Influence of Hot Pressing Sintering Temperature on β-Sialon-15R Ceramics Synthesized from Aluminum Dross

抄録

Dense β-sialon-15R ceramics were fabricated by hot pressing sintering method using aluminum dross as a raw material. The effect of hot pressing sintering temperature on densification, microstructure, mechanical properties and impurity were studied. The results indicated that the main phases of the ceramics were β-sialon and 15R AlN polytypoid at 1450, 1550, 1650 and 1750°C, and Fe₅Si₃ as the main impurity was found. The salts impurities were evaporated from the sample sintered at 1750°C. Most of Mg cations from aluminum dross were incorporated into 15R grains. AlN polytypoids in the multiphase ceramics offer an effective path to reduce the glass phase formed from the oxide impurity in aluminum dross. The aspect ratio of elongated 15R grains increased quickly with the increase of sintering temperature, and a whisker-like microstructure was formed above 1550°C. The β-sialon-15R ceramics obtained the highest density of 3.2 g/cm³ at 1750°C, and the Vickers hardness (Hv₁₀), bending strength and fracture toughness of the material could reach with the value of 12.3 GPa, 432 MPa and 4.31 MPa·m^1/2, respectively. Fe₅Si₃ impurity had a negative effect on the mechanical properties.