Nickel was covered with double-layered oxide composed of different valencies of Ni when the specimen was heated in the air depending on the temperature. The oxide layer was converted gradually to the NiO1+x and NiF2 mixture by heat treatment in NF3 atmosphere. The chemical composition, surface morphology, anodic behavior, and the corrosion resistance of these specimens were investigated to elucidate the performance of the nickel anode in NH4F . 2HF for electrochemical production of NF3.