Development And Applications Of Improved Electrochemical Corrosion Sensor In Aquatic Environment

Monitoring and detecting corrosion of metal structures in an aquatic environment is an effective way to decrease damages caused by corrosion problems of them. It makes great sense to develop a type of electrochemical corrosion sensors which could conduct measurements directly on target structures, in which way useful information concerning corrosion process could be obtained.When electrochemical measurements are applied directly to those structures, the key point is to restrict the signal distribution. So this work started with an investigation of effects of various configurations of the electrode system on the signal distribution. The experimental parameters involved in this work were: the area of the auxiliary electrode (SA), the distance between the auxiliary electrode and the working electrode (D), and the resistivity of electrolyte. It was found that in electrolyte of high resistivity such as distilled water and tap water, shortening D or decreasing SA could yield decrease in signal distribution. However, such effects were not observed in seawater, which has a much lower resistivity.An electrochemical corrosion sensor was designed and fabricated on the basis of findings shown above, and it was then evaluated in laboratory. It was found that the sensor was capable of restricting response signal distribution in some resistive mediums such as tap water, and a stable potential of its reference electrode was also observed during the test. In addition, the sensor was used on different positions of an iron plate coated with rust-resistant zinc to measure polarization resistance. The results showed that measurements performed on positions of different surface conditions would yield different values, which means a fine current confinement is achieved with the use of the sensor.