Effect of Al_2O_3 Content on Dielectric Properties of Al_2O_3/LiTaO_3 Composite Ceramics

The effect of Al2O3 addition(5vol%,10vol%,15vol% and 20 vol%) on the dielectric properties of Al2O3/LiTaO3(ALT) composite ceramics prepared by hot-press sintering were investigated.The results show that the dielectric constant and dielectric loss of ALT composite ceramics decrease with the increasing frequency.Comparing with pure LiTaO3 ceramics,adding 5vol% Al2O3 can increase its dielectric constant and decrease its dielectric loss,while the dielectric constant and dielectric loss of ALT composite ceramics increase consequently with more Al2O3 adding.With Al2O3 contents increasing,the Curie temperature initiately increases and then decreases,reaching the maximum at 5vol% Al2O3.Thus,Al2O3/LiTaO3(ALT) composite ceramics is a good composite system because the addition of the second phase Al2O3 promotes sintering of LiTaO3,and slightly improves its dielectric properties.