Corrosion behavior of Ni 3 Al-bonded TiC-based cermets in H 2 SO 4 and NaOH solutions

Abstract Corrosion behavior of multicomponent Ni 3 Al-bonded Ti(C,N)-based cermets with various Ni 3 Al contents and Ti(C 0.5 ,N 0.5 ) addition was investigated in 1 M H 2 SO 4 and 1 M NaOH solutions, using immersion tests, potentiodynamic polarization measurements, XRD, SEM and XPS. In 1 M H 2 SO 4 solution, corrosion process of all cermets consisted mainly of their binder phase dissolution, and during potentiodynamic polarization, their passivation and pseudo-passivation corresponded to passivation of their binder phase and ceramic grains, respectively. Corrosion potential and current density decreased with increasing Ni 3 Al content, while corrosion potential increased and current density decreased with Ti(C 0.5 ,N 0.5 ) addition. In 1 M NaOH solution, corrosion process of all cermets consisted mainly of their ceramic grain dissolution, and during potentiodynamic polarization, their passivation and pseudo-passivation corresponded to passivation of their ceramic grains and binder phase, respectively. Corrosion potential increased and current density decreased with increasing Ni 3 Al content, while corrosion potential decreased and current density increased with Ti(C 0.5 ,N 0.5 ) addition.