N4), silica (S1o, ), diamond (C),
Carbon, T i C, WC', B4 C%MO2C
.

Cr5C,, TtNs WSi, , TtB, , Cr
Fine particles of high-strength materials that have a reinforcing effect, such as B, Man, ZrQ, etc., and fine particles of materials that have a lubricating effect with a small friction coefficient, such as boron nitride (BN), molybdenum disulfide (MoS), and graphite, are used. It will be done. These fine particles 4 may be used alone, or two or more of them may be mixed in an arbitrary ratio, and further, particles having a #-j reinforcing effect and particles having a lubricating effect may be mixed and dispersed. As shown in FIG. 1, these fine particles 4 are dispersed so that some of them partially protrude from the surface of a magnetic metal thin film layer 5, which will be described later. Further, the amount of dispersion (mixing amount) of the fine particles 4 into the activated plating layer 3 is as follows:
Approximately 1 to 10" pieces per gram. YO per surface.
If the number is less than 10', a sufficient reinforcing effect cannot be obtained, and if the number exceeds 10', the activated plating layer 3 and the magnetic metal thin film layer 5 become brittle, the mechanical strength decreases, and the magnetic recording medium This is disadvantageous because it increases the number of media defects.

A magnetic metal thin film layer 5 is provided on the activated plating layer 3. The magnetic metal thin film layer 5 serves as a magnetic recording medium, and is made of Co-N by electroless plating, for example.
i-P plating, Co-P plating, etc. have a thickness of a05~1
It is formed to have a thickness of about 5 μm.

Next, a method for manufacturing this magnetic disk will be explained with reference to FIG.

To manufacture this magnetic disk, first, substrate IK underplating is applied (SPl). Next, the surface of the base plating layer 2 formed here is polished to make it smooth (SP2).
. Next, wash (SP) [, degrease (SP4)
> l, then perform sensitizing (sps
), pre-processing for activating (sp6) is performed. Next, N1-P plating or the like is applied to this material to form an activated plating layer 3 (SP7). At this time, by dispersing the fine particles 4 in the plating bath, the fine particles 4 are mixed into the activated plating layer 3.

Next, as soon as possible after the activation plating step (SF3), Co-Ni-P plating or the like is applied to this material to form a magnetic metal thin film layer 5 (8PB), thereby obtaining the intended magnetic disk. .

[Effect]

In such a magnetic disk, since the activation plating I-3 is provided on the base plating layer 2, processing distortion and oxide film due to polishing finish remain on the surface of the base plating layer 2.
Even if the surface activity of the base plating 1-2 is non-uniform, the activation plating layer 3 provided on the base plating layer 2 makes the surface activity uniform. Therefore, it is possible to easily form a magnetic metal thin film 715 with uniform magnetic properties, film thickness, etc. on this activated plating layer 3.

In addition, in the magnetic disk of this example, some of the particles 4 are exposed on the surface of the magnetic disk, so when the magnetic head slides or hits the surface of the magnetic disk, the particles first 4... will collide. Therefore, this magnetic disk has less frictional damage caused by the magnetic head and has excellent C8S properties.

Furthermore, in the magnetic disk of this example, fine particles 4 having a reinforcing effect are mixed and dispersed in the activated plating layer 3 which is on the base plating layer 2 and is spaced from the disk surface. This means that fine particles 4 having a large particle size can be used. Therefore, the selection conditions for the fine particles 40 used in this magnetic detach are relaxed, making it easier to select the fine particles 4 and manufacturing the fine particles 4, reducing the price of the fine particles 4, improving the performance, and improving the magnetic disk 2. It is possible to reduce manufacturing costs and improve performance.

Note that the magnetic disk of the present invention is not limited to the above embodiments. For example, a protective layer or a lubricating layer may be provided on the magnetic metal thin film layer 5 in order to further improve the C8S properties of the magnetic disk. Further, the position where the fine particles 4 for reinforcing the disk surface are dispersed is not limited to the activated plating layer 3, but may be roughly dispersed in the protective layer or the like.

[Experiment example]

Prototype a magnetic disk with the following specifications, and its electromagnetic characteristics, C8
The S-character was examined.

Substrate 1: Aluminum alloy, thickness 1.9 Undercoat plating layer 2: Electroless N1-P plating, thickness ζ 20 μm 1 Surface roughness Rmtx) Polished to 0,1 pm or less Activated plating layer 3: Electroless N1-P Plating, thickness 05μ
m fine particles 4; Ae, 01 fine particles c particle size nominal α4μm)
The amount of dispersion was 600 to 700 particles per 1 surface area.

Magnetic metal thin film layer 5; Co-N1-P plating, average thickness 1
1 μm When the film thickness of the magnetic metal thin film layer 5 of this magnetic disk was examined, it was confirmed that the average r was 1.1 μm with a variation of less than ±20%, and that the uniformity of the film thickness of the magnetic metal thin film layer 5 was improved. Ta. Furthermore, when we investigated the electromagnetic properties of this magnetic disk, we were able to confirm that the signal modulation was small and that it had excellent electromagnetic properties.

Furthermore, when this magnetic disk was subjected to a 4x1o'ti C8S test, no head crash occurred.
There was no deterioration in electromagnetic properties, and it was confirmed that this magnetic disk had excellent durability.

〔Effect of the invention〕

In the magnetic disk of the present invention, an activated plating layer is provided on the base plating layer, and fine particles are dispersed in the activation plating. Even if there is an oxide film, it is made uniform by the activation plating I-, and the non-uniform surface activity of the underlying plating layer does not affect the formation of the magnetic metal thin film 11 that will become the recording medium. Therefore, this magnetic disk has uniform magnetic properties, film thickness, etc. of the magnetic metal thin film layer, has excellent electromagnetic properties, and can be produced at a high yield, resulting in excellent productivity.

Further, since fine particles having a reinforcing effect are mixed and dispersed in the base plating layer, fine particles having a large particle size can be used. Therefore, the selection conditions for the particles used in this magnetic disk are relaxed, and the manufacturing of the particles becomes easier, reducing the price and improving the performance of the particles, thereby reducing the manufacturing cost and improving the performance of the magnetic disk. That makes me blue.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of the magnetic disk of the present invention, and FIG. 2 is a process diagram showing a method for manufacturing the same magnetic disk. l...Substrate, 2...Base plating 1gj
13...Activation plating 1-15...Magnetic metal film Ifd.

Claims (1)

[Scope of Claims] A magnetic disk in which a magnetic metal thin film layer is formed on a substrate via a base plating layer, wherein an activated plating layer is provided on the base plating layer, and an activated plating layer is provided in the activated plating layer. A magnetic disk characterized by having fine particles dispersed therein.