Porous Ni-YSZ planar anodes by powder extrusion moulding employing PMMA as pore former

Porous Ni-YSZ planar supports to be used as anodes in solid oxide fuel cells were obtained by powder extrusion moulding. The addition of poly-methyl methacrylate beads as pore-former provided an improved gas flow through the anode. Feedstocks were prepared employing a multicomponent binder based on polypropylene, paraffin wax and stearic acid in a volume ratio 42/42/16. The effect of particle size was also studied using two kinds of NiO. Poly-methyl methacrylate substituted the powder loading in a 5 vol.-% to increase the porosity. The thickness of green anodes was close to 1 mm, and subsequently removal of the binder was performed by a combined cycle: solvent and thermal debinding. After sintering and reduction stages, nickel presence was confirmed by X-ray diffraction. The porosity reached employing fine NiO was similar than employing coarse one (16%), however the mechanical strength of this anode was higher (∼140 MPa) and more suitable for the application.