Some unusual characteristics of the passive state of metals, and the processes leading to its breakdown.
主 持 人：无人机重点实验室童小燕教授
主 讲 人：剑桥大学材料冶金系G Tim Burstein教授
报告摘要：This lecture will be wide-ranging in subject matter, but will focus on the passivity of metals. The remarkable state of passivity of metals, under which most engineering metals exist, is engendered by an extremely thin oxide film, whose strange properties and characteristics control the entire state of stability of the metal. This lecture describes some unusual aspects of the state of passivity, and details how these may be measured. Localised corrosion has its genesis in tiny events, of nanometre dimensions, which can be detected as violent microscopic electrochemical current transients, provided the experimental procedures are tailored for such measurements. These processes are described and some of the implications of their existence discussed in terms of their evolution into localised corrosion. The lecture will also focus on the role of temperature, a parameter so often neglected, with particular emphasis on the application of “cyclic thermammetry”, in which a temperature programme can be applied to the passivating system. The technique allows new phenomena to be quantified. The application of these methods to developing new fuel cell catalysts is discussed.