Properties of polymeric, metallic, and ceramic materials surface-modified with low energy accelerating beam bombardment

Abstract

Polymeric, metallic and ceramic materials were implanted by ions with energies less than 100 keV and current densities of 10(15)-10(18) ions/cm(2). Single or mixed ions of N, He, and C were implanted into the Polyethylene Terephtalate (PET). Mixed ion implantation caused greater surface hardness tip to 3 times than that for single ion implantation. The surface electrical conductivity increases, along with the hardness increase, when the higher ion energy and ion dose were used, but the conductivity showed no relationship to the ion energy at lower ion energies (<= 50keV). Ion implantation with 70 keV N ions of > 5 x 10(16)/cm(2) into stainless steel resulted in a hardness that was at least 2 times higher than non-irradiated specimen, and X-ray photoelectron spectroscopy (XPS) analysis showed the implanted N ions formed mostly Cr2N without post irradiation annealing. The light absorption edge of the epitaxially grown TiO2 film shifted to lower energy by about 0.07 (0.09) eV when 5 x 10(16) (1 x 10(17)) N ionS/cm(2) were implanted, and a significant optical absorption extended into the visible region. Our band-structure calculations for N-doped TiO2 show that the bands originating from N-2p, states are located above the valence band edge, and that the band gap narrowing due to the mixing of N with O-2p states is 0.04 eV.