热电材料塞贝克系数测试仪研制

为避免热电材料在高温测试过程中被氧化,基于塞贝克效应(Seebeck effect)设计一种在真空高温环境下测试热电材料Seebeck系数的新型装置。装置主要包括真空系统、样品支架系统和控制总成3部分。该新型装置成本低廉,易于操作,其应用不但可以有效防止高温环境中样品测试的氧化现象,而且可以在高温真空环境下准确、快速地测量样品的Seebeck系数。     

热电材料塞贝克系数测试影响因素研究

为提高热电材料塞贝克系数的测试准确度,以康铜合金、钴酸钙、碲化铅、氧化锌等典型块体热电材料为测试对象进行一系列测试,研究测温热电偶的塞贝克效应、温差设置、数据处理方式对塞贝克系数测试的影响。结果表明:热电偶的塞贝克效应对Seebeck系数测试准确度的影响是显著的;样品两端温差设置在5~20℃之间,直线拟合方式采用不过原点拟合,可以使Seebeck系数测试结果的准确度得到大幅提高。     

热电材料塞贝克系数测试影响因素的研究

为提高热电材料塞贝克系数的测试准确度,主要以康铜合金和钴酸钙为测试对象进行了一系列测试,其中以典型的碲化铋、方钴矿、硒化铅块体热电材料为辅助研究对象,具体研究测温热电偶的塞贝克效应、温差设置、数据处理方式对塞贝克系数测试结果的影响。结果表明:热电偶的塞贝克效应对Seebeck系数测试准确度的影响是显著的;样品两端温差设为10K以上,多组温差间的梯度设为3K以上,直线拟合方式采用不过原点拟合,可以使Seebeck系数测试结果的准确度得到很大提高。     

热电材料塞贝克系数的不确定度评定

热电材料是一类可以将热能和电能直接相互转化的新型功能材料.塞贝克系数作为评价热电材料性能的重要参数,其准确测量尤为关键.基于准确测量方法,建立了塞贝克系数的溯源路径,研究了塞贝克系数测量仪器的溯源性,验证了测量方法的准确性,以P型碲化铋Bi2Te3块体热电材料作为测量对象进行了测量不确定度评定,其相对扩展不确定度为0....     

一种测量低温导热系数 电阻率和热电势的装置

低温下固体材料的导热系数、电阻率和热电势是三个重要的物性参数。精确而快速测量上述参数一直是人们所关心的问题。本文介绍一种能测量低温下固体材料(特别是金属材料)的导热系数、电阻率和热电势的装置。该装置主要由低温量热器和电子测量控制系统两大部分组成,包括试样、测温夹具、热汇和试样加热器、可控温热补偿屏、真空腔、内杜瓦及计算机数据采集与打印系统等。试样的长度可变化(30～80mm),截面积也可变化(0.1～6cm~2)。它可以测量零点几到数千W/m·K不同导热系数的材料。只要在内杜瓦中充装LN_2、LH_2、LHe,就可以测量从这些液化气体温度到室温范围的上述三个物性     

温差发电的热力过程研究及材料的塞贝克系数测定

建立了半导体温差发电器件的基本模型；从稳态的热传导方程出发，对发电器件进行了热力学分析，推导出P型和N型半导体内部的温度分布函数及输出功率和发电效率的表达式；测定了一种Bi-Te-Sb-Se半导体热电材料在低温下的塞贝克系数随温度的变化关系，绘制了曲线并进行数值拟合；结果表明，该种半导体热电材料在低温下性能不佳，需改进配方或生产工艺方可使用。     

锰硅化合物的制备及塞贝克效应

过渡金属高锰硅化合物MnSi1.7作为半导体和难熔金属硅化物,具有热电应用的前景.尽管对Mn-Si1.7热电材料的研究已进行多年,但若要实现商业化应用,在制备和性能优化等方面还有很多问题需要解决.本文利用高温烧结的方法,在氮气氛保护下成功地制备出了锰硅块材化合物,研究了样品中所含的相结构及其所占比例(特别是MnSi1.7相)与烧结温度、保温时间的关系及它们对热电性能的影响.实验发现,Mn-Si1.7相所占的比例随着烧结温度的升高和保温时间的增加而增加,但材料的塞贝克系数在增大到某一饱和值后就不再增加了.     

热电材料塞贝克系数的测量研究

热电材料是一类可以将热能和电能直接相互转化的新型能源材料,已广泛应用于温差发电和制冷领域,塞贝克系数是评价热电材料性能的重要参数,其准确测量尤为关键。总结了塞贝克系数的测量误差和准确测量的影响因素,并验证了建立的测量方法的准确性。     

低温导热系数测量的影响因素

结合一个棒状试样导热系数测试装置,研讨了在低温导热系数测试中的影响因素,提出了一些减少误差的方法。     

Performance of Bi–Te–Sb–Se Thermoelectric Material at Low Temperature

Thermoelectric materials are of interest for applications as heat pump and power generators. The performance of a thermoelectric material, the figure of merit, ZT, is measured. The figure of merit is interrelated to the thermal conductivity, electrical conductivity, and Seebeck coefficient. All of these parameters are functions of temperature. The performance of a Bi–Te–Sb–Se thermoelectric material at low temperature was studied experimentally in this work. Based on the experimental results, the relation between various parameters and temperature, and the figure of merit are reported. The conclusions indicate that this thermoelectric material is not suitable for power generation at low temperature, and only an improvement of production technology or the development of a new production method can improve the electrical power generation performance with this method.Paper presented at the Seventh Asian Thermophysical Properties Conference, August 23–28, 2004, Hefei and Huangshan, Anhui, P. R. China.     

Thermoelectric Effects of Nanogaps between Two Tips

This study designs a microscaled thermoelectric component featuring a nanogap of varying size (133–900 nm) between the tips of the component. Electricity and heat are transmitted between the gap of the tips through the thermionic emission of electrons. Because the gaps exhibit a discontinuous structure, the phonon's contribution to thermal conductivity can be virtually neglected, thereby enhancing the thermoelectric figure of merit (ZT) of the designed thermoelectric component. The experimental results reveal that a narrow tip gap generates stronger thermoelectric effects, with Seebeck voltage and Seebeck coefficient being respectively, one and two orders of magnitude greater than those of the thermoelectric effects of nanowires. The thermoelectric figure of merit without considering the contributions from other heat carriers is higher than the value of thermoelectric devices developed in recent years. For a set of asymmetrical thin film electrodes of differing sizes, the thermoelectric effects generated in the heating process of large thin films are stronger than those of small thin films. Furthermore, adding nanoparticles to the nanogap facilitate the thermionic emission of electrons, in which electrons hop from the hot end to the cold end, thereby intensifying the thermoelectric effects of the nanogap.     

半导体热电材料研究进展

本文从讨论热电材料的性能出发 ,讨论了提高半导体热电性能的主要途径 ,介绍了主要的半导体热电材料特别是近年来的进展情况 ,展望了其应用前景 ,并提出了亟待解决的问题。     

热电材料的研究现状及发展

随着能源的日益紧缺以及环境污染问题的日趋严重,热电材料作为一种热能和电能相互转换的功能材料受到人们的重视.系统阐述了传统热电材料和新型热电材料的研究现状,介绍了各系列热电材料的热电性能及适用范围等,指出了其今后的发展方向.     

Statistical Analysis of a Round-Robin Measurement Survey of Two Candidate Materials for a Seebeck Coefficient Standard Reference Material

In an effort to develop a Standard Reference Material (SRM™) for Seebeck coefficient, we have conducted a round-robin measurement survey of two candidate materials—undoped Bi₂Te₃ and Constantan (55 % Cu and 45 % Ni alloy). Measurements were performed in two rounds by twelve laboratories involved in active thermoelectric research using a number of different commercial and custom-built measurement systems and techniques. In this paper we report the detailed statistical analyses on the interlaboratory measurement results and the statistical methodology for analysis of irregularly sampled measurement curves in the interlaboratory study setting. Based on these results, we have selected Bi₂Te₃ as the prototype standard material. Once available, this SRM will be useful for future interlaboratory data comparison and instrument calibrations.