Method of polishing a magnetic hard disc substrate

Abstract

Polishing particles are made of artificial diamond produced by a shock method, having density of 3.0-3.35 g/cm³ and including secondary particles with average particle diameter of 30 nm-500 nm. Such polishing particles are produced by firstly obtaining a product containing artificial diamond by a shock method, then subjecting this product to an acid treatment by using one or more strong acids such as concentrated sulfuric acid, concentrated nitric acid and concentrated hydrochloric acid to thereby remove impurities from and wash the product, thereafter subjecting the product to a classification process to thereby separate artificial diamond of a first kind having secondary particles with particle diameters of 30 nm-500 nm and artificial diamond of a second kind having secondary particles with particle diameters in excess of 500 nm and selecting artificial diamond of a third kind having density of 3.0-3.35 g/cm³ out of the artificial diamond of the first kind. It is the artificial diamond of the third kind that is to be used as the diamond polishing particles.

Description

[0001]This is a continuation-in-part of application Ser. No. 10 / 974,867 filed Oct. 26, 2004, now pending, through which priority is claimed on Japanese Patent Application 2003-366851 filed Oct. 28, 2003, which is herein incorporated by reference in its entirety.BACKGROUND OF THE INVENTION[0002]This invention relates to a method of polishing a magnetic hard disc substrate and more particularly to polishing particles dispersed inside polishing slurry and diamond polishing particles suitable for the polishing and texturing process of a magnetic hard disc substrate as well as a method of producing such particles.[0003]Data processors such as computers adapted to record and play back data such as characters, images and voices require an increased data recording capacity and accuracy in playback. Data are recorded magnetically on a magnetic hard disc by means of a magnetic head of a data processor and played back from such a magnetic hard disc. The recording capacity for data and accuracy...

AI Technical Summary

Benefits of technology

[0014]By using such diamond polishing particles according to this invention, it is possible to form clear textured line mar

Problems solved by technology

If they are used for the texturing process of the surface of a glass substrate, this non-diamond carbon portion covering the surface portion acts on the substr

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