Microwave dielectric properties of (1 - X)Nd(Co _(1/2)Ti _(1/2))O _3-x(Ca _(0.8)Sr _(0.2))TiO _3 composite ceramics

摘要

(1 - x)Nd(Co _(1/2)Ti _(1/2))O _3(NCT)-xCa _(0.8)Sr _(0.2)TiO _3(CST) composite ceramics were prepared by the conventional solid-state reaction process. From the X-ray diffraction analysis, it indicates that the Nd(Co _(1/2)Ti _(1/2))O _3 phase coexists with Ca _(0.8)Sr _(0.2)TiO _3 phase, and it is easy for the cobalt volatilization to form second-phase Nd _2Ti _2O _7 as x = 0.5 and 0.7. As the content of CST increases from 0.1 to 0.9, the dielectric constant of the (1 - x)Nd(Co _(1/2)Ti _(1/2))O _3-xCa _(0.8)Sr _(0.2)TiO _3 composite ceramics increases from 29.3 to 114.7, the Q × f value decreases from 60,000 to 8,500 GHz, and the τ _f value varies from -33.8 to 271 ppm/ oC. A near zero τ _f could be achieved at 0.5NCT-0.5CST ceramics with ε r = 44.5 and Q × f = 20,000 (GHz) sintered at 1,340 °C for 4 h.