公开(公告)号：US20150262605A1

公开(公告)日：2015-09-17

申请号：US14665857

申请日：2015-03-23

Applicant: HOYA CORPORATION

Inventor： Yoichi HACHITANI ,  Kinobu OSAKABE

IPC: G11B5/73 ,  C03C3/097 ,  C03C3/095

CPC classification number: G11B5/7315 ,  C03C3/083 ,  C03C3/085 ,  C03C3/087 ,  C03C3/095 ,  C03C3/097 ,  G11B5/8404 ,  Y10T428/315

Abstract: The provided are a glass for a magnetic recording medium substrate permitting the realization of a magnetic recording medium substrate affording good chemical durability and having an extremely flat surface, a magnetic recording medium substrate comprised of this glass, a magnetic recording medium equipped with this substrate, and methods of manufacturing the same. Glasses for a magnetic recording medium substrate are, glass I comprised of an oxide glass, comprising, denoted as mass percentages: Si 20 to 40 percent, Al 0.1 to 10 percent, Li 0.1 to 5 percent, Na 0.1 to 10 percent, K 0 to 5 percent (where the total content of Li, Na, and K is 15 percent or less), Sn 0.005 to 0.6 percent, and Ce 0 to 1.2 percent; the Sb content is 0 to 0.1 percent; and not comprising As or F; glass II comprised of oxide glass, comprising, as converted based on the oxide, denoted as molar percentages: SiO2 60 to 75 percent, Al2O3 1 to 15 percent, Li2O 0.1 to 20 percent, Na2O 0.1 to 15 percent, and K2O 0 to 5 percent (where the total content of Li2O, Na2O, and K2O is 25 percent or lower); based on the total amount of the glass components, 0.01 to 0.7 mass percent of Sn oxide and 0 to 1.4 mass percent of Ce oxide are added; the content of Sb oxide is 0 to 0.1 mass percent; and not comprising As or F; and glass III comprised of oxide glass, comprising, converted based on the oxide, denoted as molar percentages: SiO2 60 to 75 percent, Al2O3 1 to 15 percent, Li2O 0.1 to 20 percent, Na2O 0.1 to 15 percent, K2O 0 to 5 percent (where the total content of Li2O, Na2O, and K2O is 25 percent or less); by comprising a 0.1 to 3.5 mass percent of total content of Sn oxide and Ce oxide, based on the total amount of the glass components; the ratio of the Sn oxide content to the total content of Sn oxide and Ce oxide (Sn oxide content/(Sn oxide content+Ce oxide content)) is 0.01 to 0.99; the Sb oxide content is 0 to 0.1 percent; and comprising no As or F.

公开(公告)号：US20140302346A1

公开(公告)日：2014-10-09

申请号：US14306675

申请日：2014-06-17

Applicant: HOYA CORPORATION

Inventor： Kazuo TACHIWANA ,  Yoichi HACHITANI ,  Xuelu ZOU ,  Mikio IKENISHI ,  Kinobu OSAKABE

IPC: G11B5/735 ,  C03C3/087

CPC classification number: G11B5/735 ,  C03C3/083 ,  C03C3/087 ,  C03C3/095 ,  C03C3/097 ,  C03C15/00 ,  C03C19/00 ,  C03C21/002 ,  C03C23/0075 ,  G11B5/7315 ,  G11B5/82 ,  G11B5/8404 ,  Y10T428/24273 ,  Y10T428/315

Abstract: According to one aspect of the present invention, provided is glass for use in substrate for information recording medium, which comprises, denoted as molar percentages, a total of 70 to 85 percent of SiO2 and Al2O3, where SiO2 content is equal to or greater than 50 percent and Al2O3 content is equal to or greater than 3 percent; a total of equal to or greater than 10 percent of Li2O, Na2O and K2O; a total of 1 to 6 percent of CaO and MgO, where CaO content is greater than MgO content; a total of greater than 0 percent but equal to or lower than 4 percent of ZrO2, HfO2, Nb2O5, Ta2O5, La2O3 Y2O3 and TiO2; with the molar ratio of the total content of Li2O, Na2O and K2O to the total content of SiO2, Al2O3, ZrO2, HfO2, Nb2O5, Ta2O5, La2O3, Y2O3 and TiO2 ((Li2O+Na2O+K2O)/(SiO2+Al2O3+ZrO2+HfO2+Nb2O5+Ta2O5+La2O3+Y2O3+TiO2)) being equal to or less than 0.28. Further provided are the substrate for information recording medium, information recording medium and their manufacturing methods according to the present invention.

Abstract translation: 根据本发明的一个方面，提供了一种用于信息记录介质的基板的玻璃，其包括以摩尔百分数表示的总和为70〜85％的SiO 2和Al 2 O 3，其中SiO 2含量等于或大于 50％，Al2O3含量等于或大于3％; 总计等于或大于10％的Li2O，Na2O和K2O; CaO和MgO的总量为1〜6％，其中CaO含量大于MgO含量; 总共大于0％但等于或低于ZrO2，HfO2，Nb2O5，Ta2O5，La2O3 Y2O3和TiO2的4％; 其中Li2O，Na2O和K2O的总含量与SiO2，Al2O3，ZrO2，HfO2，Nb2O5，Ta2O5，La2O3，Y2O3和TiO2（（Li2O + Na2O + K2O）/（SiO2 + Al2O3 + ZrO 2 + HfO 2 + Nb 2 O 5 + Ta 2 O 5 + La 2 O 3 + Y 2 O 3 + TiO 2））等于或小于0.28。 还提供了根据本发明的用于信息记录介质的基板，信息记录介质及其制造方法。