Research on multi-layer type of Peltier cooling micro-devices by assembling thermoelectric particles

近年来，新型热电材料的开发和热电器件的制造技术取得了很大的进步，并为扩大热电的应用做出了很大的努力。另一方面，微型机械、微型计算机和CPU在各种便携式产品中得到了广泛的应用。这些趋势对小型电源或局部冷却装置提出了特定的要求。为了制造一个热电组件或一个装置，通常需要几道工艺工序。主要包括热电材料的制备、切割、TE材料与电极的连接。如果我们需要几毫米大小的小模块，TE材料应该切割得更小。这将给组装高质量的热电器件带来很大的困难，因为大多数热电材料都是脆性的，很难被切成很小的块，特别是对于那些在低t…下使用的TE材料更多的温度。为了解决这一问题，将单一尺寸的小颗粒和烧结模块组装在一起是一种有效的选择。单一尺寸颗粒的组装技术也可以很容易地应用于组成功能梯度热电器件或其他结构。采用脉动孔板喷射法制备了包括热电材料球在内的高精度单颗粒BiSb合金。对于块体热电材料的烧结和连接，放电等离子烧结(SPS)和等离子体活化烧结(PAS)是有效的方法。SPS很难用于超细颗粒的烧结，但从直流电的角度来看。用普通电炉也可以制备单一尺寸的烧结热电粒子，但其微观结构难以控制，耗时较长。本项目旨在开发一种有效的烧结单尺寸热电颗粒的制备方法，并对通过放电烧结制备微型热电器件进行了一些探索。表征结果表明，放电烧结的单尺寸颗粒具有较好的性能，我们认为在5W/s的放电条件下，使热电性能达到了平衡的高水平。室温放电烧结的塞贝克结果约为82μV/K，与块体实用的BiSb合金接近。较少

Recent years, technology on development of new thermoelectric (TE) materials and fabrication of thermoelectric device has been made much progress and many efforts are made to extend the application of thermoelectric. On the other hand, micro-machine, microcomputer and CPU have been used in a lot of field in various portable products. These trends make a specific request for small-sized electric source or for local cooling device.In order to fabricate a thermoelectric module or a device, usually several technique processes are needed. The main procedures include preparation of thermoelectric materials, cutting, joining of TE material with electrode. If we need a small module that is required about the size of several millimeters, the TE material should be cut smaller. This will make a lot of difficulties for assemble a high quality thermoelectric device since most thermoelectric materials are brittle and hard to be cut in very small pieces especially for TE materials those used at low t … More emperature. To solve this problem, assembly of small monosized particles and a sintered module should be an effective choice. The assembling technique for monosized particles can also be easily applied to compose a functionally graded thermoelectric device or other structures. The authors have prepared high accuracy monosized particles including thermoelectric materials balls of Bi-Sb alloy by pulsated orifice ejection method (POEM). These enable us to do the research of assembling and sintering process of monosized particles.For sintering and joining of bulk thermoelectric materials, the method of spark plasma sintering (SPS) and plasma activated sintering (PAS) are effective processes. The SPS is difficult to use to the sintering of micro particles but in the view of using direct current. The preparation of sintered monosized thermoelectric particles is also can be done by a normal electric furnace, however, we found it is very difficult to control the microstructure and it takes long time. The project is take the aim at developing of an effective method for preparing of sintered monosized thermoelectric particles, and makes some approach to compose micro-thermoelectric device through the discharge sintering.The characterization results indicate that the discharge-sintered monosized particles shows better properties compared with others, and we consider the condition of electric discharge at 5 watt per second led the thermoelectric properties to a balanced high level. The result of Seebeck at room temperature for discharge sintering is around 82 μ V/K, it is near value from the bulk practical Bi-Sb alloy. Less