Improved dielectric permittivity of NBCTO/epoxy composite films with low dielectric loss

In this paper, NBCTO/epoxy composite films with different contents of NBCTO were prepared by solution mixing and casting method. The structure, morphology, thermostability and dielectric properties of the composite films were studied by X-ray diffraction, scanning electron microscopy, thermo-gravimetric analysis and broadband dielectric spectrometer. The composite film showed a homogeneous structure and better thermostability, and the dielectric permittivity was almost independent of the frequency range from 10 to 106 Hz at room temperature. The dielectric permittivity and dielectric loss of NBCTO/epoxy composite film increased with increasing in NBCTO content, and the dielectric permittivity was as high as 37.10 whereas the dielectric loss was only 0.019 at 1 kHz when the NBCTO volume fraction reached 50 vol%. Theoretical analysis indicated that the dielectric permittivity calculated by the EMT model was close to the experimental data. The results showed that NBCTO/epoxy composite might have potential applications in the electronic devices.