The electrochemically induced interaction between Ni and GDC was investigated using a network-shaped Ni electrode on a dense interlayer of gadolinia-doped ceria (GDC) with yttria-stabilized zirconia (YSZ) electrolyte. The sample with a platinum counter electrode and a reference electrode was treated at 1173 K for 5 h with flowing 1% H2O-H-2 gas mixture under different applied potentials. The morphology of Ni electrode changed when potential was applied. A large number of ceria particles in several ten-nanometer sizewas precipitated on the Ni surface. The Ni-GDC interaction became more significant with increasing applied potential. The relationship between electrochemically induced morphological change and overpotential-induced oxygen potential change is discussed. (c) 2019 The Electrochemical Society.