Practical applications of ion beam and plasma processing for improving corrosion and wear protection

A multi-year project for the US Army has been investigating the use of various ion beam and plasma-based surface treatments to improve the corrosion and wear properties of military hardware. These processes are intended to be complementary to, rather than competing with, other promising macro scale coating processes such high velocity oxy–fuel (HVOF) deposition, particularly in non-line-of-sight and flash chrome replacement applications. It is believed that these processes can improve the tribological and corrosion behavior of parts without significantly altering the dimensions of the part, thereby eliminating the need for further machining operations and reducing overall production costs. The ion beam processes chosen are relatively mature, low-cost processes that can be scaled-up. The key methods that have been considered under this program include nitrogen ion implantation into electroplated hard chrome, ion beam assisted chromium and chromium nitride coatings, and plasma-deposited diamond-like carbon and chromium oxycarbide coatings. Several examples of practical applications including bearing assemblies, hydraulics, and engine components, will be presented along with associated wear and corrosion test results.