Large scale re-producible synthesis and magnetic properties of Ni/graphite core-shell nanostructured materials

We designed an experimental set-up and optimized the process parameters for large scale synthesis (250 g) of low density nickel core metal with graphitic carbon shell as functional nanomaterial with highly reproducible physical properties. Structural characterization reveals formation of nano-core FCC Ni metal ~40 nm with ~7 nm thick graphitic shell after annealing at 850 °C. Room temperature field dependent magnetic (M−H) measurement reveals significant saturation magnetization in the sample even with non-magnetic graphite shell. The structural and magnetic properties are compared with small-scale batch synthesis (10 g), reported earlier. The temperature-dependent magnetic measurements suggest that Ni/graphite core-shell samples, annealed at 550 °C, and 700 °C are superparamagnetic, whereas sample annealed at 850 °C is ferromagnetic. The developed synthesis set-up is simple, environment friendly, and cost-effective. Further, to cater the end use applications of such materials for industrial, bio-medical and microwave absorption, the reported method may be further scaled up for large production.