Flame synthesis of nanophase oxide powders

For several years, we have been developing a process--called Chemical Vapor Condensation (CVC)--for the high rate production of nanophase ceramic powders. This method proved to be well-suited to the synthesis of non-oxide ceramics, such as SiC and Si₃N₄. More recently, we have been investigating the synthesis of oxide ceramics by a similar process, except for the replacement of the original hot-wall reactor with a combustion-flame reactor. A specially designed burner is used to achieve a flat flame, extending a few millimeters out of the burner, which ensures that the temperature distribution and gas phase residence time are identical over the entire burner surface. Metalorganic precursors, introduced along with the fuel/air mixture, therefore experience completely uniform decomposition and reaction, thereby yielding an uniform nanopowder product. In this talk, we will describe the progress made in flame synthesis of SiO₂, TiO₂, and Al₂O₃ nanopowders.