چكيده به لاتين
Solid Oxide Fuel Cells (SOFCs) are one of the cleanest and most efficient technologies for generating electricity. Nowadays, ferritic stainless steel has become the standard for interconnects in SOFCs. However, it has been demonstrated that excessive growth of chromia scale and chromium poisoning degrade cell performance in relatively short periods of service. Various coatings, as well as techniques to apply the coating, have been developed and studied to reduce these problems. Among various coatings, Cu-Mn spinel coatings are effective to stop chromium migration, decrease oxidation, and improve electrical conductivity of the cell.
Recently, electroplating of metals, followed by oxidation in air has been concentrated due to its low cost, ease of fabrication, and formation of dense spinel.
In this study, Cu-Mn spinel coating were deposited on AISI-430 ferritic stainless steel by electroplating of Copper and Manganese layers, followed by oxidation in air at 750°C. Scanning Electron Microscopy (SEM), equipped with energy dispersive spectroscopy (EDS), x-ray Diffraction (XRD) technique and thermal shocking test were employed to characterize and evaluate coating properties. Result showed that electroplating followed by oxidation is facile method for production of Cu-Mn spinel coating. The deposited coating stopped the migration of Cr effectively.
By using a nickel strike before copper electroplating, a dramatic improvement in coating quality and an increase in the success rate was created, both in plating and oxidation. By determining the mechanism of converting the layers to the spinel, the cause of blistering defect in the coating was identified. In an effort to control the defect, encapsulating of specimens followed by heat-treatment in 850°C was performed. The results showed that the blisters defect was removed by heat-treatment, but excess iron entered the coating during this process and prevented the formation of spinel phase.
