Published online by Cambridge University Press: 25 February 2011
A study has been made of basic mechanisms involved in a new process for the rapid synthesis of preceramic nanoparticle powders. In this process an aerosol, formed from an ultrasonically atomized liquid organosilazane monomer, (CH3SiHNH)n with n = 3 or 4, is injected into the beam of an industrial cw CO2 laser. One critical feature examined is the rapid condensation of molecular species from the laser plume, in a process involving 3-dimensional cross-linking. In accompanying studies, a model has been formulated to determine the laser plume temperature, the cooling rate of condensing species, and the particle diameter. These are obtained by analytical solution of heat conduction, momentum and mass conservation equations that consider heat loss, by gas conduction, radiation, evaporation, and convection.