Large-area surface treatment by ion beam technique

A large-area ion beam deposition system has been used extensively for depositing diamond-like carbon films by a direct ion-beam process. An ultra high vacuum ion beam system, consisting of a 20-cm diameter RF excited (13.56 MHz) ion gun and a four-axis substrate scanner, has been used to modify large surfaces (up to 1000 cm2) of various materials, including 304 and 316 stainless steel, 440C and M50 steels, aluminum, aluminum alloys, Ti-6Al-4V, silicon carbide, silicon nitride, polycarbonates, infrared windows and polycrystalline diamond, by depositing varying chemical compositions of diamond-like carbon films. The influence of ion energy, RF power, and gas composition (H2/CH4, Ar/CH4, O2/H2/CH4 and N2/H2/CH4), on the diamond-like carbon characteristics has been investigated. Particular attention was focused on the adhesion, environmental effects, coefficient of friction and wear factors of the diamond-like carbon films on the various substrates under space-like environments. A quadrupole mass spectrometer and a total ion-current measuring device have been utilized to monitor the ion compositions of the gas mixtures of CH4/H2, CH4/Ar, CH4/H2/O2 and CH4/H2/N2 during the deposition process for quality control and process optimization.