Optimization for Preparation of High Density Alumina Ceramics with Ultrafine-Grained Structure by a Fast Sintering Method

The preparation of ultrafine-grained alumina ceramics by the fast sintering technique Self-propagating High-temperature Synthesis plus Quick Pressing (SHS-QP) method was reported. The reaction heat generated by combustion reaction was applied to act as a high temperature source. An alumina compact was loaded inside the combustion reactants, which form a “SHS-furnace”, and great mechanical pressure was applied when the temperature reached the maximum. Dense ultrafine-grained alumina ceramic was prepared using a lower heating rate (900 °C /min), and the effects of sintering time, and pressure on the densification and grain size were discussed. Within a short sintering time of 3 min, full-density alumina ceramics with ultrafine-grained structure are obtained under a pressure of 120 MPa.