The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 21, 2012
Filed:
Sep. 14, 2010
Glass for information recording media substrate, glass substrate for magnetic disk and magnetic disk
Tetsuya Nakashima, Tokyo, JP;
Kei Maeda, Tokyo, JP;
Noriaki Shimodaira, Tokyo, JP;
Atsuyoshi Takenaka, Tokyo, JP;
Tetsuya Nakashima, Tokyo, JP;
Kei Maeda, Tokyo, JP;
Noriaki Shimodaira, Tokyo, JP;
Atsuyoshi Takenaka, Tokyo, JP;
Asahi Glass Company, Limited, Tokyo, JP;
Abstract
To provide a glass for an information recording media substrate, which is excellent in weather resistance. A glass for an information recording media substrate, which comprises, as represented by mol % based on oxide, from 61 to 66% of SiO, from 11.5 to 17% of AlO, from 8 to 16% of LiO, from 2 to 8% of NaO, from 2.5 to 8% of KO, from 0 to 6% of MgO, from 0 to 4% of TiOand from 0 to 3% of ZrO, provided that AlO+MgO+TiOis at least 12%, and LiO+NaO+KO is from 16 to 23%, wherein in a case of where BOis contained, its content is less than 1%. The above glass for an information recording media substrate, wherein when the glass is left under steam atmosphere at 120° C. at 0.2 MPa for 20 hours, and the amount of Li, the amount of Na and the amount of K, which precipitate on a surface of the glass are represented as C, Cand Crespectively, Cis at most 0.7 nmol/cm, and C+C+Cis at most 3.5 nmol/cm.