Corrosion of carbon-alloyed iron aluminides

[摘要] The corrosion behaviour of two carbon-alloyed intermetallics of composition Feâ€�??28.1Alâ€�??2.1C and Feâ€�??27.5Alâ€�??3.7C has been studied and compared with that of binary intermetallics. Potentiodynamic polarization studies indicated that the intermetallics exhibited activeâ€�?�passive behaviour in an acidic solution of pH = 1, whereas they exhibited stable passivity in a buffer solution of pH 8.4. Corrosion rates were also obtained by immersion testing. The variation of corrosion rate as a function of time was similar for both the intermetallics. The variation in corrosion rate as a function of time has been explained based on the observed potentiodynamic polarization behaviour. Scanning electron microscopy of corroded surfaces indicated that the carbon-alloyed intermetallics were susceptible to galvanic corrosion, due to the presence of carbides.

[学科分类] 材料工程

[关键词] Corrosion;iron aluminides;Fe3Al;potentiodynamic polarization.