A variety of techniques are being developed around the world by which vacuum or plasma coating processes are combined, either concurrently or sequentially, with energetic ion bombardment in vacuum. Reactive and nonreactive ions at energies from below 10 eV to over 100 keV are generally used, and these exceed plasma particle energies. Such coatings possess outstanding adhesion and they can be very hard, tough and in some instances may have low friction coefficients. Others have closely controlled optical properties for rugate filters and anti-reflection coatings, and all can be deposited at relatively low temperatures. This makes them suitable for thermally-sensitive substrates such as polymers. Thin transparent coatings display vivid interference colors and thus may have decorative applications. Developments in ion sources for intense large-area beams of gaseous ions are facilitating the commercial exploitation of these coatings. Further research is needed in regard to bombardment-stimulated chemisorption of gaseous species on the surface of reactive metals such as titanium, and the non-equilibrium diffusion of atoms within bombarded coatings.