GB924202A - Improvements in and relating to the production of powders of metal, alloy or other electrically conductive material - Google Patents

Abstract

In a method of and apparatus for making electrically conductive powders, an electrical circuit is established between one or more pairs of electrodes through a layer of conductive <PICT:0924202/III/1> particles wetted by a di-electric, and the particles are agitated to cause sparking which results in spark eroded powder. A container 1 for a dielectric 3 is connected by a pipe 4 to a draining valve 10 and an axial flow pump 5 which forces dielectric through a pipe 8 into a tray 13 and thence, by overflowing, back to the container 1. The tray 1 is made of plastics and contains a number of positive and negative electrodes 15 of hemispherical form arranged in rows and columns. Covering these electrodes is a layer 18 of scraps or particles of carbon to be powdered. The tray is supported by an air vibrator head 14, which is switched on at the same time as the axial pump. In a modification the columns of hemispherical electrodes are replaced by semi-circular section bars placed in rows flat side down on the tray. Connected to the pipe 9 is an otherwise closed container full of dielectric; the valve 10 may be open during erosion, in which case some of the powdered carbon sinks from the circulating dielectric into said container. Alternatively the valve 10 may remain closed during erosion.