| 摘要 |
<p>A glass-ceramic substrate for a magnetic information storage medium includes, as predominant crystal phases, lithium disilicate (Li2O.2SiO2) and at least one selected from a group consisting of alpha -quartz ( alpha -SiO2), alpha -quartz solid solution ( alpha -SiO2 solid solution), alpha -cristobalite ( alpha -SiO2) and alpha -cristobalite solid solution ( alpha -SiO2 solid solution) and has a coefficient of thermal expansion of + 65 to + 130 x 10<-7>/ DEG C at a temperature within a range from - 50 DEG C to + 70 DEG C and surface roughness (Ra) after polishing of 3 ANGSTROM - 9 ANGSTROM .</p> |
