SURFACE MODIFICATION OF SILICON-NITRIDE POWDER WITH ALUMINUM

Surface modification of Si3N4 with alumina was tried. It was achieved by simply mixing Si3N4 powder with an alumina sol up to similar to 2 w t% as alumina in an aqueous medium, dried, and followed by calcination at 400 degrees C for 1 h. A TEM micros graph showed a coating layer o f similar to 15 nm thickness. The isoelectric point of the modified Si 3N4 powder with porous alumina was at pH 7.8, which is different from 5.8 and 8.6 for Si3N4 and amorphous alumina, respectively.