| Abstract: | The crystal structure and microwave dielectric properties of Zn3-xCux(BO3)2 (x = 0–0.12) ceramics prepared via a traditional solid-state reaction method were investigated by means of X-ray diffraction (XRD) utilizing the Rietveld refinement, complex chemical bond theory, and Raman spectroscopy. XRD showed that all samples were single phase. The samples maintained a low permittivity, even at higher Cu2+ contents, which is conducive to the shortening of signal delay time, and intimately related to the average bond ionicity and Raman shift. Moreover, proper Cu2+ substitution greatly reduced the dielectric loss associated with the lattice energy. Cu2+ entering the lattice optimized the temperature coefficient of resonance frequency (τf) values and improved the temperature stability of samples by affecting the bond energy. Optimal microwave dielectric properties were: εr = 6.64, Q × f = 160,887 GHz, τf = ?42.76 ppm/°C for Zn2.96Cu0.04(BO3)2 ceramics sintered at 850 °C for 3 h, which exhibited good chemical compatibility with silver and are therefore good candidate materials for Low temperature co-fired ceramic applications. |
