Microstructural length scale of an eutectic alloy can be tuned with different cooling rates obtainable via different processing routes, such as melt spinning, suction casting and gas atomization. In this report, the thermoelectric and mechanical properties of selenium-free n-type BiSbTe compound were investigated. One kilogram of powder with a nominal composition of Bi_22.5Sb_7.5Te₇₀ was fabricated using gas atomization. The powders were consolidated into a pellet using spark plasma sintering to minimize rapid grain growth, and the morphologies were examined using scanning electron microscope and X-ray diffraction techniques. The microstructure of the pellet reveals a random eutectic plate-like morphology between the primary phase and Te. The presence of Te results in excess charge carrier injection leading to a high electrical conductivity, while the reduction in length scale in the atomized samples has contributed to the decrease in the mobility of the charge carriers leading to a reasonably good Seebeck coefficient. This microstructure feature is also responsible for the high room temperature micro-Vickers hardness and a 40% reduction in the thermal conductivity. The observed thermoelectric and mechanical properties in this gas atomization + spark plasma sintering have been compared to an earlier reported processing route of flame melting. The relationship between the observed properties and microstructure features is discussed in detail.

共晶合金的显微组织长度尺度可以通过不同的加工速率（例如熔体纺丝，吸铸和气体雾化）获得不同的冷却速率来调节。在本报告中，研究了无硒n型BiSbTe化合物的热电和机械性能。一公斤标称成分为Bi _22.5 Sb _7.5 Te ₇₀的粉末用气体雾化制造。使用火花等离子体烧结将粉末固结成颗粒，以最大程度地减少晶粒的快速生长，并使用扫描电子显微镜和X射线衍射技术检查其形貌。颗粒的微观结构揭示了在初级相和Te之间的随机共晶板状形态。Te的存在会导致注入过多的电荷载流子，从而导致高电导率，而雾化样品中长度尺度的减小则导致电荷载流子迁移率的下降，从而导致合理的塞贝克系数。这种微观结构特征还导致室温下的显微维氏硬度高，导热系数降低40％。在这种气体雾化+火花等离子体烧结中观察到的热电和机械性能已与较早报道的火焰熔化工艺路线进行了比较。详细讨论了观察到的性能和微观结构特征之间的关系。