JPS60224122A - magnetic disk - Google Patents

Abstract

PURPOSE:To obtain the titled magnetic disk having excellent durability and provided with a tough and lightweight protective layer having excellent abrasion resistance by coating a magnetic material layer formed on a thin discoid nonmagnetic substrate with titanium oxide or titanic acid. CONSTITUTION:An Ni-P alloy layer 2 and a Co-P alloy layer 3, for example, are formed successively on a discoid nonmagnetic substrate 1 made of an Al alloy, etc. to provide a laminated magnetic layer. A TiO2 layer or a layer consisting of calcium titanate, magnesium titanate, etc. is then formed on the layer 3 as a protective layer 4 by a sputtering method, etc. A lubricant layer 5 is further formed on the layer 4 by coating perfluoropolyether. The highly dependable disk which is not so much abrased by sliding-contact with a magnetic head for a long period and scarcely generates powder due to the abrasion can be obtained in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" This invention relates to a magnetic disk with high surface protection properties.

``Prior Art'' As is well known, a magnetic disk storage device consists of 1 to 10 magnetic disks arranged on the same axis at appropriate intervals and used as a storage medium. Usually one head is provided for each side of the disk, and these are
This device has a structure in which the heads are fixed to two movable mechanisms and move simultaneously in the radial direction of the disk during reading and writing.In this device, in order to increase the recording density, the head It is necessary to keep the distance between the head and the disk surface as close as possible and constant.Currently, a floating head system is used to keep the distance between the head and the disk surface by floating the airflow generated by the high-speed rotation of the disk and the disk surface. Therefore, when the disk is stopped, the head is in contact with the disk surface, and before and after the disk is started and stopped, the head is in sliding contact with the disk surface.

On the other hand, a typical thin film magnetic disk is known to be manufactured by electroless plating. This magnetic disk VcFi has a structure in which a magnetic plating layer is exposed on the surface via a lubricant, and a nickel alloy layer, a cobalt oxide layer, and an organic compound layer are formed as a protective film on the magnetic plating layer. There is also a structure in which a pressure lubricant is applied.

"Problems to be Solved by the Invention" In the conventional magnetic disk having the structure described above, the following problem occurs due to the structural relationship with the head described above, and it is desirable to solve this problem. It is rare.

In other words, in either of the two magnetic disk structures described above, whether there is a magnetic plated layer on the surface or a protective film such as a nickel alloy layer on the surface, these magnetic Since the hardness and abrasion resistance of the plating layer and protective film are relatively low, the head slides against the disk surface when the disk starts and stops, which causes wear on the disk surface over time, resulting in a decrease in output and a head crash due to abrasion particles. This is a problem that occurs.

The present invention was made in view of the above circumstances, and an object of the present invention is to provide a magnetic disk whose surface is less likely to be abraded due to the sliding contact of the head, and whose generation of abrasion particles is hardly observed. be.

The magnetic disk according to the present invention has a titanium oxide layer or a titanate layer having strong and lightweight properties on the magnetic material layer by sputtering or chemical treatment such as hydrolysis. It is designed to protect the surface.

"Function" As described above, the surface of the magnetic disk of the present invention is coated with a tough, lightweight, highly wear-resistant titanium oxide layer such as titanium dioxide or a titanate layer such as calcium titanate or magnesium titanate. Because of this, when using this disk, which comes into sliding contact with the head when it starts and stops, it does not suffer from wear that would cause problems over a long period of time, and therefore does not generate wear particles. #1 Almost never a head crash.

Next, the present invention will be explained in more detail using examples.

``Example'' As shown in the figure, a sufficiently small ridge (
50μm or less in the circumferential direction and 10μm or less in the radial direction)
A nickel-phosphorus alloy layer 2 having a thickness of 0 μm was formed by electroless plating on a disc-shaped aluminum alloy plate 1 which had a finished surface. The surface 2 of this nickel-phosphorous alloy layer 2 &
was polished to a surface roughness RmaxO of 01 μm, and a 0.05 μm thick cobalt-phosphorus alloy layer 3 was formed thereon by electroless plating. Approximately 0.01 μm of titanium dioxide is deposited on this cobalt-phosphorus alloy layer 3 by sputtering.
-4 was formed. Final Pressure Perfluoropolyether was applied as a lubricant on the titanium dioxide layer 4 to a thickness of about 0.01 μm.

The magnetic disk manufactured as described above was subjected to 40,000 cycles of C8
As a result of subjecting it to the S test (contact start/stop test), no change was observed in the electromagnetic conversion characteristics, and no wear particles or head crashes were observed.

This confirmed that the magnetic disk of the present invention has excellent durability, high reliability, and high quality.

Although the above example shows the case where a titanium dioxide layer is formed on the magnetic material layer, it has been confirmed that the same effect can be obtained when a layer of calcium titanate or magnesium titanate is formed. There is.

"Effects of the Invention" As explained above, the magnetic disk according to the present invention has
A titanium oxide or titanate layer, which is strong, lightweight, and highly wear-resistant, is formed on the magnetic material layer by a chemical method such as sputtering or hydrolysis, so the head will not slide over time. The surface is less likely to be abraded due to contact, hardly any abrasion particles are generated, and it exhibits excellent durability, high reliability, and high quality.

[Brief explanation of drawings]

The figure is a cross-sectional configuration diagram showing an embodiment of the present invention. 1... Aluminum alloy plate (non-magnetic substrate), 2...
...Nickel-phosphorus alloy layer (magnetic material layer), 3...
... Cobalt-phosphorus alloy layer (magnetic material layer), 4...
・Titanium dioxide layer. Applicant: Masatake Shiga, Patent Attorney, Tokico Co., Ltd.

Claims (1)

[Claims] +11 A magnetic disk characterized in that a magnetic material layer is formed on a thin disc-shaped nonmagnetic substrate, and the magnetic material layer is coated with titanium oxide or titanate. (2) The magnetic disk according to claim 1, wherein the titanium oxide is titanium dioxide. (3) Claim 1, characterized in that the titanate is calcium titanate or magnesium titanate.
Magnetic disk described in section.