区熔制备BiTe基温差电材料工艺研究

Study on preparing BiTe-based thermoelectric materials by zone melting method

区熔法是被广泛采用的制备BiTe基温差电材料的方法。针对批量生产中的区熔温度和温度梯度进行了一系列的实验研究,并对所获得的材料样品的电导率、塞贝克系数及功率因子进行了测试与分析,以了解材料的温差电性能;采用扫描电子显微镜(SEM)观察材料的微观结构;分段密度测试,以分析材料的均匀性。实验结果表明,在确定区熔速率和熔区宽度的前提下,适当的升高区熔温度并使材料生长过程中存在一定的温度梯度有益于提高材料的温差电性能。通过本实验得到在熔区宽度15mm、区熔走速30mm/h时的最佳区熔温度为800,850℃。

Zone-melting method is used widely to prepare BiTe based thermoelectric materials. Zone-melting temperature and temperature gradient were carried out by a series of experiments. Thermoelectric performances of the materials, including electrical conductivities, Seebeck coefficients and power factors were tested and analyzed. Morphology of the samples was observed by SEM. Different positions of the sample were measured in order to analyze uniformity. The results show that it is favored to increase zone-melting temperature and keep proper temperature-gradient at the determined zone-melting velocity and width of melting region. The best zone-melting temperature at melting-zone extent 15 mm, 30 mm/h is 800, 850℃.