Porous permeable molded body

US5853444A · kind A · utility

Assignee

• Thomas Josef Heimbach Gesellschaft mit Beschrankter Haftung & Co. · DE

Inventors

• Horst Maier · Planegg, DE
• Uwe Schumacher · Soest, DE
• Walter E. Best · Indianapolis, US
• Wolfgang Schafer · Düren, DE

Key dates

• Filing date: Mar 21, 1997
• Grant date: Dec 29, 1998
• Expiry date: Mar 21, 2017

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10S55/30
• WIPO field: Chemical engineering
• WIPO sector: Chemistry

Abstract

A porous permeable molded body designed especially for use in the removal of diesel soot particles from the exhaust gas of diesel engines is disclosed. The body includes an alternatingly closed honeycombed body made of silicon carbide and possessing the following features: ______________________________________ wall thickness: 1.25 .+-. 0.5 mm; porosity: 55 to 60%; average pore diameter: 25 to 70 .mu.m; specific permeability: 20 to 100 nPm. ______________________________________ In the production method, a starting powder of silicon or a mixture of silicon with portions of silicon carbide and/or carbon is combined with an organic binding agent that can be coked and molded into a green body. This is then subjected to a coking fire in an inert-gas atmosphere; the molded body obtained in this manner is then heated in the presence of nitrogen or a nitrogenous inert gas to a temperature where free silicon is converted with the carbon, in a reaction firing, to silicon carbide. Additionally, a recrystallization firing at greater than 2000.degree. C. is implemented.