Influence of Water on Passivation of Zr in n-butanol Solution Containing Buⁿ₄NBr

Abstract

To understand the role of water on zirconium passivation in n-butanol solutions containing Buⁿ₄NBr, composition and corrosion properties of the passive film were studied using cyclic voltammetry, X-ray photoelectron and electrochemical impedance spectroscopy. Zirconium undergoes spontaneous passivation followed by pitting corrosion as a result of passivity breakdown by the aggressive attack of bromide anions. The passive film consists mainly of ZrO₂, ZrO₂·2H₂O and a small amount of zirconium butoxide. The pitting potential shifts positively and pitting corrosion is seriously inhibited with the addition of a small amount of water. Water improves the pitting corrosion resistance of the passive film by changing the thickness and the relative ratio of OH⁻/O²⁻. The result is helpful to electrosynthesize zirconium butoxide with high energy efficiency.