Influence of Percolation Effects on Lithium Intercalation into Li[sub 0.5−x]Na[sub x]La[sub 0.5]TiO[sub 3] (0≤x≤0.5) Perovskites

Abstract

The corrosion behavior of austempered ductile iron (ADI) in alkaline environment has been investigated at the microscale by means of the electrochemical microcell technique, surface analysis methods, and at the macroscale using classical electrochemical techniques. Local electrochemical investigations have revealed that the matrix (ausferrite), far from spheres, undergoes passivation in 1M1M NaClO4NaClO4 , pH 10 solution within a wide potential range, from the corrosion potential (of about −280mV∕SCE−280mV∕SCE ) until 800mV∕SCE800mV∕SCE . Surface observations combined with local electrochemical analysis have shown that corrosion of ADI first occurs in the close vicinity of some graphite spheres and then around oxide inclusions. The oxidized regions are richer in oxygen than the matrix located far from spheres. X-ray photoelectron spectroscopy analysis has revealed that the electrochemical dissolution of ADI in 1M1M NaClO4NaClO4 , pH 10, leads to the formation of corrosion products containing mainly iron oxides and hydroxide.