Surface Conductance of Metal Surfaces in Air Studied with a Force Microscope

With a force microscope, the surface conductances of various metals in air were investigated by measuring both the contact force and the current between the metal surface and the W lever simultaneously. When the Ag surface approached the W lever, current began to flow only in the strong repulsive-force range in contrast to the Au surface, so that the Ag surface seemed to be oxidized slightly. In the case of the Ti surface, current was not observed even in the strong repulsive-force range, so that the Ti surface seemed to be oxidized thick enough to sustain this strong repulsive force.