Glass composition, glass article, glass substrate for magnetic recording media, and method for producing the same
원문보기
IPC분류정보
국가/구분
United States(US) Patent
등록
국제특허분류(IPC7판)
C03C-003/087
C03C-003/076
G11B-005/706
출원번호
US-0442933
(2003-05-22)
등록번호
US-7309671
(2007-12-18)
우선권정보
JP-P.2002-150040(2002-05-24)
발명자
/ 주소
Kurachi,Junji
Koyama,Akihiro
Yamamoto,Nobuyuki
출원인 / 주소
Nippon Sheet Glass Co., Ltd.
Hoya Corporation
대리인 / 주소
Sughrue Mion, Pllc.
인용정보
피인용 횟수 :
19인용 특허 :
6
초록▼
A glass substrate of the present invention for magnetic recording media having high heat resistance and easy chemical strengthening ability at once has not been obtained, which is a glass composition essentially comprising 60 to 70 wt % SiO2, 5 to 20 wt % Al2O3, 0 to 1 wt % Li2O, 3 to 18 wt % Na2O,
A glass substrate of the present invention for magnetic recording media having high heat resistance and easy chemical strengthening ability at once has not been obtained, which is a glass composition essentially comprising 60 to 70 wt % SiO2, 5 to 20 wt % Al2O3, 0 to 1 wt % Li2O, 3 to 18 wt % Na2O, 0 to 9 wt % K2O, 0 to 10 wt % MgO, 1 to 15 wt % CaO, 0 to 4.5 wt % SrO, 0 to 1 wt % BaO, 0 to 1 wt % TiO2 and 0 to 1 wt % ZrO2, wherein the sum of Li2O, Na2O and K2O is from 5 to 25 wt %, and the sum of MgO, CaO, SrO and BaO is from 5 to 20 wt %.
대표청구항▼
What is claimed is: 1. A chemically strengthened glass article obtained by immersing a glass article comprising a glass composition in a molten salt containing monovalent cations having an ionic radius larger than that of Na ions to conduct an ion-exchange treatment between the Na ions and the mono
What is claimed is: 1. A chemically strengthened glass article obtained by immersing a glass article comprising a glass composition in a molten salt containing monovalent cations having an ionic radius larger than that of Na ions to conduct an ion-exchange treatment between the Na ions and the monovalent cations, wherein the glass composition essentially comprises: 60 to 70 wt % SiO2; 8 to 15 wt % Al2O3; 0 to 1 wt % Li2O; 8 to 16 wt % Na2O; 0 to 3.5 wt % K2O 2 to 5 wt % MgO; 3 to 7.5 wt % CaO; 0 to 4.5 wt % SrO; and 0 to 1 wt % ZrO2, wherein the sum of Li2O, Na2O and K2O is from 11 to 18 wt %, and the sum of MgO, CaO and SrO is from 7 to 14 wt %. 2. The chemically strengthened glass article according to claim 1, which has a glass transition point of 560째 C. or higher. 3. The chemically strengthened glass article according to claim 1, which has a thermal expansion coefficient of 70횞10-7/째 C. or higher as measured in the range of from-50째 C. to 70째 C., and a thermal expansion coefficient of 80횞10-7/째 C. or higher as measured in the range of from 50째 C. to 350째 C. 4. A chemically strengthened glass substrate for magnetic recording media, which is obtained by immersing a glass substrate for magnetic recording media in a molten salt containing monovalent cations having an ionic radius larger than that of Na ions to conduct an ion-exchange treatment between the Na ions and the monovalent cations, wherein the glass substrate for magnetic recording media essentially comprises: 60 to 70 wt % SiO2; 8 to 15 wt % Al2O3; 0 to 1 wt % Li2O; 8 to 16 wt % Na2O; 0 to 3.5 wt % K2O; 2 to 5 wt % MgO; 3 to 7.5 wt % CaO; 0 to 4.5 wt % SrO; and 0 to 1 wt % ZrO2, wherein the sum of Li2O, Na2O and K2O is from 11 to 18 wt %, and the sum of MgO, CaO and SrO is from 7 to 14 wt %. 5. The chemically strengthened glass substrate for magnetic recording media according to claim 4, which has a glass transition point of 560째 C. or higher. 6. The chemically strengthened glass substrate for magnetic recording media according to claim 4, which has a thermal expansion coefficient of 70횞10-7/째 C. or higher as measured in the range of from-50째 C. to 70째 C., and a thermal expansion coefficient of 80횞10-7/째 C. or higher as measured in the range of from 50째 C. to 350째 C. 7. The chemically strengthened glass substrate for magnetic recording media according to claim 4, wherein the load at which a crack is developed with a probability of 50% by depressing a diamond penetrator of a micro Vickers hardness tester toward the substrate, is 800 g or more. 8. A method for producing a chemically strengthened sheet glass by a float process and subsequent chemical strengthening, which comprises: blending raw materials for a glass so as to give a molten glass having the following composition; and introducing the molten glass obtained by melting the raw materials onto a bath of tin to form in a sheet shape: 60 to 70 wt % SiO2; 8 to 15 wt % Al2O3; 0 to 1 wt % Li2O; 8 to 16 wt % Na2O; 0 to 3.5 wt % K2O; 2 to 5 wt % MgO; 3 to 7.5 wt % CaO; 0 to 4.5 wt % SrO; and 0 to 1 wt % ZrO2, wherein the sum of Li2O, Na2O and K2O is from 11 to 18 wt %, and the sum of MgO, CaO and SrO is from 7 to 14 wt %; and immersing the thus-formed glass sheet or portion thereof in a molten salt containing monovalent cations having an ionic radius larger than that of Na ions to conduct an ion-exchange treatment between the Na ions and the monovalent cations. 9. The method according to claim 8, wherein the sheet glass has a glass transition point of 560째 C. or higher. 10. The method according to claim 8, wherein the sheet glass has a thermal expansion coefficient of 70횞10-7/째 C. or higher as measured in the range of from-50째 C. to 70째 C., and a thermal expansion coefficient of 80횞10-7/째 C. or higher as measured in the range of from 50째 C. to 350째 C.
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이 특허에 인용된 특허 (6)
Nagai Hiroki (Osaka JPX) Yamamoto Shigeru (Kyoto JPX), Alumina package for hermetically containing an electronic device therein.
Kurachi, Junji; Koyama, Akihiro; Yamamoto, Nobuyuki, Glass composition, glass article, glass substrate for magnetic recording media, and method for producing the same.
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