Study On Corrosion Electrochemical Sensor For Metal Structures In Aquatic Environment

As the development of production and vast application of metal materials, it is more and more important for the corrosion resistance of metal structures, as well as the in field corrosion detection techniques. At present, direct and efficient detection methods are always lacking when it comes to the tie-in place of welding line in the metal structures, liquid hide area of dead angle of industrial facility container and some corrosion sensitive segments such as bolt and screw.Aiming at the above questions, this paper started with solving problems of corrosion detection technique of metal structures, and went on by developing an electrochemical sensor which can be applied in aquatic environment to monitor corrosion conditions of different structures. Based on local enclosure theory an enclosed electrolytic cell was built up by contacting the surface of the component to be tested. Magnets were employed as contacting fix up on the structure surface, which can also bring pressure on the airproof glue. Stretched inertia tentacle guarantee the electronic contacting of sensor and metal to be tested.Current enclosing capability of the sensor was verified by the experiments. The pressure that the magnet provides on the glue could ensure the current leaked out from the liquid film at the blocked location be completely ignored, which shows the current limitation effects of this sensor can fulfill the needs of corrosion monitoring .The developed sensor was applied to test welding line, base metals, and bolts of structures in NaCl solution of 3.5%. The results showed that the developed sensor can well distinguish different corrosion conditions of structures, and satisfy the in field corrosion detection need.The developed sensor was also used to conduct electrochemical measurements on four components which build up 40CrNiMoA and CuMn50. The causes and mechanisms of welding structures were also analyzed and discussed.