The size-effect of Al2O3 on the sinterability, microstructure and properties of glass-alumina composites

摘要

The glass-ceramic composites were prepared from low-softening glass CaO-B2O3-SiO2, micrometer and nanometer alumina. The influences of nano-Al2O3 on the sinterability, microstructure, dielectric property, mechanical strength, and thermal expansion of glass-alumina composites were investigated. The densification mechanism of nano-Al2O3 modified glass-alumina composites was revealed further. The results show that nano-Al2O3 effectively lowers the densification temperature of glass-alumina <= 900 degrees C. The density gradually increases with increasing nano-Al2O3 to 15 wt %, and then decreases. Dielectric constant, dielectric loss, and flexural strength respectively versus nano-Al2O3 exhibit a similar change trend to the density. The sample with 15 wt % nano-Al2O3 sintered at 900 degrees C could form the dense microstructure (similar to 2.95 g/cm(3)) and achieve the high performance: low dielectric constant (6.13), low dielectric loss (5.2 x 10(-4)), low thermal expansion (4.21 x 10(-6)/degrees C), and high mechanical strength (178 MPa).