|
|||||
|
|
Thermal and electronic charge transport in bulk nanostructured Zr0.25Hf0.75NiSn composites with full-Heusler inclusions |
|
| Authors: | Julien PA Makongo Dinesh K Misra James R Salvador Nathan J Takas Guoyu Wang Michael R Shabetai Aditya Pant Pravin Paudel Ctirad Uher Kevin L Stokes Pierre FP Poudeu |
| Institution: | aThe Advanced Materials Research Institute, University of New Orleans, New Orleans, LA 70148, USA;bChemical Sciences and Materials Systems Laboratory, General Motors R&D Center, Warren, MI 48090, USA;cDepartment of Physics, University of Michigan, Ann Arbor, MI 48109, USA;dDepartment of Physics, University of New Orleans, New Orleans, LA 70148, USA;eDepartment of Chemistry, University of New Orleans, New Orleans, LA 70148, USA;fLaboratory for Emerging Energy and Electronic Materials, Materials Science and Engineering Department, University of Michigan, Ann Arbor, MI 48109, USA |
| Abstract: | Bulk Zr0.25Hf075NiSn half-Heusler (HH) nanocomposites containing various mole fractions of full-Heusler (FH) inclusions were prepared by solid state reaction of pre-synthesized HH alloy with elemental Ni at 1073 K. The microstructures of spark plasma sintered specimens of the HH/FH nanocomposites were investigated using transmission electron microscopy and their thermoelectric properties were measured from 300 K to 775 K. The formation of coherent FH inclusions into the HH matrix arises from solid-state Ni diffusion into vacant sites of the HH structure. HH(1–y)/FH(y) composites with mole fraction of FH inclusions below the percolation threshold, y∼0.2, show increased electrical conductivity, reduced Seebeck coefficient and increased total thermal conductivity arising from gradual increase in the carrier concentration for composites. A drastic reduction (∼55%) in κl was observed for the composite with y=0.6 and is attributed to enhanced phonon scattering due to mass fluctuations between FH and HH, and high density of HH/FH interfaces. |
| Keywords: | Nanocomposite Half-Heusler Full-Heusler Microstructure Spinodal decomposition Thermoelectric properties |
| 本文献已被 ScienceDirect 等数据库收录！ | |