Electron Beam Post-Treatment of Coatings Plasma Sprayed Onto Magnesium Alloys

Abstract

Abstract Magnesium alloys are widely used as light-weight metals in the field of automotive engineering (1,2). However, there are some disadvantages regarding the wear and corrosion behaviour of these materials. Therefore, the surface treatment of Mg-alloys is an important process to extend the industrial use of magnesium (3,4). Beside the laser technology one of the innovative processes for the improvement of the surface properties of Mg is the electron beam technology. Results of the manufacture of wear resistant coatings plasma-sprayed onto magnesium and a subsequent electron beam treatment are presented. Copper and nickel were chosen as the coating material since these metals can form hard hd resistant intermetallic compounds with magnesium during the remelting. The structure and the properties of the remelted Cu- or Ni-alloyed surface layer are dependent on the properties of the plasma sprayed coating and on the parameters of the subsequent electron beam treatment (feed rate, voltage, current and beam deflection). During the electron beam treatment the influence of the substrate must be minimized. The investigations on the coatings are focused on: (i) the metallographical evaluation concerning the microstructure and the thickness of the remelting zone, (ii) occurring phases, and (iii) the determination of hardness and abrasive wear resistance.