Anodic dissolution of nickel single crystals in an acidic fluoride containing electrolyte

The influence of fluoride ions on anodic dissolution of nickel single cryst als in an acidic solution has been studied at 25 degreesC. The stationary c urrent-potential curve in a potential range of 0,1 to 1,7 V-H was investiga ted on nickel single crystals of (100), (110) and (111) orientation. The ac tive anodic nickel dissolution follows a Tafel-equation depending on crysta l orientation in the following row of dissolution rates V-(100) > V-(110) > V-(111). Influence of fluoride ions on active anodic nickel dissolution co uld not be detected. Strong influence of fluoride ions in a potential range of 0,29 V-H to 0,49 V-H is given by exhibiting another maximum in the anod ic nickel dissolution curve. Another Tafel-equation in the anodic dissoluti on curve is found. The nickel corrosion rate in this potential range decrea ses in the following row of anodic dissolution rates V-(100) > V-(110) > V- (111).