Effect of Hexagonal BN on the Microstructure and Mechanical Properties of Pressureless Sintered Porous Si3N4 Ceramics

Abstract:

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Porous silicon nitride ceramics with various amounts (25, 35, and 45 vol %) of hexagonal boron nitride (h-BN) were fabricated at 1800°C for 2h by the pressureless sintering process. With FESEM and TEM, the effects of h-BN on the microstructure and mechanical properties of Si3N4 ceramics were investigated. Results of the microstructure and mechanical properties of Si3N4/BN composites showed that the growth of the elongated β-Si3N4 were hindered by h-BN additive, which resulted in the decrease of fracture toughness of Si3N4/BN ceramics with increasing h-BN content. The morphologies of the fracture surfaces by FESEM revealed the fracture mode for Si3N4/BN composites to be intergranular. However, phase analysis by XRD indicated that the effect of h-BN on the α- to β- Si3N4 phase transformation of Si3N4/BN composites was negligible.

Info:

Periodical:

Key Engineering Materials (Volumes 434-435)

Edited by:

Wei Pan and Jianghong Gong

Pages:

697-700

DOI:

10.4028/www.scientific.net/KEM.434-435.697

Citation:

Y. F. Li et al., "Effect of Hexagonal BN on the Microstructure and Mechanical Properties of Pressureless Sintered Porous Si3N4 Ceramics", Key Engineering Materials, Vols. 434-435, pp. 697-700, 2010

Online since:

March 2010

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Price:

$35.00

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