Microwave, spark plasma and conventional sintering to obtain controlled thermal expansion β-eucryptite materials

Abstract

Lithium aluminosilicate was fabricated by conventional and nonconventional sintering: microwave and spark plasma sintering, from 1200 to 1300°C. A considerable difference in densification, microstructure, coefficient of thermal expansion behavior and hardness and Young's modulus was observed. Microwave technology made possible to obtain fully dense glass-free lithium aluminosilicate bulk material (>99%) with near-zero and controlled coefficient of thermal expansion and relatively high mechanical properties (7.1 GPa of hardness and 110 GPa of Young's modulus) compared with the other two processes. It is believed that the heating mode and effective particle packing by microwave sintering are responsible to improve these properties.