Facile synthesis of graphene surface-modified aluminum powder with low infrared emissivity and excellent anticorrosive performance

Aluminum powder, common metal filler, is always used to prepare low infrared emissivity coating. However, a higher powder content in the coating usually lead to the bad anticorrosive performance. Considering the good anticorrosive performance of graphene, here we demonstrate a novel and facile method to prepare graphene surface-modified aluminum powder, using 3-aminoproplyphosphoic acid as "link" agent. Firstly, graphene oxide, prepared by Hummers method, was functionalized by reacting with 3-aminoproplyphosphoic acid at 95℃. The remained -PO(OH)₂ functional groups on modified GO were then reacted with aluminum to obtain graphene-modified aluminum powder. The Fourier transform infrared spectra (FT-IR), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to verify the structures of the resultants. From all experimental data, it is clear that the aluminum powders were successfully coated with a layer of graphene via Al-O-P bonds. The graphene-modified aluminum powder was highly efficient in preparing lower infrared emissivity coatings with excellent anticorrosive performance. The coating with 40% graphene-modified aluminum powder exhibited a low infrared emissivity (0.406) at spectral range of 8-14μm, and remaining the appearance after 500 hours of salt spray corrosion test, while the color of coating with the original aluminum powder has been changed in only 300 hours.