INFLUENCE OF A TAR EPOXY COATING ON CORROSION FATIGUE LIFE OF 16Mn STEEL IN SEA WATER
环氧沥青基有机涂层对16Mn钢在自然海水中腐蚀疲劳寿命的影响

The effect of a tar epoxy coating on corrosion fatigue(CF) behaviour of 16Mn steel has been studied.The CF lives were compared for uncoated and coated specimens under cyclic load with a constant amplitude in air and natural sea water,and the effect of applied cathodic potential on CF life was examined.The evolution of free corrosion potential in sea water and the cathodic current in the condition of cathodic protection were measured with cyclic number.The results showed that the CF life of 16Mn steel was greatly increased by the coating,and this favorable effect of coating did not only come from its resistance to the transport of the corrosive medium. The tendancy of evolution of CF life with the applied cathodic potential was not the same for uncoated and coated specimens,indicating a difference of CF mechanism.The existance of calcium and magnesium ions in sea water has an important effect on CF life of uncoated specimen at cathodic potentials,but a small effect for coated specimen.