Research On The Fabrication Of PbTe Bulk Materials By Semisolid Powder Processing And Its Thermoelectric Properties

The research work was supported by the project entitled "Research on Stacked-Array Thermoelectric Generators and Its Fabrication Based on Semisolid Powder Microforming" from National Natural Science Foundation of China (Grant No.51175460). We have carried out some research on fabricating the n-type and p-type PbTe bulk thermoelectric materials by semisolid powder processing (SPP). Firstly, the semisolid powder processing method and the experimental equipment were introduced. Secondly, the n-type PbTe bulk thermoelectric materials were fabricated by SPP. The phase structures and microstructures of the SPP samples and their counterparts were analyzed. Then, the properties of the SPP samples and their counterparts were investigated. Based on these results, we introduced high energy ball milling method to prepare n-type PbTe nanoscale powders. The phase structures and microstructures of the n-type nanoscale powders milled in different periods were investigated. And also, the properties of the SPP samples fabricated from the finest powders were obtained. Finally, the p-type PbTe nanoscale powders were also prepared by high energy ball milling. The phase structures and microstructures of the p-type nanoscale powders were investigated. Then, the microstructures and properties of the p-type PbTe SPP samples fabricated from the nanoscale powders were obtained. We also compared their thermeoelctric performance with the samples in references fabricated by other methods.In Chapter 1, the background and significance of this research were introduced. Then, the current research situations of thermoelectric materials, their preparation and fabrication method were expatiated, and the research contents of this thesis were proposed.In Chapter 2, the semisolid powder processing method and the experimental equipment were introduced.In Chapter 3, the n-type PbTe bulk thermoelectric materials were fabricated by SPP. The phase structures and microstructures of the SPP samples and their counterparts were analyzed. Then, the properties of the SPP samples and their counterparts were investigated.In Chapter 4, we introduced high energy ball milling method to prepare n-type PbTe nanoscale powders. The phase structures and microstructures of the n-type nanoscale powders milled in different periods were investigated. And also, the properties of the SPP samples fabricated from the finest powders were obtained.In Chapter 5, the p-type PbTe nanoscale powders were also prepared by high energy ball milling. The phase structures and microstructures of the p-type nanoscale powders were investigated. Then, the microstructures and properties of the p-type PbTe SPP samples fabricated from the nanoscale powders were obtained. We also compared their thermeoelctric performance with the samples in references fabricated by other methods.In Chapter 6, the chief work of this thesis was summarized, and the further research works were proposed.