微波水热法制备KNbO_3粉体及其性能研究(英文)  

Study on Microwave-assisted Hydrothermal Synthesis and the Properties of KNbO_3 Powders

作　　者：秦波[1] 谈国强[1] 苗鸿雁[1] 夏傲[1] 程蕾[1] 

机构地区：[1]陕西科技大学教育部轻化工助剂化学与技术重点实验室,西安710021

出　　处：《无机材料学报》2011年第8期892-896,共5页Journal of Inorganic Materials

基　　金：National Natural Science Foundation of China(50872077);Natural Science Foundation Research Project of Shaanxi Province(SJ08E104,2010JM6013);Foundation of Shaanxi University of Science and Technology(SUST-A04,ZX08-11)

摘　　要：采用氯磺酸作为磺化试剂, 在多壁碳纳米管上接枝氯磺酰基, 之后通过乙二胺的胺解反应, 制备出胺基修饰的多壁碳纳米管MWCNT-NH2, 并进一步与氯磺酰基酞菁铜反应制备出MWCNT-Pc复合物. 产物采用红外光谱,紫外可见, 拉曼光谱, X射线光电子能谱, 循环伏安, 热重分析等进行了表征. 结果表明, MWCNT-NH2上磺酰胺基接枝在MWCNT表面, 而MWCNT-Pc上的酞菁基团是通过MWCNT-NH2上的酰胺基团与Pc形成复合物, 碳纳米管上约38个碳原子结合一个磺酸基酞菁分子; 该MWCNT-Pc复合物的热稳定性较MWCNT-NH2低; 利用喷涂法构筑了ITO/MWCNT-Pc光电极, 光电性能的研究结果表明在AM1.5光照条件下, 光电压及光电流分别为0.434V和0.158mA/cm^2; 在320nm处的IPCE达19.8%, 具有较优良的光电转化性能. 根据测得的MWCNT-Pc的能带结构, 推知MWCNT-Pc的光诱导电子转移过程是Pc端基发生光激发电子跃迁, 此后电子转移到MWCNTs上并进一步传递到ITO, 完成电荷分离.KNbO3 powders with different phases and morphologies were successfully synthesized through the reaction between KOH and Nb2O5 by microwave-assisted hydrothermal method at 200℃.Pure KNbO3 crystals were obtained when the concentration of KOH was maintained from 10mol/L to 14mol/L.According to the XRD,FESEM and TEM characterizations,it could be observed that as increasing the concentration of KOH from 10mol/L to 15mol/L,the KNbO3 phases changed from rhombohedral to orthorhombic then to tetragonal,and the corresponding morphology of the KNbO3 powders changed from pyramid-like to rod-like then to cubic-like.Some Nb2O5 phases were found when the concentration of KOH increased to 15mol/L.KNbO3 ceramics were sintered from the KNbO3 powders by conventional processing.The piezoeletric properties such as the piezoeletric constant d33,the relative permittivity ε33/ε0,the dielectric loss tanδ,the electromechanical coupling factors kp and the mechanical quality factor Qm of the sintered KNbO3 ceramics were 80 pC/N,302,0.023,0.17,70,respectively.The tetragonal to orthorhombic and cubic to tetragonal phase transitions temperatures were 223℃ and 420℃,respectively.

关 键 词：铌酸钾 微波水热 压电性能 介电性能 

分 类 号：TQ171[化学工程—玻璃工业]