Wang Lu, Qi He, Gao Botao, Liu Ye, Liu Hui, Chen Jun
Beijing Advanced Innovation Center for Materials Genome Engineering, University of Science and Technology Beijing, Beijing 100083, China.
Department of Physical Chemistry, University of Science and Technology Beijing, Beijing 100083, China.
Mater Horiz. 2022 Mar 7;9(3):1002-1009. doi: 10.1039/d1mh01680f.
The development of high-performance lead-free piezoceramics for replacing Pb-based perovskites has attracted lots of attention, and comparable room-temperature piezoresponse has been realized in (Na,K)NbO and BaTiO-based ceramics with local structure heterogeneity adjusting polymorphic phase boundary. In this work, a new method of oxygen octahedron tilt design is used in NaNbO-based lead-free ceramics, which usually shows complex oxygen octahedron tilt information inherited from NaNbO. The substitution of Ba(FeNb)O and BaTiO with high tolerance factor into NaNbO leads to a gradual elimination of anti-parallel cation displacement and anti-phase tilt along the three axes; as a result, a single tetragonal phase with 4 space group and only in-phase tilt along axis is achieved in 0.88NaNbO-0.04Ba(FeNb)O-0.08BaTiO ceramic. Accompanying the decreased oxygen octahedral tilt degree, a drastically improved up to 367 pC N (over ten times that of NaNbO ceramic) is obtained, reaching a record high in NaNbO-based lead-free ceramics. Together with temperature insensitive piezoresponse originating from thermally stable oxygen octahedral tilt structure, the studied NaNbO-based materials show large potential for replacing Pb-based ceramics in some electronic devices. The oxygen octahedron tilt engineering would be used for designing more high-performance lead-free ceramics with high piezoresponse and excellent thermal stability simultaneously.
开发用于替代铅基钙钛矿的高性能无铅压电陶瓷备受关注，通过调整多晶型相界的局部结构异质性，在（钠，钾）铌酸盐和钛酸钡基陶瓷中实现了可比的室温压电响应。在这项工作中，一种新的氧八面体倾斜设计方法应用于铌酸钠基无铅陶瓷，该陶瓷通常呈现出从铌酸钠继承而来的复杂氧八面体倾斜信息。用高容忍因子的钡（铁铌）酸盐和钛酸钡替代铌酸钠，导致沿三个轴的反平行阳离子位移和反相倾斜逐渐消除；结果，在0.88铌酸钠-0.04钡（铁铌）酸盐-0.08钛酸钡陶瓷中获得了具有4空间群且仅沿轴的同相倾斜的单一四方相。随着氧八面体倾斜度的降低，获得了大幅提高至367皮库仑/牛顿（是铌酸钠陶瓷的十倍以上），在铌酸钠基无铅陶瓷中达到了创纪录的高水平。连同源自热稳定氧八面体倾斜结构的对温度不敏感的压电响应，所研究的铌酸钠基材料在某些电子器件中显示出替代铅基陶瓷的巨大潜力。氧八面体倾斜工程将用于同时设计更多具有高压电响应和优异热稳定性的高性能无铅陶瓷。
