Phase development in La2O3 doped Al2O3 : TiO2 ceramic membranes

The phase development of sol derived diphasic Al2O3:TiO2 membranes doped wi th La2O3 is described together with their pore structure and microstructure . These nanostructrual membranes have been characterised using Al-27 MAS-NM R, TEM, BET, XRD and thermal analysis in an attempt to derive a comprehensi ve description. The membrane materials have been subjected to heat treatmen ts ranging from 275 degrees C to 1200 degrees C in air. Doping the diphasic membrane has been shown to increase the transformation temperature of the low temperature phases (gamma-alumina and anatase) by as much as 200 degree s C. There is indication that La2O3 doping also retards the reorganisation of Al in the gamma-alumina phase preventing it from forming other intermedi ate aluminas. (C) 1999 Published by Elsevier Science Limited. All rights re served.