Method for manufacturing a crystalized glass magnetic disk substrate

摘要

A magnetic disk substrate is made of a glass-ceramic having crystal phases of lithium disilicate (Li2O.2SiO2) and alpha-quartz (SiO2). The crystal phase of alpha-quartz is formed of grown crystal grains each having a globular grain structure made of aggregated particles. Each globular grain has a size within a range from 0.3 mu m to 3 mu m. Surface roughness (Ra) of a polished surface of the magnetic disk substrate is within a range from 15 ANGSTROM to 50 ANGSTROM which is an optimum range of surface roughness for the magnetic disk.