Study On Electrochemical Corrosion Of 6082 Aluminium Alloy In Different Medium

Electrochemical corrosions are easily encountered by 6082 aluminum alloy under working conditions?i.e.snow water containing NaCl snow melting agent?,which brings great potential safety hazards to road traffic.Therefore,it is of great significance to study the effect of chloride ions content on aluminum alloy and analyze the electrochemical corrosion process and mechanism of 6082 aluminum alloy in NaCl corrosion medium.In addition,the selection of appropriate corrosion inhibitor is an effective means of controlling the electrochemical corrosion of aluminum alloys.This paper studied the corrosion resistance of 6082 aluminium alloy in corrosive media with different salinity?NaCl mass fraction?by suing potential polarization curve test combining with scanning electron microscopy?SEM-EDS?,transmission electron microscopy?TEM?,backscatter electron diffraction?EBSD?and X-ray diffraction?XRD?.For the T6 state of 6082 aluminum alloy,as the NaCl mass fraction increased from 0.5%to1.5%,the corrosion current density(I_corr)gradually increased,and the corrosion depth gradually deepened.It was intergranular corrosion around the second phase.The electrochemical corrosion of T6 state of 6082 aluminum alloy in 48 hours was closely related to the second phase of the alloy surface?Mg₂Si second phase,Si second phase and AlFeMnSi second phase?.The corrosion process was mainly divided into two periods:The first period was 0⁴ hours.During this period,the corrosion morphology of the aluminum alloy was mainly characterized by the dissolution of the aluminum alloy matrix around the second phase of Si and AlFeMnSi and the dissolution of the second phase of Mg₂Si.The Nyquist curve of the impedance spectrum at this time was a double-capacity arc resistance,and the electrode reaction is mainly controlled by the electrode potential?E?and the coverage???of the adsorbed intermediate product.The impedance modulus has subtle changes during this period.The second period was 4⁴8 hours,during which the corrosion product accumulation areas appeared on the second phase concentrated areas of the sample surface.Obvious intergranular corrosion cracks could be observed on the surface of the sample.With the increase of immersion time,the corrosion products cracked completely,and the surface of the aluminum alloy gradually lost effectiveness.The impedance spectrum Nyquist curve during this time was still a double-capacity arc resistance.The electrode reaction was mainly controlled by the electrode potential?E?and the thickness of the corrosion product film???.The impedance modulus of this period was significantly lower than that of previous period.In this paper,the corrosion phenomenon and corrosion mechanism of T6 state of 6082 aluminum alloy during 48 hours was analyzed.Based on this,different concentrations of rare earth corrosion inhibitor CeCl₃ were added into the NaCl corrosion medium,and the dynamic potential polarization curve test and the alternating current impedance?EIS?test were carried out combined with metallographic microscope and scanning electron microscopy?SEM?.It was found that CeCl3 was a cathode film-forming corrosion inhibitor,which mainly reduced the cathodic reaction on the surface of aluminum alloy by forming a stable film.120mg/L was the best corrosion inhibition concentration of T6 state of 6082 aluminum alloy in 1.5%NaCl corrosion medium,and CeCl3 has good corrosion inhibition effect on T6 state of 6082 aluminum alloy within 48 hours.