HIGH-EFFICIENCY TWO-PHASE HEUSLER THERMOELECTRIC MATERIALS

摘要

A thermoelectric material may be composed of an isostructural pair of Heusler compounds, either a pair of full Heusler (FH) X₂YZ compounds or a pair of half Heusler (HH) XYZ compounds. In the FH pair, a first compound of the pair may the formula (X1)₂Y1Z1, wherein X1 is selected from Fe and Co; Y1 is selected from Ti, V, Nb, Hf, and Ta; and Z1 is selected from Al, Ga, Si, and Sn and a second compound of the pair has the formula (X2)₂Y2Z2, wherein X2 is selected from Mn, Fe, Co, Ru, and Rh; Y2 is selected from Ti, V, Mn, Zr, Nb, Hf, and Ta; and Z2 is selected from Be, Al, Ga, Si, Ge and Sn. The first and second compounds of the pair may share two elements in common and have third elements which are different and are either isovalent or have a valency which differs by ±1. In the HH pair, a first compound of the pair may have the formula X1Y1Z1 wherein X1 is selected from Ni and Fe; Y1 is selected from Ti, V, and Nb; and Z1 is selected from Sn and Sb and a second compound of the pair has the formula X2Y2Z2 wherein X2 is selected from Fe, Ru and Pt; Y2 is selected from Ti, V, and Nb; and Z2 is selected from Sn and Sb. The first and second compounds of the pair may share two elements in common and have third elements which are different and are either isovalent or have a valency which differs by ±1. The thermoelectric material at room temperature may have a nanostructured two-phase form having a matrix phase composed of the first compound of the FH pair or the first compound of the HH pair and a nanostructured phase composed of the second compound of the FH pair or the second compound of the HH pair, respectively.