ZnAl2O4-TiO2-SrAl2Si2O8 low-permittivity microwave dielectric ceramics

(1-x)(0.75ZnAl(2)O(4)-0.25TiO(2))-xSrAl(2)Si(2)O(8) (abbreviated as (1-x)ZAT-xSAS) ceramics were prepared by the solid-state reaction. The effects of SAS content on shrinkage, phase compositions, microstructure and microwave dielectric properties were investigated. It shows that SAS with a rare negative shrinkage characteristic can effectively adjust the shrinkage of the (1-x)ZAT-xSAS ceramics to near-zero value. In addition, ZnAl2O4 spinel, TiO2 rutile and SrAl2Si2O8 monoclinic phases can coexist in the (1-x)ZAT-xSAS system, which is helpful to control the microwave dielectric properties and obtain a serial epsilon(r) value from 3.56 to 12.20 by changing the phase composition. Therefore, (1-x)ZAT-xSAS could be a kind of zero-shrinkage and low-permittivity microwave dielectric ceramics for many potential applications in the future. (C) 2012 Elsevier Ltd and Techna Group S.r.l. All rights reserved.