JPS6220127A - Substrate for magnetic disk - Google Patents

Abstract

PURPOSE:To realize a disk which excels in low defectiveness, chemical stability, surface accuracy and head crush resistance by applying a titanium nitride film for an underlying film of a substrate for a magnetic disk. CONSTITUTION:An aluminum alloy is used as a base body and the titanium nitride film is formed thereon by vapor deposition or sputtering method and further the above-mentioned surface is polished. For example, a 5086 type Al alloy contg. 4.5% Mg is used for the aluminum alloy base body 1 and is finished to 210phi outside diameter, 100phi inside diameter, 1.9t sheet thickness and 0.1mum Rmax surface roughness. After the surface of the Al alloy base body is cleaned, the base body is set in a hollow cathode vapor deposition device in order to form the titanium nitride film and the titanium nitride film 2 is formed to 8.0mum film thickness. The surface is polished to about 1mum after the formation of the titanium nitride film and is finished to 0.05mum Rmax surface roughness, by which the substrate for the magnetic disk is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a magnetic disk substrate, and more particularly to a disk substrate trap having excellent head clarity resistance, surface smoothness, and defect-free property.

[Background of the invention]

As a conventionally known substrate, there is an alumite substrate disclosed in Japanese Patent Application Laid-open No. 48505/1983. However, in order to achieve heat resistance in the 9-piece board, the thickness of the anodic oxide film (alumina) must be 4 (5 μm or less) or less.Therefore, there is an essential problem that the mechanical strength decreases. Furthermore, in order to reduce defects in alumite, it is necessary to increase the purity of aluminum, which has the disadvantage of increasing the cost of the M material.

[Purpose of the invention]

The object of the present invention is to improve the problems of conventionally known substrates,
The objective is to realize a disk with low defectivity, chemical stability, surface area, and head crush resistance.

[Summary of the invention]

The key point of the present invention is to focus on titanium nitride film (TIN), which is a highly hard, strong, and chemically stable material that has a proven track record of being formed on the tips of tools, etc. This is applied to the geological membrane.

[Embodiments of the invention]

Example 1 As an aluminum alloy base, 5086 series AJ alloy containing 4.5% M was used, and the outer diameter was 210ψ and the inner diameter was 10.
0φ, plate thickness 1.9t, surface roughness 0, I Ji
Finished to m Fbnax. Next is AI! After the surface of the alloy substrate was cleaned, it was set in a Horoya sword evaporator to form a titanium nitride film, and a titanium nitride film with a thickness of 8.0 μm was formed under the following conditions.

After forming the titanium nitride film under the above conditions, the surface was
It was polished to a surface roughness of 0.05 μm Rynax and completed as a magnetic disk substrate.

Example 2 In this example, an example in which a magnetic medium is further formed on a substrate will be described.

A titanium nitride film was formed on the M alloy by vapor deposition in the same manner as in Example 1, and then polished to create a substrate. Next, in order to form an iron oxide magnetic thin film on this substrate, after cleaning the substrate surface, F#, o4 (
A thin film (magnetite) was formed using a sputtering method.

After forming the Fg, 04 thin film, the disk is then placed in a thermal oxidation furnace and treated at 500°C x 5A to form γ-Fg,
It was converted into O, (maghematite). Furthermore, a fluorocarbon thread lubricant was applied as a lubricating layer to the top layer, and the magnetic disk was completed.

〔Effect of the invention〕

According to the present invention, it is possible to form a substrate that achieves the above object, and it is possible to obtain a magnetic disk with significantly superior performance compared to those using conventional alumite substrates.

The excellent properties of titanium nitride film will be described below in accordance with the purpose.

Defect-free □Since the formation method is vapor deposition or sputtering, it is deposited on the atomic order (therefore, it is essentially defect-free. However, care must be taken when cleaning the substrate and the purity of the evaporated material.

Chemical stability □Titanium nitride, for example, has been used recently as a coating on the exterior of wristwatches, and has good corrosion resistance and chemical resistance (it is crushed in the manufacturing process. Therefore, it does not generate pinholes on the M substrate). If the film is formed with care, it is possible to achieve long-term corrosion-resistant reliability as a disk substrate.In addition, since titanium nitride is chemically stable, the magnetic t1: of the iron oxide medium formed on it: Reaction, diffusion occurs ((,
It can be said that it is an excellent material in this respect as well.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a magnetic disk substrate according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view of the grooves of a magnetic disk according to another example of the present invention. 1...M alloy substrate 5...Iron oxide magnetic thin film 2...
・Titanium nitride film 4... Lubricating protective film - Attorney Katsutoshi Ogawa. Figure 1 Figure 2

Claims (1)

[Claims] 1. A magnetic disk substrate comprising an aluminum alloy as a substrate, a titanium nitride film formed thereon by vapor deposition or sputtering, and the surface thereof further polished.