Formation of monodisperse refractory metal particles by impulse discharge

A new method of forming monodisperse metal particles has been developed, in which the tip of a consumable wire electrode is fused and then formed into a separating droplet by an impulse discharge. The properties of the particles make them suitable for application in calibrating devices for particle size analysis, specialized applications in powder metallurgy and creating new tools. An experimental study has been carried out to test optimum conditions for dispersion. The physical processes occurring during impulse discharge when a droplet of molten metal forms and detaches have been examined to obtain conditions for producing monodisperse particles. It has been shown that initiation of the impulse discharge under conditions required for production of monodisperse droplets is possible when a non-equilibrium system containing 'hot' electron and 'cool' molecular subsystems is formed in the interelectrode space. The interaction between electrons obtaining their energy from the electric field and the surface of the consumable electrode provides the heat and force required to form and separate the metal droplets. The high energy concentration on the melting electrode gives rise to monodisperse metal powders with unique properties.