The Cr deposition reaction is investigated between the La0.9Sr0.1 MnO3 (LSM) cathode and Fe-Cr alloy interconnect at 750 degrees C for solid oxide fuel cell. The poison effect on cathode is observed by a group of orthogonal experiments at the presence of Fe-Cr alloy involving with air flow and current passages. After the current polarization, the cathode layer has been delaminated from the electrolyte (YSZ), and the Cr deposition reaction is accelerated with adding air partial pressure. When the LSM cathode has undergone Cr poison for 3000 min with current passage of 400 mA cm(-2) and air flow of 100 mL(-1) two rapid increase stages of polarization potential E-cathode are found, which can be reasonably explained by Cr deposition resulting in cathode delaminated from the electrolyte layer. Furthermore, the Cr deposition ring and two kinds of Cr-contain agglomerates are observed in the interface of LSM/YSZ, which indicates that the formation of Cr2O3 and (Cr,Mn)(3)O-4 oxides, respectively. This suggests that the deposition of Cr species would preferentially occur at the three phase boundary region and the trend to agglomeration in long time operation. (C) 2011 Elsevier B.V. All rights reserved.