Microwave dielectric properties of low temperature sintering Ca5Mn4(VO4)6 ceramics

Low temperature sinterable Ca5Mn4(VO4)(6) ceramics were fabricated by the conventional solid-state reaction route and their microwave dielectric properties were investigated for the first time. The formation of Ca5Mn4(VO4)(6) main phase was confirmed by XRD diffraction pattern. The correlations between sintering temperature, packing fraction, and microwave dielectric properties in Ca5Mn4(VO4)(6) ceramics were also studied. The Ca5Mn4(VO4)(6) ceramics sintered at 875 A degrees C for 5 h possessed good microwave dielectric properties: epsilon(r) = 11.2, Q x f = 33, 800 GHz (at 10.5 GHz) and tau(f) = -70 ppm/A degrees C. The material was found to react seriously with Ag when sintered at 875 A degrees C, forming (AgCa2)Mn-2(VO4)(3) phase.