Flame spray pyrolysis of a polymeric precursor is used to prepare ultrafine powders that, when sintered, convert to essentially pure phase lithium-doped sodium ␤؆-alumina. O]ؒx(HOCH 2 CH 2 OH) has been synthesized from stoichiometric amounts of metal hydroxides and triethanolamine (N(CH 2 CH 2 OH) 3 , TEA) in excess ethylene glycol. The precursor is dissolved in ethanol, and an atomized spray of the solution is combusted in a specially constructed flame spray apparatus. Combustion occurs at ∼2000°C, followed by immediate quenching. This procedure provides for a measure of kinetic control over the process. The resulting nanopowder particles are 50-150 nm in diameter and exhibit powder X-ray diffractometry patterns similar to ␤؆-alumina. Heating the nanopowder at 30°C/min to 1200°C with a 1 h isotherm converts it to pure ␤؆-alumina. In preliminary sintering studies, green powder compacts (∼65% theoretical density) sintered at 1600°C for 12 min densify to 3.0 ± 0.1 g/cm 3 (∼92% theoretical density) with minimal loss of Na 2 O. This procedure offers several processing and cost advantages over conventional ␤؆-alumina syntheses.

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