WEB Effects of sintering profile on microstructure and mechanical properties of Ce0.8Gd0.2O2-δ-FeCo2O4 oxygen transport membranesWednesday (01.01.2020) 00:00 - 00:15 Part of:
Ceramic oxygen transport membranes offer potential economic and environmental benefits for high purity oxygen separation and production. Ce0.8Gd0.2O2-δ-FeCo2O4 composites are promising material candidates as oxygen transport membranes with excellent stability under harsh application environments. With a purpose to obtain a dense microstructure with fewer defects and improved mechanical properties, the current work focuses on the design and optimization of the sintering profiles for Ce0.8Gd0.2O2-δ-FeCo2O4 composites. The phase interactions in the initial powder mixture were investigated by high-temperature X-ray diffraction. The microstructure and flexural strength of the sintered pellets were characterized by scanning electron microscopy and ring-on-ring test, respectively. The results reveal that the phase interaction at ~1050 ℃ accelerates the densification process and contributes greatly to reducing the porosity. The membrane with the highest density (> 99 %) and the highest flexural strength (~266 MPa) was sintered at an intermediate temperature (1200 ℃) instead of the highest temperature (1350 ℃) within the selected temperature range. The lower density at the highest temperature is attributed to the formation of large and isolated pores. The optimal sintering temperature accounting for both microstructural aspects and mechanical properties was determined to be 1200 ℃.