Process of producing a glass-ceramic, the glass-ceramic made therby and its uses

US8141387B2 · kind B2 · utility

Assignee

• Schott AG · DE

Inventors

• Martin Letz · Mainz, DE
• Mark J. Davis · Grafton, GB
• Bernd Ruedinger · Wörrstadt, DE
• Bernd Hoppe · Ingelheim am Rhein, DE
• Bianca Schreder · Pocking, DE
• Maria-Louisa Aigner · Frankfurt am Main, DE
• Daniela Seiler · Alzey, DE

Key dates

• Filing date: Feb 25, 2009
• Grant date: Mar 27, 2012
• Expiry date: May 26, 2030

Classification

• Technology area (CPC H): Electricity
• CPC primary: H01G4/30
• WIPO field: Electrical machinery, apparatus, energy
• WIPO sector: Electrical engineering

Abstract

The process of making the glass-ceramic includes ceramicizing a starting glass at a heating or cooling rate during the ceramicization of at least 10 K/min, so that the glass-ceramic contains at least 50% by volume of ferroelectric crystallites with a maximum diameter of from 20 to 100 nm and not more than 10% by volume of nonferroelectric crystallitesis. The glass ceramic produced by the process contains no pores or not more than 0.01% by volume of the pores and a value of e′·V2max of the glass-ceramic is at least 20 (MV/cm)2, wherein e′ is the dielectric constant at 1 kHz and Vmax is the breakdown voltage per unit thickness. The ferroelectric crystallites preferably have a perovskite structure and are composed of substantially pure or doped BaTiO3 and/or BaTi2O5.