Additions of molybdenum to nickel impart a pseudopassive behavior to the resulting alloy in nonoxidizing acids, which gives it good resistance to corrosion (Ref 10). However, contamination of the environment with oxidizing ions such as Fe3+ or Cu2+ destroys this behavior and dramatically increases the corrosion rate. Consequently, the nickel-molybdenum alloys should never be used where oxidizing conditions are known to exist.