Microwave dielectric properties of (Ca_1-xZn_x) ₂P₂O₇

The phase evolution, sintering behavior and microwave dielectric properties of mixed pyrophosphates (Ca_1-xZn_x)₂P ₂O₇ (x=0.1-0.9) were investigated in this paper. The results show that samples with x=0.1-0.4 exhibit mixture phases of CaZnP ₂O₇ and β-Ca₂P₂O₇, and the samples with x=0.6-0.9 exhibit mixed phases of CaZnP₂O ₇ and Zn₂P₂₇. A single-phase composition of CaZnP₂O₇ could be formed when x=0.5. The mixed pyrophosphates (Ca_1-xZn_x)₂P ₂O₇ (x=0.1-0.9) exhibit low sintering temperature (≤900°C), low relative permittivity (<9), high Q×f value and negative temperature coefficient of resonant frequency. Maximum Q×f value of 63,130 GHz could be obtained for CaZnP₂O₇ sintered at 900°C/2 h. Its dielectric constant and τ_f value are 7.56 and -82 ppm/°C, respectively.