Correlation between texture and corrosion properties of magnesium coatings produced by PVD

Abstract

Physical vapour deposition with energetic ions is an established technology for creating functional surfaces where changing morphologies are observed with increasing energy deposition. In this presentation, magnetron sputtering (MS) is compared with ion beam sputtering (IBS) and vacuum arc deposition (VAD) for corrosion resistant Mg coatings. With increasing average energy flux along the three methods, a transition from a columnar growth regime towards a layer-by-layer growth at increased energies was observed, while a basal texture with the c-axis normal to the surface was found in all cases. However, the full width at half maximum (FWHM) of the corresponding Mg(002) rocking curves showed a pronounced minimum of 3° for IBS deposited films, apparently caused by the reflected high energy primary Ar+ ions. For pure Mg films, no larger differences in the corrosion potential and the corrosion rates were measured.