Nanocomposite Si/C/N Powder Production by Laser–Aerosol Interaction

Abstract

Ultrafine preceramic Si/C/N powders were obtained via ultrasonic injection of aerosol particles into a highpower CO, laser beam, using hexamethyldisilazane, which strongly absorbs the CO, laser radiation at 10.6 pm, as the precursor. Introduction of aerosol droplets via a flowing argon or argon-NH, mixture into the laser beam yielded nanosized (30 to 60 nm), amorphous powders. Yield and particle composition were controlled by varying the synthesis conditions. Powder changes, such as crystallization during heat treatment under nitrogen or argon, were studied.

Versatility of Laser Pyrolysis Applied to the Synthesis of TiO2 Nanoparticles – Application to UV Attenuation

“…[9] The experimental setup with aerosol generator, reaction chamber, and powder collector has already been described. [13] The confinement of the precursor flow by an argon or helium chimney right at the exit of the inlet nozzle avoids any reaction with the reactor walls, protecting the powders from any contamination. The main synthesis parameters are pressure, laser power, composition of the reactant mixture, and flow rate of the precursor stream.…”

Generation and Sizing of Particles for Aerosol-Based Nanotechnology

“…, or a laser beam (e.g. Cauchetier et al 1994). The high temperatures cause rapid evaporation of the solvent of the droplets and the initiation of inter-particle reactions that lead to the final product.…”

Microwave absorbing property and complex permittivity of nano SiC particles doped with nitrogen

“…4 shows the ε and ε of the pure nano SiC particles doped with nitrogen pressed at 100 Mpa versus frequency (ε = 46.46-27.69, ε = 57.89-38.556). The density of this pure sample is 2.45 g/cm 3 . In an effort to find a moldable material with a continuously variable dielectric constant for microwave applications, composites of paraffin and nano SiC particles doped with nitrogen were prepared, because the melting point of paraffin is low and easy to mix with the particles.…”

“…The characterizations of the nano Si/C/N powders, such as chemical and phase compositions, particle size, grain size, grain morphology, defect, specific surface area, lattice constant and local structure of microcrystallines, have been studied efficiently. Much work has been reported on the synthesis, sinterability and heat-treatment of these nano powders [1][2][3][4][5][6][7][8][9][10][11][12].…”

“…Recently, nano Si/C/N composite materials have stimulated wide interest because they exhibited some new features compared with mixtures of pure Si 3 N 4 and SiC phase. Several papers concerning the microstructure of ultrafine Si/C/N particles or deposits, suggested that promising features of nano Si/C/N composite materials would be due to more complicated Si, C, and N atomic chemical environment than in a mixture of pure SiC and Si 3 N 4 phases [1][2][3][4][5][6]. Because of the decrement of particle size, some physical and mechanical properties of the nano materials will be changed greatly.…”