Effect of Several Alloying Elements on Electrochemical Corrosion Behavior of a Novel Superalloy Co-Al-W Super Alloy

Corrosion behavior of novel Co-Al-W superalloy with addition of several alloying elements was investigated.The results showed that the addition of Mo,Nb,Ta and Ti could improve the corrosion resistance of the alloy in NaCl solution.The alloy-2Mo showed superior corrosion resistance compared to alloys-2Nb and 2Ta,while the alloy-2Ti was the worst.In NaCl solutions with different pH value,Co-Al-W alloys suffered from serious pitting corrosion which mainly located at grain boundaries.The pitting corrosion was attributed to the migration of Cl~- into the pits from solution.