Crystal structures and microwave dielectric properties of CaZn₁ -x Mg x P 2 O 7 ceramics

Abstract CaZn₁₋xMgxP2O7 (CZMP, 0 ≤ x ≤ 0.08) ceramics were fabricated via the conventional solid-state reaction method, and the influences of Mg²⁺ substitution on the crystal structures and microwave dielectric properties of CaZnP₂O₇ ceramics were systematically studied. The results revealed that moderate MgO substitution facilitates densification, lowered the sintering temperature of CZMP ceramics, and optimized their microwave dielectric properties simultaneously. The densification temperature of the samples with x = 0.04 dropped from over 900 ℃ for the pure sample to 800 ℃, accompanied by a bulk density of 3.296 g/cm3 and a high relative density of 99.25%. finally, the CaZn0.96Mg0.04P2O7 ceramics sintered at 800 ℃ possessed outstanding microwave dielectric properties: a dielectric constant (εr) of 7.49, a quality factor (Q×f) of 86,762 GHz, and a temperature coefficient of resonant frequency (τf) of -23.36 ppm/℃. The results demonstrated that the as-prepared ceramic was highly promising for high-frequency electronic devices including filters and dielectric substrates.