INFLUENCE OF A REACTIVE ELEMENT OXIDE COATING ON THE HIGH-TEMPERATUREOXIDATION OF CHROMIA-FORMER ALLOYS

MOCVD technique was used to deposit Nd2O3 coatings on two chromia-form ers alloys. Oxidation experiments were performed at 1000 degrees C und er air at atmospheric pressure on uncoated alloys and Nd2O3-coated all oys. The beneficial effects generally ascribed to the reactive element s were confirmed : the oxidation rates were decreased and the adherenc e of the oxide scales was drastically improved. The reactive element w as located at the top of the oxide scale after oxidation. X-ray diffra ction measurements identified NdCrO3 as the phase containing the react ive element, This work is compared to a previous study [1] concerning the influence of Nd2O3 on the high temperature oxidation behaviour of a Ti-containing chromia-former alloy in the oxide scale of which a com plex phase close to CeTi21O38 was characterized.