Atmospheric corrosion and in-door corrosion are the types of corrosion
which is expedited under thin water film and are observed on various
kinds of metal structures and equipments. Too many factors controlling
these phenomena have hindered us from looking into the corrosion of s
teel under thin water film. Then, water adsorption onto material surfa
ces and kelvin potential change as a function of relative humidity wer
e investigation for pure iron, SUS304, Ni and Cr. It is thought that c
larifying those phenomena makes it possible to more clearly understand
a corrosion behavior under thin water film. Water adsorption increase
s with RH. And hydroxyl groups are influencial for water adsorption on
metal surfaces. Moreover, Kelvin potential for metal is understood to
fall with water adsorption. Observing changes of water adsorption and
Kelvin potential behavior, on metal surfaces can afford to make acces
s to fundamental understuding of atmospheric corrosion.