An eco-friendly nitrogen doped carbon coating derived from chitosan macromolecule with enhanced corrosion inhibition on aluminum alloy

Aluminum alloy plates used in proton exchange membrane fuel cells fail to provide long-term stability due to the corrosion. Here, a nitrogen doped carbon film derived from chitosan macromolecule is prepared on Al alloy to improve anti-corrosive ability by spraying and calcining process. Electrochemical tests of the as-prepared carbon film are investigated in a simulated environment of fuel cells (0.5 M H 2 SO 4  + 2 ppm HF). As results, the corrosion potential of the carbon film coated Al alloy shows a positive shift by 157 mV. Its corrosion current density is ~3 orders of magnitude lower than bare Al alloy. Impedance modulus at 0.01 Hz of the coated Al alloy is remarkably improved and it shows a high coating resistance. Furthermore, the carbon film still exhibits a high coverage on the substrate after 50 times peeling off by scotch tape. The high protection efficiency of the carbon film in the acidic condition is attributed to the strong adhesion to the Al alloy and the physical barrier effect. This strategy provides an eco-friendly and facile method for designing a protective coating on Al alloy used in the acidic environment.