High Pressure Preparation Of In Filled (Te,Se) Replacement Pyroelectric Materials Of Skarnite

In this thesis,the composite doped CoSb₃-based thermoelectric materials were prepared by atom filling and replacement under the method of high temperature and high pressure,and the samples we synthesized were tested by XRD,SEM,Seebeck coefficient,resistivity and thermal conductivity.We optimized the performance of the material by changing the experimental pressure,the proportion of doping elements and the temperature.The experimental results show that the high temperature and high pressure can quickly adjust and shorten the synthesis time,simplify the procedure,preserve the high pressure characteristics of the ambient pressure,and effectively reduce the thermal conductivity of the material.In addition,atomic doping can also reduce thermal conductivity.The experimental results obtained in this paper are as follows:（1）In_xCo₄Sb_11.4Te_0.6（x=0.2,0.4,0.5）was prepared by replacing the samples with Te filled In and adjusting the filling proportion of In element.According to the experimental test results,the absolute value of Seebeck coefficient showed an overall rising trend within a certain range of synthetic pressure.This shows that the synthesis method of high temperature and high pressure can effectively change the carrier concentration of the sample,thus significantly improving the thermoelectromotive force.The maximum absolute value of Seebeck coefficient at room temperature is 178.60μVK^-1 for In_0.4Co₄Sb_11.4Te_0.6 at the synthetic pressure of 3.0 GPa.The maximum power factor of In_0.2Co₄Sb_11.4Te_0.6 was 27.54μWcm^-1K^-2 when the synthetic pressure was 1.0 GPa.（2）The In_yCo₄Sb_12-xSe_x（x=0.4,y=0.1,0.2,0.5;x=0.5,0.6,y=0.05,0.1）series samples.It is found that the thermal conductivity of In_0.5Co₄Sb_11.95Se_0.05 reaches the minimum value of2.26 Wm^-1K^-1 at 573.15 K and the maximum value of z T is 1.25 at 723.15 K when the synthetic pressure is 1.5 GPa.At the synthetic pressure of 3.0 GPa and temperature of 773.15K,the minimum resistivity of In_0.6Co₄Sb_11.9Se_0.1 is 2.46 m（?）·cm.The lowest thermal conductivity of In_0.6Co₄Sb_11.9Se_0.1 was 1.61 Wm^-1K^-1 when the temperature was 473.15 K.（3）Finally,we carried out In filling and Te and Se double substitution for Co Sb₃,the experimental results showed that the synthetic pressure is 3.5 GPa,sample In_0.5Co₄Sb_11.35Se_0.05Te_0.6Seebeck coefficient value of the maximum value of 173.30μVK^-1;In synthesis pressure is 2.0 GPa,sample In_0.5Co₄Sb_11.35Se_0.05Te_0.6 the resistivity of the minimum value of 0.85 m（?）·cm;In synthesis pressure is 3.5 GPa sample In_0.6Co₄Sb_11.35Se_0.05Te_0.6 maximum of power factor to achieve this 30.03μWcm^-1K^-2,by Te,Se replacement make samples（2）described in the series of electrical transport properties has been further optimized.