Electrochemical behavior of metal surfaces subjected to pulsed ion beam surface treatment

Pulsed high energy ion beams have been used to thermally treat metal surfaces to alter their electrochemical response. Two general processing regimens have been explored: 1) rapid melt and resolidification (RMR) and 2) ion beam mixing (IBM). RMR uses the pulsed ion beam to melt and in some cases ablate the topmost several microns of the surface. Subsequent solidification is sufficiently fast (>10⁶ C/s) for nonequilibrium structures and compositions to be attained. IBM uses the ion beam to mix a previously applied metallic layer into the substrate to produce a compositionally and structurally distinct surface alloy. The surface that results from these treatments often displays interesting characteristics. For example, a Grade-2 Ti sample, which pits at a potential of 1.7 V, is immune to pitting up to 2 V following ion beam treatment. This paper discusses the changes in electrochemical behavior of several alloys following ion beam treatment.