The dependence of the
oxidation rate of lead films on the pressure of oxygen was investigated by
ellipsometric and resistance techniques for oxygen pressures between 200 Pa and
100 kPa and in the temperature range 323-423 K.
Measurements of the pressure dependence were obtained by studying the change in
oxidation rate following an abrupt change in pressure. The results of all
experiments indicated a small positive dependence, though significant
variations in the values were observed both with extent of oxidation, and
between experiments conducted at different temperatures. During the first few
minutes of the reaction an unusual trend was noted in the observed kinetics
which could be interpreted as being due to absorption of oxygen, by the metal
close to the metal-oxide interface, resulting in changes to the metal
conductivity and the refractive index, determined by ellipsometry,
of the lead substrate.