Combining Chemical Reaction and Physical Barrier to Improve the Corrosion Resistance of Aluminum Alloys

Aluminum alloys has widely used in many fields because its advantages. However, the existing corrosion protection methods have insufficient protection ability and cannot achieve long-term protection. In this paper, 1-Hydroxyethylidene-1,1-diphosphonic acid (HEDP) molecules are used to prepare the active protective film on the surface of aluminum alloy. Then, Lauric acid/Graphene (LA/rGO) film is used to prepared on the surface of HEDP film. SEM, XRD, EDS, Raman, XPS and WCA were conducted to analyze physical and chemical features of coatings. The total resistance of the film reaches 1.0×10 20 Ω·cm 2 , the corrosion inhibition efficiency reaches 99.99 % , corrosion spots appeared on the 28th day in the salt spray test which 5 wt % NaCl was used as a corrosive medium. The theoretical study of the quantum chemical calculation indicated that the HEDP/LA/rGO composite film could be adsorbed on the Al alloy surface by P-O-Al and P-O-C chemical bond. This work presents a scientific perspective and novel design philosophy to fabricate the efficient anti-corrosion coating to protect aluminum alloy and then expand their potential applications in another field.