Microwave dielectric properties of a novel low-temperature sintering H3BO3-added Ca2V2O7 ceramics

Abstract H3BO3 was added to Ca2V2O7 ceramics to decrease the sintering temperature by the solid-state reaction. The effects of H3BO3 addition on microstructure, sintering mechanism, and microwave dielectric properties of Ca2V2O7 ceramics were investigated. The results indicated that H3BO3, as a sintering aid, accelerated the mass transportation and facilitated the densification during the sintering process. An appropriate amount of H3BO3 doped Ca2V2O7 resulted in the decrease of sintering temperature along with the promotion of microwave dielectric properties. Moreover, the decline of V O bond energy and the formation of CaV2O6 explained the variation of τf for Ca2V2O7. In particular, Ca2V2O7 + 9 wt% H3BO3 ceramics sintered at 725 °C exhibited good microwave dielectric properties of er = 10.36, Q×f = 37,565 GHz and τf = −106.56 ppm/°C.