Microstructure and microwave dielectric properties of Ba(Mg1/3Nb2/3)O3-MgO composite ceramics with nano-silica added

Ba(Mg1/3Nb2/3)O-3-MgO composite ceramics were prepared by solid-phase method. The ceramic exhibited the 1:2 ordered structure. By adding a proper amount of MgO, the permittivity decreased rapidly compared with other Ba(Mg1/3Nb2/3)O-3-based ceramics. The Q x f values of the samples were greatly improved by nano-silica. Raman spectra showed that the permittivity and Q x f value showed a strong correlation with Raman shift and full width at half maximum of the A(1g)(O) phonon mode, respectively. The Raman shift of A(1g)(O) was consistent with the variation trend of permittivity. And the full width at half maximum of the A(1g)(O) phonon mode had a negative correlation with the Q x f value. The results showed that upon adding 1.5 wt% nano-silica to the ceramics, the ceramics sintered at 1550 degrees C for 5 h had the lowest Raman shift and the narrowest full width at half maximum, achieving the best microwave dielectric properties: epsilon(r) = 22.22, Q x f = 80,436 GHz, tau(f) = - 5.89 ppm/degrees C.

Automated summary

Ba(Mg1/3Nb2/3)O-3-MgO composite ceramics were prepared by solid-phase method, and the effect of adding different amounts of nano-silica on their properties was studied. The results showed that adding a proper amount of MgO could significantly decrease the permittivity of the ceramics, while adding nano-silica greatly improved the Q x f values of the samples.