| 摘要 |
<p>A glass-ceramic substrate for a magnetic information recording medium contains, as a main crystal phase or phases, one or more crystal phases selected from the group consisting of beta -quartz ( beta -SiO2), beta -quartz solid solution ( beta -SiO2 solid solution), beta -spodumene ( beta -Li2O . Al2O3 . SiO2), beta - spodumene solid solution ( beta -Li2O . Al2O3 . SiO2 solid solution), beta -eucryptite ( beta -Li2O . Al2O3 . 2SiO2, a part of Li2O being capable of being substituted by MgO and/or ZnO) and beta -eucryptite solid solution ( beta -Li2O . Al2O3 . 2SiO2 solid solution, a part of Li2O being capable of being substututed by MgO and/or ZnO). Alternatively, the glass-ceramic contains , as a main crystal phase or phases, gahnite (ZnAl2O39 and/or gahnite solid solution (ZnAl2O3 solid solution). The glass-ceramic substrate has a high heat resisting property and a super flat surface capable of achieving a high recording density according to the perpendicular magnetic recording.</p> |
