Microwave dielectric properties of Na2xBa1-xLi2Ti6O14 ceramics and their chemical compatibility with silver

A series of Na2xBa1-xLi2Ti6O14 (x = 0.1, 0.2, 0.3, 0.4) ceramics were prepared by conventional solid-state reaction method. The effects of Na+ substitution on sintering behavior, crystal structure and microwave dielectric properties of Na2xBa1-xLi2Ti6O14 were studied. Na+ substitution effectively lowered the sintering temperature of BaLi2Ti6O14 to 950 °C and successfully adjusted τf value to shift toward the positive side. The microwave dielectric properties were investigated in terms of ionic polarization, packing fraction, bond valence, and octahedral distortion. All ceramics were well densified at 950 °C for 4 h and the best microwave dielectric properties were achieved at x = 0.2 with εr = 31.2, Q × f = 26,500 GHz (at 7.3 GHz), and τf = +1.13 ppm/°C. The chemical compatibility with the Ag electrode was also studied on Na2xBa1-xLi2Ti6O14 ceramics.