Glass with high proportion of zirconium-oxide and its uses

US6627569B1 · kind B1 · utility

Assignee

• Schott Glas · DE

Inventors

• Karin Naumann · Ober-Olm, DE
• Norbert Greulich-Hickmann · Mainz, DE
• Uwe Kolberg · Mainz, DE
• Werner Kiefer · Ingelheim am Rhein, DE

Key dates

• Filing date: Jul 5, 2001
• Grant date: Sep 30, 2003
• Expiry date: Jul 5, 2021

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C03C13/002
• WIPO field: Materials, metallurgy
• WIPO sector: Chemistry

Abstract

The silicate glass has a composition (in % by weight, based on oxide) of SiO2, 54-72; Al2O3, 0.5-7; ZrO2, >10-<18; B2O3, 0-<5; Na2O, 2-<10; K2O1 0-5; with Na2O+K2O, 2-<10; caO, 3-11; MgO, 0-10; SrO, 0-8; BaO, 0-12; with CaO+MgO+SrO+BaO, >5-24; La2O3, 0-6; and TiO2, 0-4. The glass has at least 0.6% by weight of La2O3 or at least 0.1% by weight TiO2. The glass is in hydrolytic glass 1, acid class 3 or better, preferably acid class 1, and lye class 1. It has a glass transition temperature (Tg) of at least 640&deg; C., a thermal expansion coefficient (&agr;20/30O) of 4.1&times;10&#8722;6 to 8.0&times;10&#8722;6/K, a refractive index (nd) of 1.53 to 1.63, an Abb&eacute; number (&ngr;d) of 47 to 66 and a negative anomalous partial dispersion in a blue spectral region (&Dgr;Pg,F) of up to &#8722;0.0130.