The enhanced and polarized Raman spectra on the spherical aluminum powders encapsulated within graphene nanosheets

This article deals with the Raman spectroscopic research of aluminum–graphene (Al–Gr) composites obtained by aqueous suspension-based mixing to improve dispersion of graphene sheets in composite powders. Raman spectra of composite powders reflect encapsulated nanostructure of Al–Gr composite powders and chemical interaction of oxygen groups on graphene oxide (GO) with magnesium ions (Mg²⁺), depending on the added Mg²⁺ content. First, the enhanced Raman signal for our composite powders is an apparent evidence of that graphene sheets with uniform dispersion on Al matrix are in close contact with the spherical surface of Al powders. The polarization dependence of the Raman spectra, which are dependent on the incident laser spot, also confirms that the graphene sheets surrounded the spherical powder. SEM image, XPS and FT-IR spectra for the composite powders provide additional data to decipher the Raman analysis results.