Chemical Behavior And Corrosion Inhibition Of Zinc Electrode In Phosphate Solutions Under Open Circuit Conditions

Abstract

The electrochemical behavior of zinc electrode has been studied in different concentrations of Na 3 PO 4 .12H 2 O solution using a simple potentiometric method. The study involves the measurement of the electrode potentials under open-circuit conditions. The potential was followed as a function of both time and Na 3 PO 4 .12H 2 O solution concentration until the values of steady-state potential are obtained. The steady potential changed on the addition of increasing amounts of different aggressive anions due to the breakdown of passivity. The way of variation of the steady-state potentials of zinc electrode in aggressive solutions upon the addition of increasing quantities of some inhibitors as the type of inorganic inhibitors are also concerned. The potential shifts towards more positive values the addition of inhibitors and the potential curves recall those reported in aggressive anion-free solution indicating pitting corrosion. The micrograph of zinc surface in presence of different concentrations of aggressive ions was investigated using Scanning Electron Microscope SEM.