Formation of Spinel from Fe-Ni Coating Electrodeposited on AISI 430 Ferritic Stainless Steel

Abstract

Ferritic stainless steels exhibit properties, such as good electrical conductivity, good corrosion resistance and low cost, that are beneficial for their application as interconnects in intermediate temperature solid oxide fuel cells (ITSOFC) that function at temperatures between 600°C and 800°C. However, the stainless steel corrosion resistance is attributed to the amount of Cr, which is an element that forms a chromium oxide (Cr2O3) layer, acts as an oxidation protective barrier at high temperatures, and reduces the interconnector performance due to its low electrical conductivity. In this context, the objective of this work was to obtain spinel coatings from the Fe and Ni metallic alloy thermal conversion on AISI stainless steel 430 substrate produced by electrodeposition. The morphology and microstructure of the spinel films deposited on stainless steel were characterized by SEM, EDS, XRD and adherence analysis. The results obtained showed that the films were adherent, dense and continuous along the AISI stainless steel 430 substrate surface. In addition, the heat treatment procedure effectively produced crystalline spinels ((NiFe)3O4).

High Temperature Oxidation of Aisi 439 Ferritic Stainless Steel in Synthetic Air Atmosphere

“…The presence of titanium and manganese was detected in the oxide scale at 850 ºC, and these elements together with chrome produced mixed oxides in the structure as shown in Figure 12. The spinels play a decisive role in the quasi-ternary Cr-Mn-Ti oxide system [21,27]. The spinel MnCr2O4 may be regarded as the central connection [21].…”

Effect of Off-Stoichiometry on Electrical Conductivity in Ni-Fe and Mn-Co Spinel Systems

“…Nickel ferrite spinels based on NiFe 2 O 4 are potentially a costeffective alternative and have recently been evaluated as both interconnect coatings and cathode-side contacts. [9][10][11][12][13][14] Although NiFe 2 O 4 and (Mn,Co) 3 O 4 based spinels have been widely studied, there are large discrepancies concerning their reported electrical properties at the SOFC operating temperatures. The conductivity of NiFe 2 O 4 has been reported to be as low as 0.05 S•cm −1 15 to as high as 15.6 S•cm −1 16 at 800 °C in air.…”