Enhancing dielectric properties of epoxy-based nanocomposites reinforced with yttrium oxide (Y2O3) nanoparticles for high-voltage insulation applications

This study investigates the enhancement of dielectric properties in epoxy resin-based nanocomposites by incorporating yttrium oxide nanoparticles ($Y_2{O}_3$) for high-voltage insulation applications. Nanocomposites with $Y_2{O}_3$ concentrations of 3, 6, 9, 12, and 15 wt % were fabricated and characterized. Dielectric relaxation spectroscopy (10⁻²–10⁶ Hz) was used to evaluate key parameters—including permittivity, conductivity, activation energy, and conduction mechanisms—across temperatures ranging from 30 to 170 °C. Structural and morphological analyses via scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX) and X-ray diffraction (XRD) confirmed uniform nanoparticle dispersion in the epoxy matrix, with minor agglomeration observed at higher filler loadings. The 6 wt % nanocomposite exhibited optimal performance, demonstrating the lowest permittivity, conductivity, and activation energy (9.5 meV). In contrast, increasing the $Y_2{O}_3$ concentration to 15 wt % raised the activation energy to 11 meV and increased permittivity. Conductivity showed a temperature-dependent rise, consistent with thermal activation. A transition in the conduction mechanism from quantum mechanical tunneling to correlated barrier hopping (CBH) occurred at 110 °C, accompanied by a decrease in permittivity and a shift in crossover frequency (toward lower frequencies at reduced temperatures and higher frequencies at elevated temperatures). The β-relaxation mode remained dominant across the entire temperature range, highlighting the potential of epoxy/$Y_2{O}_3$ nanocomposites as advanced dielectric materials for high-voltage systems. These findings underscore a promising balance between thermal stability and dielectric efficiency.