Raman spectroscopy study of graphene formed by “in situ” chemical interaction of an organic precursor with a molten aluminium matrix

Abstract A study of graphene “in situ” formed during the chemical interaction of glucose with molten aluminium under a layer of molten alkaline halides in air at temperatures of 750–850°C is presented. By means of Raman and X‐ray photoelectron spectroscopy and electron microscopy, it is shown that graphene films synthesize in the aluminium. The number and defectiveness of graphene layers inside aluminium matrix depends on synthesis temperature– at 750°C two‐layer graphene and at 850°C three‐layer graphene form. The most defective graphene films synthesized at 750°C with the formation of five‐ and seven‐membered rings in plane of the graphene grid; the number of defects of graphene films is less for composite obtained at higher temperature. The evaluated defectiveness of graphene not exceed 14%; it evidences the formation of perfect graphene in aluminium matrix. The compressive stress value is the smallest for the sample obtained at 750°C and increases with temperature and plastic deformation because of differences in the crystal lattice parameters and their thermal expansion coefficients of aluminium and graphene. This fact explains the relation of defects number in graphene with temperature and plastic deformation. No aluminium carbide and graphene oxide were formed during synthesis inside aluminium matrix because of formation of defect‐free perfect graphene with high chemical stability. The absence of aluminium carbide was proven by means Raman spectroscopy, X‐ray photoelectron, transmission electron microscopy, and corrosion test with distilled water. It allows to propose aluminium‐graphene composites for numerous practical applications as a constructive material.