: According to desirable mechanical properties and also resistance to corrosion and oxidation, carbides cemented by iron or nickel aluminides have been considered as potential alternatives for WC-Co hardmetals. The addition of boron as an interstitial element to the matrix composition of these composites, provides good ductility and fracture toughness. According to the service situation of cutting, drilling and machining tools fabricated by these materials, the resistance to corrosion in aqueous media is one of the important properties. Thus in present study, corrosion behavior of uniaxial hot-pressed WC-40vol%Ni 3 Al aluminide matrix composites with different amounts of boron additive were investigated in sulfuric acid and hydrochloric acid solutions and compared. For this purpose, general electrochemical tests including electrochemical impedance spectroscopy, potentiodynamic polarization and chronoamperometry were used. In addition, to determine the corrosion mechanism and to compare the amounts of dissolved ions in different potentials, the solutions were analyzed by means of inductively coupled plasma optical emission spectroscopy (ICP-OES). According to EIS results, the behavior of composite specimens/solution interface, was simulate by an equivalent electric circuit.The shape of both bode and nyquist plots and also impedance values of constant phase element (CPE) in the open circuit potential revealed that the composite specimens were in active corrosion situation. Polarization behavior of composites was almost similar qualitatively and included active, pseudo-passive and trans-passive regions. According to the results of chemical analyzes of solutions and based on the scanning electron microscopy micrographs from the surface of corroded specimens, the corrosion mechanism in the active region was leaching of nickel and aluminum elements from the binder phase. However, the specimens showed an active corrosion behavior in hydrochloric acid and the transition from active to pseudo-passive behavior was not seen. The presence of nickel and aluminum elements in the binder composition of composite improved the corrosion resistance in comparison to WC-Co hardmetals in acid solutions. Keywords: corrosion, aluminide matrix composites, intermetallics, hardmetals, Boron
