Improvement of surface properties of magnesium alloy by plasma immersion ion implantation-deposition

Magnesium and its alloys have received interest due to its low mass density as potential applications in the construction and environmental industry. However, its poor corrosion resistance has hampered wide acceptance in the industry. In this work, we conduct plasma immersion ion implantation-deposition (PIII-D) on magnesium alloys and have found that PIII-D processes can effectively improve the corrosion resistance of the materials. The technique can also treat objects possessing irregular shape thereby boding well for commercial components. In addition, the sticking force between the deposited film and substrate can be enhanced by ion beam mixing that is intrinsic to the technique. In our experiments, we employ a chromium cathodic arc to generate a metal plasma for the deposition and investigate the influence of the bias voltage on the surface conditions. The anti-corrosion behavior of the samples is evaluated using immersion and potentiodynamical polarization tests whereas the film structure and chromium indepth distribution are determined using X-ray diffraction and Rutherford backscattering spectrometry.