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| Crevice Corrosion Experiment and Simulation Study of 7B04 Aluminum Alloy for Aircraft |
| Received:September 14, 2016 Revised:March 15, 2017 |
| View Full Text View/Add Comment Download reader |
| DOI：10.7643/ issn.1672-9242.2017.03.008 |
| KeyWord:7B04 aluminum alloy crevice corrosion numerical calculation boundary condition |
| Author | Institution |
| WANG Chen-guang |
Qingdao Branch, Naval Aeronautical Engineering Institute, Qingdao , China |
| CHEN Yue-liang |
Qingdao Branch, Naval Aeronautical Engineering Institute, Qingdao , China |
| ZHANG Yong |
Qingdao Branch, Naval Aeronautical Engineering Institute, Qingdao , China |
| BIAN Gui-xue |
Qingdao Branch, Naval Aeronautical Engineering Institute, Qingdao , China |
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| Abstract: |
| Objective To develop the crevice corrosion simulation study of 7B04 aluminum alloy for aircraft, understand the mechanism of crevice corrosion, and find out key factors affecting crevice corrosion. Methods Types of crevice corrosion were analyzed, crevice corrosion tests were developed, a mathematical crevice corrosion model was established, proper boundary conditions were selected, and simulating calculation was performed with the finite element method. Results The calculation result of pH value distribution in the crevice was consistent with test measurement value, and when crevice mouth communicated with external liquid/atmosphere, the solution in the crevicewas in acidic or in alkaline respectively. The solution at the crevice mouth was relatively low in potential, the aluminum alloy near the crevice mouth corroded relatively fast, and most Al-containing corrosion products were concentrated near the crevice mouth. The corrosion rate of the aluminum alloy was not affected by change of the crevice width in the range of 0.1~0.3 mm; if the depth of the crevice was increased, the solution potential difference between the crevice mouth and the bottom was increased, the corrosion area of the aluminum alloy was increased, but the maximum corrosion current density of the aluminum alloy was unchanged. If the potential rose, corrosion of the aluminum alloy in the crevice was intensified, the potential was increased by 10 mV, the corrosion current density of aluminum alloy interface in the crevice after 24 h corroding was increased by 59 times, and the maximum concentration of Al(OH)2Cl was 30 times that of Al(OH)2Cl under natural potential. Conclusions Crevice corrosion is mainly affected by cathode reduction reaction outside the crevice. The potential has a maximum influence on crevice corrosion of aluminum alloy. High-potential materials should be prevented from making direct contact with aluminum alloy in the aircraft structure. |
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