Microstructural Characterization of Partially Combusted Fe7Si Powder in Laminar Flow Reactor

Details

Supervisors

Jacques, Pascal ; Choisez, Laurine

Faculty

Ecole polytechnique de Louvain

Degree label

Master [120] : ingénieur civil en chimie et science des matériaux, à finalité spécialisée

Abstract

enIron-based metal fuels are promising materials for carbon-free energy carriers due to their high energy density, recyclability, and low toxicity. While the combustion behavior for high-purity iron particles have been extensively studied, impurity-bearing iron powders such as that containing silicon impurities are less studied despite their greater practical relevance in industrially produced iron-based materials. In particular, silicon can modify the microstructural formations during combustion such as oxide-shell development, and phase evolution, which in turn may significantly affect the performance of such particles as energy carriers. In the present work, the post-combustion microstructure of oxidized Fe7Si particles obtained from Laminar Flow Reactor combustion experiments were investigated at different height-above-burner (HAB), focusing on the evolution of the internal microstructure of the particles and local phase distributions using serial polishing, Scanning Electron Microscope (SEM) and elemental characterizations by Energy Dispersive X-Ray Spectroscopy (EDS), together with supervised machine learning segmentation performed using ilastik to distinguish key microstructural regions. The segmented cross-sections were used for quantitative microstructural analysis, while local phase constitution was interpreted from EDS compositions in combination with Fe-Si-O ternary phase relations and expected oxide stoichiometries. The observations indicate heterogeneous oxidation microstructure with non-uniform internal phase distributions and localized Fe-Si-O regions that vary with HAB, which suggests the role of the addition of silicon in modifying oxidation pathways.