ABSTRACT
Acknowledgments ................................................................................................ 225
References ............................................................................................................ 225
6.1 INTRODUCTION
Corrosion is an interdisciplinary field and the complicated environmental conditions
and the interaction of several factors for corroding systems require as much infor-
mation as possible to understand its leading mechanisms. Usually various surface
methods are applied to learn about the chemical composition of surfaces and thin
surface films that decisively influence the kinetics of corrosion processes. The appli-
cation of photoelectron spectroscopy and ion spectroscopies together with in situ
techniques like infrared (IR) spectroscopy provides a detailed insight into the chem-
istry of metal surfaces. However, the atomic structure of most surfaces and surface
layers still remains unknown. An interesting activity started within the last 10 to 15
years when high-resolution scanning methods like scanning tunneling microscopy
(STM) and scanning force microscopy (SFM) became available. These methods may
be used as in situ techniques to study surfaces even with atomic resolution. Adsorb-
ates and thin films have a pronounced influence on the corrosion properties of metals
and their detailed structure plays a decisive role. Therefore, their structure is of much
interest. However, the mentioned scanning methods are surface methods and thus
sample the outmost atomic layer. Only in some cases does STM yield structural
information on an outer and an inner part of a passive layer through a variation
of the conditions for the tunnel current. Furthermore, the results of these tunnel
methods refer to a small surface area only. The high lateral resolution permits the
study of an extremely small fraction of the total surface. For these reasons laterally
integrating methods are complimentary alternatives.
