Spark erosion in a metal spheres bed: Experimental study of the discharge stability and energy efficiency

Pulsed spark discharge in metallic granular beds in aqueous media was studied for the granular bed geometry affecting the discharge parameters, stability and powder production. Experiments were carried out in horizontal bed and columnar reactors filled with 4-mm steel spheres. The pulse energy and the powder production depend on the bed height, showing its maximum within 9–14 mm growing with the pulse repetition frequency from 200 to 800 pulses per second and degrading in spark erosion time due to the bed vibrational compaction and accumulation of the erosion products short-circuiting intergranular gaps.