Synthesis of Silicon Carbide–Silicon Nitride Composite Ultrafine Particles Using a Carbon Dioxide Laser

The synthesis and the structure of silicon carbide‐silicon nitride (SiC─Si 3 N 4 ) composite ultrafine particles have been studied. SiC─Si 3 N 4 composite ultrafine particles were prepared by irradiating a SiH 4 , C 2 H 4 , and NH 3 gas mixture with a CO 2 laser at atmospheric pressure. The composition of composite powders changed with the reactant gas flow rate. The carbon and nitrogen content of the powder could be controlled in a wide range from 0 to 30 wt%. The composite powder, which contained 25.3 wt%. carbon and 5.8 wt% nitrogen, had a (β‐SiC structure. As the nitrogen con‐ tent increased, SiC decreased and amorphous phase, Si 3 N 4 , Si appeared. The results of XPS and lattice constant measurements suggested that Si, C, and N atoms were intimately mixed in the composite particles.