Commercial magnesium anodes were evaluated using ASTM G97-89 as standard test and attached to the ASTM test arrangement a technique of electrochemical impedance was also used . Cylindrical samples were cut from the as-cast Mg anodes. Several treatments and different cooling rates were carried out. The anodic efficiency determined as a function of the cooling rate, showing an increment around 10 to heat was 12%
above the efficiency showed by the non-treated commercial anodes (as-cast condition). The efficiency increments were related to the microstructural characteristics i.e particle size and/or grain size. Also some morphological aspects were considered .The appearance of second phase particles influences the different forms that the corrosion process exhibits.
Keywords: Magnesium. Anodes, Heat Treatment, Efficiency.