Abstract
The author studied the application of impulse current produced by instantaneous discharge of energy, which had been charged in a capacitor, to a tungsten filament in a vacuum. It was found by the author that the filament was explosively dispersed under specified conditions of electric circuit and discharge energy. The filament was dispersed into gaseous state by high discharge energy; or by concentrated energy resulting from reduced circuit inductance. For instance, the dispersion into gaseous state was obtained by the application of a current higher than 1 kamp through a filament of 0.2mm in dia. and 5mm in length; but the filament was dispersed into spheroidal balls under a current of lower than 1 kamp. A thin crystalline tungsten film was formed on a substrate placed near the filament, and the average thickness of the film violently decreased with an increase of energy. The film formed from the gaseous state was larger in thickness than that formed from the dispersed spheroidal state. The number of grains in these thin films depended on the discharge energy and circuit inductance. More grains were contained in the film by the discharge under lower energy or higher inductance; and grains were less in the film formed from the gaseous state that formed from the dispersed spheroidal state. In particular, very few grains were contained in the film formed from the gaseous state by the discharge of low circuit inductance.
