公开(公告)号：US06818576B2

公开(公告)日：2004-11-16

申请号：US10156659

申请日：2002-05-29

申请人： Mikio Ikenishi ,  Atsuko Morita ,  Xuelu Zou

发明人： Mikio Ikenishi ,  Atsuko Morita ,  Xuelu Zou

IPC分类号： C04B3089

CPC分类号： G11B5/7315 ,  B24B37/042 ,  C03C3/064 ,  C03C3/083 ,  C03C3/085 ,  C03C3/089 ,  C03C3/091 ,  C03C3/093 ,  C03C19/00 ,  C03C21/00

摘要： Disclosed are a glass substrate for an information recording medium, having excellent scratch resistance and a light weight and having high fracture toughness, the glass substrate having a fragility index value, measured in water, of 12 &mgr;m−1/2 or less or having a fragility index value, measured in an atmosphere having a dew point of −5° C. or lower, of 7 &mgr;m−1/2 or less, or the glass substrate comprising, by mol %, 40 to 75% of SiO2, 2 to 45% of B2O3 and/or Al2O3 and 0 to 40% of R′2O in which R′ is at least one member selected from the group consisting of Li, Na and K), wherein the total content of SiO2, B2O3, Al2O3 and R′2O is at least 90 mol %, and a magnetic information recording medium comprising a magnetic recording layer formed on the glass substrate.

摘要翻译： 公开了一种用于信息记录介质的玻璃基板，具有优异的耐擦伤性和重量轻并且具有高断裂韧性，玻璃基板在水中测得的脆性指数值为12mum -1/2以下， 在露点为-5℃以下的气氛中测定的具有7mum -1/2以下的脆性指数值，或者摩尔％含有40〜75％的摩尔％ SiO2，2〜45％的B2O3和/或Al2O3和0〜40％的R'2O，其中R'为选自Li，Na和K中的至少一种），其中SiO 2的总含量， B 2 O 3，Al 2 O 3和R'2O为至少90摩尔％，磁性信息记录介质包含形成在玻璃基板上的磁记录层。