Phase formation and microwave dielectric properties of BiMVO5 (M = Ca, Mg) ceramics potential for low temperature co-fired ceramics application

Two low-firing BiMVO5 (M = Ca, Mg) ceramics were prepared in the sintering temperature range of 760-850 degrees C. Their differences in phase formation, sintering behavior, and dielectric performances were investigated. BiCaVO5 formed a single phase with an orthorhombic structure, while BiMgVO5 crystallized in a monoclinic structure that needs longer dwelling time to obtain single phase. The optimized microwave dielectric properties were obtained with epsilon(r) = 15.70, Q x f = 55 000 GHz (at 10.6 GHz), and tau(f) = -71 ppm/degrees C for BiCaVO5, epsilon(r) = 18.55, Q x f = 86 860 GHz (at 9.63 GHz), and tau(f) = -65 ppm/degrees C for BiMgVO5. In addition, the large negative tf values of BiMVO5 (M = Ca, Mg) ceramics were successfully adjusted by forming composite ceramics with CaTiO3 and near-zero tau(f) values of +2 ppm/degrees C and -3 ppm/degrees C were obtained in 0.92BiCaVO(5)-0.08CaTiO3 and 0.94BiMgVO(5)-0.06CaTiO(3), respectively. Both ceramics exhibited good chemical compatibility with Ag electrode. The results demonstrate BiMVO5 (M = Ca, Mg) ceramics to be attractive candidates in LTCC technology.