Ni-W-P／Pr2O3化学镀层的电化学行为

Electrochemical Behavior of Electroless Ni-YV-P/Pr_2O_3 Coating

采用极化曲线技术研究化学镀层的电化学性能,受到测量信号的干扰,且不能研究其中各子过程及其动力学的特征。以化学镀方法制备了Ni-W-P/Pr2O3镀层和Ni-W-P镀层,利用交流阻抗技术,研究了基体、Ni-W-P和Ni-W-P/Pr2O3合金镀层在3.5%NaCl水溶液中的腐蚀电化学行为,得出了电位时效图、交流阻抗谱图,并利用拟合程序EQUIVCRT对阻抗试验数据进行了拟合。结果表明:Ni-W-P/Pr2O3镀层电阻随着时间的延长呈现出不断增长的趋势,钝化膜在不断生成;镀层电阻在6.0h后迅速增大,镀层有自封闭现象,稀土失去电子,使镀层更加致密;Ni-W-P/Pr2O3镀层比Ni-W-P镀层具有更优异的耐蚀性能。

Ni-W-P/Pr2O3 and Ni-W-P coatings were prepared by electroless plating. The corrosion and electrochemical behavior of the Ni-W-P and Ni-W-P/Pr2O3 coatings in 3.5% NaCl solution was evaluated using alternating impedance technology. The potential-timeliness diagramand alternating impedance spectrum were recorded, while the impedance data were fitted using EQUIVCRT program. Results showed that the resistance of electroless Ni-W-P/Pr2O3 coating continuously increased with increasing time, showing that passivation film was generated continuously. At the same time, the resistance of Ni-W- P/Pr2O3 coating increased quickly after 6 hours, and the coating was characterized by self-healing and becamemore compact along with lossing of electrons by the rare earths. Moreover, Ni-W-P/Pr2O3 coating showed better corrosion resistance than Ni-W-P coating.