Thermal and electrical conductivities of intermetallic compound nial with non-stoichiometric composition

Abstract

Thermal conductivity of B2 type intermetallic compounds, NiAl and CoAl, have been measured at room temperature on about thirty specimens of different compositions. The conductivity-composition plots are characterized by a sharp maximum at stoichiometry in both compounds. These are the first extensive observations of such phenomena in intermetallic compounds. Electrical resistivity data are also reviewed in a wide compositional range of B2 single phase field. The field dependence of the transport properities were evaluated in terms of the Wiedmann-Franz relation. A quantitative discussion for the influence of the defect structure on the properties is developed. The dominant carrier of thermal conduction in NiAl and CoAl seems to be electrons rather than phonons in the non-stoichiometric compositions.