Selective oxidation of Fe-Mn (1wt%) binary alloy during continuous annealing - Archive ouverte HAL Accéder directement au contenu
Communication Dans Un Congrès Année : 2021

Selective oxidation of Fe-Mn (1wt%) binary alloy during continuous annealing

Résumé

The study presented here focuses on the selective oxidation of Fe-Mn (1 wt.%) binary alloy. The samples were annealed by means of a laboratory furnace with a temperature profile relevant to the galvanizing line practice. The sample was first heated to 800°C at a rate of approximately 6°Cs-1. It was kept at that temperature for 60 s before being cooled to room temperature. The gas atmosphere consists in a mixture of N2 – 5 vol.% H2 with a dew point of -40°C. To obtain information on the nucleation and growth of oxide particles, we interrupted annealing at 700°C during the heating phase. Some specimens were held at 800°C during 0, 60, 120 and 300 seconds. The rapid cooling of the samples, that occurs when the annealing furnace is stopped, is considered to act like a quench for selective oxidation reactions. During annealing, the native iron oxides are reduced and the manganese diffuses to the surface where it is preferentially oxidized and forms MnO oxide particles. These selective oxide particles were characterized using several complementary analysis techniques. The surface of the samples was observed in a Field Emission Gun Scanning Electron Microscope (FEG-SEM) to obtain high resolution images and analyzed by Electron Back-Scattered Diffraction (EBSD). Image analysis was used to measure the geometric parameters that characterize oxide particles in two dimensions. Thin cross-sections were extracted from the oxidized samples using a Focused Ion Beam Microscope (FIB) and characterized in a Transmission Electron Microscope (TEM). We studied the oxide particles present on three ferrite grain orientations: Fe(100), Fe(110) and Fe(111) as a function of annealing time. It has been demonstrated that, on our model material, MnO particles are monocrystalline. Their shape, size, nucleation and growth depend on the ferrite grain orientation where they are formed. Elementary mechanisms of the oxidation reaction are proposed and discussed to explain this behavior.
Fichier non déposé

Dates et versions

hal-04431803 , version 1 (01-02-2024)

Identifiants

  • HAL Id : hal-04431803 , version 1

Citer

N. Ruscassier, L. Gong, P. Haghi-Ashtiani, L. Yedra Cardona, M.-L. Giorgi. Selective oxidation of Fe-Mn (1wt%) binary alloy during continuous annealing. 12th International Conference on Zinc and Zinc Alloy Coated Steel Sheet GALVATECH, Jun 2021, Vienna ( virtual ), Austria. ⟨hal-04431803⟩
5 Consultations
0 Téléchargements

Partager

Gmail Facebook X LinkedIn More