The effects of Ni3Al binder content on the electrochemical response of melt-infiltration processed TiC–Ni3Al cermets

Abstract

TiC–Ni3Al samples were successfully fabricated with varying amounts of the Ni3Al intermetallic binder (alloy IC-50), ranging from 10 to 40 wt-%, through a simple melt-infiltration method. Each sample was then tested to determine the degree of resistance of that composition to electrochemical corrosion in an aqueous solution containing 3.5 wt-% NaCl, using a range of testing procedures including open-circuit potential, potentiodynamic polarisation and cyclic polarisation. Results indicate that the lowest binder content results in greater potential to resist corrosion. It is demonstrated that the Ni3Al binder undergoes dissolution for the examined conditions, which was confirmed through the high amount of Al and Ni in the electrolyte solutions following testing. It was also confirmed from the electrochemical experiments and the SEM that localised corrosion was visible.