Methods for quantification of anode support microstructure

Degradation observed on long term stack tests may be explained in part by microstructural changes of the electrodes. Particularly at the anode side, the coarsening of nickel particles will affect its performances. Increasing the metal particle size will first diminishes the Three-Phase Boundary (TPB) where fuel oxidation takes place, and secondly decrease the electronic conductivity [1]. In order to quantify the changes in anode microstructure, SEM images analysis is used. Some techniques can be time consuming therefore sample preparation, image treatment and analysis have been optimized to be more efficient. The application of different SEM sample preparation and analysis methods on HTceramix anode supports each show advantages and drawbacks.. One quick method consists in polishing the anode without infiltration and analyzing images manually [2]. A second method requires more elaborate preparation, with image analysis carried out using a Mathematica code. These methods are applied on as sintered and aged (in- stack test) cells based on two different HTceramix anode support structures. 1. Simwonis, D., Tietz, F., and Stoever, D., 2000, Nickel coarsening in annealed Ni/8YSZ anode substrates for solid oxide fuel cells: Solid State Ionics, v. 132, p. 241-251. 2. Monachon, C., Hessler-Wyser, A., Faes, A., Van herle, J., and Tagliaferri, E., 2007, A quick method for characterizing Nickel-Yttria stabilized Zirconia cermet microstructure by scanning electron microscopy: to be submitted.