The interaction of the metallic interconnects with the cathode and the resulting time-dependent resistance of these material combinations is a major problem in solid oxide fuel cells (SOFCs). In this study, different conductive oxide coatings were used as protective layers to improve surface stability and electrical performance, as well as to mitigate or prevent chromium poisoning of the cells. Dense layers were obtained on the steel by electron-beam physical vapor deposition, by screen printing and by electroplating. The degradation of the interface between the coated Crofer22APU alloy and the
normalLa0.8normalSr0.2FenormalO3
(LSF) cathode was studied by resistance measurements in air at
800°C
up to
1000h
and analyzed by scanning electron microscopy, energy-dispersive X-ray analysis, X-ray diffraction, and secondary ion mass spectrometry after exposure.
normalLa0.6normalSr0.4FenormalO3
measured the lowest resistance between the tested coatings. The highest resistance was found for
CenormalO2
, which also showed low protection against
SrCrnormalO4
formation.
normalY2normalO3
exhibited the lowest resistance increase; however, this coating was not protective enough to prevent the formation of
SrCrnormalO4
, especially during cyclic operation. Among the Mn–Co–Fe spinel compositions tested, the lowest resistivity values and the highest Cr retention were obtained with the
MnnormalCo1.9normalFe0.1normalO4
spinel.