Immersion Corrosion Resistance of Binary High-Strength Cu-Mg Alloys

Copper and copper alloys are generally known for good corrosion resistance which varies in regard to the type and amount of alloying additive. In the current study, forgings made of pure copper, CuMg2.8 and CuMg3.2 alloys were subjected to the immersion corrosion resistance test in a 3.5 wt.% NaCl solution for up to 2520 h (15 weeks). Samples were analyzed in terms of the decrease in their weight, electrical conductivity and hardness. Additionally, samples after 15 weeks of immersion were analyzed using a scanning electron microscope. The results proved that Cu-Mg alloys are more resistant to corrosion than pure copper obtained in the same conditions. What is more, as the amount of magnesium increased, so did corrosion resistance. Better corrosion resistance was attributed to the morphology and chemical composition of the tarnish on the surface of the samples and less significant signs of degradation of the alloys microstructure.