Pressure Sintering of Si3N4 System for Near-Net Shape Forming

Abstract

Yttria and alumina have been used with particular success, either singly or in combination, as densification aids for hot pressing and sintering of silicon nitride. To obtain desirable mechanical, physical, and chemical properties, it is necessary to minimize the addition of alumina as a densifying agent, however, very low amount of alumina additive reduces the possibility of sintering silicon nitride to high theoretical density. In this paper the authors have elucidated a sintering process which densifies silicon nitride to near theoretical density even with low amount of alumina doping.