CO-SINTERING BEHAVIOUR OF POROUS NI-YSZ COMPOSITE SOFC ANODES

摘要

In order to successfully co-sinter solid oxide fuel cell components together, the sintering shrinkage of each component must match. However, the sintering behavior of the Ni/YSZ composite anode differs from that of the pure YSZ electrolyte due to constrained sintering associated with its composite structure. For example only a small addition of Ni powder to a YSZ cast tape can dramatically alter its shrinkage response during sintering. Despite the importance of this sintering phenomenon to cell fabrication and microstructural stability, it has not been systematically studied. The goal of the study was to experimentally determine the role nickel oxidation has on constrained sintering of anode structures by examining the sintering behaviour of tape-cast porous Ni/YSZ and NiO/YSZ composite SOFC anode structures. The dimensional changes during sintering were measured using a high temperature dilatometer and results show that the sintering rate, as well as total shrinkage of the anodes, decreased with an increase in the Ni content. The oxidation of the nickel metal during processing also causes a significant decrease in sintering shrinkage of the Ni/YSZ structures compared to the NiO/YSZ anode structures.