Effect of Titania Nanoparticles on Micro-Arc Anodizing of AM60B Magnesium Alloy
Oxide films have been produced on the AM60B magnesium alloy using micro-arc oxidation process in an environmentally friendly alkaline solution with and without addition of titania nanoparticles. The surface morphology and cross-section of anodized samples were analyzed by Scanning Electron Microscopy (SEM) coupled with EDS and the phase composition was investigated by X-ray Diffraction (XRD). Hardness tests were performed by means of a micro-hardness tester and the corrosion resistance was evaluated in 3.5% NaCl solution using potentiodynamic polarization tests. Addition of titania nanoparticles doesn’t affect corrosion resistance significantly, but the oxide films produced in titania-containing solution are denser, thicker and have more uniform morphology. In the oxides produced at 130V-140V in presence of titania (4g dm-3) a spinel (MgAl2O4) was observed. Spinel phase increases the hardness up to 550 HV (10mN, 10 s). The addition of titania nanoparticles in the solution could be an interesting way to synthesize hard coatings on magnesium alloy AM60B by micro-arc oxidation in a short process time (10 minutes).
Jian-Feng Nie and Allan Morton
A. da Forno et al., "Effect of Titania Nanoparticles on Micro-Arc Anodizing of AM60B Magnesium Alloy", Materials Science Forum, Vols. 654-656, pp. 1876-1879, 2010