ZL115铸铝合金和C41500海军黄铜电偶腐蚀的边界元仿真研究

Boundary Element Simulation of Galvanic Corrosion of ZL115 Casting Aluminum Alloy and C41500 Naval Brass

通过电化学实验测得ZL115铸铝合金和C41500海军黄铜的极化曲线。基于边界元法,以极化数据作为边界条件,建立了铝合金表面涂层损伤后与黄铜接触时的电偶腐蚀模型并进行仿真。结果表明:铸铝合金活性随电解液浓度的升高而增加,耐蚀性降低;相同条件下,黄铜变化微弱。电解液浓度和液膜厚度的增加均会加剧电偶腐蚀,相较而言,液膜厚度的影响更为强烈;阴阳极面积比的增加会明显增大电偶腐蚀中阳极处的局部腐蚀电流,即加剧阳极损耗;阴阳极间距的增加会在一定程度上削弱电偶腐蚀,但这种削弱效果十分有限。

The polarization curves of ZL115 cast aluminum alloy and C41500 navy brass were measured by electrochemical experiments. Based on boundary element method,the model of galvanic corrosion between aluminum alloy with damaged surface coating and brass was established and simulated using polarization data as boundary condition. The results show that the liveness of the cast aluminum alloy rose with the increase of electrolyte concentration and its resistance of corrosion decreased. Under the same conditions,the brass changed slightly. Moreover,the increase of electrolyte concentration and film thickness aggravated galvanic corrosion. By contrast,the influence of film thickness is more obvious; the increase of the area ratio of cathode to anode would significantly fortify the local corrosion current at the anode,intensifying the loss of anode. Increasing the distance between cathode and anode would weaken the galvanic corrosion to a certain extent; however,this effect was very limited.