THE ION-BEAM PROCESSING OF POWDERS

Many of the properties of a powder are determined by the its surface. Therefore, surface modification is one useful tool for modifying powde r properties. Ion-beam techniques have the advantage of being highly c ontrollable, single-step processes. One problem, however, is that ion beams are line-of-sight processes; hence, rather sophisticated devices must be used to agitate the powder in the beam. In this review, diffe rent facilities for the ion-beam treatment of powder, including ion im plantation and ion-beam-assisted deposition, are described. Basic resu lts on radiation damage, annealing behavior, degree of doping, and res ulting properties are discussed. As examples for potential application s, results on the catalytic activity of ion-beam-modified powders for gas-phase reactions and electrocatalysis in aqueous systems are discus sed.