Investigation of the Microstructure and Thermoelectric Properties of P-Type BiSbTe Alloys by Usage of Different Revolutions Per Minute (RPM) During Mechanical Milling

• Published in: Archives of metallurgy and materials 2017-06, Vol.62 (2), p.1167-1171
• Main Authors: Yoon, S.-M., Madavali, B., Yoon, Y.-N., Hong, S.-J.
• Format: Article
• Language: English
• Subjects: Alloys; Bi0.5Sb1.5Te3 alloys; Crystal structure; Electrical resistivity; Fracture surfaces; Heat transfer; Mechanical alloying; Mechanical milling; Microstructure; Plasma sintering; Power factor; Spark plasma sintering; Temperature dependence; Thermal conductivity; Thermoelectric properties; Thermoelectricity; X-ray diffraction
• ISSN: 2300-1909; 1733-3490; 2300-1909
• DOI: 10.1515/amm-2017-0171

In this work, p-type Bi Sb Te alloys were fabricated by high-energy ball milling (MA) and spark plasma sintering. Different revolutions per minute (RPM)s were used in the MA process, and their effect on microstructure, and thermoelectric properties of p-type Bi Sb Te were systematically investigated. The crystal structure of milled powders and sintered samples were characterized using X-ray diffraction. All the powders exhibited the same morphology albeit with slight differences find at 1100 RPM conditions. A slight grain size refinement was observed on the fracture surfaces from 500 to 1100 RPM specimens. The temperature dependence of Seebeck coefficient, electrical conductivity, and power factors were measured as a function of temperature with different RPM conditions. The power factor shows almost same (~3.5 W/mK at RT) for all samples due to unchanged Seebeck and electrical conductivity values. The peak ZT of 1.07 at 375K is obtained for 1100 RPM specimen due to low thermal conductivity.