Response of p-type and n-type Half-Heusler thermoelectric materials to fast neutron irradiation

The thermoelectric materials working in radioisotope thermoelectric generators or space reactor power system will be exposed to neutron irradiation in space missions . Herein, the influences of neutron irradiation with doses of 10 13 n/cm 2 and 10 15 n/cm 2 on the transport properties of p- and n-type Half-Heusler thermoelectric alloys were investigated. It was found that, neutron irradiation showed negative effects on thermoelectric properties of p-type Hf 0.5 Zr 0.5 CoSb 0.85 Sn 0.15 and p-type Hf 0.5 Ti 0.5 CoSb 0.85 Sn 0.15 . But neutron irradiation had no effects on thermoelectric properties of n-type Hf 0.5 Zr 0.5 NiSn 0.985 Sb 0.015 and n-type ZrNiSn 0.985 Sb 0.015 . After 10 15 n/cm 2 neutron irradiation, the electrical conductivity , power factor and ZT of p-type Half-Heusler alloys decreased by 7–22%, which was caused by the decreased carrier concentration. However, the radiation-induced changes in the thermoelectric properties proved to be essentially healed by annealing at 773 K ~ 873 K. The anti-annealing effects were also studied.