Published online by Cambridge University Press: 31 January 2011
Laser-driven synthesis of Al2O3 based ceramic powders from gaseous precursors has been accurately investigated. Different concentrations of the reactant gaseous precursors are shown to influence both the process yield and the synthesized powder composition. Depending on the relative concentration of TMA: Al(CH3)3 and N2O, the process leads either to the formation of nanocrystalline γ−Al2O3 with large free carbon contamination and traces of the Al3O3Nphase or to the formation of a mixed γ−Al2O3, Al2OC compound. The different reaction paths have been attributed to the intermediate formation of aluminum carbide. Particular attention has been paid to the gaseous reaction products to correctly interpret the source of carbon contamination observed in the formed powders. Calcining at moderate (900 °C) and high (1400 °C) temperatures induces nanosized γ−Al2O3 powder and the γ → α-Al2O3 transition with particle coalescence and growth.