Premium
The oxidation of FeNb alloys in 1 atm of pure oxygen at 600–800°C
Author(s) -
Niu Y.,
Gesmundo F.,
Rizzo F. C.,
Rebelo M. Castro,
Viani F.
Publication year - 1995
Publication title -
materials and corrosion
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.487
H-Index - 55
eISSN - 1521-4176
pISSN - 0947-5117
DOI - 10.1002/maco.19950460406
Subject(s) - niobium , alloy , oxide , internal oxidation , materials science , oxygen , metal , ternary operation , dispersion (optics) , phase (matter) , solubility , phase diagram , inorganic chemistry , thermodynamics , analytical chemistry (journal) , metallurgy , chemistry , physics , organic chemistry , chromatography , computer science , optics , programming language
The corrosion of two Fe‐Nb alloys containing 15 and 30 wt% Nb has been studied at 600–800°C under 1 atm of pure oxygen. The reaction followed the parabolic rate law to a reasonable approximation with rate constants much lower than for the oxidation of pure iron under the same conditions. Internal oxidation and depletion of niobium in the alloy have never been observed. The external scales were composed of a matrix of Fe 2 O 3 containing a dispersion of double Fe‐Nb oxide, while FeO and Fe 3 O 4 were not observed. The oxidation behavior of these alloys is interpreted with reference to an approximate phase diagram of the ternary system FeNbO, taking into account the effects of the low solubility of niobium in the base metals and of the presence of two metal phases in the alloy.