Development of Remote-controlled Corrosion Monitoring System of Steels Using Electrochemical Impedance Method

基于电化学阻抗原理，研制了一套钢的大气腐蚀远程监测系统。在监测系统中，使用交流腐蚀监测器(Riken Denshi)连续自动测量10 kHz和10 MHz两种不同频率的阻抗。利用研制的监测系统对普通碳钢(CS)、耐候钢(WS)和含镍耐候钢(NiWS)三种钢在4种不同气氛下的腐蚀行为进行了监测。将CS、WS和NiWS的梳状探头电极暴露在远离海岸线的4个不同位置。在这次大气腐蚀监测中，STE…表面的湿润时间(TOW)从10 kHz的高频阻抗可以监测到更多ELS本身，因为高频阻抗提供了溶液电阻。从低频和高频的阻抗差异，监测了钢材的腐蚀速度。从2003年9月18日开始监测冲绳，2003年11月11日开始监测富图，2003年12月9日开始监测初石，2003年12月5日开始监测筑波，至今仍在继续监测。监测所获得的腐蚀量和腐蚀量均按筑波的顺序递增，表明环境的侵袭性随着离海岸线的距离的减小而增加。将三种钢的试件与探头一起暴露在四个部位，以测量腐蚀质量损失。在暴露0.5年和1.0年后，将优惠券从暴露部位收回，并在去除锈迹后测量质量损失。结果表明，交流阻抗监测数据与质量损失数据具有很高的相关性。较少

A remote-controlled monitoring system of atmospheric corrosion of steels on the basis of theory of electrochemical impedance has been developed. In the monitoring system, the impedance at two different frequencies of 10 kHz and 10 mHz is continuously and automatically measured with an Ac Corrosion Monitor (Riken Denshi). The measured data are stored in a hard disc of a computer once and regularly transferred to our laboratory using a cellular phone system.The corrosion monitoring of three different steels of ordinary carbon steel (CS), weathering steel (WS) and Ni-containing weathering steel (NiWS) was carried out at four different atmospheres, using the developed monitoring system. The comb-type probe electrodes of CS, WS and NiWS were exposed to four different sites in the distance from coastal lines. The distances were 0 km for Okinawa, 0.5 km for Futtu, 4 km for Choushi and 45 km for Tsukuba.In this atmospheric corrosion monitoring, the time of wetness (TOW) for surfaces of the ste … More els themselves was monitored from the high frequency impedance at 10 kHz, since high frequency impedance provides the solution resistance. Form the impedance difference of the low and high frequencies, the corrosion rate of the steels was monitored. The monitoring has started from September 18,2003 for Okinawa, November 11,2003 for Futtu, December 9,2003 for Choushi and December 5,2003 for Tsukuba and still continued at all sites.Both the TOW and amount of corrosion obtained from the monitoring increased in order of Tsukuba <Choushi<Futtu<Okinawa, indicating that the aggressiveness of environments increased with decreasing the distance from the coastal lines. The coupon specimens of the three steels were also exposed to the four sites together with the probes in order to measure the corrosion mass loss. The coupons were withdrawn from the exposure sites after 0.5 and 1.0 year-exposure and the mass loss was measured after removing the rusts. The results showed very high correlation between the Ac impedance monitoring data and the mass loss data. Less