Fabrication of Sr- and Co-doped lanthanum chromite interconnectors for SOFC

Many studies have been performed dealing with the processing conditions of electrodes and electrolytes in solid oxide fuel cells (SOFCs). However, the processing of the interconnector material has received less attention. Lanthanum chromite (LaCrO3) is probably the most studied material as SOFCs interconnector. This paper deals with the rheology and casting behaviour of lanthanum chromite based materials to produce interconnectors for SOFCs. A powder with the composition La0.80Sr0.20Cr0.92Co0.08O3 was obtained by combustion synthesis. Aqueous suspensions were prepared to solids loading ranging from 8 to 17.5 vol.%, using ammonium polyacrylate (PAA) as dispersant and tetramethylammonium hydroxide (TMAH) to assure a basic pH and providing stabilization. The influence of the additives concentrations and suspension ball milling time were studied. Suspensions prepared with 24 h ball milling, with 3 wt.% and 1 wt.% of PAA and TMAH, respectively, yielded the best conditions for successful slip casting. Sintering of the green discs was performed in air at 1600 °C for 4 h leading to relatively dense materials.

FESEM micrographs of the fresh fracture surfaces for the La0.80Sr0.20Cr0.92Co0.08O3 sintered specimens cast from optimised suspensions with 13.5, 15 and 17.5 vol.% solids loading. Aqueous suspensions were prepared using ammonium polyacrylate (PAA) as dispersant and tetramethylammonium hydroxide (TMAH) to assure a basic pH and providing stabilization. Sintering of the green discs was performed in air at 1600 °C for 4 h.Figure optionsDownload as PowerPoint slideHighlights
► Optimum casting slips were achieved with 3 wt.% of ammonium polyacrylate and 1 wt.% of tetramethylammonium hydroxide.