Preparation And Study Of Triazinedithiol Polymeric Nanofilm For Corrosion Protection On Copper Alloy Surface

Copper alloy is extensively used in electrical, electronics, transportation industries and high-technology due to its excellent properties, such as beautiful color and luster, strong mechanical properties and excellent electrical and thermal conductivity. However, copper alloy are inclined to be severe corroded in a humid environment or the solution containing corrosive medium. Not only its surface structure and composition will be changed, but also the property will be greatly decreased. This will shorten the service life of copper alloy, and greatly limit its use in various fields. Therefore, it is important to research and development environment-friendly and good corrosion resistance of copper alloy surface treatment. Due to thermally stable triazine ring and two highly reactive thiol groups, triazinedithiol compounds have been used for metal surface protection, it mainly used to prepare protective nanofilm by self-assembly technique and electrochemical assisted deposition technology. Besides,technological process of the triazinedithiol nanofilm is simple, non-toxic and pollution-free,and the nanofilm has a good application prospect in the field of metal anti-corrosion.In this paper, we chose 6-N,N-diallylamino-1,3,5-triazine-2,4-dithiol monosodium(DAN)and 6-(N-allyl-1,1,2,2-tetrahydroperfluorodecyl)amino-1,3,5-triazine-2,4-dithiol monosodium(AF17N) as triazinedithiol monomer. Firstly, we fabricate the polymeric nanofilm with the aid of self-assembled technique. Surface wettability of the nanofilms were investigated by contact angle and surface free energy. The film compactness was carried out by cyclic voltammograms. Surface morphologies of copper alloy were observed by scanning electron microscopy(SEM). Anticorrosion ability of the nanofilms were studied by potentiodynamic polarization and saline immersion test. The results show that the contact angle of copper surface modified by cured AF17 N self-assembled film is up to 124.1° with the lowest surface free energy of 9.653 mJ/m2. Cyclic voltammetry, potentiodynamic polarization and saline immersion test demonstrate that the cured AF17 N self-assembled film has better anticorrosion ability. Then, different single and composite functional polymeric nanofilms were constructed by the galvanostatic electrodeposition method on the surface of the copper alloy. The potentiodynamic polarization curve and electrochemical impedence spectroscopy results revealed that the optimum current density to conduct triazinedithiol film is 0.06 mA/cm2.Meanwhile, AF17 N film which prepared under the current density has excellent corrosionresistance performance. Properties of these electrodeposite films were characterized by many methods. The results showed that the contact angle of copper alloy surface modified by different single and composite films became larger, and the contact angle of composite film was up to 122.7°, which effectively improved the hydrophobic properties of copper alloy surface. The good consistence of cyclic voltammetry, potentiodynamic polarization and electrochemical impedance spectroscopy indicated the best anticorrosion performance of complex nanofilm. Also, results from saline test prove that the corrosion resistance of electrodeposition composite film was superior to single film.