极化作用对6082铝合金在3.5%NaCl溶液中微动腐蚀行为的影响

Effect of Applied Potential on the Fretting Corrosion Behavior of 6082 Aluminum Alloy in 3.5%NaCl Solution

采用高精度多功能微动磨损试验机(MFC-01),结合电化学和摩擦性能测试以及扫描电镜(SEM)和X射线光电子能谱(XPS)分析等,研究了极化作用对6082铝合金在3.5%NaCl溶液中微动腐蚀行为的影响.结果表明:材料在阳极电位极化下,表面更易发生滑动,滑移区扩展,混合区和部分滑移区范围收窄;微动摩擦系数则随极化电位正移逐渐减小、在自腐蚀电位达到最小值、之后回升,阴极电位下摩擦系数大于阳极电位下的数值.在阴极极化和自腐蚀电位极化下,微动加速了磨损区域的腐蚀,使得腐蚀电流密度增加;而在阳极极化下,微动减弱了磨损区域的腐蚀、腐蚀电流减少.材料的整体损失速率随着外加电位的正移而增大.在阴极极化和自腐蚀电位极化下,材料的磨损机制主要表现为剥层机制和磨粒磨损,磨损区域腐蚀产物主要为Al2O3;在阳极极化下,以腐蚀磨损和磨粒磨损为主要特征,磨损区域腐蚀产物主要为Al2O3、Al(OH)3和AlCl3.

The fretting corrosion behavior of 6082 aluminum alloy in 3.5%NaCl solution under natural and applied potential polarization conditions was studied by using a high-precision multi-functional fretting-corrosion apparatus.Its fretting behavior,wear mechanism,corrosion behavior and the effect of the applied potential were analyzed in detail by scanning electron microscope and X-ray photoelectron spectroscopy.The results indicated that under the anodic potential polarization,the surface of the material was more prone to slip,so the range of gross slip zone was expanded,mixed zone and partial slip zone were narrowed.Friction coefficient decreased firstly and reached the minimum value at the self-corrosion potential.And then friction coefficient raised with the increasing potential.The friction coefficient at the cathode potential was larger than that at the anode potential.Under cathodic and self-corrosion potential polarization,the corrosion of the wear region was accelerated by the fretting behavior,which increased the corrosion current.While under the anodic polarization,the corrosion of the wear region and corrosion current was reduced by the fretting behavior.The damage degree of the material increased with the positive shift of the applied potential.Under cathodic and self-corrosion potential polarization,the wear mechanism of 6082 aluminum alloy was mainly delamination wear and mild abrasive wear,while under anodic potential polarization,that was mainly abrasive wear and corrosive wear.