Effect of varying mixture ratio of raw material powders on the thermoelectric properties of AlMgB14-based materials prepared by spark plasma sintering Original Research Article

Thermoelectric properties of AlMgB14-based materials prepared by spark plasma sintering were investigated. Al, Mg, and B powders were used as raw material powders. The raw powders were mixed using a V-shaped mixer, and then the mixture was sintered at 1673 K or 1773 K. The mixture ratio of raw powders was varied around stoichiometric ratio of AlMgB14. X-ray diffraction patterns of samples showed that all samples consist of AlMgB14 and MgAl2O4. The Seebeck coefficient of the samples exhibited significant change depending on the varying mixture ratio and sintering temperature. One sample exhibited a large negative value for the Seebeck coefficient (approximately −500 μV/K) in the temperature range from 573 K to 1073 K, while others showed positive value (250–450 μV/K). Thus n-type AlMgB14-based material has been realized by varying raw material ratio and sintering temperature.