Effect of Different Rare-Earth on Microstructure and Properties of α-Sialon Ceramics

Abstract

Abstract: Densified Yb-, Y-, Dy-, Sm- and Nd-α-Sialon ceramics were prepared by two-step hot sintering. The variation of microstructure and properties with different rare-earth was investigated. The ceramics doped with smaller cations (Yb3+, Y3+ and Dy3+) are fully composed of α-Sialon, while in the larger cations (Sm3+ and Nd3+) doped ceramics also exist a few intergranular phase M′ (Re2Si3-xAlxO3+xN4-x) in triple-point pockets. With increasing the radius of the rare-earth cations, the elongated α-Sialon grains form instead of the equiaxed grains in Yb-α-Sialon, and the aspect ratio of grains increases. All the ceramics possess high hardness, and the value of 21 GPa is achieved for Yb- and Y-α-Sialon. With increasing the ionic size of rare-earth, the hardness decreases slightly but the toughness tends to increase. Nd-α-Sialon possesses the highest toughness with the value of 5.4 MPa•m1/2.

Key words: α-Sialon, Rare-earth, Microstructure, Mechanical properties

Chunfeng LIU, Feng YE, Yu ZHOU, Yongliang WANG, Jiancun RAO. Effect of Different Rare-Earth on Microstructure and Properties of α-Sialon Ceramics[J]. J Mater Sci Technol, 2008, 24(06): 878-882.

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