Study of the dielectric properties, relaxation mechanisms and electrical conduction mechanisms of epoxy/ α–Iron oxide nanocomposites

In this study, the dielectric properties , relaxation mechanisms, and electrical conduction mechanisms of epoxy resin-based nanocomposites were enhanced using ferric oxide α − Fe 2 O 3 nanoparticles . Composites containing 3–12 wt% nanoparticles were analyzed for relative permittivity , impedance, modulus, alternating conductivity, activation energy , and hopping energy across a temperature range of 30–150 °C and frequencies of 10 − 2 - 10 6 Hz using dielectric relaxation spectroscopy. Nanoparticle dispersion and structural formation within the epoxy matrix were confirmed using scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy and X-ray diffraction. The results revealed that the electrical permittivity and impedance increased with temperature, whereas the conductivity, modulus, and activation energy decreased. The relaxation behavior was analyzed using the Havriliak-Negami model via WinFit software. Distinct conduction mechanisms were observed at lower filler concentrations (3–6 wt%). %) exhibited modified Non-Overlapping Small Polaron Tunneling and modified Correlated Barrier Hopping, whereas higher concentrations (9–12 wt%) transitioned to Quantum Mechanical Tunneling and modified Correlated Barrier Hopping. The results showed that the relative permittivity of the epoxy samples increased with increasing temperature. Specifically, the relative permittivity of the epoxy/ 3 wt% sample at room temperature was 3 and it increased to 12 at 150°C. Additionally, a slight increase in AC conductivity was observed owing to thermal activation, with AC conductivity values increasing from 10 − 8 to 10 − 7 S/cm within the specified temperature range for the epoxy/ 12 wt% sample. Furthermore, a gradual decrease in impedance was noted as the temperature increased, with values decreasing from 10 11 to 10 9 Ω for the epoxy/ 3 wt% sample. Analysis of the Cole-Cole plots revealed a variation in the relaxation time that depended on the filler concentration, indicating a notable impact of the filler content on the dielectric relaxation behavior. These findings demonstrate the potential of epoxy-α- Fe 2 O 3 composites as high-performance insulation in high-voltage applications. • New method enables semi-uniform filler distribution in polymer samples. • Increased filler concentration's impact on dielectric properties analyzed. • Temperature effects on epoxy/ Fe 2 O 3 ₃ nanocomposites' dielectric properties. • Investigating dielectric relaxation mechanisms in nanocomposite systems. • Analyzing conduction mechanisms within epoxy-based nanocomposites.