Sam Sopheap, Odagawa Soma, Nakatsugawa Hiroshi, Okamoto Yoichi
Yokohama National University, Yokohama 240-8501, Japan.
National Defense Academy, Yokosuka 239-8686, Japan.
Materials (Basel). 2023 Jan 18;16(3):927. doi: 10.3390/ma16030927.
A thermoelectric generator, as a solid-state device, is considered a potential candidate for recovering waste heat directly as electrical energy without any moving parts. However, thermoelectric materials limit the application of thermoelectric devices due to their high costs. Therefore, in this work, we attempt to improve the thermoelectric properties of a low-cost material, iron silicide, by optimizing the Ni doping level. The influence of Ni substitution on the structure and electrical and thermoelectric characteristics of bulk -FeNiSi (0 ≤ x ≤ 0.03) prepared by the conventional arc-melting method is investigated. The thermoelectric properties are reported over the temperature range of 80-800 K. At high temperatures, the Seebeck coefficients of Ni-substituted materials are higher and more uniform than that of the pristine material as a result of the reduced bipolar effect. The electrical resistivity decreases with increasing x owing to the increases in metallic ε-phase and carrier density. The ε-phase increases with Ni substitution, and solid solution limits of Ni in -FeSi can be lower than 1%. The highest power factor of 200 μWmK at 600 K is obtained for x = 0.001, resulting in the enhanced value of 0.019 at 600 K.
作为一种固态装置，热电发电机被认为是一种无需任何移动部件就能直接将废热回收为电能的潜在候选者。然而，热电材料因其高成本限制了热电装置的应用。因此，在本工作中，我们试图通过优化镍掺杂水平来改善低成本材料硅化铁的热电性能。研究了镍替代对采用传统电弧熔炼法制备的块状FeNiSi（0≤x≤0.03）的结构以及电学和热电特性的影响。报道了在80 - 800 K温度范围内的热电性能。在高温下，由于双极效应减弱，镍替代材料的塞贝克系数比原始材料更高且更均匀。由于金属ε相和载流子密度的增加，电阻率随x的增加而降低。ε相随镍替代而增加，并且镍在FeSi中的固溶极限可能低于1%。对于x = 0.001，在600 K时获得了200 μWmK的最高功率因数，导致在600 K时优值提高到0.019。
