Nucleation and growth of oxide particles on a binary Fe-Mn (1 wt. %) alloy during annealing

• Published in: Corrosion science Vol. 177; p. 108952
• Main Authors: Gong, L., Ruscassier, N., Chrétien, P., Haghi-Ashtiani, P., Yedra, L., Giorgi, M.-L.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Ltd 01-12-2020; Elsevier BV; Elsevier
• Subjects: A. Alloy; Annealing; B. AFM; B. SEM; B. STEM; Binary alloys; C. Selective oxidation; Chemical Sciences; Dew point; Ferrite; Grain orientation; Manganese; Nucleation; Oxidation; Oxides; B. SEM; B. STEM; B. AFM; A. Alloy; C. Selective oxidation
• ISSN: 0010-938X; 1879-0496
• DOI: 10.1016/j.corsci.2020.108952

•An Fe-Mn (1 wt.%) alloy is heated to 800 °C in N2-H2 (5 vol.%) with a dew point of −40 °C)•The influence of ferrite grain orientation on the nucleation and growth of external MnO oxides was studied;•MnO oxides nucleate successively on Fe(110), Fe(111) and Fe(100) between 650 and 700 °C;•The oxides’ shape, size and surface density are strongly dependent on the ferrite grain orientation.•The oxides extend mainly laterally on Fe(110) and horizontally and vertically on Fe(100) and Fe(111);
An Fe-Mn (1 wt. %) alloy was annealed at 800 °C in N2-5 vol. % H2 with a dew point of −40 °C. The nucleation and growth of external selective oxides of MnO were characterized as a function of ferrite grain orientation. Nucleation occurs successively on Fe{110}, Fe{111} and Fe{100} at 650–700 °C. The oxides are faceted and their shape, size and surface density, measured accurately, are strongly dependent on the ferrite grain orientation. The oxides grow as the annealing time increases. New oxides are formed after 180 s at 800 °C. The associated external selective oxidation mechanisms are discussed.