FARADAY 1ST LAW OF GROWTH KINETICS AND CABRERA MOTT STUDIES OF ZIRCONIA

Abstract

The Cabrera – Mott theory implies anodic polarization of zircaloy-4 is limited by the field – facilitated activated jumps of metal ions at the metal – oxide interface was originally proposed to interpret growth of thin oxide films on planar metal surfaces. The growth kinetics of zircaloy-4 have been studied at constant current densities ranging from 6 to 16 mA.cm -2 at room temperature in order to investigate the dependence of ionic current density on the field across the zirconia. Thickness of the oxide films was estimated from capacitance data. The formation rate, faradaic efficiency and differential field were found to increase with increase in the ionic current density for zirconia. The addition of anions found to improve the growth kinetics of different colours covering entire thin films on the surface of the different anodization voltages. A plot of logarithm of anodization rate vs. logarithm of current density is fairly linear. From linear plots of logarithm of ionic current density vs. Differential field and applying the Cabrera – mott theory. The half – jump distance (a) and height of energy barrier (W) were deduced as 1.09 Ǻ and 0.94eV.