Corrosion Studies of Fe[sub 3]Al–Fe[sub 3]AlC Intermetallics in 0.25 N H[sub 2]SO[sub 4] using Microelectrochemical Method and SAES Analysis

Abstract

Aqueous corrosion behavior of the dual-phase Fe3 Al- Fe3 AlC iron aluminide was investigated in 0.25 N H2 S O4 using a microelectrochemical technique and scanning Auger electron spectroscopy (SAES) to explore corrosion and passivation behavior of the individual phase, i.e., Fe3 Al and Fe3 AlC. The corrosion resistance of the matrix (Fe3 Al) phase evaluated in terms of electrochemical parameters such as corrosion current density, passive current density, and critical current density were found superior to that of the carbide phase. The passive film formed on the matrix phase was more stable compared with that on the carbide phase. Low Al content and presence of C in the carbide phase were attributed to its poor passivation behavior. © 2007 The Electrochemical Society.