Oxygen distribution in AlN and Si3N4 powders as revealed by chemical and spectroscopy techniques

The oxygen content and the surface composition of pure AlN and Si3N4 powders, synthesized by SHS reactions and commercial routes, have been studied using X-ray photoelectron spectroscopy (XPS) and hot gas extraction techniques. Surface stoichiometry is identified and discussed for each powder. The AlN and Si3N4 powders synthesized by SHS technology were subjected to a sputtering process with rare gas bombardment (Ar+) in order to progressively remove the uppermost layers. A gradient in the oxygen distribution between the particle surface and the interior was measured. Differences in the oxygen distribution for the AlN and Si3N4 powders depending on the route of synthesis have been observed.