ABSTRACT
On Earth, most surfaces are covered with oxide lms, which hinder adhesion and reduce friction. Even at low concentrations, oxygen is quickly adsorbed and reduces friction considerably, as shown in Figure 11.1. In the vacuum of outer space, after oxides are removed from rubbing surfaces, they cannot re-form due to the lack of oxygen, and galling occurs (Fusaro, 1991). Also, although rolls in a hot strip mill consist mainly of iron, even before oxides are formed later in the rolling schedule, friction is much lower than that of pure iron due to the adsorption of atmospheric oxygen.
