MECHANISMS OF PLASMA-ASSISTED SINTERING IN THE SI3N4 CERAMIC SYSTEM

The plasma assisted sintering (PAS) process has been successful in the consolidation of submicron, doped silicon nitride to > 99% of the the oretical density (TD) at 1750 degrees C in less than 5 min. Ube Indust ries, SN-10E silicon nitride powder was used in this study with variou s oxide additives. A critical amount of oxide additives was found to b e required for consolidation using the PAS equipment. The effectivenes s of the PAS processing method is theorized to be dependent on the die lectric nature of the oxide additives. As the dielectric storage capac ity of the additive is exceeded, high temperatures are generated betwe en powder particles as the electrical energy is released.