NaF掺杂的Ca_3Co_4O_9粉体制备及其热电性能研究  

STUDY ON THE PREPARATION AND THERMOELECTRIC PROPERTIES OF THE CA_3CO_4O_9 POWDERS DOPED WITH NAF

作　　者：翟向伟[1] 林逸榕[2] 仲洪海[1] 管其刚[1] 蒋阳[1] 程继贵[1] 

机构地区：[1]合肥工业大学材料科学与工程学院,安徽合肥230009 [2]合肥工业大学电气与自动化工程学院,安徽合肥230009

出　　处：《粉末冶金工业》2012年第3期16-20,共5页Powder Metallurgy Industry

基　　金：中国博士后科学基金资助项目(20100470827);合肥工业大学校博士后科学基金资助项目(103035037)

摘　　要：本文以CaCO3、NaF、Co(NO3)2.6H2O、HNO3为原料,去离子水为溶剂,柠檬酸为螯合剂,采用自蔓延法制备了NaF掺杂的Ca3Co4O9(Ca3-xNaxCo4O9-xFx)(x=0,0.05,0.1,0.15,0.2,0.25)粉体。粉末的XRD表明图谱中主要衍射峰是Ca3Co4O9的特征峰,有极小部分CaF2存在。粉体的粒度分布在1～100μm之间,平均粒径为11.276μm。烧结试样的SEM显示NaF的掺杂能促进烧结。在温度473～973K下,烧结体热电性能的测试结果显示,随NaF掺杂量的增加,电导率和Seebeck系数先升高后降低。加入20%NaF的Ca3Co4O9烧结体在973K时seebeck系数和功率因子达到最大值,分别为220μV/K和4.39×10-4 W/mK2。Abstract. The CaCO3、NaF、Co（NO3）2·6H2O、HNO3 （x = 0,0.05,0.1,0.15,0.2,0. 25 ） polycrystalline samples were prepared by a simple self-propagation route, using CaCO3, NaF, Co（NO3）2·6H2 O, and HNO3 as the raw material, de-ionized water as dissolvent and citric acid as chelating a- gent. The synthesized powders were analysed by XRD. The results indicate that there are a Ca3-xNaxCo4 O9-xFx phase and a little other phases generated in powders. The particle size of powder is from 1 μm to 100μm. The average particle size is 11. 276 μm. The microstructure of the sinted sample by SEM shows that the doping NaF can inhibit grain growth in the sin- tering process. The thermoelectric properties of Ca3-xNaxCo4 O9-xFx were carefully studied from 473 K to 973 K. The results exhibit that the electrical conduction and Seebeck coeffi- cients of Ca3-xNaxCo4 O9-xFx sample are first increased and then decreased with increasing NaF. The maximum Seebeck coefficients and the power factor of Ca3-xNaxCo4 O9-xFx（x=0.2） sample are 220μV/K and 4.39×10^-4 W/（m ·K） at 973 K respectively.

关 键 词：自蔓延法 Ca3-xNaxCo4O9--xFx 热电性能 

分 类 号：TN304[电子电信—物理电子学]