Nanostructuring approach on TiNiSn-based half-Heusler (HH) thermoelectric materials (TE) has been well established as the most prominent paradigm for achieving high figure of merit (ZT). Herein, we have extended this approach on our previously reported bulk nanocomposite (BNC), containing HH and Full Heusler (FH) with little traces of Ti₆Sn₅ phase in a stoichiometric composition Ti₉Ni₇Sn₈ for the optimization of high thermoelectric performance. A synergistic effect of nanostructuring of Ti₉Ni₇Sn₈ bulk nanocomposite (BNC) on its thermoelectric properties was noticed, revealing an enhanced value of ZT ~ 0.83 at 773 K. This enhancement in ZT value is mainly ascribed to significant reduction in thermal conductivity (κ ~ 1.0 W/mK at 773 K), through modification in grain as well as phase boundary scattering. The marginal enhancement in Seebeck coefficient observed is attributed to charge carrier filtering effect at the interface of HH/FH phases.

中文翻译：

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块状纳米复合Ti 9 Ni 7 Sn 8的纳米结构对优化高热电性能的影响

基于TiNiSn的半霍斯勒（HH）热电材料（TE）的纳米结构方法已被公认是实现高品质因数（ZT）的最突出范例。在此，我们将这种方法扩展到了先前报道的大体积纳米复合材料（BNC）中，该材料包含HH和Full Heusler（FH），在化学计量组成Ti ₉ Ni ₇ Sn _8中几乎没有痕量的Ti ₆ Sn ₅相，用于优化高热电性能性能。Ti ₉ Ni ₇ Sn ₈纳米结构的协同效应它的热电性能的纳米复合材料块体（BNC），注意到，揭示ZT〜0.83的在773 K.此增强在ZT值的增强的值主要归因于热传导性显著减少（κ  〜1.0W / mK的在773 K），通过改变晶粒以及相界散射。所观察到的塞贝克系数的边际增强归因于HH / FH相界面处的载流子滤波效应。