Oxidation behaviour of FeAl intermetallics.The effects of Y and/or Zr on isothermal oxidation kinetics

The isothermal oxidation behaviour of doped and undoped Fe–37 at% Al intermetallic compounds in an ambient atmosphere over the temperature range of 1000–1200°C was studied. The oxidation products were identified by X-ray diffraction (XRD). Characterisation of the specimens after oxidation was conducted using scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The rate constants of the isothermal oxidation were determined using three methods. The effective diffusion coefficients for the oxidation of doped and undoped Fe–37Al are discussed based on oxide grain size and the effects of reactive elements in lattice and grain boundaries. The effects of reactive elements on the isothermal oxidation kinetics of Fe–37Al were analysed based on oxide morphologies and microstructures.