Fabrication of 8-YSZ thin-wall tubes by powder extrusion moulding for SOFC electrolytes

In this work the processing steps for producing YSZ thin tubes by means of powder extrusion moulding (PEM) technique are investigated. Different feedstocks were prepared from a commercial YSZ powder and a multicomponent thermoplastic binder system based in polypropylene and paraffin wax. The surface coating of YSZ powder with stearic acid in a high-performance dispersing instrument reduces the viscosity of the feedstock one order of magnitude respect to a feedstock with a same composition and un-coated powder. This fact allows increasing the solid loading up to 58 vol.% to obtain sintering tubes with densities higher than 97% and with wall thickness lower than 200 μm.