Effects of complex substitution of La and Nd for Bi on the microwave dielectric properties of BiNbO4 ceramics

Abstract La 2 O 3 and Nd 2 O 3 were used to substitute Bi 2 O 3 and the effects of complex substitution on the sintering behavior and the microwave dielectric properties of BiNbO 4 ceramics were studied. With 0.5 wt.% CuO–V 2 O 5 mixtures addition, all of the Bi 1− x (La 0.38 Nd 0.62 ) x NbO 4 ceramics could be densified below 920 °C. The triclinic phases are identified in Bi 1− x (La 0.38 Nd 0.62 ) x NbO 4 ceramics with x =0.01 sintered at 820 °C and the triclinic intensities increase with increasing the x value and sintering temperature. The saturated bulk density slightly decreases from 7.17 to 7.13 g/cm 3 and the e r value from 44.24 to 42.76 with increasing x from 0 to 0.07 for Bi 1− x (La 0.38 Nd 0.62 ) x NbO 4 ceramics. The saturated Q × f value is between 10,300 and 12,400 GHz depending on the x value. The τ f values of dense Bi 1− x (La 0.38 Nd 0.62 ) x NbO 4 ceramics decrease from 28.32 to 12.79 ppm/°C with x varying from 0 to 0.01 and remain almost unchanged with further increasing x .