Deposition of Cobalt onto the Fe-17%Cr alloy for Interconnect applications in SOFCs

In order to reduce the oxidation and increase the ferritic stainless steels electrical conductivity, which are used as interconnect material in solid oxide fuel cell, a layer of protective/conductive coating can be deposited on the surface. In this study cobalt has been deposited onto the substrate AISI 430 ferritic stainless steel by pack cementation technique. In order to optimize the quality of the formed coating, the effective factors of pack cementation process was investigated by changing these factors, which are salt activator content in the pack powder (0.5- 2%w.t.), deposition temperature (700-800 °C) and deposition time (2-3h).The ascoated samples were examined with Scanning Electron Microscopy (SEM) associated with Energy Dispersive Spectroscopy (EDS). The results showed that each parameter affect the thickness of coating layer, coating quality and the integrity of coating. It was revealed that the formed coating layer in the optimized conditions included CoCr and MnCo2O4 phases, that MnCo2O4 is a spinel composition and has acceptable electrical conductivity in operating conditions of SOFCs.

Keywords:

cobalt , Solid oxide fuel cell , AISI 430 ferritic stainless steel , Interconnect , pack cementation