1 Department of Energy Conversion and Storage, Technical University of Denmark2 Ceramic Engineering & Science, Department of Energy Conversion and Storage, Technical University of Denmark3 Mixed Conductors, Department of Energy Conversion and Storage, Technical University of Denmark4 Risø National Laboratory for Sustainable Energy, Technical University of Denmark5 Swiss Federal Laboratories for Materials Testing and Research
Porous magnesium oxide (MgO) structures were prepared by thermoplastic processing for use as supports in asymmetric thin film oxygen transport membranes (OTMs). The open porosity, pore size distribution, and resulting gas permeability of the MgO structures were measured for different feedstock compositions and sintering temperatures. For a composition with 19 vol.% graphite as a pore‐former, sintering temperatures of 1300 °C and 1400 °C, resulted in support porosities of 36% and 26%, respectively, and gas permeabilities of 1.4 × 10‐16 m2 and 3.1 × 10‐16 m2, respectively. Electron microscopy showed that the unexpected increase in gas permeability at temperatures above 1300 °C was a result of the growth of macro‐pores and the opening of bottle‐neck pores which resulted in improved pore connectivity. Mercury intrusion porosimetry experiments confirmed an increase in average pore size for samples sintered above 1300 °C, despite a significant decrease in total porosity.