Fabrication of Tilted Mg₂Si/Ni Multilayer Composite Modules Using Polylactic Acid Resin Molds and Evaluation of the Thermoelectric Power Generation Performance

Abstract

Mg₂Si is a promising n-type thermoelectric material for thermoelectric power generation in the middle range of temperature and is lightweight. Both Mg and Si, the raw materials of Mg₂Si, are abundant in the Earth’s crust. However, it is hard to make Π-type modules since p-type Mg₂Si materials have not been developed enough, and Mg₂Si has low fracture toughness. The transverse thermoelectric effect occurs by tilting the multilayer composite of thermoelectric and metallic materials. The effect makes it possible to fabricate modules using only one type of thermoelectric material and to enhance mechanical strength by sandwiching the fragile Mg₂Si between metals. In this research, the molds with polylactic acid resin (PLA) were fabricated using a 3D printer. Mg₂Si and Ni powders were packed in the PLA mold, creating the tilted multilayer composite modules by spark plasma sintering (SPS). The power generation performance of the modules was then evaluated.