Sinterable ceramic powder, process for its production, silicon nitride ceramic produced therefrom, process for its production and its use

US5162272A · kind A · utility

Assignee

• Hoechst GmbH · DE

Inventors

• Marcellus Peuckert · Hofheim, DE
• Tilo Vaahs · Kelkheim, DE
• Martin Bruck · Hofheim, DE
• Hans-Jerg Kleiner · Kronberg, DE
• Ralf Riedel · Echterdingen, DE
• Martin Sehr · Stuttgart, DE
• Gunter Petzow · Echterdingen, DE

Key dates

• Filing date: Mar 23, 1990
• Grant date: Nov 10, 1992
• Expiry date: Mar 23, 2010

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C04B35/589
• WIPO field: Materials, metallurgy
• WIPO sector: Chemistry

Abstract

The invention relates to a novel sinterable ceramic powder, to its preparation and to its further processing to give a silicon nitride ceramic, and to this material itself and its use. The sinterable ceramic powder is produced by melting a polysilazane or dissolving it in an organic solvent, suspending a powdered sinter aid in this melt or solution, then pyrolyzing the melt, or the residue obtained after evaporation of the solvent, at 500.degree. to 1600.degree. C. in a protective gas atmosphere, the polysilazane either PA1 A) being obtainable by reacting at least one of the oligosilazanes of the formula (I) ##STR1## in which a, b, c and d are the mole fractions of the respective structural units and where 0.ltoreq.a.ltoreq.1, 0.ltoreq.b.ltoreq.1, 0.ltoreq.c.ltoreq.0.7, 0.ltoreq.d.ltoreq.0.7, 0.3.ltoreq.a+b, c+d.ltoreq.0.7 and n is approximately 2 to approximately 12, with at least one of the chlorosilanes R.sup.6 R.sup.7 SiCl.sub.2, R.sup.8 SiCl.sub.3, Cl.sub.2 R.sup.9 Si--CH.sub.2 CH.sub.2 --SiR.sup.9 Cl.sub.2 and Cl.sub.3 Si--CH.sub.2 CH.sub.2 SiR.sup.10 Cl.sub.2 at 30.degree. to 300.degree. C., where, independently of one another, R.sup.1, R.sup.2, R.sup.4, R.sup.6, R.sup.7 and…