Electrochemical Preparation And Characterization Of Anticorrosive Film On Copper

Corrosion protection for metals is very important to the development of national economy.It is a hotspot to protect metals by making a fiat of polymer film on metals surface at the present time.We studied corrosion behaviors of copper in alkaline solution within and without inhibitior BTA;synthesis and corrosion prevention effects of both polyaniline and polyphenol on copper were studied in this graduation thesis.The corrosion behaviors of copper and inhibition effects of BTA on copper were studied,respectively,in alkaline solution involving 0.1 mol/L NaOH and 0.2 mol/L Na₂SO₄,using cyclic voltammetry,linear sweep voltammetry and constant potential. Results indicate that there are three anodic peaks and two cathodic peaks on CV voltammagrams,which were proved that the three anodic peaks are corresponding to the oxidation of copper from Cu to Cu⁺ and from Cu⁺ to Cu²⁺and the two cathodic peaks are corresponding to the reduction of copper from Cu²⁺to Cu⁺ and from Cu⁺ to Cu.Other results show that BTA has special inhibition effect on copper's oxidation, especially on the formation of cuprous oxide.But this effect is not notable until the concentration of BTA is higher than 1×10^-3mol/L.We preprated polypaniline on copper surface in different concentron of sodium oxalate and anilin solution.And studied the corrosion pretection of it by the methods of open circuit potential-time,AC impedance,Tafel plots and electron microscope. The results indicate that aniline can make polymer on copper surface in sodium oxalate solution and block the small hole of the polymer of copper oxalate on copper surface,and arose high passivation immediately.But this polymer has a poor stabitity, the prevention to copper decreases very quickly by the prolonging time dipped in solution involving 3%NaCl.We concluted this was relative to the poor compactability of copper oxalate polymer and copper.The synthesis of polyphenol and its corrosion prevention on copper were studied in sodium carbonate solution,using cyclic voltammatry,open potential-time,AC impedance Tafel plot and scanning electron microscope(SEM).The results indicate that the polyphenol film synthesized in sodium sulfate solution by cyclic voltammatry is insulated and it has good inhibition to copper corrosion.Its corrosion resistance is relative to the concentration of phenol,scan speed of cyclic voltammatry,scan circles of cyclic voltammatry and concetron of sodium carbonate.The polyphenol film has good compactability and corrosion resistance when lower scan speed.They drop by the increased concentration of phenol when its concentration is above 0.05 mol/L, while the result reverses when the concentration is lower 0.05 mol/L,it means the best suitable concentratron of phenol is 0.05 mol/L,the concetron of sodium carbonate has little effect to polyphenol film.We studied the formation by constant potential and studied the corrosion prevention of polyphenol film synthesized.Results show that polyphenol film synthesized by constant potential has bad stability,leading to lower corrosion prevention effect than synthesized by cyclic voltammatry.