局部腐蚀引起电感探针数据的失真

摘要

The data distortion of a 20# steel probe was analyzed by SEM,metallographic microscopy and EDS.The macro and micro morphologies showed that some corrosion pits were distributed on the surface of the probe.The results of metallographic analysis revealed that the material of the probe was qualified and the crystal structure was uniform.The results obtained from EDS indicated that some chloride ions and sulfur element were accumulated in the corrosion pits.The un-uniform covering and the influence of corrosive medium caused the localized electrochemical corrosion and even induced some corrosion pits.More corrosion pits resulted in moer change of the value of resistance and thus induced the data distortion.%为探讨局部腐蚀对探针读数的影响，采用扫描电镜、金相显微镜、能谱等表征方法对20号碳钢探针的失效进行了研究。宏观和微观形貌表明，探针表面随机分布着大小不均的腐蚀坑；金相结果表明，探针材质合格，晶体组织均匀；能谱分析表明，腐蚀坑内存在氯离子和硫元素的局部聚集现象。不均匀的覆盖物在探针表面的形成，以及在电位差及腐蚀介质的影响下，探针表面发生了局部电化学腐蚀，较多腐蚀坑的出现引起了感应电阻信号的跳动，产生了数据的失真。