动态直流干扰下排流地床镁合金阳极的腐蚀失效行为  

Anodic Corrosion Failure Behavior of Magnesium Alloy in Drainage Ground Bed under Dynamic DC Interference

作　　者：贾斌 高博文 闫茂成[2] JIA Bin;GAO Bowen;YAN Maocheng(Inner Mongolia Institute of Special Equipment Inspection and Research,Baotou 150200,China;Institute of Metal Research,Chinese Academy of Sciences,Shenyang 110016,China)

机构地区：[1]内蒙古特种设备检验研究院,包头150200 [2]中国科学院金属研究所,沈阳110016

出　　处：《腐蚀与防护》2024年第7期71-77,共7页Corrosion & Protection

基　　金：国家自然科学基金(52071320)。

摘　　要：杂散电流干扰下排流地床牺牲阳极材料的腐蚀影响了阳极的电流输出和排流性能。采用周期性直流干扰模拟地铁动态直流干扰,每隔300s施加100s的5A/m^(2)恒电流直流干扰,通过电化学测量、腐蚀形貌观察、腐蚀产物分析和失重试验等方法,研究了动态直流干扰下镁合金阳极地床的腐蚀行为和失效规律。结果表明:土壤环境动态直流干扰下,镁合金阳极极化行为呈活化控制,施加干扰3d时其实际腐蚀速率达18.0mm/a。随干扰时间延长,镁合金阳极持续腐蚀溶解,导致电位正移,接地电阻呈指数升高。动态直流干扰下,镁合金阳极腐蚀有效接地面积减小。表面形成的Mg(OH)2和MgCO3氧化层,以及土壤水电迁移致使地床周围干燥,导致阳极地床接地电阻上升,排流效率降低或阳极地床失效。The corrosion of sacrificial anode material under stray current interference affects the current output and drainage performance of the anode.The periodic DC interference was used to simulate the dynamic DC interference of the subway.A constant current DC interference of 5 A/m^(2) was applied every 300 seconds for 100 seconds.The corrosion behavior and failure law of the magnesium alloy anode ground under dynamic DC interference were studied through electrochemical measurement,corrosion morphology observation,corrosion product analysis,and weight loss test methods.The results show that under the dynamic DC interference of soil environment,the anodic polarization behavior of magnesium alloy was activated and controlled.When the interference was applied for 3 days,the actual corrosion rate reached 18.0 mm/a.As the interference time prolonged,the magnesium alloy anode continued to corrode and dissolve,resulting in a positive potential shift and an exponential increase in grounding resistance.With dynamic DC interference,the effective grounding area of magnesium alloy anode corrosion decreased.The formation of Mg(OH)2 and MgCO3 oxide layers on the surface,as well as soil water and electricity migration causing dryness around the ground bed,led to an increase in the grounding resistance of the anode ground bed,a decrease in drainage efficiency,or the failure of the ground bed.

关 键 词：埋地管道 阳极地床 杂散电流 动态干扰 接地电阻 

分 类 号：TG172[金属学及工艺—金属表面处理]