Abstract: A workpiece is processed by abrading a surface of its amorphous coat layer (12) over a substrate (10) such that Ni particles (13) and crystallized compounds (14) of Ni and P are produced locally and only on the surface of the coat layer (12) and along grooves (17) formed by abrading. Mechanical strength and anti-corrosive property of the coat layer can thus be maintained, and ferromagnetic materials can be affixed thereon and can be magnetized in a desired direction.

Abstract: An object of the present invention is to provide a method for manufacturing a magnetic hard disk wherein a magnetic material layer adhered on a surface of a substrate of the magnetic hard disk has a flat surface.A method for manufacturing a magnetic hard disk comprising steps of: structurally transforming a surface of an amorphous Ni--P alloy film layer formed a substrate (10) of the magnetic hard disk; and adhering a magnetic material layer on the surface of a substrate (10), wherein the step of structurally transforming the a-Ni--P alloy film layer is a step of heating only a desired portion of the surface of the substrate (10) by an electric discharge to generate Ni and crystallized compounds of Ni and P only at the desired portion (T) of the surface thereof.

Abstract: A process for preparing an abrasive sheet having abrasive particles adhered on a base sheet in monolayer is disclosed, wherein mixed slurry of abrasive particles and binder adhesive is foamed, the foamed slurry is uniformaly painted on the base sheet, and foams formed in the slurry is broken by heating thereby to form the abrasive sheet having good flatness.

Abstract: An abrasive sheet is formed by uniformly painting slurry made of mixture of abrasive particles and adhesives on a surface of a base sheet with a pattern of irregularities by embossing. The slurry layer formed on the sheet hardens by drying at adequate temperature to form an abrasive layer. The abrasive layer has high and low abrasive parts formed by the surface tension of slurry, corresponding to the irregularities of the base sheet. The abrasive sheet is characterized by good planar precision of the abrasive layer, hardness to be peeled off the base sheet, and relatively easy producing method in which grooves are formed by the surface tension.

Abstract: A process for preparing an abrasive sheet comprising(a) mixing abrasive particles with an adhesive resin to form a slurry, and stirring the slurry(b) painting the slurry uniformly on a base sheet(c) permitting the slurry to dry and harden(d) spraying the abrasive sheet with an organic solvent(e) immediately thereafter spraying the surface of the abrasive sheet with compressed air of nitrogen gas.