Preparation And The Thermoelectric Properties Of The Bi₂Te₃ Based Pseudo-ternary Thermoelectric Materials

Thermoelectric materials is called temperature electric materialswhich can realize transition between electricity and heat directly.Bi₂Te₃-based pseudo-ternary thermoelectric material is one of the best thermoelectric performance materials at room temperature.We prepared n-type pseudo-ternary alloy powder by mechanical alloying method , which based on the development of domestic and foreign thermoelectric materials . We prepared the pseudo ternary alloy bulk materials doped with Er by sintering and cold pressing sintering.And we Analysis microstructure of the pseudo-ternary alloys Er-doped materials by mechanical alloying powder by SEM and XRD. We study the Er doping concentration and preparation technology parameters on the material properties effective by the test block material thermoelectric performance. We improve and enhance the thermoelectric properties of Bi₂Te₃ based on n-type pseudo-ternary Er-doped mechanical alloying power. In addition to, we prepared n-type Bi₂Te₃ base pseudo-ternary more crystalline material by metal type unidirectional solidification process of.And we Analysis microstructure of the pseudo-ternary alloys Er-doped materials by mechanical alloying powder by SEM and Electrical properties test. Studies show that the directional solidification of metallic materials can improve the performance a lot.We mixed different concentration rare earth Er with high purity element Bi and Sb and Te and Se （purity p≥99.99%）. We successfully preparated n-type doped pseudo ternary alloying powder Er by mechanical alloying method. XRD analysis showed that elemental elements Bi, Sb, Te, Se and rare earth Er are achieved alloying by the 100h milled to achieve alloying; SEM analysis shows that crystal particles uniform change small ,Particle size is 5nm-50nm.We used n-type constraint ternary mixed Er mechanical alloying powder materials, to prepare n-type constraint ternary mixed mechanical alloying Er hot-pressing block material In different hot-pressing temperature,XRD analysis shows that hot-pressing samples of the main body of strong diffraction peak was shorter, the peak width of deformation d was larger.It shows that grain growth during hot-pressing process and the degree of crystal enhance.SEM analysis shows that the space inside hot-pressing samples decreased significantly decrease in the number of simultaneously and compact between grains with hot-pressing temperature increases.Thermal parameters analysis shows that thermoelectric properties is closely related to doping concentration and sintering temperature.Seebeck coefficient of the material is increased and then decreases with the doping concentration increases.which get its maximum when doping concentration is 0.5wt%.Seebeck coefficient and electrical conductivity of the material are increased with the increase of sintering temperature when range of hot temperature is 180²60℃.we prepared n-type pseudo doped Er MA cold pressing sintering material by cold pressing sintering,Thermoelectric performance test results indicate that cold sintering block thermoelectric performance is closely related to Er doping concentration and the sintering temperature and sintering time.We found that the material of the Seebeck coefficient and power factor are shown first increased and then decreased with the sintering temperature,Seebeck coefficient and power factor values are maximum in the sintering temperature of 450℃.Electrical conductivity showed the tendency of increase gradually with the sintering temperature rise.Seebeck coefficient of the material is decreases with increasing doping Er concentration in the sintering temperature is 450℃, the sintering time was 0.5h.Seebeck coefficient is maximum when doping concentration is 0.1wt% at the time,conductivity is increases with doping concentration increases.It has the best power factor when the content is 0.1wt% Er.Seebeck coefficient of the material is first increases and then decreases with the change of sintering time, Seebeck coefficient is maximum when the sintering time was 1h,The electrical conductivity and power factor have shown the trend of first decreases and then increases.Bi₂Te₃ based N-type Pseuo-ternary materials were prepared by directional solidification using metal mold method. And we compared with pseudo ternary solid by zone melting .The results of the study show that it can greatly shorten preparation time by directional solidification using metal mold method, and it has certain orientation of materials of the crystal growth, and increased material defects types, for example dislocation, transforminged. Little Fe Makes See consant decreased and increased...