n型Bi_(2)Te_(2.7)Se_(0.3)热电材料的冷烧结制备及其性能研究

Thermoelectric Properties of Cold Sintered n-type Bi_(2)Te_(2.7)Se_(0.3)

冷烧结技术(Cold Sintering Process,CSP)是一种利用辅助液相可使陶瓷在300℃以下达到致密的新型烧结技术,不仅操作简单、成本低廉,而且节能降耗,在制备块体热电材料方面有极大的前景。本文通过溶剂热法制备了Bi_(2)Te_(2.7)Se_(0.3)粉体,分别与0 wt%液相、10 wt%H2O、10 wt%EG、10 wt%NaOH溶液混合均匀,通过冷烧结方法制备了Bi_(2)Te_(2.7)Se_(0.3)块体热电材料,并与放电等离子烧结(SPS)所制备的样品作对比。XRD测试结果表明,所有样品均未被氧化,密度测试结果显示,冷烧结添加NaOH溶液或者H2O的样品的致密度高达97%左右,比添加0 wt%液相的样品高约7%。添加NaOH溶液的样品在375 K时具有最高的ZT值0.9,在较低温度段(300~400 K)比SPS所制备的样品的ZT值高。我们的研究表明,通过液相辅助的冷烧结技术制备Bi_(2)Te_(2.7)Se_(0.3)块体热电材料是一种非常有前途的方法。

The cold sintering process(CSP)is a new sintering technology which is able to densify ceramics below 300℃with the assistant liquid phase.CSP is not only simple to operate,low in cost,but also energy-saving and consumption-reducing,developing great prospects in preparing bulk thermoelectric materials.In this paper,Bi_(2)Te_(2.7)Se_(0.3)powder was prepared by a solvothermal method.The corresponding bulk was fabricated by CSP with the addition of 0 wt%liquid phase,10 wt%H2O,10 wt%EG and 10 wt%NaOH solution respectively,and then compared with the sample prepared by spark plasma sintering(SPS).XRD pattern shows that all samples are not oxidized by air.The density measurement results show that the density of samples added with NaOH solution or H2O is as high as about 97%,which is about 7%higher than that of sample added with 0 wt%liquid phase.Among all the samples prepared by CSP,the sample added with NaOH solution has the highest ZT value of 0.9 at 375 K,which is higher than that of the sample prepared by SPS from300 K to 400 K.Our results show that CSP is a very promising method to prepare Bi_(2)Te_(2.7)Se_(0.3)bulk thermoelectric material.