Low temperature synthesis of ultrafine LiTaO₃ powders

Controlled chemical polymerization of tantalum ethoxide in the presence of glacial acetic acid (HOAc/Alk. = 16) and solubilized lithium acetate (Li/Ta = 1.00, H₂O/Alk. = 55.55) was used for the preparation of an amorphous gel precursor to LiTaO₃. Although additional investigations are required, the results suggest that successful formation of amorphous gel network, as opposed to that of colloidal tantalum (hydrous) oxide, may be due to the generation of a new organotantalum precursor via a structural modification reaction between the tantalum ethoxide and glacial acetic acid. The evolution of LiTaO₃ ceramics from pre-ceramic gels was investigated using thermal analysis, electron microscopy, and x-ray diffraction. The results indicate that after the completion of gel pyrolysis (200–400 °C) and crystallization (T_c = 590 °C), ultrafine (average particle size 100–300 nm), single phase, crystalline (a = 5.243, c = 13.812 Å) LiTaO₃ powders can be prepared at low processing temperatures.