Thin films of titania have been prepared by spin coating on fused silica, Si(lOO), and rutile(llO), starting with a sol-gel process. The alkoxide solution was chelated with diisopropanolamine, and the resulting precursor solution was hydrolyzed prior to coating. Oriented rutile films were obtained on fused silica and Si(lOO), while epitaxially oriented film was formed on rutile(ll0). X-ray diffraction results indicated that the as-deposited films transformed to rutile via anatase with increasing temperature. The phase transformation temperature was found to be dependent on the substrate, and it was in general higher on the substrates than that observed for the gel powder. Microstructural studies revealed that these films consisted of finely dispersed grains of 0.05 to 0.15 pm in size. [

Homogeneous and stoichiometric PbTiO 3 and PbZro.52Tio.4sO3 gel fibers were drawn from viscous solutions prepared by sol-gel processing of alkoxide precursors. The fibrous gels on heating at 450 and 600 °C, respectively, formed the well-crystallized phases of PbTiO 3 and PbZro.52Tio.48O3. Fibers heat treated at 700 °C are a few centimeters long and 50 to 150 ^im in diameter. PbZro.52Tio.4sO3 fibers subjected to heat treatment at 700 °C for 1 h consisted of fully dense submicron grains (0.15 to 0.2 /im). However, PbTiO 3 fibers under analogous conditions showed a few micropores with grains of ~0.1 ^m. Dielectric constants of these PbTiO 3 and PbZro.52Tio.4sO3 fibers were approximately 300 and 800, respectively.

Lanthanum and neodymium titanates were prepared by a sol-gel route. Synthesis of La 2 Ti 2 0 7 from pure alkoxide precursors yielded an intermediate perovskite type phase, La ( i-^)TiO 3 , which partially transformed to La 2 Ti 2 07 on heating to 1500 °C. Substitution of the lanthanum acetylacetonate for alkoxide precursor yielded La 2 Ti 2 0 7 without any intermediate phase at a very low temperature of 700 °C. Sintering of the La 2 Ti 2 0 7 gel powder yielded a highly dense ceramic with -97% theoretical density. Similar sintering treatment resulted in ~92% theoretical density for Nd 2 Ti 2 O 7 .

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