Spinel and perovskite functional layers between Plansee metallic interconnect (Cr-5 wt % Fe-1 wt % Y2O3) and ceramic (La0.85Sr0.15)(0.91)MnO3 cathodematerials for solid oxide fuel cells

The degradation of the interface between Plansee Ducrolloy alloy (Cr-5 wt% Fe-1 wt %Y2O3) (PD) and (La0.85Sr0.15)(0.91),MnO3 (LSM) ceramic was studied by means of electrical resistance measurements at 900 degrees C in air hum idified with 2% H2O and with a de load of 100 mA/cm(2) and by scanning elec tron microscopy/energy-dispersive spectroscopy of cross sections of the sam ples. One sample of PD alloy with plasma-sprayed La0.9Sr0.1CrO3 and a conta cting layer of La0.8Sr0.2CoO3 exhibited little degradation, estimated to be 0.066 Ohm cm(2) after 10,000 h. Other samples of PD were coated by differe nt spinel-forming slurries pretreated in H-2/H2O/Ar mixtures at 950 and 100 0 degrees C. Coatings forming MnCr2O4 spinel and using La0.8Sr0.2CoO3 as a contacting layer showed a low estimated degradation of 0.04-0.06 Ohm cm(2) after 10,000 h. Another spinel (Co,Mn)(3)O-4 appeared to reduce Cr diffusio n significantly, and when used together with a mixed perovskite made of 1:1 of LSM and La0.8Sr0.2CoO3 as a contacting layer, exhibited estimated degra dation of 0.024 Ohm cm(2) for 10,000 h. (C) 2000 The Electrochemical Societ y. S0013-4651(00)02-023-1. All rights reserved.