Gm Global Technolgoy Operations, Inc.

Raymond E Bedford

Chih-Hao M Tsang

Carl F Schaefer

William J LaBarge

Morris Berg

Nancy Jean Paulus

Terrence B Boyer

The invention includes a metal substrate having an insulative coating thereon, wherein the insulative coating is prepared from a composition including .gamma.-alumina (gamma alumina) with a wide particle size distribution that includes at least 10 percent of the particles having by weight being larger than 20 micrometers, 5 to 10 percent by weight pseudo-boehmite, and a catalyst. The composition is sprayed onto the metal substrate at a distance from about 12 to about 15 inches using a round orifice spray nozzle operated at a pressure ranging from about 15 to about 25 psi. A polyvinyl alcohol overcoat is applied to the insulative coating to prevent flaking and chipping when coated metal substrate are stacked on each other. The insulative coating is particularly useful on folded foils used to construct metal monoliths for electrically heating catalytic converters.

Metal substrate with insulative coating thereon and method of making the

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.

Ceramic coating for a catalyst support

A high surface area ceria-alumina washcoat is disclosed in which the ceria is prepared from cerium acetate.

Method of making a support containing an alumina-ceria washcoat for a

An improved particulate washcoat for use on a ceramic or metallic support is disclosed for the treatment of automotive exhaust gases. The mixture consists essentially of high surface area ceria particles and alumina particles wherein the ceria particles bear copper oxide. Preferably, one of chromium oxide, manganese oxide and tin oxide are dispersed over both the ceria and alumina particles of the washcoat.

Base metal automotive exhaust catalysts with improved activity and

A high strength, high macro-pore volume, porous cordierite bead support having a dimpled or respberry-like surface resulting from processing of inexpensive raw materials to produce cordierite on firing and including high plasticity clay and colloidal silica.

Cordierite bead catalyst support and method of preparation

An alumina base catalyst carrier material which is thermally stable and possesses a high surface area consisting of a cerium oxide coating on active alumina granules. The carrier is prepared by the precipitation of cerium hydroxide from an aqueous slurry of the alumina granules also containing the water soluble salts of cerium.

Method for forming high surface area catalyst carrier and catalyst using

A method for making improved pellet type catalysts utilizing a support material having relatively high alkali metal content, comprising the steps of grinding the support material to the desired size, forming the pellet into the desired shape and size, calcining the pellet to obtain the desired surface area, soaking the calcined pellet in a dilute acid for a short period of time to form the alkali metal salt of the acid to a controlled depth inward from the surface of the pellet, and impregnating the pellet with the desired catalytically active metallic material after draining the acid wash solution, the depth of penetration of the catalytic material being limited to the depth treated by the acid wash.

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Burton, MI, United States of America

Raymond E Bedford