Effect of Cu on the diffusion behavior and electrical properties of Ni-Co conversion coating for metallic interconnects in solid oxide fuel cells

The Ni-Co and Ni-Co-Cu alloy coatings, as the interconnect for solid oxide fuel cells, were fabricated on the SUS430 substrate by electroplating to reduce the oxide growth kinetics and outward diffusion of Cr. Ni-Co and Ni-Co-Cu alloy coatings were oxidized at 800 degrees C for 1000 h. Our experimental results indicated that the Cu addition improved the electrical behavior of Ni-Co alloy coating. Cu doping reduced the activation energy (Ea) of electrons hopping and inhibited the growth of Cr2O3 oxide layer. Furthermore, the oxidation kinetics and electrical properties of the Ni-Co and Ni-Co-Cu alloy coatings were obtained. These results showed that the Ni-Co-Cu coated steels achieved the minimum parabolic rate constant (1.82 x 10(-14) g(2)cm(-4)s(-1)) and area specific resistance (13.44 m Omega.cm(2)) after the thermostatic oxidation process. (C) 2021 Elsevier B.V. All rights reserved.