Stannate conversion coatings on Mg-8Li alloy

The stannate conversion coatings (SnCC) on Mg-8Li alloy were investigated by simple immersion method. The surface morphology and composition were studied by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction spectroscopy (XRD) techniques. The corrosion resistance was assessed by means of potentiodynamic polarization measurements and electrochemical impedance spectra (EIS). The effects of time of a stannate bath on the quality of stannate conversion coatings were investigated by SEM and EIS. It was found that the coating particles were mainly composed of hemispherical particles MgSnO3 . 3H(2)O. A comparison of results revealed the coating treated for 60 min exhibited the most uniform, dense and corrosion-resistant. (C) 2008 Elsevier B. V. All rights reserved.