Covalent surface modification of LY12 aluminum alloy surface by self-assembly dodecyl phosphate film towards corrosion protection.

• A layer of dodecyl phosphate (DDPO4) film on LY12 aluminum alloy substrate was prepared. • P was enriched at the SAMs/oxide layer interface, revealing that the P O bond in the DDPO4 adsorbed on oxide surface. • The prepared film showed superior corrosion resistance in the chloride-containing solution. The goal of this work was to prepare a layer of dodecyl phosphate (DDPO4) film on LY12 aluminum alloy substrate for corrosion protection using self-assembly technique. The prepared DDPO4 Film properties were characterized by X-ray photoelectron spectroscopy (XPS), water contact angle measurement, and electrochemical measurement. Experimental results indicated that DDPO4 was successfully assembled on aluminum alloy substrate via covalent bond attachment. The modified surface was hydrophobic due to the DDPO4 attached to the oxide surface and a hydrocarbon tail-up orientation. Accelerated corrosion test showed that the DDPO4 modified LY12 aluminum alloy substrate exhibited excellent corrosion resistance in an electrolyte containing 0.01 M Cl− + 0.01 M SO 4 2−, and no apparent corrosion pits were observed after an exposure of 96 h. The charge transfer resistance of the DDPO4 covered aluminum alloy was ∼100 times larger than that of the blank aluminum alloy. [ABSTRACT FROM AUTHOR]