초록 ▼

A novel Li.sub.2 O--Al.sub.2 O.sub.3 --SiO.sub.2 series glass-ceramics for magnetic disc substrate use, which can prevent deformation of the substrate at a large temperature change and provide a strong, small and compact magnetic disc substrate without trouble and much reading and/or writing informa

A novel Li.sub.2 O--Al.sub.2 O.sub.3 --SiO.sub.2 series glass-ceramics for magnetic disc substrate use, which can prevent deformation of the substrate at a large temperature change and provide a strong, small and compact magnetic disc substrate without trouble and much reading and/or writing informations on the smoothened surface of the substrate, is provided. The glass-ceramics has a main crystal phase of lithium disilicate (Li.sub.2 O.2SiO.sub.2) phase, the peak intensity I of cristobalite phase (CRI) of at least 20 but not more than 50 when the peak intensity of I of lithium disilicate (L2S) phase measured by an X-ray diffraction analysis is taken as 100, and containing 1.0-3.0 parts by weight of Cr.sub.2 O.sub.3 and 1.0-3.0 parts by weight of MnO when the sum of metal oxides other than Cr.sub.2 O.sub.3 and MnO is taken as 100 parts by weight.

대표청구항 ▼

[ What is claimed is:] [1.] A Li.sub.2 O--Al.sub.2 O.sub.3 --SiO.sub.2 series glass-ceramics for magnetic disc substrate use, which has a main crystal phase of lithium disilicate (Li.sub.2 O.2SiO.sub.2) phase, the peak intensity I (CRI) of cristobalite phase of at least 20 but not more than 50 when

[ What is claimed is:] [1.] A Li.sub.2 O--Al.sub.2 O.sub.3 --SiO.sub.2 series glass-ceramics for magnetic disc substrate use, which has a main crystal phase of lithium disilicate (Li.sub.2 O.2SiO.sub.2) phase, the peak intensity I (CRI) of cristobalite phase of at least 20 but not more than 50 when the peak intensity of I of lithium disilicate (L2S) phase measured by an X-ray diffraction analysis is taken as 100, and containing 1.0-3.0 parts by weight of Cr.sub.2 O.sub.3 and 1.0-3.0 parts by weight of MnO when the sum of metal oxides other than Cr.sub.2 O.sub.3 and MnO is taken as 100 parts by weight.