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

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 theoretic al density after the direct consolidation. Corrosion potentials and rates o f the composites in a 50% NaOH solution were -982.7 mV(SHE) and 3.6x10(-6) A cm(-2) for TiC/50% Ni and -1074.8 mV(SHE) and 8.12x10(-6) A cm(-2) for Ti C/46.5% Ni-3.5% Mo, respectively. Wear resistance determined by abrasive we ar increased with molybdenum addition. Electron probe microanalysis reveale d that F-phase was formed around titanium carbide in the TiC/Ni-Mo composit es. 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 t he formation of delta -phase and the high dislocation density around carbid e due to the difference of thermal expansion coefficient between carbide an d matrix. (C) 2001 Elsevier Science Ltd. All rights reserved.