Passivity of Zirconium in Sulfuric Acid Solutions—Effect of Cathodic Pretreatment

The effect of cathodic pretreatment at -1.3 V vs a saturated calomel electrode (SCE) on the passivity of Kroll zirconium in 5, 10, and 20 vol % H₂SO₄ solution at room temperature was determined through potentiostatic anodic polarization studies. The cathodic treatment made the attainment of passivity easier and reduced the passive currents considerably. Studies on potential vs time and active and passive currents vs time indicated a protective film formation during the cathodic treatment. The possibility of a zirconium oxide film formation due to cathodic polarization induced alkalinity at -1.3 V (SCE) is discussed.