Effects of pH Value on Corrosion Behavior of Thermal-Sprayed Al-Si Coated Q235 Steel in Simulated Soil Solutions

摘要

Electrochemical corrosion behavior of a thermal-sprayed Al-Si coated Q235 steel has been investigated in simulated soil solutions. The as-received Q235 steel and galvanized steel for grounding grids were also examined for comparison purpose. The effects of pH value of testing solutions have been examined. The thermal-sprayed Al-Si coated steel showed better corrosion resistance in acidic and neutral solutions than the as-received Q235 steel and galvanized steel, having the largest polarization resistance, the lowest anodic current density, and the largest film resistance. However, in strong alkaline solution, the corrosion resistance of the thermal-sprayed Al-Si coated steel degraded rapidly due to the change of corrosion product scale. Related corrosion mechanisms are also discussed.