Mg 3 Sb 2 -based thermoelectric materials attract attention for applications near room temperature. Here, Mg-Bi films were synthesized using magnetron sputtering at deposition temperatures from room temperature to 400 C. Single-phase Mg 3 Bi 2 thin films were grown on c-planeoriented sapphire and Si(100) substrates at a low deposition temperature of 200 C. The Mg 3 Bi 2 films grew epitaxially on c-sapphire and fiber-textured on Si(100). The orientation relationships for the Mg 3 Bi 2 film with respect to the c-sapphire substrate are (0001) Mg 3 Bi 2 k(0001) Al 2 O 3 and [1120] Mg 3 Bi 2 k[1120] Al 2 O 3 . The observed epitaxy is consistent with the relatively high work of separation, calculated by the density functional theory, of 6.92 J m À2 for the Mg 3 Bi 2 (0001)/Al 2 O 3 (0001) interface. Mg 3 Bi 2 films exhibited an in-plane electrical resistivity of 34 lX m and a Seebeck coefficient of þ82.5 lV K À1 , yielding a thermoelectric power factor of 200 lW m À1 K À2 near room temperature.

The results of flexural tests of basalt fibre-reinforced cementitious mortars in terms of flexural strength and the occurrence of the bridging effect are summarised. Mixture proportions and curing conditions were altered for various series. The main parameters concerning mixture proportions were water to cement ratio (w/c), micro-silica and plasticiser addition and fibre dosage (1%, 3% and 6.2% by binder’s mass). Various curing conditions were defined by different temperatures, humidity and time. The influence of the amount of water inside the pores of the hardened cementitious matrix on the flexural strength values, as far as the impact of the alkaline environment on basalt fibres’ performance is concerned, was underlined. The designation of flexural strength and the analysis of post-critical deformations were also performed on the reference series without fibres and with the addition of more common polypropylene fibres. The bridging effect was observed only for the basalt fibre-reinforced mortar specimens with a relatively low amount of cement and high w/c ratio, especially after a short time of hardening. For the lowest value of w/c ratio (equalling 0.5), the bridging effect did not occur, but flexural strength was higher than in the case of non-reinforced specimens. Comparing mortars with the addition of basalt and polypropylene fibres, the former demonstrated higher values of flexural strength (assuming the same percentage dosage by the mass of the binder). Nevertheless, the bridging effect in that case was obtained only for polypropylene fibres.

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