Glass-ceramic substrate for a magnetic disk
AssigneeKabushiki Kaisha Ohara
InventorKatsuhiko Yamaguchi
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Abstract
A glass-ceramic substrate for a magnetic disk suitable for use as a contact recording type magnetic disk includes alpha-cristobalite (alpha-SiO2) and lithium disilicate (Li2O·2SiO2) as main crystal phases. The ratio of alpha-cristobalite/lithium disilicate is within a range from 0.20 to less than 0.25, a grain diameter of crystal grains is within a range from 0.1 μm to 1.0 μm, surface roughness (Ra) of the substrate after polishing is within a range from 2 Å to 9 Å.
Claims4
A glass-ceramic substrate for a magnetic disk comprising alpha-cristobalite (alpha SiO2) and lithium disilicate (Li2O·2SiO2) as main crystal phases and having surface roughness (Ra) after polishing within a range of 2 Å to 10 Å.
Dependencies are inferred from the claim text.