Affect Of A/B-site Replace Of The Same Valence Elements And Sintering Aids On The Performance Of KNN-based Lead-free Piezoelectric Ceramics

Lead-based piezoelectric ceramics, such as Pb（Zr,Ti）O₃andPb(Mg_1/3Nb_2/3)O₃-PbTiO₃, have been widely used in different fields due to its excellentpiezoelectric and dielectric performances. But, serious environmental pollution hasbeen made by a large amount of lead. Therefore, it becomes inevitable thatlead-based piezoelectric ceramics should be replaced by lead-free materials. Theelectrical properties of doped KNN based lead-free ceramics are comparable to thetraditional PZT piezoelectric ceramics. So the synthesis of high quality lead-freepiezoelectric ceramics becomes an important research topic.Typical perovskite structure of potassium sodium niobate （KNN） based lead-freepiezoelectric ceramic was synthesized as the research object, potassium sodiumniobate based ceramic material doped with different elements and sintering aidswere prepared by a conventional solid-state method. The KNLN, KNLS, and KNLTceramics were prepared by a conventional solid-state reaction process, where x=0,0.01,0.03,0.05,0.07,0.09, respectively. In addition, the influence of two sinteringaids of CuO and CeO₂on the structure and performance of ceramics was studied. Thecrystal structure and the electrical performance of the samples were analyzed by theX-ray diffraction method （XRD）, Scanning electron microscope（SEM）, Piezoresponseforce microscope （PFM）, etc. The impact of A, B-substituted modified and sinteringaids on the structure and performance of KNN based lead-free piezoelectric ceramicswas studied and its mechanism was preliminarily discussed. The aim of the study wasto explore the change of the microstructure and physical properties of the materialsafter doping different elements. Expect to find the variations of doping different ionsin Sodium Potassium Niobate-based Lead-free Piezoelectric Ceramics. In addition, the relationship between electrical properties and shrinkage duringsintering was also discussed. We found that the electrical properties of ceramicsdidn’t show its optimum at maximal shrinkage. The ceramics represent optimalelectrical properties at an appropriate shrinkage ratio. A piezoresponse forcemicroscope （PFM） was used to investigate the surface domain structures of thepolished samples by means of contact topography and piezoresponse modes.