The Preparation Research Of Bi₂Te₃ And NaGaSn₂ Thermoelectric Materials By High Energy Ball Milling And Spark Plasma Sintering?HEBM+SPS?

Thermoelectric materials are the use of solid internal carriers to achieve the role of electricity and heat conversion of the thermoelectric materials,which has a wide using prospects in waste heating.The performance of the thermoelectric material is determined by the dimensionless figure of merit,and the ZT value of the material is closely related to its Seebeck coefficient,thermal conductivity and electrical conductivity.A good kind of thermoelectric material has a high Seebeck coefficient,high conductivity and low thermal conductivity.This article mainly explores the three aspects:First,the preparation of bismuth telluride thermoelectric material by high energy ball milling and spark plasma sintering method?HEBM+SPS?;Second,the preparation research of Bi_0.48Sb_1.52Te₃ composited by Mn_0.8Cu_0.2Sb₂Se₄ by HEBM+SPS;Third,the effect of HEBM+SPS process on crystallinity and thermoelectric properties of NaGaSn₂.The main contents are as follows:First,Bi₂Te(_3-x)Se_x samples with different Se doping ratios were prepared by high energy ball milling and spark plasma sintering process?HEBM+SPS?.The effects of different doping ratios on the performance of the samples were investigated.It is found that the particle size of the sample obtained by this method is small and there is no obvious preference orientation.The thermoelectric properties of the sample have obvious regularity with the increase of Se doping amount.The ZT value of the sample was 0.65 when the doping amount was 0.5.Second,Bi_0.48Sb_1.52Te₃ samples with xmol%Mn_0.8Cu_0.2Sb₂Se₄ were prepared by HEBM+SPS method.The results show that the performance of the composite is better than that of the matrix Bi_0.48Sb_1.52Te₃.The thermoelectric properties of the samples are improved after doping,and the best performance appeared when x=2,in this case the ZT value is 1.46,which is 40%higher than that of the matrix samples.Finally,the effect of spark plasma sintering on the crystallinity of NaGaSn₂thermoelectric materials was investigated.The results show that the preparation process of NaGaSn₂ has a great effect on the purity of NaGaSn₂.Both sintering time and cooling process have played important role in the the purity of NaGaSn₂,among them,the best effect of liquid nitrogen quenching is the best,at this sistution the purity up to 85%.Compared with the two preparation techniques,the technological advantages of this paper are that the preparation cycle is shortened and the process is simple,the density is higher and the thermal conductivity of the sample is significantly reduced.