Improvement of high temperature oxidation resistance of rare earth metal-added Fe-20%Cr-5%Al alloys by pre-annealing treatment

K. Fukuda, K. Takao, T. Hoshi, Y. Usui, Osamu Furukimi

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16 Citations (Scopus)

Abstract

Fe-20mass%Cr-5mass%Al alloy foils have recently been used as a catalytic converter substrate for automobiles because of their good oxidation resistance. In this study, the effect of pre-annealing on the oxidation behaviour of Fe-20mass%Cr-5mass%Al alloy foils containing a small amount of La-Zr and La-Hf was examined by a cyclic oxidation test at 1373K in air. The Al 2O3 scale formed by oxidation was analyzed with a scanning electron microscope (SEM) and transmission electron microscope (TEM) equipped with an energy-dispersive X-ray spectrometer. The oxidation rate of these alloys was reduced by pre-annealing in a reducing atmosphere. The Al 2O3 scale which formed on the pre-annealing alloys was characterized by a thinner outer equiaxed grain layer and larger inner columnar grain size than the scale layer which formed on as-cold rolled alloys of the same material. It is inferred that, with the pre-annealed alloys, the low-density of grain boundaries in the Al2O3 limited oxygen diffusion along the Al2O3 grain boundaries, resulting in a decreased growth rate of Al2O3 scale.

Original languageEnglish
Pages (from-to)319-326
Number of pages8
JournalMaterials at High Temperatures
Volume20
Issue number3
DOIs
Publication statusPublished - Sep 1 2003

All Science Journal Classification (ASJC) codes

  • Ceramics and Composites
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering
  • Metals and Alloys
  • Materials Chemistry

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