Metallic powders are formed by the electrically exploded wire (EEW) process. An apparatus (20) for manufacturing such powders includes a closed loop recirculating gas path between a reaction chamber (100) and an extractor (32). A wire (31) is delivered from a source (400) along a wire path from ambient conditions outside the chamber to within the chamber. Within the chamber, a first electrode (200) has an aperture circumscribing the wire path and a second electrode (203) is located proximate to a terminal end of the wire path. A source (26) of electrical energy applies a discharge voltage between the electrodes to explode the length of wire therebetween to form an initial particulate. The initial particulate may be selectively extracted and processed to produce desired powders, in particular, energetic powders which are passivated for stability under ambient conditions.