The Research On The Influence Of Bismuth Film On Bi₂Te₃ Optimal Value Of Thermoelectric Materials

Semiconductor refrigeration,compared with the traditional refrigeration,has many advantages,such as:simple structure,cooling rapidly,without condensing agent,good adaptability,large range of refrigeration power and so on.At the beginning of the 20th century,semiconductor refrigeration technology attracted many scientists to study it.At present,semiconductor refrigeration technology plays an irreplaceable role in many aspects,such as biological engineering,medical and health,scientific research,military and so on.In the future,semiconductor refrigeration technology is an important development direction in the field of refrigeration,which has great potential for development,and has great impetus for promoting social development and improving people's life.This paper firstly summarizes the current status of semiconductor refrigeration technology and the problems in the development,and the trend of the development of semiconductor refrigeration in the future the simple discussion,then analyzes the thermoelectric coefficient of merit ZT values,which is the key factor that influence efficiency of semiconductor refrigeration,and the principle of thermoelectric refrigeration and currently the most widely application scope Bi2Te3 thermoelectric materials,as well as metal bismuth made roughly introduction.In this paper,Bi₂Te₃ was prepared by mechanical alloy method,and the selection of ball material ratio was 10:1.The ball grinding tank was made of stainless steel ball grinding tank.In the grinding tank,2.09gBi and 1.91gTe were used to prepare Bi2Te3.Samples of XRD spectrum analysis experiment,and the STA lindsay,thermal analyzer,the thermal-analysis of samples,determine the Bi₂Te₃ sample is obtained by mechanical alloying method and theory of Bi₂Te₃ physical properties,verify the feasibility of manufacturing Bi2Te3mechanical alloying method.Next,Bi₂Te₃ samples were electroplated bismuth film experiments,and the Bi₂Te₃ sample was coated with a metal bismuth film by electroplating solution.The mean diameter of bismuth on the surface of Bi₂Te₃ was calculated by using Scherrer equation.Finally through to the bismuth film plating Bi₂Te₃ sintering experiments and analyses the Seebeck coefficient and electrical resistivity and thermal conductivity and the relationship between the temperature and pressure,and it has made the analysis of mechanism,and finally determine the optimum sintering temperature is 750 k,the best pressure is 0.94 GPa,and then through the sintering of samples under different working temperature of thermal power optimal value coefficient of ZT value analysis and comparison,it is concluded that the sample of the largest thermal power optimal value coefficient was 1.22,compared with traditional Bi₂Te₃ material thermal power optimal value coefficient of 1.1,a larger increase,preliminary confirmed Bi₂Te₃ surface plating bismuth can improve the thermoelectric coefficient of optimal value,and put forward the follow-up prospects,by changing the preparation method of Bi₂Te₃ and bismuth film thickness change its surface to improve its thermal power optimal value coefficient.