打磨引起的残余应力对BaTiO_(3)陶瓷挠曲电响应的影响

Effects of residual stress caused by abrasion on the flexoelectric response of BaTiO_(3)ceramics

铁电陶瓷中测量得到的大的挠曲电响应可以用来源于应力弛豫的自发极化表面层机理来解释。然而,产生极化表面层的应力来源尚未完全清楚。本工作系统地研究了表面应力对不同粒度砂纸打磨的BaTiO_(3)陶瓷的微观结构、介电性能和挠曲电响应的影响。与原始样品相比,打磨后的BaTiO_(3)陶瓷的挠曲电系数由~600μC/m降至200μC/m以下。但经过200℃热处理并且缓慢冷却后,所有样品的挠曲电系数都恢复到~500μC/m。结果表明,打磨在铁电陶瓷的表面层上引入了应力,在一定程度上影响了其挠曲电响应,但打磨引入的应力不是极化表面层形成的主要原因。

The spontaneously polarized surface layer,which originates from stress relaxation,has been proposed for the unexpectedly large flexoelectric response measured in ferroelectric ceramics.However,the source of the stress that led to the polarized surface layer is still not completely known.In this work,the effect of surface stress on the microstructure,dielectric properties and flexoelectric response of BaTiO_(3) ceramics abraded by abrasive papers of various grit sizes was systematically studied.Compared with the as-prepared sample,the flexoelectric coefficients of abraded BaTiO_(3)ceramics decreased from~600μC/m to less than 200μC/m.The flexoelectric coefficients of all the samples,however,recovered to~500μC/m following heat treatment at 200°C and a subsequent slow cooling process.The results indicate that abrasion can introduce stress on the surface layers and affect the flexoelectric response of ferroelectric ceramics to some extent,but the stress is not the main reason for the formation of polarized surface layers.