Ion-Beam-Deposited DLC Coatings on Fine-Grain CVD Diamond

Ion-beam-deposited surface layers of diamond-like carbon (DLC) on fine-grain chemical-vapor-deposited (CVD) diamond have been found to be effective in reducing friction and wear in a variety of environments, including ultrahigh vacuum. This discovery opens the possibility of taking fuller advantage of the properties of CVD diamond and DLC to manufacture protective coatings to provide solid lubrication and resistance to wear, erosion, and corrosion. Such coatings could be applied to surfaces of bearings, valves, cams, gears, and magnetic recording disks and tapes, for example. Notwithstanding the high costs of natural diamonds of gem quality, the costs of DLC and CVD diamond are similar to those of CVD and physical-vapor-deposited (PVD) carbide and nitride films. The one major disadvantage of DLC is its lack of resistance to high temperature; its use must be restricted to temperatures ≤250 °C in air and ≤350 °C in vacuum.