Va. Hackley et al., EFFECTS OF SOXHLET EXTRACTION ON THE SURFACE OXIDE LAYER OF SILICON-NITRIDE POWDERS, Materials chemistry and physics, 36(1-2), 1993, pp. 112-118
An aqueous soxhlet extraction procedure was used to surface-clean five
commercial silicon nitride powders. The solid-solution interface prop
erties were characterized before and after extraction by electrokineti
c sonic amplitude measurements. The isoelectric point (pH(iep)) was fo
und to increase significantly for some powders after treatment. The po
wder surface was analyzed using X-ray photoelectron spectroscopy and X
-ray induced Auger electron spectroscopy before and after extraction.
The surface oxygen content and oxide layer thickness decrease after tr
eatment. A linear correlation was found between oxide thickness and pH
(iep), which yields a pristine pH(iep) of about 9.7 for the unoxidized
Si3N4 particle.