Thermal conductivities, electrical resistivities, and thermal expansion of titanium carbonitrides and oxycarbides

Conclusions

• 1. An Investigation was carried out into the variation of the coefficients of linear thermal expansion, thermal conductivities, and electrical resistivities of titanium carbonitrides and oxycarbides with temperature and composition. The thermal conductivities of these compounds were found to grow with rise in temperature.

• 2. It is shown that the thermal and electrical conductivity isotherms of these compounds pass through extreme points, with a minimum of ρ and a maximum of λ at compositions close to TiC_0.3N0.6 (which are attributable to ordering in the metalloid sublattice). By contrast, the coefficients of thermal expansion slightly grow with increase in nitrogen concentration in the whole composition range.

• 3. No apparent correlation was found between the λ and ρ vs composition curves for titanium oxycarbides: While λ monotonically decreases with rise in oxygen concentration, ρ at first (up to y =0.4) slightly decreases and only then begins to increase rapidly with rise in y. Such changes are evidently attributable to complex changes in both the electron and phonon spectra, which in turn are due to increased defectiveness of both sublattices and increased contributions from ionic interactions at higher oxygen contents and also to ordering in the nonmetal sublattice (at approximately equal concentrations).