3D reconstruction of porous ceramic films by using FIB/SEM technique

LAURA BAQUÉ; FABIANO E. MONTORO

Bariloche

Congreso; 18º Congreso Internacional de Metalurgia y Materiales SAM-CONAMET 2018; 2018

Sociedad Argentina de Materiales (SAM) y Sociedad Chilena de Metalurgia y Materiales (SOCHIM)

3D FIB tomography is a powerful technique used in biological, geological and material science for reconstructing the tridimensional microstructure of different kinds of samples. It consists in alternating the acquisition of scanning electron microscopy (SEM) images with the removal of a thin slice of the sample by using a focused ion beam (FIB). One of the main advantages of this technique is that it allows analyzing volumes of typically ~1000 um3 with a resolution in the range of few tens of nanometers down to few nanometers. This capability is very useful for studying porous materials used in electrochemical devices where the surface/volume ratio and the conduction pathways play a fundamental role in the device performance. In particular, 3D FIB tomography can be used not only for characterizing the particle size, porosity and surface specific area of a sample but also for getting information on particle-to-particle connectivity as well as on critical pathways for electrons, ions and reactants transport.This work aims at reconstructing the nano/microstructure of La0.4Sr0.6Co0.8Fe0.2O3-d (LSCFO) porous cathode films by using 3D FIB tomography. These films are used as cathodes for solid oxide fuel cells which convert fuels into electricity and heat. LSCFO porous films were deposited on a Ce0.9Gd0.1O2-d (CGO) dense substrate by dip coating technique and sintered at different temperatures. Cathode microstructure was reconstructed by 3D FIB tomography and cathode performance was investigated by electrochemical impedance spectroscopy (EIS). The relation between the cathode microstructure, the sintering temperature and the cathode performance will be discussed as well as some aspects regarding 3D FIB tomography of particular importance to porous ceramic films such as sample preparation and data acquisition will be also discussed.