Microwave dielectric properties of (1 − x)Nd(Co1/2Ti1/2)O3–x(Ca0.8Sr0.2)TiO3 composite ceramics

摘要

(1 − x)Nd(Co1/2Ti1/2)O3(NCT)–xCa0.8Sr0.2TiO3(CST) composite ceramics were prepared by the conventional solid-state reaction process. From the X-ray diffraction analysis, it indicates that the Nd(Co1/2Ti1/2)O3 phase coexists with Ca0.8Sr0.2TiO3 phase, and it is easy for the cobalt volatilization to form second-phase Nd2Ti2O7 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(Co1/2Ti1/2)O3–xCa0.8Sr0.2TiO3 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.