Ordered coalescence of nano-crystals in alkaline niobate ceramics with high remanent polarization  

作　　者：Zhijian Shen Daniel Gruner Mirva Eriksson Lyubov M.Belova Ce-Wen Nan Haixue Yan 

机构地区：[1]Department of Materials and Environmental Chemistry,Arrhenius Laboratory,Stockholm University,10691,Stockholm,Sweden [2]Department of Materials Science and Engineering,Royal Institute of Technology,10044,Stockholm,Sweden [3]School of Materials Science and Engineering,Tsinghua University,Beijing,100084,China [4]School of Engineering and Materials Science,Queen Mary University of London,Mile End Road,London,E14NS,UK

出　　处：《Journal of Materiomics》2017年第4期267-272,共6页无机材料学学报（英文）

基　　金：This work was supported by grants of the Swedish Research Council(to Z.S.and L.B.);the Royal Society(to Z.S.and H.Y.);the National Natural Science Foundation of China(to C.N.and Z.S.);L.B.acknowledges support from the Knut and Alice Wallenberg Foundation and the Swedish Foundation for Strategic Research.SEM and TEM studies were performed at the Electron Microscopy Centre at Arrhenius Laboratory,Stockholm University,which is supported by the Knut and Alice Wallenberg Foundation.

摘　　要：Lead-free alkali niobates Na_(0.5)K_(0.5)NbO_(3)(NKN)ceramics,with significantly enhanced ferroelectric remanent polarization(Pr),were prepared using Spark Plasma Sintering(SPS).Three types of boundaries were observed in the ceramics,being grain boundaries between faceted grains,domain boundaries that separate ferroelectric domains inside individual grains,and nanoscale sub-grain boundaries that reveal the nano-scale mosaicity of individual grains.Part of the sub-grain boundaries were from initial powder particles.The other sub-grain boundaries were built by ordered coalescence of nano-crystals during rapid SPS process.It was worthwhile to emphasize that the ordered coalescence of nano-crystals in bulk ceramics during sintering takes place and completes within minutes.These sub-grain features would disappear at higher temperature by long time sintering.Rapid Spark Plasma Sintering allowed us to capture this transient microstructure.The significantly enhanced ferroelectric Pr of NKN was attributed to nanoscale sub-boundaries,which stimulated the dynamics of ferroelectric domain formation and switching.

关 键 词：LEAD-FREE NKN SPS Remanent polarization Ordered coalescence 

分 类 号：TQ1[化学工程]