Fabrication And Properties Of P-type PbTe-based Thermoelectric Material

With the continuous development of science and technology,people are not satisfied with the development of the near earth space,and become more and more interested in deep space exploration.Many countries have developed their own deep space exploration program,they ready to launch space probe to the moon,Mars and even Pluto.However,the natural environment of the deep space is very bad.For example,the time of moon night is about fourteen earth days,the temperature of moon night can reach-180?.Under these conditions,the general power supply,such as solar cells,chemical energy battery and so on are unable to work properly.Therefore,the energy supply of deep space probe has become a very important issue.The thermoelectric generator which use the radioactive isotope as the heat source,have the high specific power of mass(above 110Wh),long life(above 5 years),good environmental adaptability and high reliability.So the thermoelectric generator is suitable for be used in the deep space exploration.The properties of thermoelectric generator are mainly determined by the thermoelectric materials.Therefore,the research of thermoelectric materials has an important significance for the production of thermoelectric generator.P-type PbTe-based thermoelectric material is a kind of common middle temperature thermoelectric materials,it is widely used in deep space exploration,deep sea exploitation,waste heat power generation and pipeline cathodic protection.In order to improve the thermoelectric properties of P-type PbTe-based thermoelectric material,we have done a lot of work on the research of thermoelectric material preparation process.Thermoelectric material preparation technology is mainly divided into material mixing,material smelting,material grinding,material hot pressing and material annealing.We have analyzed these technology processes,and expounded the problems needing attention in the process.We also focus on the material hot pressing which is the key technology processe.Main technical parameters of the material hot pressing is hot pressing temperature and pressure.Through the adjustment of these parameters,we have prepared the thermoelectric material samples,and selected the best hot pressing parameters according to the results of the samples performance test.By using the final p-type PbTe-based thermoelectric material preparation technology,we fabricated thermoelectric materials and its performance is tested.The test result show that the dimensionless figure of merit ZT was 0.88.In addition,the material sample has passed 100 hours of high temperature creep test,which verifies its reliability.Through the research work of p-type PbTe-based thermoelectric material preparing technology,we are fully aware that preparing technology has great influence on the properties of the thermoelectric material,we also have a profound understanding for thermoelectric material preparing technology.These experiences have laid a solid foundation for the development of thermoelectric materials with better thermoelectric properties in the future.