ON THE INFLUENCE OF YTTRIUM AND SULFUR ON THE HIGH-TEMPERATURE OXIDATION BEHAVIOR OF ALUMINA-FORMING HIGH-PURITY FECRAL ALLOYS

Many hypotheses have been published in the literature to explain the b eneficial effect of reactive elements on the oxidation behaviour of al loys. Although this effect has been known for more than 50 years, the mechanisms involved are not yet very well understood. In order to mini mize the influence of impurities in the alloys, in our approach pure m etals are used to produce alloys which guarantee wen defined starting conditions for two-stage-oxidation experiments. SNMS was chosen to inv estigate transport phenomena and the growth mechanisms of oxide scale. Sulphur and yttrium yield significant differences in oxide scale comp osition and microstructure during oxidation at 1200 degrees C.