Magnetic hard disk substrate

Abstract

A magnetic hard disk substrate is produced by rotating an aluminum substrate or a glass substrate, supplying polishing slurry on its surface, pressing a polishing tape on the surface and running it in a direction opposite to the direction of rotation of the substrate. Texturing marks are formed with a line density greater than 70 lines/μm in the radial direction on the surface. The polishing slurry has abrading particles dispersed in a dispersant. The abrading particles may be monocrystalline diamond particles, polycrystalline diamond particles or cluster particles with such monocrystalline and polycrystalline diamond particles with diameters in the range of 1-50 nm. Agglomerated particles of such cluster particles that are agglomerated in the dispersant may also be included as the abrading particles.

1 . A magnetic hard disk substrate comprising a substrate selected from the group consisting of aluminum substrates and glass substrates, said substrate having a surface, a radial direction being defined on said surface, said surface having texturing marks with a line density greater than 70 lines/μm in said radial direction.  
     
     
         2 . The magnetic hard disk substrate of  claim 1  wherein said surface has an average surface roughness less than 0.5 nm, the average of the ratio between the depth and pitch of said texturing marks being 0.02-0.2.  
     
     
         3 . The magnetic hard disk substrate of  claim 1  wherein said surface has an average surface roughness less than 0.5 nm, the ratio between the depth and pitch of said texturing marks being 0.01-0.3, the average of said ratio being 0.02-0.2  
     
     
         4 - 16 . (canceled)