The Anisotropic Properties of the Tape Cast Si3N4 Ceramics with Rod-Like β-Si3N4 Seeds Addition

Abstract:

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Lu2O3 and SiO2 were used as sintering additives and rod-like β-Si3N4 seeds were added to enhance β-Si3N4 grain unidirectional growth. Silicon nitride ceramics were prepared by tape casting and gas pressure sinteringat 1950oC in 10 atm nitrogen atmosphere for 6 h. Compare to the no-seeded Si3N4, the seeded and tape-cast Si3N4 ceramics have obvious anisotropic microstructure and anisotropic properties. When a stress applied along with the grain alignment direction, the bending strength of the seeded and tape-cast Si3N4 at 1500oC was 738 MPa, which was almost the same as its room temperature bending strength. However, the bending strength of the seeded and tape-cast at room temperature was 556 MPa (perpendicular direction); and their thermal conductivity were 67 W/m·K (perpendicular direction) and 83 W/m·K (parallel direction), respectively. The anisotropic properties of the seeded and tape-cast Si3N4 were attributable to the elongated Si3N4 grain alignment.

Info:

Periodical:

Key Engineering Materials (Volumes 317-318)

Edited by:

T. Ohji, T. Sekino and K. Niihara

Pages:

593-596

DOI:

10.4028/www.scientific.net/KEM.317-318.593

Citation:

Y. P. Zeng et al., "The Anisotropic Properties of the Tape Cast Si3N4 Ceramics with Rod-Like β-Si3N4 Seeds Addition", Key Engineering Materials, Vols. 317-318, pp. 593-596, 2006

Online since:

August 2006

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$35.00

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