【摘要】 利用掺杂离子交换体制备了含不同交换离子品种的阴离子选择性、阳离子选择性和双极性酚醛涂层,研究了涂装不同离子选择性酚醛涂层的铜电极在3％NaCl溶液中的腐蚀电化学行为,讨论了各种离子选择性涂层对铜防护性能的差别,并与没有离子选择性的涂层作了比较。更多还原

【Abstract】 Anion-selective, cation-selective and bipolar phenolic coatings were prepared by mixing phenolic varnish with ion exchangers. MoO42- anion exchanger resin and ammonium molybdophosphate were utilized as anion and cation exchangers respectively. The bipolar coating consisted of an anion-selective inner layer on the metal side and a cation-selective outer layer on the solution side. The polarization curves and Nyquist plots of copper electrodes covered with various ion-selective phenolic coatings and nonionic-selective phenolic coating as contrast in 3% NaCl solution were measured by poltentio-dynamic method and EIS technique. The results indicated that, compared with the nonionic- selective coating, the anion-selective coating accelerated the propagation of metal corrosion, cation-selective coating decelerated corrosion propagation, and bipolar coating was the most corrosion-resistant among the four types of phenolic coatings. With the bipolar coating, the anodic current was greatly suppressed, while no current blockage occurred in the cathodic direction. Thus there arose rectification of ion movement retarding the ionic current in the anodic direction. The rectification phenomenon blocked the flow of anodic ion transport and led to metal passivation. This showed that the bipolar coating possessed some function of passivation membrane and had important effect on the process of anodic dissolution.更多还原