Electrical conductivity activation energy of cobalt-composite-coated interconnects used in solid oxide fuel cell

Long – term stability and oxidation resistance of ferritic stainless steels which are used as interconnects in solid oxide fuel cells can be improved by use of a protective, effective, relatively dense and well adherent coating. The objective of this work was to evaluate the electrical conductivity of cobalt-coated AISI 430 ferritic stainless steel by pack cementation method. Coated samples were characterized using scanning electron microscopy (SEM). Electrical conductivity of the coated substrates was tested as a function of temperature by annealing the samples from room temperature to 800 ºC. Also electrical conductivity has been investigated as a function of oxidation time during isothermal oxidation at 800 ºC. Results showed the increase of temperature caused to the decrease of electrical conductivity and also, the coating layer transformed to cobalt-spinel composites during annealing in isothermal oxidation. The formation of MnCo2O4-CoCr2O4 spinel composites improved electrical conductivity activation energy of coated substrates (0.027 eV) compared to uncoated substrates (0.031 eV).

کلیدواژه ها:

Electrical conductivity activation energy ، cobalt ، composite ، solid oxide fuel cell