Effect of High DC Electric Field with 400 kV/m on Wet-dry Cyclic Accelerated Corrosion Behavior of 5052 Aluminum Alloy in NaCl Solution
The study of high voltage DC electric field on the corrosion behavior of 5052 aluminum alloy in coastal high temperature and humid environment has not been reported.The wet-dry cyclic corrosion tests of 5052 aluminum alloy under 400 kV/m DC electric field intensity was carried out,the solution was 3.5wt%NaCl and one cycle was 12 h.The effect of DC electric field on the corrosion morphology and corrosion behavior of 5052 aluminum alloy was evaluated by using SEM,EDS,XPS and electrochemical tests.The results show that with the increase of the wet-dry cyclic corrosion time at 400 kV/m DC electric field,the weight loss increases and the corrosion weight loss rate decreases.But the weight loss rate of the samples is bigger than that of the corresponding samples without electric field.Without electric field,the surface microelectric couple corrosion composed of the cathode Al-Si and the anode Al occurs first,then pitting around the Al-Si phase occurs until a large number of corrosion pits appear.The Al-Si phase promotes the dissolution of the Al matrix in depth direction.Under the action of the electric field,the corrosion potential decreases and the corrosion current increases,the passivation membrane and the matrix constitute the corrosion of large cathode-small anode,which promotes corrosion.The whole process is passivation-passivation film rupture-electrocouple corrosion-spalling,which is very different from the corrosion without electrical field.
aluminum alloywet-dry cyclic corrosionhigh voltage DC electric field
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