Long-term stability of phase-separated half-Heusler compounds. Issue 44 (21st October 2015)

• Record Type: Journal Article
• Authors: Krez, J.; Balke, B.; Ouardi, S.; Selle, S.; Höche, T.; Felser, C.; Hermes, W.; Schwind, M.
• Is Part Of: Physical chemistry chemical physics. Volume 17:Issue 44(2015)
• Page Start: 29854
• Page End: 29858
• Publication Date: 2015-10-21
• Subjects: Chemistry, Physical and theoretical -- Periodicals; 541.3
• DOI: 10.1039/c4cp04875j
• Languages: English
• ISSNs: 1463-9076

Abstract

Abstract : The long-term stability of n- and p-type thermoelectric half-Heusler materials is investigated. The dendritic microstructure is temperature resistant and maintained the low thermal conductivity values ( κ < 4 W m −1 K −1 ) even after 500 heating and cooling cycles. Abstract : Half-Heusler (HH) compounds have shown high figure of merit up to 1.5. Here, we address the long-term stability of n- and p-type HH materials. For this purpose, we investigated HH materials based on the Ti0.3 Zr0.35 Hf0.35 NiSn-system after 500 cycles (1700 h) from 373 to 873 K. Both compounds exhibit a maximum Seebeck coefficient of | α | ≈ 210 μV K −1 and a phase separation into two HH phases. The dendritic microstructure is temperature resistant and upon cycling the changes in the microstructure are so marginal that the low thermal conductivity values ( κ < 4 W m −1 K −1 ) could be maintained. Our results emphasize that phase-separated HH compounds are suitable low cost materials and can lead to enhanced thermoelectric efficiencies beyond the set benchmark for industrial applications.