Microstructural Investigation of the Initial Oxidation of the FeCrAlRE Alloy Kanthal AF in Dry and Wet O-2 at 600 and 800 degrees C
Artikel i vetenskaplig tidskrift, 2010

The FeCrAlRE (where RE is reactive element) alloy Kanthal AF was exposed isothermally at 600 and 800 degrees C for 72 h in dry O-2 and in O-2 with 10 vol % H2O. The mass gains were 3-5 times higher at the higher temperature. The presence of water vapor increased the oxidation rate at 800 degrees C, while no significant effect was observed at 600 degrees C. A thin two-layered oxide formed at 600 degrees C: an outer (Fe, Cr)(2)O-3 corundum-type oxide, containing some Al, and an inner, probably amorphous, Al-rich oxide. At 800 degrees C a two-layered oxide formed in both environments. The inner layer consisted of inward grown alpha-Al2O3. In dry O-2 the originally formed outward grown gamma-Al2O3 had transformed to alpha-Al2O3 after 72 h. Water vapor stabilized the outward grown gamma-Al2O3 and hence no transformation occurred after 72 h in humid environment. RE-rich oxide particles with varying composition (Y, Zr, and Ti) were distributed in the base oxide at both temperatures and in both environments. The RE-rich particles were separated from the alloy substrate by a layer of Al-rich oxide. At 800 degrees C the Y-rich RE particles were surrounded by thick oxide patches in both dry and humid O-2. (C) 2010 The Electrochemical Society. [DOI: 10.1149/1.3391447] All rights reserved.

fecraire alloys

900 degrees-c

40-percent h2o

mg-incorporation

oxide scales

alumina scales

water-vapor

growth

cyclic oxidation

high-temperature oxidation

Författare

Sead Canovic

Chalmers, Teknisk fysik, Mikroskopi och mikroanalys

Josefin Hall

Hogskolan Dalarna

Fang Liu

Chalmers, Teknisk fysik, Mikroskopi och mikroanalys

Haiping Lai

Chalmers, Teknisk fysik, Mikroskopi och mikroanalys

Mikael Götlind

Chalmers, Kemi- och bioteknik, Oorganisk miljökemi

Kristina M Hellström

Chalmers, Kemi- och bioteknik, Oorganisk miljökemi

Jan-Erik Svensson

Chalmers, Kemi- och bioteknik, Oorganisk miljökemi

Lars-Gunnar Johansson

Chalmers, Kemi- och bioteknik, Oorganisk miljökemi

M. Olsson

Hogskolan Dalarna

Mats Halvarsson

Chalmers, Teknisk fysik, Mikroskopi och mikroanalys

Journal of the Electrochemical Society

0013-4651 (ISSN)

Vol. 157 6 C223-C230

DOI

10.1149/1.3391447