The effect of gelatin on the preparation of silica coated iron particles

A method is described for coating fine iron particles(similar to1 mum) with a uniform silica layer, produced by the hydrolysis of tetraethyl orthosilicate. The presence of a small amount of gelatin on the surface of the iron particles facilitates this process. The X-ray photoelectron measurements indicated that the gelatin interacted with the surface of the iron particles by means of both nitrogen(in -NH2 groups) and oxygen(in -COOH groups) and then bound to the silica. The silica coating increases the resistance of the iron particles to oxidation on heating in air, which makes the temperature at which an observable oxidization occurs from 330 degreesC to 400 degreesC raised.