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

近年来，热电材料的开发和热电器件的制备技术取得了很大的进步，人们为扩大热电材料的应用范围做了大量的工作。另一方面，微机械、微型计算机和CPU在各种便携式产品中得到了广泛的应用。这些发展趋势对小型化电源或局部冷却装置提出了特殊的要求，为了制造热电模块或热电装置，通常需要几种工艺过程。其主要工序包括热电材料的制备、切割、热电材料与电极的连接。如果我们需要一个大约几毫米大小的小模块，TE材料应该被切割得更小。这给高质量热电器件的组装带来了很大的困难，因为大多数热电材料都很脆，很难切割成很小的碎片，特别是对于那些在低温下使用的TE材料。 关于我们 温度为了解决这个问题，组装的小尺寸的颗粒和烧结模块应该是一个有效的选择。单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。采用脉冲喷孔喷射法（POEM）制备了Bi-Sb合金热电材料球等高精度单粒度颗粒。放电等离子烧结（SPS）和等离子体活化烧结（PAS）是块体热电材料烧结连接的有效方法。但是从使用直流电的角度来看，SPS很难用于微细颗粒的烧结。用普通电炉也可以制备出烧结均匀的热电颗粒，但是我们发现其微观结构很难控制，而且需要很长的时间。本课题旨在开发一种有效的烧结单粒径热电颗粒的制备方法，并对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，放电烧结单粒径热电颗粒具有较好的性能，我们认为每秒5瓦的放电条件使热电性能达到平衡的高水平。放电烧结的Seebeck法的结果为82 μ V/K左右，接近于块体实用Bi-Sb合金的数值。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