Phase Boundary Mapping in ZrNiSn Half-Heusler for Enhanced Thermoelectric Performance.

ABSTRACT: The solubility range of interstitial Ni in the ZrNi1+x Sn half-Heusler phase is a controversial issue, but it has an impact on the thermoelectric properties. In this study, two isothermal section phase diagrams of the Zr-Ni-Sn ternary system at 973?K and 1173?K were experimentally constructed based on the binary phase diagrams of Zr-Ni, Zr-Sn, and Ni-Sn. The thermodynamic equilibrium phases were obtained after a long time of heating treatment on the raw alloys prepared by levitation melting. Solubilities of x < 0.07 at 973?K and x < 0.13 at 1173?K were clearly indicated. An intermediate-Heusler phase with a partly filled Ni void was observed, which is believed to be beneficial to the lowered lattice thermal conductivity. The highest ZT?value~0.71 at 973?K was obtained for ZrNi1.11Sn1.04. The phase boundary mapping provides an important instruction for the further optimization of ZrNiSn-based materials and other systems.

SUBMITTER: Li X 

PROVIDER: S-EPMC7013278 | biostudies-literature | 2020

REPOSITORIES: biostudies-literature