Development of α-SiAlON-SiC ceramic composites by liquid phase sintering

• Published in: International journal of refractory metals & hard materials Vol. 25; no. 1; pp. 77 - 81
• Main Authors: Souza, J.V.C., Santos, C., Kelly, C.A., Silva, O.M.M.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 2007
• Subjects: Composites; Mechanical properties; Microstructure; Silicon carbide; Sintering; α-SiAlON; β-SiC; Composites; Silicon carbide; α-SiAlON; Sintering; Mechanical properties; β-SiC; Microstructure
• ISSN: 0263-4368; 2213-3917
• DOI: 10.1016/j.ijrmhm.2006.01.004

In this work, “in situ” α-SiAlON-SiC ceramic composites were obtained by liquid phase sintering, using SiC as reinforcement. Different β-SiC powder contents (0–20 wt.%), were added to Si 3N 4–AlN–RE 2O 3 powder mixtures, and compacted by cold isostatic pressing. The samples were sintered at 1950 °C for 1 h, in N 2 atmosphere. Sintered samples were characterized by relative density, weight loss, X-ray diffraction and scanning electron microscopy. Furthermore, mechanical properties such as hardness and fracture toughness were determined by Vickers indentation method. Lattice parameters of the α′ phase did not considerably change with increase of SiC content. However, morphology, average grain size and aspect ratio of the α′ phase were considerably changed with increase of the SiC content. These behavior influences significantly the mechanical properties of this hard ceramic composite.