The cavitation erosion and erosion-corrosion behavior of carbon steel in simulating solutions of three rivers of China

摘要

The corrosion behaviour of the Q235 carbon steel in simulation solution of Yangtze, Yellow and Talimu river of China was investigated by mass loss, electrochemical measurements (polarization curves, linear polarization resistance and electrochemical impedance spectroscopy) and the damaged surfaces were observed by a scanning electron microscope (SEM) under static, cavitation erosion and erosion-corrosion conditions. It was shown that under static condition, the E{sub}(corr) was almost the same in the three solutions but the anodic current density in Talimu river was about one order of magnitude larger than that in Yangtze and Yellow river. Under dynamic conditions including cavitation erosion and erosion-corrosion, the E{sub}(corr) in the three solutions all shifted in positive direction from that under static condition, but the extent of △E{sub}(corr) increased in the order of Yangtze, Yellow and Talimu river. The corrosion rate under dynamic conditions greatly enhanced, especially in Talimu river. It was confirmed that the corrosion played an important role in the synergistic effect under cavitation erosion and erosion-corrosion conditions. The test results suggested that when the structure materials used in the different rivers were chosen, the difference of corrosiveness of the rivers must be taken into account, especially under dynamic conditions. The materials used in the aggressive rivers such as Talimu river under dynamic conditions must resist the synergistic effects between erosion and corrosion.