Numéro
J. Phys. IV France
Volume 03, Numéro C7, Novembre 1993
The 3rd European Conference on Advanced Materials and Processes
Troisiéme Conférence Européenne sur les Matériaux et les Procédés Avancés
Page(s) C7-1481 - C7-1484
DOI http://dx.doi.org/10.1051/jp4:19937232
The 3rd European Conference on Advanced Materials and Processes
Troisiéme Conférence Européenne sur les Matériaux et les Procédés Avancés

J. Phys. IV France 03 (1993) C7-1481-C7-1484

DOI: 10.1051/jp4:19937232

Nanosized Si/C/N composite powders formed by laser-aerosol coupling

N. HERLIN, O. CROIX, M. CAUCHETIER, M. LUCE and E. MUSSET

CEA-DSM-DRECAM, Service des Photons, Atomes et Molécules, CE Saclay, 91191 Gif-sur-Yvette cedex, France


Abstract
Recently it has been shown that ultrafine preceramic Si/C/N powders in the nanometric range can be obtained by combining the ultrasonic injection of a liquid precursor with the CO2 laser irradiation. At the CEA the first experiments were conducted with hexamethyldisilazane - (CH3)3SiNHSi(CH3)3 - (or HMDS) as the precursor. The aerosol droplets formed by the Pyrosol process are carried out with a flow of argon or argon - ammonia mixture into the beam of a high powered industrial continuous wave CO2 laser. At laboratory scale up to 100cm3/hr of liquid are displaced with a conversion efficiency (liquid → powder) of about 45%. The chemical composition is controlled by varying the synthesis conditions. The C/N atomic ratio changes from 3 (under argon) to 0.35 (under argon + ammonia). The as-formed powders are amorphous, monodispersed and nanosized (<100nm). The effect of heating under nitrogen atmosphere has been studied by various diagnostics (chemical analysis, BET, XRD).



© EDP Sciences 1993