The electrochemical corrosion behavior of 300M ultra high strength steel in chloride containing environment was investigated by potentiodynamic polarization technique, electrochemical impedance spectroscopy （EIS） an...The electrochemical corrosion behavior of 300M ultra high strength steel in chloride containing environment was investigated by potentiodynamic polarization technique, electrochemical impedance spectroscopy （EIS） and scanning electron microscopy （SEM）. The results show that uniform corrosion occurs on 300M steel during the elec- trochemical measurements because no anodic passivation phenomenon is observed on polarization curves within the measurement range. The tests also show that 300M steel is highly susceptible to chloride containing solution, which is characterized by corrosion current density increasing with the addition of chlorides, and corrosion potential shifting towards positive direction and corrosion resistance decreasing, pos- itively suggesting that chloride ions speed up the corrosion rate of 300M steel. Mean- while corrosion products on the 300M steel surface formed during the salt spray test are too loose and porous to effectively slow down the corrosion rate. Additionally, a schematic structure of uniform corrosion mechanism can explain that 300M steel has better property of stress corrosion cracking （SCC） resistance than stainless steels.展开更多
基金supported by the Chinese National Science and Technology Infrastructure Platforms Construction Project (Grant No.2005DKA10400)Beijing Science and Technology Project (No.D09030303790901)
文摘The electrochemical corrosion behavior of 300M ultra high strength steel in chloride containing environment was investigated by potentiodynamic polarization technique, electrochemical impedance spectroscopy （EIS） and scanning electron microscopy （SEM）. The results show that uniform corrosion occurs on 300M steel during the elec- trochemical measurements because no anodic passivation phenomenon is observed on polarization curves within the measurement range. The tests also show that 300M steel is highly susceptible to chloride containing solution, which is characterized by corrosion current density increasing with the addition of chlorides, and corrosion potential shifting towards positive direction and corrosion resistance decreasing, pos- itively suggesting that chloride ions speed up the corrosion rate of 300M steel. Mean- while corrosion products on the 300M steel surface formed during the salt spray test are too loose and porous to effectively slow down the corrosion rate. Additionally, a schematic structure of uniform corrosion mechanism can explain that 300M steel has better property of stress corrosion cracking （SCC） resistance than stainless steels.
