Synthesis of manganese-cobalt spinel via wet chemistry methods and its properties

Abstract

Abstract Mn 1.2 Co 1.8 O 4 spinel was synthesized via co-precipitation and EDTA gel processes to optimize the performance of high-quality spinel protective-conducting films deposited on steel interconnects. In the case of co-precipitation, in which ammonium hydroxide, ammonium oxalate, and ammonium carbonate were used as precipitating agents, two procedures were applied. In the first one, which was conventional, the precipitating agent was introduced into a mixture of salts, while in the other one, filter paper pre-saturated with a mixture of salts was soaked in the precipitating solution. The calcinated powders prepared via both conventional co-precipitation with ammonium hydroxide and EDTA gel processes were pure cubic spinels. The remaining powders had a dual-phase composition with cubic and tetragonal phases. Aside from the sinter obtained from the powder prepared via conventional co-precipitation with ammonium carbonate, which had a composition of Mn 1.5 Co 1.5 O 4 , all sinters were Mn 1.2 Co 1.8 O 4 cubic spinels. The highest electrical conductivity at 1023 K was observed for the spinel obtained from the powder prepared via conventional co-precipitation with ammonium hydroxide (61.5 S cm −1 ), while the lowest conductivity was measured for the Mn 1.5 Co 1.5 O 4 spinel (14.7 S cm −1 ). The study confirmed that the Mn 1.2 Co 1.8 O 4 spinel prepared via conventional co-precipitation with ammonium hydroxide is a suitable material for the surface modification of ferritic stainless steel applied in IT-SOFC interconnects.