Preparation of Self-Coating Al₂O₃ Bonded SiAlON Porous Ceramics Using Aluminum Dross and Silicon Solid Waste under...

Al₂O₃-bonded SiAlON ceramic with self-coating was prepared using aluminum dross and silicon solid waste as starting materials under ambient air conditions. The changes in phase, microstructure, and physical properties of the ceramic with temperature were analyzed and the formation mechanism of the SiAlON phase was elucidated. The results showed that higher temperature was more suitable for the preparation of SiAlON ceramics. As the temperature increased from 1400 to 1600 °C, the main phases in the ceramic transformed from mullite, Al₂O₃, and SiAlON to Al₂O₃ and SiAlON. An Al₂O₃-rich layer spontaneously coated the surface of the porous ceramic as Al melted and oxidized at high temperature. The thickness of this layer decreased as the temperature increased. The presence of Al₂O₃-rich coating layer impeded air flow, allowing nitriding of Si and Al, and the formation of the SiAlON phase in ambient air conditions. This study not only presents a strategy to successfully recycle aluminum dross and silicon solid waste but also offers a straightforward approach to preparing SiAlON material in air atmosphere.