Thermal Conductivity and Electrical Resistivity of Cemented Transition‐Metal Carbides at Low Temperatures

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Abstract
The thermal conductivity, K, and electrical resistivity, ρ, of cemented transition‐metal carbides—a class of composites of high toughness—were measured for the first time at cryogenic temperatures. The dependence of these quantities on composition, grain size, and binder content was explored. The major qualitative findings are the following: (1) K for WC/Co grades has a gentle maximum ranging from 80 to 160 W/(m · K) around 150 K; (2) WC/Co has higher values of K and lower values of ρ than TiCx/NiMo, because of vacancy scattering of electrons and phonons in the latter; (3) grades with larger grains have higher values of K; (4) grades with higher percentages of binder phase have lower values of K; (5) the lattice and electronic components of K are comparable for TiCx/NiMo; (6) multicarbide grades have lower values of K than WC/Co; (7) a Callaway analysis of the lattice component of K identifies scattering of phonons by grain boundaries, point defects, electrons, and other phonons as significant for these materials, with defect scattering dominating in the liquid‐nitrogen range.