The morphology of Ag contacts was observed by scanning electron microscopy (SEM) in different breaking DC current arcs in air. It was found that when an arc develops into the gaseous phase the cathode surface was usually smooth, and that the anode surface was characterized as three parts (“wave-shape” with plastic deformation in part I, smooth with pinholes in part II, and rough with globules in part III) from the center to the outside of the arced spot. The pinholes in part II are about 10 μm in diameter, and the globular particles in part III are as big as 32μm in diameter. The temperature of the base metal is considered to control the formation of these characteristics, and a plausible mechanism is proposed. This mechanism was also verified by using Pd material, which is considered to be oxide free, as well as Ag material with breaking arcs in nitrogen gas with different oxygen concentrations.