Temperature-dependent thermal expansion of cast and hot-pressed LAST (Pb-Sb-Ag-Te) thermoelectric materials

• Published in: Philosophical magazine (Abingdon, England) Vol. 89; no. 18; pp. 1439 - 1455
• Main Authors: Ren, F., Hall, B.D., Case, E.D., Timm, E.J., Trejo, R.M., Meisner, R.A., Lara-Curzio, E.
• Format: Journal Article
• Language: English
• Published: Abingdon Taylor & Francis Group 21.06.2009; Taylor & Francis
• Subjects: Condensed matter: structure, mechanical and thermal properties; Exact sciences and technology; LATTICE PARAMETERS; MATERIALS SCIENCE; Physics; powder diffraction; semiconductor; THERMAL EXPANSION; Thermal expansion; thermomechanical effects and density; Thermal properties of condensed matter; Thermal properties of crystalline solids; THERMOELECTRIC MATERIALS; thermomechanical analysis; X-RAY DIFFRACTION; Temperature dependence; Antimony; Silver additions; XRD; High temperature; Lattice parameters; Thermal properties; Silver; Thermal expansion; Thermoelectric materials; Hot pressing; Bismuth tellurides; Lead tellurides; Thermal expansion coefficient; Thermomechanical analysis; Crystal structure
• ISSN: 1478-6435; 1478-6443
• DOI: 10.1080/14786430903002376

The thermal expansion for two compositions of cast and hot-pressed LAST (Pb-Sb-Ag-Te) n-type thermoelectric materials has been measured between room temperature and 673 K via thermomechanical analysis (TMA). In addition, using high-temperature X-ray diffraction (HT-XRD), the thermal expansion for both cast and hot-pressed LAST materials was determined from the temperature-dependent lattice parameters measured between room temperature and 623 K. The TMA and HT-XRD determined values of the coefficient of thermal expansion (CTE) for the LAST compositions ranged between 20 × 10 −6 K −1 and 24 × 10 −6 K −1 , which is comparable to the CTE values for other thermoelectric materials including PbTe and Bi 2 Te 3 . The CTE of the LAST specimens with a higher Ag content (Ag 0.86 Pb 19 Sb 1.0 Te 20 ) exhibited a higher CTE value than that of the LAST material with a lower Ag content (Ag 0.43 Pb 18 Sb 1.2 Te 20 ). In addition, a peak in the temperature-dependent CTE was observed between room temperature and approximately 450 K for both the cast and hot-pressed LAST with the Ag 0.86 Pb 19 Sb 1.0 Te 20 composition, whereas the CTE of the Ag 0.43 Pb 18 Sb 1.2 Te 20 specimen increased monotonically with temperature.