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Morpho-chemical investigations and thermodynamic study of Nb-rich passive nodules grown on AISI 441 oxidized in wet atmosphere
Author(s)
Parry, Valérie
Wongpromrat, Wichitra
Latu-Romain, Laurence
Pascal, Céline
Chandra-ambhorn, Somrerk
Wouters, Yves
Galerie, Alain
Date Issued
August 15, 2018
Type
Article
Abstract
AISI 441 sheets were oxidized from 4 to 24 h at 800 °C in wet atmosphere. Micrometric oxide nodules containing Ti, Nb, Cr and Mn were observed to form on the passive scale. The internal microstructure of these objects was investigated using STEM–EDX and FIB-SEM tomography. Experimental results reveal a complex microstructure linked with the presence of Si and Nb and their competition for interfacial oxidation. Eventually, the chemical compositions of the nodule and of the oxidation affected zone in the nodule vicinity are discussed in relation with thermodynamic calculations investigating the stability of the different oxides.
Citation
Corrosion Science, 141, 255-263, 2018