Study On The Inhibiton Effect Of Self-assembled Films For Copper Corrosion In 0.5 M HCl Solutions

Copper is widely used in the fileds of production and daily life because of its good corrosion resistance. However, it will be corroded and damaged remarkedly in the harsh condition, such as, the water full of oxygen (the oxygen rich water), the oxidizing acid solution and solution containing CN- or Cl- ions. To inhibit the corrosion of copper, great efforts have been put into the investigation. Among them, the self-assembly technology has been the focus of science academy owing to its simple cooperation, the highly ordered films, the high inhibition efficiency and the controlable thickness of the film.In this paper, the protective films were prepared on copper electrodes by self-assembly technology. And the ability of different self-assembled films to inhibit the copper corrosion in 0.5 M HCl solutions were investigated by electrochemistry tsets and the surface morphology were characterized, the inhibition mechanism was also discussed.The main research work is as follow:1. Study on corrosion inhibition of copper by 2,5-dimercapto-1,3,4-thiadiazole films in acidic solution2,5-Dimercapto-1,3,4-thiadiazole (DMTD) films were prepared on the fresh copper surface to form protective monolayer against copper corrosion in acidic solution. Its corrosion inhibition was investigated in 0.5 M HCl solution by electrochemistry tsets. Surface observation was performed to ensure the films were self-assembled on the copper surface successfully using scanning electron microscope (SEM), contact angle goniometer(CA) and Fourier transform infrared (FT-IR) spectrometer. The inhibition efficiency of the DMTD films on copper was above 84% according to the data analysis of potentiodynamic polarization and electrochemical impedance spectroscopy curves and showing that the DMTD films has good protective ability for copper corrosion in 0.5 M HCl solution. The adsorption model of DMTD molecule on Cu(111) surface was established by molecular simulation, this result provide theoretical support at the molecular level to the experiments and will lead to design more efficient inhibitor.2. Study on corrosion inhibition of copper by 4-octylphenol films in acidic solution4-Octylphenol (OP) self-assembled films were prepared on copper to inhibit the copper corrosion in 0.5 M HCl solution. Its corrosion inhibition was investigated in 0.5 M HC1 solution by electrochemistry tsets. The inhibition efficiency of the OP films on copper was above 80% according to the data analysis of potentiodynamic polarization and electrochemical impedance spectroscopy curves and showing that the OP films has good protective ability for copper corrosion in 0.5 M HC1 solution. Surface observation was performed to analyse the structure of the films on the copper surface using SEM, CA and FT-IR. The molecular simulation provided the adsorption model of OP molecule on the Cu(111) surface.3. Study on corrosion inhibition of copper by the double self-assembled filmsDopamine (DA) and 3-mercaptopropyl trimethoxysilane (MPTS) mixed films were prepared on copper to inhibit the copper corrosion in 0.5 M HCl solution. Its corrosion inhibition was investigated in 0.5 M HCl solution by electrochemistry tsets. The inhibition efficiency of the mixed films on copper achieved a value of 80% according to the results obtained from the potentiodynamic polarization and electrochemical impedance curves and showing that the mixed films have good protective ability for copper corrosion in 0.5 M HCl solution. the results revealed that the mixed films inhibited the copper corrosion effectively with the optimum self-assembly time of 24 h in 2 g/L DA solution and 48 h in 1.0 mM MPTS tris-HCl solution. The copper surface morphology was characterized by SEM and FT-IR measurements.