Effect of solvent on anodization of Zr-4 in L-ascorbic acid - SEM studies

Anodization of Zircaloy-4 in 0.1 M L-ascorbic acid has been carried out. Kinetics of anodic oxidation of Zircaloy-4 has been studied at a constant current density of 8 mA.cm-2 and at room temperature. The plots of formation voltage vs time, reciprocal capacitance vs time and reciprocal capacitance vs formation voltage were drawn. From these plots, formation rate, current efficiency and differential field were calculated. The addition of solvent (ethylene glycol) showed better kinetic results for 20, 40, 60 and 80% aquo-glycolic media, the dielectric constant values are low leading to the marked improvement in the kinetics. The surface morphology of the anodic films was also studied by Scanning Electron Micrographs (SEM). (author)