Feng Hangbin, Zhang Lixia, Zhang Jialun, Gou Wenqin, Zhong Sujuan, Zhang Guanxing, Geng Huiyuan, Feng Jicai
State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001, China.
Zhengzhou Research Institute of Mechanical Engineering, Zhengzhou 450001, China.
Materials (Basel). 2020 Mar 3;13(5):1130. doi: 10.3390/ma13051130.
CoSb-based skutterudite alloy is one of the most promising thermoelectric materials in the middle temperature range (room temperature-550 °C). However, the realization of an appropriate metallization layer directly on the sintered skutterudite pellet is indispensable for the real thermoelectric generation application. Here, we report an approach to prepare the metallization layer and the subsequent diffusion bonding method for the high-performance multi-filled -type skutterudite alloys. Using the electroplating followed by low-temperature annealing approaches, we successfully fabricated a Co-Mo metallization layer on the surface of the skutterudite alloy. The coefficient of thermal expansion of the electroplated layer was optimized by changing its chemical composition, which can be controlled by the electroplating temperature, current and the concentration of the Mo ions in the solution. We then joined the metallized skutterudite leg to the Cu-Mo electrode using a diffusion bonding method performed at 600 °C and 1 MPa for 10 min. The Co-Mo/skutterudite interfaces exhibit extremely low specific contact resistivity of 1.41 μΩ cm. The metallization layer inhibited the elemental inter-diffusion to less than 11 µm after annealing at 550 °C for 60 h, indicating a good thermal stability. The current results pave the way for the large-scale fabrication of CoSb-based thermoelectric modules.
基于CoSb的方钴矿合金是中温范围（室温至550°C）内最具前景的热电材料之一。然而，对于实际的热电发电应用而言，在烧结的方钴矿颗粒上直接制备合适的金属化层是必不可少的。在此，我们报道一种制备金属化层的方法以及随后用于高性能多填充型方钴矿合金的扩散连接方法。通过电镀并结合低温退火方法，我们成功地在方钴矿合金表面制备了Co-Mo金属化层。通过改变其化学成分对方镀层的热膨胀系数进行了优化，这可以通过电镀温度、电流以及溶液中Mo离子的浓度来控制。然后，我们使用在600°C和1 MPa下进行10分钟的扩散连接方法，将金属化的方钴矿腿与Cu-Mo电极连接起来。Co-Mo/方钴矿界面呈现出极低的比接触电阻率，为1.41 μΩ·cm。在550°C下退火60小时后，金属化层抑制元素间扩散至小于11 µm，表明具有良好的热稳定性。目前的结果为基于CoSb的热电模块的大规模制造铺平了道路。
