Sputtered MnCu metallic coating on ferritic stainless steel for solid oxide fuel cell interconnects application

MnCu (Mn:Cu = 1:1, atomic ratio) metallic coatings have been deposited by magnetron sputtering on bare and on 100 h pre-oxidized SUS 430 steel for planar solid oxide fuel cells interconnects application. After oxidation at 800 °C in air, the MnCu coating directly deposited on the bare steel has been thermally converted to (Mn,Cu)3O4 spinel with Fe, containing discrete CuO on the outer surface. Nevertheless, the converted (Mn,Cu)3O4/CuO layer from the MnCu coating deposited on the pre-oxidized steelis almost free of Fe. A double-layer oxide structure with a main (Mn,Cu)3O4 spinel layer atop a Cr-rich oxide layer has been developed on the bare and pre-oxidized steel samples with MnCu coatings after thermal exposure. The outer layer mainly consisted of (Mn,Cu)3O4 spinel has not only significantly suppressed Cr outward migration to the scale surface, but also effectively reduced the area specific resistance (ASR) of the scale. The sputtered MnCu metallic coating is a very promising candidate for steel interconnect coating material.