C₂H₂ plasma immersion ion implantation-deposition (PIIID) of AZ31B magnesium alloy

The lightweight of magnesium has attracted much interest to reduce the consumption of fuel and environment pollution. Many industries including aerospace, automotive, and computer etc, benefit from the low density of magnesium alloy, compared with that of steel and aluminum. Unfortunately, magnesium alloys are active to oxygen and a loose oxide layer forms on the top surface which exhibits poor corrosion resistance. Hence it has hampered its wide use in many applications. Plasma immersion ion implantation and deposition (PIIID), boasted for its non-line-of-sight, may treat large and complex-shaped specimens and multiple samples simultaneously without manipulation. In this paper, AZ31B magnesium alloy was treated by C₂H₂ plasma ion implantation and deposition to improve the surface properties such as the hardness, frictional behavior, corrosion resistance et al. To achieve good surface properties, the processing parameters including bias voltage, plasma source power, treatment time, etc have to be optimized. Pin-on-disk test results reveal that wear-resistance of treated samples is enhanced indicated by a lower friction coefficient and small wear tracks The potentiodynamic polarization tests show that C₂H₂ plasma treatment can effectively improve the corrosion-resistance of magnesium alloy. The surface structure and the elemental distribution will also be discussed in the paper.