Effect of addition of rare earth oxide concentrates on oxidation resistance of AISI 304L

Author(s)

Pillis, M. F. ; de Araujo, E. G. ; Ramanathan, L. V. ; Salgado, L ; Filho, FA

• Document type: Journal article
• Source: Materials Science Forum; v. 530-531, p. 3-pg., 2006-01-01.

Abstract

Rare earth elements are often added to chromium dioxide forming alloys to improve its high temperature oxidation resistance. The rare earths can be also added as oxide dispersions. Significant cost reductions are possible if rare earth oxide concentrates can be used instead of pure rare earth oxides, the former being the precursor to obtaining pure rare earth oxide. In this study the effect of adding pure and concentrates of rare earth oxides to AISI 304L on its oxidation behavior has been evaluated. AISI 304L stainless steel powder compacts containing 2 vol% of pure lanthanum and yttrium oxides or their concentrate were prepared by milling followed by pressing. The compacts were vacuum sintered and isothermally oxidized in air for up to 200h at 900 degrees C. The parabolic rate constants were determined and the reaction products examined using a scanning electron microscope. X-ray diffraction analysis of the reaction products was also carried out. The compacts with pure rare earth oxides and the concentrates exhibited similar oxidation behavior. (AU)