Pb. Pavlovic et al., PLASMA-CHEMICAL SYNTHESIS OF ULTRAFINE SILICON-NITRIDE (SI3N4) POWDERIN A REACTOR WITH AN ELECTRIC-ARC PLASMATRON, High energy chemistry, 27(4), 1993, pp. 311-318
The main elements are presented of a theoretical approach for thermody
namic calculation and for calculations of two-phase flow in a plasmatr
on together with the main design decision for a plasma unit, including
both the method of feed of the starting materials, freezing of the st
ream, and recovery of the powder product, as well as results of an inv
estigation of the properties of the obtained powder. Ultrafine (approx
imately 20-nm) silicon nitride (Si3N4) particles were synthesized in a
reactor with an electric-arc plasmatron with a linear circuit with ed
dy arc stabilization. Metallic silicon and a nitrogen-ammonia gas atmo
sphere were used for preparation of the silicon nitride. The powder pa
rticles were collected on a bag filter and on the wall of the plasma-c
hemical reactor. The powder samples consisted mainly of an amorphous p
hase with a smaller fraction of alpha and beta phases and traces of si
licon.