Reactions between phases and surface segregation in a two component mixed electronic ionic conducting ceramic membrane
Makuch, David M.
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The work reported in this thesis involves the study of the solid state chemical interactions between Strontium doped Lanthanum Manganate (LSM) and Scandia doped Zirconia (SDZ). Dual phase composite disks (60% SDZ by weight) were fired at temperatures between 1200°C and 1400°C and the surfaces and cross sections of samples were analyzed using multiple analytical techniques. Secondary Ion Mass Spectrometry (SIMS) showed that the amount of strontium on the surface of the samples was significantly greater than in the bulk (from cross sections). X-ray Diffraction (XRD) showed a third phase which was identified as La 2 Zr 2 O 7 in the bulk. Two hypotheses are considered, first, that this reaction product was formed due to the lack of strontium in the bulk, or second, that the formation of this reaction product resulted in excess strontium in the bulk which migrated to the surface.