▎ 摘　　要

NOVELTY - A graphene-coated variable phase nano magnetic composite material comprises a core-shell structure. The core comprises magnetic core containing variable nano magnetic particles with grain diameter of 10-90 nm. The shell comprises multiple layers of graphene. The thickness of the shell layer is 5-50 nm. USE - Graphene-coated variable phase magnetic nano composite material (claimed). ADVANTAGE - The graphene-coated variable phase magnetic nano composite material has reduced toxicity and environmental pollution due to the use of ferrocene powder as reactant. The composite material has uniform distribution of particle diameter, good degree of sphericity, and is mass produced within a short period of time. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for preparation of graphene-coated variable phase nano magnetic composite material, which involves using ferrocene powder as iron source and carbon source.