Optimization of the Processing of 8-YSZ Powder by Powder Injection Molding for SOFC Electrolytes

The development of a new multicomponent thermoplastic binder system for injection molding of yttria-stabilized zirconia (8-YSZ) bars based in polypropylene and paraffin wax (PW) is presented in this paper. The surface coating of YSZ powder with stearic acid in a high-performance dispersing instrument reduced the viscosity of the feedstock by one order of magnitude with respect to a feedstock with the same composition and uncoated powder. This fact allowed us to obtain a feedstock with a viscosity curve more suitable for the injection process without requiring high proportions of PW in the binder composition. The density of the samples was > 98% and the conductivity of sintered parts are comparable to those of samples uniaxially compacted, around 0.10 S/cm at 900 degrees C.