Abstract: A foamed polishing sheet for use in a free particle polishing method using abrading particles with average particle diameter less than 0.1 &mgr;m is produced by applying a foaming paint of a foaming resin on a surface of a form-providing film such as a plastic film, foaming the foaming paint by a wet foaming method to form a foamed sheet on the surface of the form-providing film, and peeling off the foamed sheet from the form-providing film so as to form a polishing surface on the foamed sheet having the same shape as the surface of the form-providing film.

Abstract: An agent used for texturing a surface of a substrate for a magnetic disk includes an aqueous solution containing a glycol compound serving as surfactant in an amount of about 1-25 weight % and agglomerated polycrystalline diamond particles with average diameter of 0.01-2 &mgr;m in an amount of 0.001-3 weight % formed with very small polycrystalline diamond particles with average diameter of 1-20 nm. When the substrate surface is textured, the substrate is rotated, the agent is supplied to the target surface to be textured and a polishing tape is pressed and run against it. A substrate thus processed has a surface with very fine and uniform textured lines without any abnormal protrusions.

Abstract: A polishing tape makes use of a foamed material such as polyurethane foam attached to a plastic backing material. The foamed material is elastic and some of its gas holes formed inside but near one of its surfaces are exposed externally. Because of its elastic nature, it can be deformed even if there are abnormally large abrading particles contained in a liquid slurry and such abrading particles do not become embedded in the target surface being textured. These externally exposed gas holes can also serve to absorb the debris generated by the texturing and to protect the target surface from being scratched thereby. Such a tape is used for a texturing process while dropping a liquid slurry containing abrading particles and rotating the disk substrate and pressing the tape against the target surface.

Abstract: A polishing tape makes use of a foamed material such as polyurethane foam attached to a plastic backing material. The foamed material is elastic and some of its gas holes formed inside but near one of its surfaces are exposed externally. Because of its elastic nature, it can be deformed even if there are abnormally large abrading particles contained in a liquid slurry and such abrading particles do not become embedded in the target surface being textured. These externally exposed gas holes can also serve to absorb the debris generated by the texturing and to protect the target surface from being scratched thereby. Such a tape is used for a texturing process while dropping a liquid slurry containing abrading particles and rotating the disk substrate and pressing the tape against the target surface.

Abstract: Polishing compositions with phosphoric ester added to a suspension containing abrasive particles can have an improved ability to have the abrasive particles dispersed again after they are left for an extended period of time such that the particles may have condensed into aggregates. Those with abrasive particles such as diamond powder dispersed in an aqueous solution containing a glycol compound, metallic salt of a higher aliphatic acid and phosphoric ester have an improved polishing ability.