Oxide transformations during sintering of in situ oxidised FeAl powders

Powder metallurgy has been used to prepare FeAl powders with in situ created oxidation products. The aim of this study was to analyse the types of oxide formed as a function of sintering conditions. Highly oxidised powders have been used to give evidence of these transformations by X-ray diffraction. It has been shown that low temperature sintering (T < 1200 °C) results in the formation of FeAl2O4 spinel, while higher sintering temperatures lead to its transformation into α-Al2O3 and coarsening. An attempt, based on thermodynamic calculations, has been made to explain the formation of FeAl2O4 spinel.