Method for producing porous permeable molded body

US6017473A · kind A · utility

Assignees

• Verein zur Forederung des Instituts fur Prozess-und Anwendungstechnik · DE
• 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: Aug 12, 1998
• Grant date: Jan 25, 2000
• Expiry date: Aug 12, 2018

Classification

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

Abstract

A porous, flow-through molded body, designed specifically for use in the removal of diesel soot particles from the exhaust gas of diesel engines. It includes a reciprocally closed honeycombed body made of silicon carbide and possessing the following features. PA1 wall thickness: 1.25.+-.0.5 mm; PA1 porosity: 55 to 60%; PA1 average pore diameter: 25 to 70 .mu.m; PA1 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.