Improvement of Thermoelectric Properties and Development of Fabrication Processes for Environmental-friendly Half-Heusler Thermoelectric Materials

我们把重点放在了半-Heusler类化合物MNiSn(M=Ti，Zr，Hf)作为环境友好的热电材料上，这使得我们可以设计出不依赖于有毒元素的材料。用本征物理性质评价了MNiSn的热电性能，并用相平衡的方法确定了TiNiSn3种金属间化合物的相分离，即处于相同的半Heusler有序结构之间。提出了基于锡(液)和钛镍(固)反应、SnO2还原和钛氧化的新的制备工艺。对TiNiSnTi氧化物复合合金的热电性能进行了评价。

We have focused on half-Heusler type compounds MNiSn (M=Ti, Zr, Hf) as environmental-friendly thermoelectric materials which allow us the materials design without depending on toxic elements. Thermoelectric properties of MNiSn were evaluated as their intrinsic physical properties, and the phase separation of TiNiSn from ZrNiSn and HfNiSn, i.e. between the same half-Heusler ordered structure, was determined with related phase equilibria. New fabrication processes were proposed based on the reaction between Sn (liquid) and TiNi (solid) as well as based on the reduction of SnO_2 and oxidization of Ti. Thermoelectric properties were evaluated for TiNiSn/Ti-oxides composite alloys.