Laser-induced Gas-phase Reaction Research Articles

Comparison of the SiH 4C 2H 4 and SiH 2Cl 2C 2H 4 systems during the synthesis of silicon carbide ultrafine particles by laser-induced gas-phase reaction

The synthesis conditions of SiC ultrafine particles from SiH 4 and C 2H 4 using a CO 2 laser were studied and a comparison was made between SiH 4C 2H 4 and SiH 2Cl 2C 2H 4 systems. Ultrafine SiC particles were synthesized by irradiating a SiH 4 and C 2H 4 gas mixture with a CO 2 laser at atmospheric pressure. SiC particles were obtained at a laser power of more than 0·92 kW/cm 2. The behavior of the reaction flame temperature and the extent of the laser light absorption by SiH 4C 2H 4 was different from that of SiH 2Cl 2C 2H 4, although an abrupt temperature increase was observed in both cases. In the case of SiH 4C 2H 4 an abrupt increase in the laser light absorption was not observed, whilst it was observed in the case of SiH 2Cl 2C 2H 4. This difference resulted from the difference in liability to form solid carbon particles.

Composite Si/C/N powder production by laser induced gas phase reactions

Ultrafine amorphous Si/C/N ternary powders have been prepared in a CO2 laser assisted process. We demonstrate the possibility to drive the C/N ratio in the powder by properly choosing the experimental conditions and the gaseous reactant ratio in the initial mixture containing silane, dimethylamine, and ammonia. A kinetic model that accounts for reaching the equilibrium between the gaseous reaction intermediates and the solid products is proposed.

Laser induced gas phase reaction between chromyl chloride and some polyhalogenoethenes

Gas phase reaction between chromyl chloride and some polyhalogenoethenes induced with the radiation of continuous-wave CO2 laser yields carbonyl halides and compounds arising from oxygen donation to alkene and 1,2-rearrangement of halogen.