Cerium sulfate preparation from egyptian monazite's rare earth cake for its application as corrosion inhibitor of aluminum alloy AA6061

Abstract

Pure cerium sulfate was prepared from economic natural resources using Egyptian monazite rare earth cake. About 90% of the former was extracted by tri-butyl phosphate in kerosene at the optimum conditions: 15% solvent concentration, equilibrium pH of 1.7, equilibrium time 7 min and O/A ratio of 1/1. The aim of the present work was studying the corrosion inhibition properties of cerium sulfate towards aluminum alloy AA6061 in two solutions; 1.0 M disodium hydrogen orthophosphate and 3.5 % sodium chloride (simulation of sea water). The corrosion inhibition was evaluated using electrochemical techniques under different experimental conditions. The results showed that, in the presence of cerium sulfate, the AA6061 surface is well protected due to formation of passive film composed of Ce2O3/Ce(OH)3 which precipitated on the electrode surface.