Constitution of the binary M-Sb systems (M = Ti, Zr, Hf) and physical properties of MSb2

This study is closely related to the chemical interactions in thermoelectric joints of a hot metal electrode with p- and n-type skutterudite. As a result of this work, a first and complete phase diagram has been constructed for the Ti–Sb system as well as partial phase diagrams (>65 at.% Sb) for the systems Zr–Sb and Hf–Sb. Investigations are based on X-ray powder and single crystal analyses (determination of the crystal structure of Ti5Sb8with Zr2.6Ti2.4Sb8-type, space group I4122; RF= 0.032), electron probe microanalyses (EPMA) and differential thermal analyses (DTA). Physical properties were evaluated for the binary compounds MSb2(M = Ti, Zr, Hf) comprising electrical resistivity (from 4.2 K to 825 K), specific heat, thermal conductivity and thermal expansion coefficient (from 4.2 K to 300 K), Seebeck coefficient (from 300 K to 825 K) and elastic moduli at 300 K. These data will serve to evaluate the potential of MSb2compounds (M = Ti, Zr, Hf) for thermoelectric devices, where these phases predominantly appear in the diffusion zones of the hot metal electrode with p- and n-type skutterudite.