Corrosion and wear properties of TiC/Ni–Mo composites produced by direct consolidation during a self-propagating high-temperature reaction

Abstract TiC/Ni–Mo composites were prepared by one-step direct consolidation during a self-propagating high-temperature synthesis reaction and their corrosion and wear properties were studied. The composites reached 99.8% of theoretical density after the direct consolidation. Corrosion potentials and rates of the composites in a 50% NaOH solution were −982.7 mVSHE and 3.6×10−6 A cm−2 for TiC/50% Ni and −1074.8 mVSHE and 8.12×10−6 A cm−2 for TiC/46.5% Ni–3.5% Mo, respectively. Wear resistance determined by abrasive wear increased with molybdenum addition. Electron probe microanalysis revealed that δ-phase was formed around titanium carbide in the TiC/Ni–Mo composites. Transmission electron microscopy revealed that the dislocation density around the carbide in the composites was high. The improved wear resistance was associated with increases of the interfacial bonding strength due to the formation of δ-phase and the high dislocation density around carbide due to the difference of thermal expansion coefficient between carbide and matrix.