海水压力对深海用环氧涂层防护性能的影响

摘要

The electrochemical corrosion behavior of the epoxy heavy-duty coating immersed in seawater under the alternating pressure was investigated by electrochemical impedance spectroscopy (EIS) and local electrochemical impedance spectroscopy(LEIS). The results showed that compared with atmospheric pressure, the coating resistance was lower, but the coating capacitance was higher under the alternating pressure. The coating resistance remained above 107Ω·cm2, showing that both coatings had good protective properties. The impedance around the defect region of the coating systems with artificial point defects was lower under the alternating pressure. It indicated that the permeation process of the electrolyte solution to the coating metal interface was easier under the alternating pressure, accelerating the corrosion of the steel under the coatings.%采用电化学阻抗谱（EIS）技术与局部交流阻抗技术（LEIS）研究了深海环境用重防腐环氧涂层H44-61在深海模拟环境（青岛海水，常压以及6 MPa交变压力）下的腐蚀电化学行为，探讨了交变压力对深海用涂层防护性能的影响。结果表明，涂层在6 MPa交变压力下的涂层电容较常压下高且涂层电阻较低，涂层的防护性能下降，但低频阻抗膜值均在107Ω·cm2以上，说明涂层仍有较好的防护性能；LEIS的研究表明交变压力下人造缺陷区域的阻抗值较小，缺陷周围涂层的剥离面积较大，说明压力交变能加快电解质溶液向涂层金属界面扩散，加速涂层下金属的腐蚀过程，降低涂层的防护性能。