Curing epoxy with electrochemically synthesized GdxFe3-xO4 magnetic nanoparticles

•Synthesized electrochemically and characetrized Fe3O4 and gadolinium-doped (Gd2+-Fe3O4).•Compared curability of nanocomposites containing Fe3O4 and Gd2+-Fe3O4.•Explained qualitatively cure potential of nanocomposites in terms of Cure Index.•Replacement of Fe2+ by Gd2+ cations resulted in all sorts of cured epoxy/Gd2+-Fe3O4 composites: Poor, Good, and Excellent. In this work, supermagnetic lanthanide-doped Fe3O4 nanoparticles were synthesized through electrodeposition method by partial doping in gadolinium (Gd) to be intended in the near future in developing oxidation-resistant epoxy-based coatings. Partial substitution of Fe3+ ions in Fe3O4 by Gd3+ lanthanide cations was confirmed by X-Ray diffraction (XRD) patterns and Fourier-transform infrared spectroscopy (FTIR) spectra. Field-emission scanning electron microscopy (FE-SEM) and vibrating sample magnetometer (VSM) were employed to evaluate particle size distribution and magnetic nature of the nanoparticles, respectively. Low-filled nanocomposites containing 0.1 wt.% of Fe3O4 and Gd3+-doped Fe3O4 were prepared and their curing ability was assessed in terms of qualitative measurements on network formation by the use of Cure Index. Having a wide range of curing behavior led to development of Poor, Good, and Excellent cured coatings depending on nanoparticle bulk composition and heating rate applied in the nonisothermal differential scanning calorimetry (DSC). Overall, incorporation of Fe3O4 into epoxy decreased exothermic heat release of epoxy, while Gd3+-doped nanoparticles facilitated curing reaction between epoxy and aliphatic amine curing agent. Moreover, glass transition temperature of the prepared nanocomposites decreased compared to the blank epoxy. The developed epoxy/lanthanide-doped Fe3O4 nanocomposites are potential candidates for developing oxidation-resistant coatings thanks to the presence of Gd3+ cations.