Fabrication of Highly Porous Yttria‐Stabilized Zirconia by Acid Leaching Nickel from a Nickel‐Yttria‐Stabilized Zirconia Cermet

Abstract

Porous Y 2 O 3 ‐stabilized ZrO 2 (YSZ) samples were synthesized by preparing NiO/YSZ composites by tape casting and calcining at 1800 K, reducing the NiO to nickel in H 2 at 973 K, and finally leaching the nickel out of the structure with 2.2 M HNO 3 at 353 K. Porous YSZ was prepared from NiO/YSZ composites containing 0, 20, 40, and 50 wt% NiO. Complete removal of the nickel was demonstrated by XRD, weight changes, and porosity increases. Porosities >75% could be achieved without structural collapse of the YSZ phase. Finally, the method was applied to the fabrication of a solid oxide fuel cell with a copper‐based anode operating on H 2 and n ‐butane.