Wear and corrosion resistance of Al ion implanted AZ31 magnesium alloy

The Al ion implantation into AZ31 magnesium alloy is carried out in a MEVVA 80-10 ion implantation system with an ion implantation dose ranging from 2 x 10(16) ions/cm(2) to 1 x 10(17) ions/cm(2) at an ion energy of 40-50 keV. The concentration-depth profile of implanted Al in AZ31 magnesium alloy was a Gaussian-type distribution in the depth up to about 840 nm with the maximum Al concentration up to about 10 at.% measured by using Rutherford backscattering spectrometry (RBS). The microstructure, which is composed of alpha-Mg phase, intermetallic beta-Mg17Al12 and MgO phases is observed on the ion implanted samples by X-ray diffraction (XRD). Potentiodynamic anodic polarization curves in 0.01 M NaCl solution with pH = 12 showed that the increase of corrosion potential and pitting breakdown potential and the decrease of the passive current density are obtained for the Al ion implanted samples. The Al ion implanted AZ31 magnesium alloy with the ion implantation dose of 2 x 1016 ions/cm(2) achieved the high pitting breakdown potential to about - 1000 mV(SCE). The wear rate of the Al ion implanted AZ31 magnesium alloy is approximately reduced by 30-40%, compared with that of the unimplanted sample. (C) 2006 Elsevier B.V. All rights reserved.