A Time Resolved Study of Precoated AISI 441 for SOFC Interconnects Using STEM-EELS - Part II

Precoated AISI441 for SOFC interconnectors were investigated by STEM-EELS looking at the diffusion processes in the initial stage of the oxidation. The PVD coating contained Ce and Co/Mn-alloy in two layers with at total thickness of 800nm. The samples were exposed up to 1000 hours at 800°C then characterized by TEM. Trivariate analysis of multiple linear least squares (MLLS) maps show that Cr₂O₃, (Co, Cr)-spinel, (Co, Cr, Mn).spinel and (Co,Mn)-spinel phases can be identified (Figure 1). Oxidation states are characterized from white line ratios of the present transition metals in these phases and can be correlated to changes in the O K-edge fine structure.