Spark Plasma Sintering of Nanosized Amorphous Silicon Nitride Powder with a Small Amount of Sintering Additive

Authors: Hotta, Mikinori; Shinoura, Takanori; Enomoto, Naoya; Hojo, Junichi

Source: Journal of the American Ceramic Society, Volume 93, Number 6, June 2010 , pp. 1544-1546(3)

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Abstract:

Dense and fine-grained β-Si₃N₄ ceramics were successfully obtained with a small amount of sintering additives, 1.5 mass% Y₂O₃ and 0.5 mass% Al₂O₃, using nanosized amorphous Si₃N₄ powder by spark plasma sintering at temperatures of 1500°-1800°C and a pressure of 30 MPa under N₂. The β-Si₃N₄ ceramics were composed of equiaxed grains with an average size of 300 nm. A higher sintering temperature was required for the densification of submicrometer-sized α-Si₃N₄ powder with the small amount of the additives. The use of nanosized amorphous Si₃N₄ powder accelerated the densification and the transformation to the β-phase.