Synthesis of {beta}{double_prime}-Al{sub 2}O{sub 3} polymer precursor and its pyrolysis to ultrafine {beta}{double_prime}-Al{sub 2}O{sub 3} powders

{beta}{double_prime}-Alumina, an important high-temperature solid electrolyte, was synthesized in ultrafine particle form from inexpensive starting materials via a polymeric, metalloorganic precursor. The precursor, made by reacting NaOH, LiOH, and Al(OH){sub 3} with triethanolamine (TEA) in ethylene glycol (EG) while distilling off product water, is a glassy thermoplastic at room temperature, and dissolves in polar solvents, e.g. ethanol. Spheroidal, non-agglomerated particles of < 100 nm diameter were formed by flame-spray pyrolysis of ethanolic solutions of the precursor. X-ray powder diffraction showed the as-formed powders to be an intermediate phase which transforms to {beta}{double_prime}-alumina upon heating above 1,000 C.