聚二甲基硅氧烷涂层自修复过程中的弛豫时间分布研究

Distribution of Relaxation Time of Polydimethylsiloxane Coatings During Self-healing Process

针对传统电化学分析技术不能完全反映有机涂层腐蚀电化学过程的问题,采用弛豫时间分布(DRT)技术分析电化学阻抗谱(EIS),研究了聚二甲基硅氧烷(PDMS)涂层在长效防腐过程及“人工划伤-自修复”循环过程中的动态弛豫时间分布。结果表明:结合等效电路模型分析方法,DRT技术能够清晰地分析PDMS涂层电化学过程中总电化学阻抗的组成及各部分贡献率,并从理论方面阐明了EIS等效电路中各元件对应的弛豫时间归属问题。为腐蚀电化学机理研究提供了一种新的分析技术。

Traditional electrochemical analysis techniques cannot fully reflect the electrochemical process of organic coating corrosion. Hence, distribution of relaxation time(DRT) technique was adopted to fit the electrochemical impedance spectrum(EIS), meanwhile, the distribution of relaxation time of the long-term anticorrosion process of polydimethylsiloxane coatings without and with artificial scratches was investigated, in other word, the later one experienced self-healing cycles. The results show that the function of the EIS itself as a whole and the contribution proportion of each element of the EIS of the coating during the corrosion process can be clearly analyzed via the DRT technique combined with equivalent circuit model analysis. Meanwhile, the corresponding relaxation time of each element in EIS equivalent circuit was discussed theoretically. This paper provides a new analytical technique for corrosion electrochemical mechanism study.