Electrochemical studies of general and localized corrosion processes

本研究的主要目的是开发模型来预测工业和环境重要材料腐蚀过程随时间的演变。主要关注领域包括高放废物处置库中重要材料的腐蚀和输气管线钢。环境绩效评估模型的主要目标是证明所选择的情景将满足设定的监管目标。工业腐蚀模型的主要目标是证明系统适合继续使用或优化维护操作的调度，以实现最小的过程干扰。在大多数这些应用中，材料表面上的氧化膜和/或腐蚀产物沉积物是抗腐蚀的主要防御。如果要证明其使用是合理的，则必须彻底了解其特性以及它们如何随时间和暴露环境而反应。该建议的主要重点是必要的机械理解的实验发展和基本模型参数的值的确定。有人建议，局部腐蚀过程的各个方面进行研究，从薄膜和沉积物的性质，必须失败的局部过程开始，特定的腐蚀过程，描述如何在重要的暴露期内累积损伤的损害函数的发展。这将通过耦合电化学技术，这有一个长期的应用历史，这些问题，与一系列的新的表面分析技术，我们已经开发或适应这些应用程序在过去的几年中。其中包括电化学方法和中子反射计的新耦合以及扫描电化学显微镜的自适应，该技术可以映射不均匀分布的腐蚀部位。

The primary aim of this research is to develop models to predict the evolution with time of industrially and environmentally important materials corrosion processes. Key areas of interest include corrosion of important materials in high level nuclear waste repositories and gas transmission pipeline steels. The primary goal of an environmental performance assessment model is the demonstration that the chosen scenario will meet the set regulatory goals. The primary goal of an industrial corrosion model is to either demonstrate that the system is fit to remain in service or to optimize the scheduling of maintenance operations for minimal process disturbance. In the majority of these applications oxide films and/or corrosion product deposits on the surface of the materials are the primary defense against corrosion. A thorough understanding of their properties and how they respond with time and exposure environment is essential if their use is to be justified. The primary focus of this proposal is the experimental development of the necessary mechanistic understanding and the determination of the values of essential model parameters. It is proposed that all aspects of localized corrosion processes be studied, from the properties of the films and deposits which must fail for localized processes to initiate, to the development of damage functions for specific corrosion processes, which describe how damage accumulates over the important exposure period. This will be achieved by coupling electrochemical techniques, which have a long history of application to these problems, with a range of novel surface analytical techniques which we have developed or adapted to these applications over the past few years. These include the novel coupling of electrochemical methods and neutron reflectometry and the adaptation of scanning electrochemical microscopy, a technique which can map inhomogeneously distributed corrosion sites.