Abstract
Complex shapes are created from Yb14MnSb11, a high-temperature thermoelectric Zintl phase, via a two-step process: i) layer-by-layer 3D-extrusion of ink containing partially-reacted powders which are ball-milled from a blend of Yb, MnSb, and Sb powders; ii) heat treatment to synthesize the ternary compound Yb14MnSb11 and densify the extruded powders. A high phase purity for Yb14MnSb11 (83–94%) is achieved in both cast and 3D-extruded ink specimens via a solid-state reaction between Yb, MnSb, and Yb4Sb3 during reactive sintering. Pressure-free sintering at temperatures of 1200–1400 °C densifies the powders to 82% relative density but can also induce the decomposition of the Yb14MnSb11 phase due to Yb sublimation. A process window with optimized sintering temperature and time is identified, achieving both low porosity and high phase purity and reaching a maximum zT = 0.61 at 1000 °C, about half of the maximum zT value for bulk Yb14MnSb11 made via conventional processes (pressure sintering of precursor powders). The present approach – direct ink writing of ball-milled powders, combined with reactive sintering – is a scalable and affordable method to fabricate thermoelectric legs with intricate 3D shapes, for enhanced performances in high-temperature thermoelectric applications.
| Original language | English (US) |
|---|---|
| Journal | Advanced Functional Materials |
| DOIs | |
| State | Accepted/In press - 2024 |
| Externally published | Yes |
Funding
M.S., G.J.S., and D.C.D. are grateful for the financial support of the Department of Energy (via a subcontract from Aerojet Rocketdyne, Inc. (PO 200136011//DE\u2010EE0009104)). The authors thank L. Borgsmiller (Department of Materials Science & Engineering, Northwestern University) for insightful discussions and assistance with Yb shaving, MnSb synthesis, and thermoelectric properties measurements. The authors thank T. Abbott (NUANCE Center, Northwestern University) for assistance with SEM characterization, Dr. S. Kewalramani (Jerome B. Cohen X\u2010Ray Diffraction Facility, Northwestern University) for assistance with XRD measurements, Dr. C. D. Malliakas (IMSERC, Northwestern University) for assistance with TGA measurements. This work made use of the Jerome B. Cohen X\u2010Ray Diffraction Facility supported by the MRSEC program of the National Science Foundation (DMR\u20102308691) at the Materials Research Center of Northwestern University and the Soft and Hybrid Nanotechnology Experimental (SHyNE) Resource (NSF ECCS\u20101542205) and the IMSERC X\u2010Ray facility, which has received support from the Soft and Hybrid Nanotechnology Experimental (SHyNE) Resource (NSF ECCS\u20102025633), and Northwestern University (NU). This work also made use of the EPIC facility of Northwestern University's NUANCE Center, which has received support from the Soft and Hybrid Nanotechnology Experimental (SHyNE) Resource (NSF ECCS\u20101542205); the MRSEC program (NSF DMR\u20101720139) at the Materials Research Center; the International Institute for Nanotechnology (IIN); the Keck Foundation; and the State of Illinois, through the IIN. Part of this work was performed at the California Institute of Technology/Jet Propulsion Laboratory under contract with the National Aeronautics and Space Administration.
Keywords
- direct ink writing
- high-temperature thermoelectric material
- reactive sintering
- zintl phase compound
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- General Chemistry
- Biomaterials
- General Materials Science
- Condensed Matter Physics
- Electrochemistry