Method of producing a composite material having a high SiO2 content, composite material obtained according to the method, and permanent mold made thereof

US6660671B2 · kind B2 · utility

Assignee

• HERAEUS QUARZGLAS GMBH & CO. KG · DE

Inventors

• Waltraud Werdecker · Hanau, DE
• Udo Gertig · Goldbach, DE
• Johann Leist · Schongau, DE
• Rainer Koeppler · Seligenstadt, DE

Key dates

• Filing date: Mar 21, 2002
• Grant date: Dec 9, 2003
• Expiry date: Jun 8, 2022

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10S977/90
• WIPO field: Materials, metallurgy
• WIPO sector: Chemistry

Abstract

Composite material with high resistance to temperature changes and a high density, and having an SiO2-containing matrix with quartz glass grains embedded therein is produced by preparing a suspension from a particle mixture of finely divided SiO2 powder having at least two different particle fractions and of the quartz glass grains, forming a green compact and sintering the compact. The matrix has an SiO2 content of at least 99% by wt. and is formed from at least first and second particle fractions, each of which is present as granules of nanoscale, amorphous, synthetically produced SiO2 primary particles having a mean primary particle size of less than 100 nm. The composite material has an SiO2-containing matrix with an SiO2 content of at least 99% by wt. It is particularly suited for applications such as starting material for producing a permanent mold for melting solar silicon.