الفهرس 
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Abstract
Student Name: ASHRAF MOKHTAR ABD EL-WAHAB Title of the Thesis: “ELECTROCHEMICAL STUDIES ON EFFECT OF PHOSPHORIC ACID ON IMPROVEMENT OF LEAD-ANTIMONY GRIDS IN LEAD-ACID BATTERIES” Degree: MASTER (PHYSICAL CHEMISTRY) The corrodibility of the commercial Pb-1.7%Sb alloy in sulphuric acid solutions in the absence and presence of phosphoric acid under open circuit and potentiostatic and galvanostatic polarization conditions were studied by potential, cyclic voltammetry and electrochemical impedance spectroscopy. Addition of H3PO4 increase the corrodibility of the alloy by retardation of the growth of the passive PbSO4 film that in turn slowdown the corrosion rate. The efficiency of PbO2 formation and the self-discharge of PbO2 decreases with increasing oxidation current. The presence of H3PO4 leads to a substantial decrease in both the efficiency of PbO2 formation and consequently its self-discharge. Life cycle tests show that H3PO4 causes lesser surface penetration as a result of inhibition of PbSO4 via formation of PbHPO4 and adsorption of phosphate on PbSO4. Key Words: low-antimony alloys, lead-acid batteries, phosphoric addition, life-cycle