PbTe基热电器件的界面优化和性能研究

RESEARCH ON INTERFACE OPTIMIZATION AND PERFORMANCE OF PBTE-BASED THERMOELECTRIC DEVICE

张中弛

11930064

硕士

材料工程

何佳清

2021

2021-06-11

南方科技大学

深圳

当今化石能源的短缺以及废热废气对环境的影响成为影响社会可持续发展的重要问题，热电器件因其固态、不需要排放废污气体、组成简单并且能把大量分散的废热变成电能等特点而受到科学家们重点研究。随着使用温度越高，高温下电极与材料之间会出现元素间的相互扩散和反应，这会严重增加界面处的接触电阻从而导致器件的性能变差。本课题以碲化铅基热电材料为基础，通过电镀的方式制备防止元素间相互扩散的阻挡层，通过测试添加不同阻挡层的碲化铅材料制备的器件的性能，来确定适合的阻挡层材料以及工艺参数。 （1）采用传统的放电等离子烧结的方式制备P型的Pb0.98Na0.02Te-2 %MgTe材料以及N型的Pb1.02Te0.94S0.04I0.02材料，P型在800 K下有最大的ZT为2.3，N型在750 K下有最大的ZT为1.5；采用装有铜电极的陶瓷基板将所制备好的P型和N型材料，制备成热电臂尺寸为2.0 mm×2.0 mm×7.5mm和4.0 mm×4.0 mm×11.5 mm的热电器件，高度为7.5 mm的器件在417 ℃的温差时有最大转换效率2.37 %；高度为11.5 mm的器件在317 ℃的温差时有最大转换效率1.88 %。（2）采用电镀Ni的方式制备热电材料的阻挡层，制备成热电臂尺寸为2.0 mm×2.0 mm×7.5 mm和4.0 mm×4.0 mm×11.5 mm的热电器件，高度为7.5 mm的器件在467 ℃的温差时有最大转换效率3.12 %；高度为11.5 mm的器件在467 ℃的温差时有最大转换效率4.18 %，将电镀Ni阻挡层的热电材料与Cu通过高温焊料焊接后，进行模拟器件测试时的环境与条件的时效实验，发现Ni层在477 ℃下保温1 h后，以完全被消耗，失去了阻挡层的作用。（3）采用电镀Co的方式制备热电材料的阻挡层，制备成热电臂尺寸为2.0 mm×2.0 mm×7.5 mm和4.0 mm×4.0 mm×11.5 mm的热电器件，高度为7.5 mm的器件在高温下电阻提高的斜率趋近于直线；高度为11.5 mm的器件在517 ℃的温差时有最大转换效率5.02 %。将电镀Co阻挡层的热电材料与Cu通过高温焊料焊接后，进行模拟器件测试时的环境与条件的时效实验，发现Co层在527℃下保温一小时后，焊接界面仍保持较好，仍有阻挡层的作用。

Today’s shortage of fossil energy and the impact of waste heat and waste gas on the environment have become important issues affecting the sustainable development of society. Thermoelectric devices are solid, not need to emit waste gas, have simple composition, and can turn a large amount of dispersed waste heat into the characteristics of electric energy have been emphatically studied by scientists. With the higher the temperature, the better the performance of the material, and the performance of the device should get better, but at high temperature, the interface between the electrode and the material will appear inter-diffusion and reaction between elements, which will seriously increase the interface resistance at the interface. As a result, the performance of the device deteriorates. This topic is based on lead telluride-based thermoelectric materials, prepares barrier layers to prevent inter-diffusion of elements through electroplating, prepares thermoelectric devices by reflow soldering, and tests the devices made of lead telluride materials with different barrier layers. Performance, to determine the appropriate barrier material and process parameters. (1) The traditional spark plasma sintering method is used to prepare P-type Pb0.98Na0.02Te-2 %MgTe material and N-type Pb1.02Te0.94S0.04I0.02 material The P-type has the largest value at 800 K, ZT 2.3, N-type has the largest ZT 1.5 at 750 K; using a ceramic substrate equipped with copper electrodes, the prepared P type and N type materials will be prepared into thermoelectric power generation devices with thermoelectric arm dimensions of 2.0 mm×2.0 mm×7.5 mm and 4.0 mm×4.0 mm×11.5 mm. The device with a height of 7.5 mm has a maximum conversion efficiency of 2.37 % at a temperature difference of 417 ℃; the device with a height of 11.5 mm has a maximum conversion efficiency of 1.88 % at a temperature difference of 317 ℃. (2) The barrier layer of thermoelectric material is prepared by electroplating Ni, and prepared into thermoelectric power generation devices with thermoelectric arm dimensions of 2.0 mm×2.0 mm×7.5 mm and 4.0 mm×4.0 mm×11.5 mm. The device with a height of 7.5 mm is at 467 ℃ The maximum conversion efficiency is 3.12 % when the temperature difference is higher; the maximum conversion efficiency of the device with a height of 11.5 mm is 4.18 % when the temperature difference is 467 ℃. After the thermoelectric material of the electroplated Ni barrier layer and Cu are welded through high temperature solder, the simulation device test is performed According to the aging experiment of the environment and conditions, it was found that the Ni layer was completely consumed after being kept at 477 °C for 1h and lost its function as a barrier. (3) The barrier layer of thermoelectric materials is prepared by electroplating Co, and prepared into thermoelectric power generation devices with thermoelectric arm dimensions of 2.0 mm×2.0 mm×7.5 mm and 4.0 mm×4.0 mm×11.5 mm. The height of the device is 7.5 mm under high temperature. The slope of the resistance increase approaches a straight line; the device with a height of 11.5 mm has a maximum conversion efficiency of 5.02 % at a temperature difference of 517 ℃. After welding the thermoelectric material of the electroplated Co barrier layer with Cu through high-temperature solder, an aging experiment was performed to simulate the environment and conditions of the device test. It was found that after the Co layer was kept at 527 °C for one hour, the soldering interface was still maintained well, and kept its function as a barrier.

碲化铅 电镀 阻挡层 器件

Lead telluride electroplate barrier layer device

中文

独立培养

南方科技大学

张中弛. PbTe基热电器件的界面优化和性能研究[D]. 深圳. 南方科技大学,2021.