The maximal power outputs of 37 . 0 mw / cm2 and 30 . 0 mw / cm2 for the p - and n - type laminated materials respectively at the temperature difference 490 have been experimentally obtained , which are about 2 . 5 and 3 . 0 times those of - fesi2 . chemical analyses show that the interface failure between the bridge alloy and the semiconductor bi2te3 results mainly from the eutectic mixtures with low melting point and brittle compounds formed during welding and long time annealing at 190 . it is found that the electrical properties of a laminated structure are mainly controlled by the wettability of the bridge alloy on the semiconductor surface 发现： 1 )叠层材料具有明显优于均质材料的热电性能，在490温差下， p -型和n -型叠层材料的最大输出功率分别达到37 . 0和30 . 0 ( mw / cm ~ 2 ) ，是同类型均质- fesi _ 2的2 . 5和3倍； 2 )在焊接过程和190长时间退火处理过程中，焊接过渡层合金和基体半导体(特别是bi _ 2te _ 3 )之间存在明显的元素相互扩散，从而在过渡层中形成一些低熔点共晶体和脆性化合物，这是导致叠层材料破坏的主要原因； 3 )焊接过渡层合金与半导体基体之间的润湿性是影响界面层电性能的主要因素。
The open voltages and power outputs of graded materials are much higher than monolithic materials , and when the length was kept at 15 : 2 , the maximum values were achieved . the measured maximum power outputs of graded materials is about 320 wm " 2 when the loaded is fixed at 0 . 1 , which is about 1 . 8 times than that of cosbj compounds ( 178wm " 2 ) Sb :热电材料具有最大的开路电压输出和功率输出;梯度热电材料bizte3 / cosb3在外界负载为0 . iq时的功率输出约为32owm “ ，约为均质材料cosb3功率输出178wm一2的1
In this paper , firstly , monolithic materials cosb3 and bi2te3 were prepared by sparkle plasma sintering ( sps ) respectively , and at the same time the microstructure of cosb3 and bi2te3 were studied by sem ; the seebeck coefficients and electrical conductivities of monolithic materials were measured by standard - four - probe method ( ulvac zem - 700 ) in a he atmosphere simultaneously , and their thermal conductivities were investigated by laser flash method ( tc - 7000 ) in vacuum . secondly , the junction temperature of graded bi2te3 / cosb3 thermoelectric materials was optimized based on the thermoelectric transport properties of monolithic materials , also when graded materials were used in the temperature difference ranging from 300k to 800k , the length ratio of monolithic materials cosb3 and bi2te3 were optimized in theory . thirdly , graded bi2te3 / cosb3 thermoelectric materials were prepared by two - step sps sintering , and the relationship between its average seebeck coefficients and temperature were calculated by theory mo del 均质材料cosb _ 3和bi _ 2te _ 3的电导率和seebeck系数采用标准四端子法于he气氛下在zem - 1上同时进行测量；热导率采用激光微扰法( tc - 7000 )于真空状态下进行测量；其次，在对均质材料cosb _ 3和bi _ 2te _ 3热电传输特性研究的基础上，对结构梯度bi _ 2te _ 3 cosb _ 3热电材料的界面温度进行了优化；为了使结构梯度bi _ 2te _ 3 cosb _ 3热电材料在300k至800k的温度范围内具有最佳的热电性能，本研究同时对梯度结构热电材料当中均质材料cosb _ 3和bi _ 2te _ 3材料的长度进行了优化设计；第三，通过两步放电等离子烧结的方法制备出了结构梯度bi _ 2te _ 3 cosb _ 3热电材料；采用理论计算的方法研究了梯度结构热电材料平均seebeck系数和温度的关系；同时为了验证设计的结果，本论文对结构梯度bi _ 2te _ 3 cosb _ 3热电材料的开路输出电压和热端温度之间的关系及梯度材料在300k至800k的温度范围内使用时的功率输出进行了相应的研究。
