Electrophysical properties of TiC-Nb, TiC-Ta, TiC-Mo, and TiC-W cermets

Conclusions

• 1. A study was made of the effect of temperature, in the range 20–1100°C, on the electrical resistivity and thermo-emf of TiC-Nb, TiC -Ta, TiC-Mo, and TiC-W cermets with metal-to-carbide ratios of 25∶75, 50∶50, and 75∶25 at. and mole %, and their Hall constants at 20°C were determined.

• 2. It was established that property vs composition curves for these materials exhibit extreme points at 50 at.%. Nb and Ta and 25 at.% Mo and W. The plots of ρ vs t andα vs t obtained for these cermets were found to be straight lines, demonstrating that their conductivity has a metallic character. The electrical resistivity of the TiC -Nb and TiC -Ta cermets investigated is seven to fourteen times that of the starting metals (16 for Nb and 14.7 /μΩ-cm for Ta) and two to four times that of titanium carbide (53 μΩ-cm). The electrical resistivity of cermets of the systems TiC-Mo and TiC-W is one order higher than that of the starting metals and up to three times higher than that of titanium carbide, the only exceptions being 25 TiC-75 Me^II cermets (where Me^II is Mo or W), whose electrical resistivity is slightly less than that of titanium carbide.