Effects of the medium on synthesis of nanopowders by wire explosion process

Silver nanopowder was produced in air and water media by wire explosion process. Size of the particles formed in water was smaller than that in air. In water medium, compared with air, the delay of plasma formation resulted in a higher energy deposition in the wire. As a consequence, there were no micrometer size particles in the powder, which is attributed to the complete vaporization of the wire. It is considered that the wire explosion in liquid medium meets three conditions to form smaller particles, namely, higher energy deposition in the wire, sufficient expansion volume, and quick cooling of the particles. (C) 2007 American Institute of Physics.