Electrical contacts of Wsngbnd;Ga and Resngbnd;Ga were studied using a field ion microscope in which the emitter tips of the microscope were contacted with liquid gallium in vacuum. Threshold values of the closing voltage and opening current needed to create an amorphous state of the surface atoms of the emitter were obtained for Wsngbnd;Ga contacts. Similar characteristics were noted for the Resngbnd;Ga contact although a clear determination of the threshold values was overshadowed by a Resngbnd;Ga reaction. The observed threshold closing voltages are significantly lower than known values for short arcs. The cause of amorphism on a tip surface at these low closing voltages, therefore, is explained to be the result of the field emission from the Ga cathode in the case of positive tip and of the bombardment by the fieldhyphen;ionized gallium ions in the case of the negative tip. The threshold values for closing and opening contacts were dependent on tip radius.
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