Alumina scale formation on a powder metallurgical FeCrAl alloy (Kanthal APMT) at 900-1100°C in dry O2 and in O2 + H2O
Journal article, 2010

A Rapidly Solidified Powder (RSP) metallurgical FeCrAl alloy, Kanthal APMT, was exposed in dry and humid O-2 for 72 h at 900-1,100 A degrees C. The formed oxide scales were characterized using gravimetry in combination with advanced analysis techniques (SEM, EDX, TEM, XRD, AES and SIMS). The oxide scales were at all exposures composed of two-layered alpha-Al2O3 scales exhibiting a top layer of equiaxed grains and a bottom layer containing elongated grains. A Cr-rich zone, originating in the native oxide present before exposure, separated these two layers. The top alpha-Al2O3 layer is suggested to have formed by transformation of outwardly grown metastable alumina, while the inward-grown bottom alpha-Al2O3 layer had incorporated small Zr-, Hf- and Ti-rich oxide particles present in the alloy matrix. The scale also contained larger Y-rich oxide particles. Furthermore, in the temperature range studied, the presence of water vapour accelerated alloy oxidation somewhat and affected scale morphology.

Oxidation

FeCrAl

Water vapour

Alumina

Author

Josefin Engkvist

Chalmers, Chemical and Biological Engineering, Environmental Inorganic Chemistry

Sead Canovic

Chalmers, Applied Physics, Microscopy and Microanalysis

Kristina M Hellström

Chalmers, Chemical and Biological Engineering, Environmental Inorganic Chemistry

Anders Järdnäs

Chalmers, Chemical and Biological Engineering, Environmental Inorganic Chemistry

Jan-Erik Svensson

Chalmers, Chemical and Biological Engineering, Environmental Inorganic Chemistry

Lars-Gunnar Johansson

Chalmers, Chemical and Biological Engineering, Environmental Inorganic Chemistry

M. Olsson

Dalarna university

Mats Halvarsson

Chalmers, Applied Physics, Microscopy and Microanalysis

Oxidation of Metals

0030-770X (ISSN) 1573-4889 (eISSN)

Vol. 73 1 233-

Subject Categories

Inorganic Chemistry

Other Engineering and Technologies not elsewhere specified

DOI

10.1007/s11085-009-9177-7

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4/1/2019 9