Effect of manganese additions on the corrosion behavior of an extruded Mg–5Al based alloy

The effect of manganese on the corrosion properties of Mg–5Al alloy was investigated by electrochemical techniques in 0.6 M NaCl solution and surface analyses. The electrochemical tests indicated that the corrosion rate and hydrogen evolution of the Mg–5Al specimens decreased with increasing Mn content. Surface analyses indicated that Mn promoted the formation of the corrosion products in the absence of Mn products. In addition, to this Mn addition also resulted in reduction of grain size and increase of Mn in the Mg matrix.

► Alloying effect of Mn on Mg–5Al alloy.
► The improved corrosion resistance with increasing Mn content.
► An increase of Mn content reduces the grain size and increases of Mn in the α-Mg matrix.
► Mn addition promotes the formation of the corrosion products in the absence of Mn products.