Colloidal processing and sintering of porous percolative Ni-YSZ layers

Electrocatalytic applications of metal–ceramic composites (CerMet), such as Ni-YSZ materials, require processing adjustments to ensure the structural integrity of porous structures. In this paper, the fabrication of a porous Ni-YSZ (50/50, v/v) material through colloidal processing of Ni particles with a thread like shape is presented. Phase segregation and similar deposition rates for both powders are achieved by milling the suspension and adding a binder. Suspension parameters such as viscosity and homogeneity of dispersed powders are controlled before shaping 500 μm thick self-supported layers by electrophoretic deposition. A thermal treatment that includes an oxidation step at 1100 °C and a reduction step at 800 °C was designed through the thermal and microstructural characterization of Ni-YSZ specimens. The maintenance of the thread like shape of the nickel particles allows the fabrication of percolative and mechanically stable materials with structural density > 80% and porosity > 65%.