Process for making opaque quartz glass and opaque component made according to the process

US6381987B1 · kind B1 · utility

Assignee

• HERAEUS QUARZGLAS GMBH & CO. KG · DE

Inventors

• Waltraud Werdecker · Hanau, DE
• Johann Leist · Schongau, DE
• Heinz Fabian · Alzenau, DE
• Rolf Göbel · Gelnhausen, DE
• Bruno Uebbing · Alzenau, DE
• Erich Rosin · Bruchköbel, DE

Key dates

• Filing date: Jan 14, 2000
• Grant date: May 7, 2002
• Expiry date: Jan 14, 2020

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C30B35/002
• WIPO field: Surface technology, coating
• WIPO sector: Chemistry

Abstract

Based on a known process for the manufacture of opaque quartz glass, by mixing SiO2 particles and an additive which is volatile at a melting temperature, forming a body and melting said body with an advancing melt front forming in the body, it is proposed according to the invention that in order to reduce the danger of contamination, a body (1) be formed with an inner bore (6) and be heated in such a manner that the melt front (10) advances from the inner bore (6) to the outside. The article of pure opaque quartz glass according to the invention has high resistance to temperature change, high mechanical strength and good chemical durability. It is distinguished by an opening (6) enclosed by an inner wall (9), with an inner SiO2 surface layer (15) having a layer thickness ranging from 30 mm to 500 mm and a density of at least 2.15 g/cm3.