Study on the interface properties and thermal stability of PbTe/FeMn thermoelectric joint
The mechanical properties and thermal stability of Fe/PbTe thermoelectric joints are poor due to the mismatch of thermal expansion coefficient and mechanical interlocking interface connection.Considering the controllability of the thermal expansion coefficient of the alloy,specific active elements are added to Fe to form metallurgical bonding at the interface through diffusion and reaction,which can improve the interface bonding performance.In this paper,we selected Fe100xMnx(x=0,5,10,15)alloy as electrodes through high-through-put experiments and connected them with n-type Pb0.98 Ga0.02 Te using spark plasma sintering(SPS)technology.The results show that the thermal expansion coefficient of FeMn alloy becomes closer to that of Pb0.98Ga0.02 Te with the increase of Mn content,which effectively reduces the interface mismatch.The Fe-Pb-Ga element inter-diffusion layer appeared at the interface after aging 15 d,which demonstrating metallurgical bonding character-istics.The contact resistivity of Fe90Mn10/Pb0.98Ga0.02Te/Fe90Mn10 is 10.12 μΩ·cm2 after aging for 15 d.The conversion efficiency remains stable at about 4.3％.The shear strength increases to 21.44 MPa.Based on the high-throughput selection of alloy electrodes,the above technical route provides a new way to design the ther-moelectric interface.
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维普
