Formation and Properties of TiSi₂ as Contact Material for High-Temperature Thermoelectric Generators

Abstract

Thermoelectric generators (TEG) are capable of transforming waste heat directly into electric power. With higher temperatures the yield of the devices rises which makes high-temperature contact materials important. The formation of titanium disilicide (TiSi2) and its properties were analyzed and optimized for the use in TEG. Depending on a direct or an indirect transformation into the C54 crystal structure the process forms a layer with a resistivity of 20-22 μΩcm. Process gases influence the resistivity and result in difference of 20 %. The growing rate of TiSi2on silicon dioxide was determined; it shows a strong dependence on the used atmosphere and temperature. A maximum overgrowing length of 30 μm was found.

Mechanical and electrical properties of 3Y‐TZP/TiSi2 composites sintered at different temperatures

“…A new phase of Ti 5 Si 3 (melting point 2130 • C) 25 was observed in all B-D composites after sintering. The formation of Ti 5 Si 3 phase suggested deficiency of Si during the process of vacuum sintering, in which the actual melting point of TiSi 2 (melting point 1520 • C) 17 would be lowered due to the vacuum atmosphere. The liquid phase that was formed during sintering wetted the ZrO 2 grains and filled the pores of the compact.…”

“…Because of these properties, it is commonly used in (a) Schottky barrier and ohmic contacts, (b) gate and interconnection metal, and (c) as an epitaxial conductor in heterostructures. TiSi 2 typically has two phases: C49 and C54, which have different crystal structures and properties 17–19 . C54 phase TiSi 2 has the excellent electrical properties mentioned above, which makes it a promising option for the conductive phase of composite for heating elements.…”

“…TiSi 2 typically has two phases: C49 and C54, which have different crystal structures and properties. [17][18][19] C54 phase TiSi 2 has the excellent electrical properties mentioned above, which makes it a promising option for the conductive phase of composite for heating elements. 3Y-TZP ceramics exhibit exceptional fracture toughness, chemical stability, strength, corrosion resistance, hardness, and insulation resistivity at room temperature.…”

An approach to prepare high-purity TiSi2 for clean utilization of Ti-bearing blast furnace slag

“…TiSi 2 is a useful structural material above 1473 K due to its low specific weight, high melting point, and good oxidation resistance. 28 Due to its low electrical resistivity (approximately 13–16 μΩ cm), high-temperature stability, and good corrosion resistance, TiSi 2 has been widely employed to manufacture microelectronic devices, such as gate electrode wiring, connector products, Schottky barriers, and ohmic contact materials. 29 Currently, the methods to prepare TiSi 2 include chemical vapor deposition, 30 self-propagating high-temperature synthesis, 31 and mechanical alloying.…”