文章信息/Info

Title:

Preparation and Thermoelectric Properties of Micro-Nanostructured Yb0.3Co4Sb12

作者:

吳興國; 周蓓瑩; 周振興; 沈宏偉; 王連軍; 江 莞

東華大學材料科學與工程學院 纖維材料改性國家重點實驗室

Author(s):

WU Xingguo;  ZHOU Beiying;  ZHOU Zhenxing;  SHEN Hongwei;  WANG Lianjun;  JIANG Wan

State Key Laboratory for Modification of Chemical Fibers and Polymer Materials,
College of Materials Science and Engineering, Donghua University

關鍵詞:

熱電材料; 塊體Yb0.3Co4Sb12; 高能球磨; 納米級粉體; 熱電性能

DOI:

10.7502/j.issn.1674-3962.2016.01.09

文獻標志碼:

A

摘要:

采用熔融法結合SPS燒結技術制備了不同Yb含量摻雜的CoSb3塊體熱電材料，當Yb含量為0.3時，其熱電性能最佳，ZT值在800 K達到了1.19。隨后采用高能球磨技術，對熔融法合成的Yb0.3Co4Sb12粉體進行球磨得到納米尺度粉體，利用SPS燒結技術制得Yb0.3Co4Sb12塊體熱電材料。采用X射線衍射（XRD）、場發射掃描電鏡（FESEM）、透射電鏡（TEM）、熱電測試裝置（ZEM-3）及激光熱導儀等儀器對樣品進行表征。XRD分析結果表明球磨后Yb0.3Co4Sb12粉體沒有發生相變和分解。從FESEM和TEM分析結果可以看出，球磨可以顯著細化粉體，SPS燒結之后樣品的晶粒尺寸小于500 nm，其中部分晶粒小于100 nm。通過對比球磨前后粉體SPS燒結樣品的熱電性能發現，晶粒尺寸減小之后塞貝克系數有一定程度的增加，熱導率下降明顯，降低了1/3，但是材料的電導率下降更為顯著，降低了10倍左右，因此導致材料最終的ZT值相應下降。

Abstract:

Yb-filled bulk CoSb3 skutterudites were prepared by melting method combining with Spark Plasma Sintering (SPS). Bulk Yb0.3Co4Sb12 compounds with superior thermoelectric properties（ZT=1.19,800 K） were achieved at last. Then high-energy ball milling was employed to prepare nano-sized particles. After that, the nano-sized Yb0.3Co4Sb12 particles were sintered by SPS apparatus to get bulk sample. Particle morphology and microstructure observation were performed by X-ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM) and Transmission Electron Microscopy (TEM). The thermoelectric properties of bulk materials were measured by ZEM-3 and LFA427. There were no decomposition and crystal form transition appeared after milling 10 h according to XRD patterns. The particle size decreased greatly according to FESEM and TEM observation and after sintering the grain size was ~500 nm and partly was less than 100 nm. Compared with the bulk without milling, the Seebeck coefficient after milling increased a little and thermal conductivity decreased 1/3. However, at the same time, the electrical conductivity decreased about 10 times so that the ZT of milled bulk Yb0.3Co4Sb12 decreased.