JPS61242334A - Production of magnetic disk - Google Patents

Abstract

PURPOSE:To promote the orientation of a magnetic plated film and to improve the squareness ratio and the resolving power and recording density of the electromagnetic transducing characteristics of the titled disk by forming concentric and regular parallel ground traces on the surface of an Ni alloy-plated film as the substrate of the magnetic thin film of the magnetic disk. CONSTITUTION:Ni-P is plated on an aluminum alloy substrate, the surface is mirror-finished and the Ra is regulated in the range 0.01-0.02mum. Then a substrate having parallel and regular ground traces 2 in the circumferential direction 3 is prepared by using a working means such as tape grinding while rotating the substrate. Then a Co-Ni-P magnetic plated film is formed in 0.06mum thickness on the substrate in a wet process and a fluororesin or freon soln. is spin-coated thereon as a lubricant.

Description

[Detailed description of the invention] [Technical field to which the invention pertains]

The present invention is directed to a method of manufacturing a magnetic disk for high-density recording and reproduction, which comprises plating an aluminum alloy substrate with Ni alloy and plating a magnetic thin film made of, for example, a Co alloy thereon.

[Prior art and its problems]

Conventionally, magnetic disks in which magnetic ml is formed using plating technology are plated with N1-P alloy to a thickness of several tens of microns on the surface of an aluminum alloy substrate, and this is coated with a surface roughness of Ra0.0.
Those used were mirror-finished to a thickness of 1μ or less and then plated with a magnetic film. However, with the trend toward higher density recording, further improvements in magnetic properties are required.

[Purpose of the invention]

An object of the present invention is to provide a method for manufacturing a magnetic disk with further improved magnetic properties in response to the above-mentioned requirements.

[Key points of the invention]

The present invention aims to improve the orientation of the generated magnetic plating film because the mirror-finished substrate used in the production of conventional magnetic disks has disordered polishing marks 12 on the surface of the substrate l as shown in FIG. This is based on the recognition that the magnetic characteristics, especially 511 (coreship squareness), which is closely related to recording density, will be deteriorated. The surface is processed to a mirror surface with a surface roughness Ra of 0.02μ or less, and further processed to create concentric parallel polishing marks on the surface,
The above objective is then achieved by plating a magnetic alloy thin film.

[Embodiments of the invention]

Examples of the present invention will be described below along with a comparison column. After applying N1-P plating on an aluminum alloy substrate, mirror-finishing it and forming it to a range of Ra 0.01 to 0.02n, the substrate was rotated and processed using tape polishing or other processing means to form the shape shown in Fig. 1. A substrate according to an embodiment of the present invention having regular polishing marks 2 parallel to the circumferential direction 3 as shown in an enlarged view;
As a comparative example, substrates that had been mirror-finished to a surface roughness of 0.01js or less after N1-P plating were prepared.Next, a wet Co-N1-P magnetic plating film was applied to these substrates.
A sample was prepared by spin-coding a 0.01% Freon solution of fluorine thread resin, DuPont's product name Talitex 15711S, as a lubricant thereon. The sample disk size is 5 x inches. The magnetic properties of the above-mentioned sample were measured using a vibrating magnetometer, and the electromagnetic conversion characteristics were measured using a magnetic head made of Mn-Zn ferrite at a circumferential speed of 2.
Measured at 2.61-1 seconds. The obtained results are the first
．． The magnetic properties shown in Table 2 were measured with the applied magnetic field direction of the vibrating magnetic force measuring device both in the circumferential direction and in the radial direction of the magnetic disk substrate. As can be seen from Table 1 and Table 2, the substrate of the embodiment of the present invention on which concentrically regular band-shaped polishing marks were formed has excellent magnetic properties, and in particular, the squareness ratio S8 is 0 compared to the conventional substrate. .87 to 0.92
and has improved. Furthermore, in the substrates of Examples, the difference in magnetic properties depending on the direction of the applied magnetic field indicates that the parallel and regular polishing marks contribute to the orientation of the plated film. The concentric polishing marks according to the present invention can be effectively formed not only by tape polishing but also by mechanochemical polishing.

【Effect of the invention】

According to the present invention, by forming concentric regular parallel polishing marks on the surface of the Ni alloy plating film as the base of the magnetic thin film of the magnetic disk, the orientation of the magnetic plating film is promoted, and S* and Since the resolution per electromagnetic conversion characteristic and the recording density are improved, a magnetic disk with a high recording density can be easily manufactured.

[Brief explanation of drawings]

FIG. 1 is an enlarged view of the surface of a substrate before formation of a magnetic plating film in an embodiment of the present invention, and FIG. 2 is an enlarged view of the surface of a similar conventional substrate. 1 aluminum alloy substrate, 2: polishing marks, 3: circumferential direction.

Claims (1)

[Claims] 1) After applying nickel alloy plating to an aluminum alloy substrate, processing the surface to a mirror surface with Ra0.02 or less,
A method of manufacturing a magnetic disk, which further comprises processing the surface so that parallel polishing marks are formed in a concentric circle, and then plating a magnetic alloy thin film. 2) A method for manufacturing a magnetic disk according to claim 1, characterized in that concentric parallel polishing marks are formed by tape polishing. 3) A method for manufacturing a magnetic disk according to claim 1, characterized in that concentric parallel polishing marks are formed by mechanochemical polishing.