PROCESS AND CATALYST FOR THE PREPARATION OF ALDONIC ACIDS

Disclosed is a process for the prodn. of surface-oxidized metallic wools or fibers which involves dry scraping, with a set of grooved knives or equiv. tools, of a taut metallic wire which is made to slide between two rollers, characterized in that said process includes regulation of the wire-scraping temp. or subsequent heat treatment of the wire after cutting, to obtain controlled surface oxidn. of the wool. The products obtained are useful as basic materials to prep. supports for catalysts and materials for various applications, such as sensors, catalysts or friction materials. Examples of coating of metallic wools and fibers with oxides, in particular ceramic oxides, for the formation of catalytic composite materials with a metallic core, are disclosed for this type of use. Said metallic wire is made of aluminum, steel, stainless steel, copper, brass, zinc or other metals or alloys. The coating precursor compd. is selected from alkoxides of aluminum, titanium, silicon, or from silica, zirconia or alumina.