The Correlations between Complex Chemical Bond Theory and Microwave Dielectric Properties of Ca 2 MgSi 2 O 7 Ceramics

Magnesium melilite (Ca 2 MgSi 2 O 7 ) ceramic with tetragonal crystal structure was prepared through the conventional solid-state method. Crystal structure and complex chemical bond theory were used to analyze the microwave properties of Ca 2 MgSi 2 O 7 ceramics and the correlations between the bond ionicity, lattice energy, bond energy and relative dielectric constant ( ε r ), quality factor ( Q × f 0 ), temperature coefficient of resonant frequency ( τ f ) were discussed in depth. Optimum microwave dielectric properties were obtained when sintered at 1300°C for 4 h: ε r = 9.86, the dielectric loss (tan δ ) was 1.24 × 10 −4 (at 1 MHz), Q × f 0 = 8016 GHz (resonant frequency f 0 = 7.90 GHz), τ f = − 42 ppm/°C.