This research looks at the stability of specific LaxA1-xFeO3-y , perovskite-type, materials that are candidate for use in future commercial gas separation processes including Syngas (CO-H2) production. These materials would be expected to survive for long times under highly reducing as well as oxidizing conditions to temperatures approaching 1000°C. Using a combination of x-ray and neutron diffraction, dilatometry, electron microscopy, magnetometry, TGA, DSC, and DTA, the phase relations and stability of LaxA1-xFeO3-y were assessed, with emphasis on understanding the behavior of LaxA1-xFeO3-y and certain derivatives. Several interesting phase transformations were observed including a ferro- to paramagnetic phase transformation near 400°C and an orthorhombic to rhombohedral transformation near 900°C. Reitfeld refinement and neutron diffraction were used to assess atomic positions of atoms and vacancies in order to characterize the mechanisms of the phase transformations.
Available at: http://works.bepress.com/darryl_butt/31/