CERAMIC COATING FOR A CATALYST SUPPORT

• Main Authors: BEDFORD, RAYMOND E, TSANG, CHIH-HAO MARK
• Format: Patent
• Language: English; French
• Published: 07.05.1996
• Edition: 6
• Subjects: BLASTING; CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOIDCHEMISTRY; CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TOTRANSPORTATION; COMBUSTION ENGINES; COMBUSTION ENGINES IN GENERAL; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; HEATING; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS; INTERNAL-COMBUSTION PISTON ENGINES; LIGHTING; MECHANICAL ENGINEERING; PERFORMING OPERATIONS; PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL; SEPARATION; TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION; TECHNICAL SUBJECTS COVERED BY FORMER USPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS; TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINSTCLIMATE CHANGE; THEIR RELEVANT APPARATUS; TRANSPORTING; WEAPONS

In a preferred method, particles of amorphous silica are used to provide a silica coating suitable for carrying dispersed catalyst particles for the treatment of diesel engine exhaust emissions. The silica coating is formed from a mixture consisting essentially of two groups of the fine silica particles of respective average sizes and size ranges which are virtually non-overlapping. The particles of the first of the two groups have a first average size sufficient to permit the particles of the first group (smaller group) to occupy voids between the particles of the second group (larger group) in a packed arrangement, and preferably the second group has a second average size which is at least 20 times greater than the first average size. Although particles of amorphous silica are preferred for use in forming a coating with improved adherence suitable for the treatment of diesel exhaust, the method of the invention is also useful to improve the adherence of coatings formed of other ceramics, such as alumina, titania, zirconia and zeolite.