Chromium vapor species over solid oxide fuel cell interconnect materials and their potential for degradation processes

Alloys protected from corrosion by a chromia scale and LaCrO3-based perovskites are used as materials for the interconnect of solid oxide fuel cells (SOFCs). The chromium vaporization of these materials was studied by thermochemical modeling. Partial pressures of the vaporizing species were determined for different O-2 and H2O concentrations in the oxidizing gas. CrO2(OH)(2)(g) and CrO3(g) are the most abundant species in air with and without humidity, respectively. The potential of the Cr-containing vapor species for the degradation of the electrical properties of an SOFC was analyzed by thermodynamic computations. The electrochemical reduction of the Cr-containing vapor species at the cathode/electrolyte/gas phase boundary can lead to polarization losses.