Influence of nitrogenizing and Al-doping on microstructures and thermoelectric properties of iron disilicide materials

Thermoelectric properties of hot-pressed Al- and Co-doped iron disilicide materials

“…The temperature dependent electrical conductivity below 770 K could be attributed to the carrier mobility effect, which decreased with the temperature increase, since the acceptors were exhausted and the movement of carrier was blocked by lattice vibration. The intrinsic conduction predominated when the temperature was above 770 K, which led to the increase of electrical conductivity with increasing the temperature [16]. The electrical conductivities of the Co-doped FeSi 2 increase with the measuring temperature in the investigated temperature range.…”

“…The trend transition temperatures and the maximal absolute values for Aland Co-doped samples are 750 K and 264 V K −1 and 790 K and 205 V K −1 , respectively. The preceding increase of Seebeck coefficient could be attributed to a more acute scattering of carriers with the increase in temperature, and the subsequent decrease of Seebeck coefficient could be due to a rapid increase in carrier concentration with the increase in temperature [16].…”

“…where L is the Lorenz number, which is 2.45 × 10 −8 V 2 K −2 for doped ␤-FeSi 2 [16]. The lattice thermal conductivity was obtained by subtracting κ c from κ.…”

Effects of Doping Elements in β-FeSi₂ Prepared Utilizing Cast Iron Scrap Chips

“…The electrical conductivities for the Co-doped (0.02 < Co < 0.08) and Mn-doped (0.06 < Mn < 0.1) ¢-FeSi 2 prepared using cast iron scrap chips, along with other examples reported in the literature, 9,1216) are nearly constant over the temperature range from room temperature to 800°C. This behavior is typical for the extrinsic conductivity range.…”

Evolution under thermal annealing of Mn-doped iron disilicides obtained by ball milling

“…Additives like V, Cr, Mn and Al can turn the material into a p-type semiconductor [3][4][5][6]. In particular, the Mn-doping encloses intriguing fundamental issues related to the occurrence of metastable phases due to the structural difference between iron and manganese silicides and also to the occupancy of the two non-equivalent Fe sites (Fe I and Fe II ) in the β-FeSi 2 structure [7].…”