Sintering of Ba0,5Sr0,5Co0,8Fe0,2O3-φ Perovskite, the (Grain) Boundary Between Functional and Mechanical Properties?

Markus Zwick ,  Ewald M. Pfaff ,  Christoph Broeckmann 

Institute for Materials Applications in Mechanical Engineering, Aachen University (IWM), Nizzaallee 32, Aachen 52072, Germany

Abstract

Perovskite structured materials with mixed ionic/electronic conductivity (MIEC) can be used as oxygen transport membrane (OTM) for generating pure oxygen, for syngas processes or oxyfuel combustion. A lot of investigations are dealing only with the functional properties. But for using perovskite components in industrial applications also the thermo-mechanical properties have to be taken into consideration carefully. Because both functional and mechanical properties are depending on microstructure a compromise has to be found.

In the following work the influence of microstructure on the functional and mechanical properties of Ba0,5Sr0,5Co0,8Fe0,2O3-φ, a material with highest oxygen permeation rate, was analysed.

To verify microstructure of poly crystalline ceramics you have to understand the sintering mechanisms. The sintering mechanisms depending on temperature were analysed and special sintering curves were designed to create different microstructures. Isostatic pressed tubes were sintered using these different sintering curves. Polished and thermal etched samples were analysed by SEM concerning grain size distribution and porosity. The influence on mechanical properties was compared. Oxygen permeation at 800 °C was determined and correlated to the mechanical properties to find the best compromise between functional properties, mechanical properties and microstructure.

The results of this work are used in the German project OXYCOAL-AC with focus on emission free coal combustion.
 

Related papers
  1. Module Design for MIEC Membranes in Energy Applications

Presentation: Oral at E-MRS Fall Meeting 2009, Symposium G, by Markus Zwick
See On-line Journal of E-MRS Fall Meeting 2009

Submitted: 2009-05-05 17:10
Revised:   2009-06-07 00:48