Fracture mode, microstructure and temperature-dependent elastic moduli for thermoelectric composites of PbTe PbS with SiC nanoparticle additions

Journal Article · Tue Jan 01 00:00:00 EST 2013 · Philosophical Magazine

DOI:https://doi.org/10.1080/14786435.2013.833354· OSTI ID:1093167

Ni, Jennifer E ^[1]; Case, Eldon D ^[2]; Hogan, Timophy P. ^[2]; Trejo, Rosa M ^[1]; Lara-Curzio, Edgar ^[1]; Kanatzidis, Mercouri G. ^[3]

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1. ORNL
2. Michigan State University, East Lansing
3. Northwestern University, Evanston

Twenty-six (Pb0.95Sn0.05Te)0.92(PbS)0.08 0.055% PbI2 SiC nanoparticle (SiCnp) composite thermoelectric specimens were either hot pressed or pulsed electric current sintered (PECS). Bloating (a thermally induced increase in porosity, P, for as-densified specimens) was observed during annealing at temperatures >603 K for hot-pressed specimens and PECS-processed specimens from wet milled powders, but in contrast seven out of seven specimens densified by PECS from dry milled powders showed no observable bloating following annealing at temperatures up to 936 K. In this study, bloating in the specimens was accessed via thermal annealing induced changes in (i) porosity measured by scanning electron microscopy on fractured specimen surfaces, (ii) specimen volume and (iii) elastic moduli. The moduli were measured by resonant ultrasound spectroscopy. SiCnp additions (1 3.5 vol.%) changed the fracture mode from intergranular to transgranular, inhibited grain growth, and limited bloating in the wet milled PECS specimens. Inhibition of bloating likely occurs due to cleaning of contamination from powder particle surfaces via PECS processing which has been reported previously in the literature.

• Research Organization: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE Office of Science (SC)
• DOE Contract Number: DE-AC05-00OR22725
• OSTI ID: 1093167
• Journal Information: Philosophical Magazine, Journal Name: Philosophical Magazine; ISSN 1478--6435
• Country of Publication: United States
• Language: English