Spray Forming of FeSi₂ Thermoelectric Material by High-velocity Oxy-fuel Thermal Spraying

Abstract

Large sized n-and p-type FeSi₂ thermoelectric devices were spray-formed by high-velocity oxy-fuel thermal spraying (HVOF) method. One is a plate 100mm square with the thickness of 6mm and another is a tube-type device which was formed on a stainless tube (25 mm in diameter, 500 mm long) with the thickness of 5 mm. Their microstructure and physical properties were compared to those of hot-pressed material. The bulk density of HVOF-formed FeSi₂ was lower than that of hot-pressed materials due to higher amount of pore. For n-type FeSi₂, Seebeck coefficient and thermal conductivity of HVOF-formed material were comparable to those of hot-pressed material. While electrical conductivities of both n-and p-type HVOF-FeSi₂ were quite lower than that of hot-pressed n-type material, resulted in low performance as thermo electric device.