LA P/857 20250425 20060101
C
03 C 3 085 A 20060101
C
03 C 3 087 A 20060101
C
03 C 3 091 A 20060101
G
11 B 5 73 A LA P/857 20221012 JP 2016-221389 20161114 HOYA CORPORATION
6- 1 0- I Nishi-Shinjuku, Shinjuku-ku, Tokyo 1608347 JAPAN JP
JP HASHIMOTO Kazuaki
c/o HOYA CORPORATION, 6-10-1, NishiShinjuku, Shinjuku-ku, Tokyo 1608347 JAPAN JP
SATO Koichi
c/o HOYA CORPORATION, 6-10-1, Nishi-Shinjuku, Shinjuku-ku, Tokyo 1608347 JAPAN JP
Tilleke & Gibbins International Ltd
No. 302/1B, 3rd Floor, Vieng Vang Tower, Unit 15, Boulichan Road, Dongpalan Thong Village, Sisattanak District, Vientiane Capital, Lao PDR LA
GLASS FOR MAGNETIC RECORDING MEDIUM SUBSTRATE, MAGNETIC RECORDING MEDIUM SUBSTRATE, MAGNETIC RECORDING MEDIUM AND GLASS SPACER FOR MAGNETIC RECORDING AND REPRODUCING APPARATUS GLASS FOR MAGNETIC RECORDING MEDIUM SUBSTRATE, MAGNETIC RECORDING MEDIUM SUBSTRATE, MAGNETIC RECORDING MEDIUM AND GLASS SPACER FOR MAGNETIC RECORDING AND REPRODUCING APPARATUS 301 20250425 20250422 20421012 20221012 20250422 20250425 Patent - PCT National Phase

<p>Provided is a glass for magnetic recording rnedium substrate, which is an amorphous oxide glass, wherein, in terms of mol7o, an SiOz content ranges from 45 to 680/o; an AlzOr content ranges from 5 to 20o/o; a total content of SiOz and AlzOl ranges from 60 to 80o/r; a BzO: content ranges from 0 to 5o/o; an MgO content ranges from 3 to 28o/o; a CaO content ranges from 0 to I8%o; a total content of BaO and SrO ranges from 0 to 2o/o; a total content of alkali earth metal oxides ranges from 12 to 30o/o; a total content of alkali metal oxides ranges fi&#39;om 3.5 to l5o/o; and at least one kind selected fi&#39;orn the group consisting of Sn oxide and Ce oxide being included, a total content of Sn oxide and Ce oxide ranges from 0.05 to 2.00Yo, a glass transition temperature is equal to or higher than 625&quot;C; a Young&#39;s modulus is equal to or more than 83 GPa; a specific gravity is equal to or less than 2.85; and an average linear expansion coeffrcient at 100 to 300oC is equal to or more than 48x l0&#39;7 P&nbsp;</p>