The Synthesis and Crystal Chemistry of Ca12Al14O33 doped with Fe2O3

The crystal chemistry of Fe doped mayenite (Ca12Al14-xFexO33) samples prepared using solid state and sol-gel synthesis techniques were compared. Five samples were prepared using solid state process with varying Fe concentration (x) where x = 0, 0.05, 0.1, 0.25 and 0.3; two sets of samples were made via the sol-gel, the first set was prepared for studying the amount of Fe substituted by varying the Fe concentration where x = 0, 0.05, 0.1, 0.2, 0.3 and 0.4 and the second set was prepared for studying the firing temperature and did not contain Fe additions (x = 0). Samples produced via the sol-gel method were more likely to be single phase with incorporation of Fe2O3 while solid state samples contained multiple phases over the same range of Fe2O3 substitutions. The refined lattice parameters, of samples prepared using both methods were observed to increase with increasing Fe concentration, suggesting Fe is replacing Al since Fe has larger ionic radii than Al. Samples prepared via the sol-gel method were found to be single phase at lower temperatures compared to samples prepared via solid state synthesis. Samples synthesized using the sol-gel method were found to have multiple phases when fired at 800 ˚C but were single phase when fired at 900˚C. In comparison, samples synthesized using traditional solid state techniques showed single phase when fired at a temperature of 1350˚C.