Effect Of Fe Doping On The Structure And Properties Of Barium Zirconate Titanate-based Lead-free Ceramics

Piezoelectric material is a high-performance material that can mutually convert mechanical energy and electrical energy.Piezoelectric ceramics have become one of the most commonly used piezoelectric materials with their excellent electrical properties and simple manufacturing process.Lead element,which generally accounts for more than 70%of lead-based piezoelectric ceramics,has irreversible damage to human health and the environment.Therefore,research on lead-free piezoelectric ceramics that are environmentally friendly and can replace lead-based piezoelectric ceramics in performance has become the current An important subject for researchers.Barium calcium zirconate titanate?BCZT?based lead-free piezoelectric ceramics is a new type of high-performance lead-free piezoelectric ceramics with a high piezoelectric constant and the potential to replace lead-based piezoelectric ceramics.But higher sintering temperature and lower Curie temperature are the key factors hindering its further application.This article starts with the current research status of barium-calcium zirconate titanate system ceramics at home and abroad,using traditional solid-phase sintering method to prepare barium-calcium zirconate titanate-based piezoelectric ceramics with different phase structures,and doping with metal oxide Fe₂O₃Ceramics undergo modification studies.Using X-ray diffraction,scanning electron microscope,dielectric-temperature tester,piezoelectric tester,hysteresis loop tester and other instruments and equipment,the influence of phase boundary and ion doping on the structure and shape of barium calcium titanate ceramics.In order to improve the overall performance of the barium-calcium zirconate titanate system ceramics.The main research and results are as follows:?1?BCZTx(?1-x?%Ba(Zr_0.2Ti_0.8)O₃-x%(Ba_0.7Ca_0.3)Ti O₃)ceramics with x value of44-56 were successfully prepared by traditional solid-phase reaction method.All seven groups of BCZTx ceramics showed a pure perovskite structure with no obvious change in grain size.The study of the phase structure of the system ceramics at room temperature shows that BCZT50 ceramics are in a quasi-homotype phase boundary state,BCZTx ceramics with a value of x less than 50 present a rhombohedral phase,and BCZTx ceramics with a value of x higher than 50 present a tetragonal phase.BCZT50 ceramic has the best performance:Curie temperature 98?,residual polarization intensity 7.41?C/cm²,coercive field 2.31k V/cm.?2?Doping Fe to BCZT44,BCZT50 and BCZT56 ceramics.The results show that Fe ions can completely enter the crystal lattice structure of the ceramic and form a solid solution.The grain size of Fe-BCZTx ceramics will gradually decrease with the increase of Fe ion doping.With the increase of Fe ion content,the Curie temperature of ceramic samples will gradually decrease,and the Curie temperature of the 2%Fe-BCZTx and 4%Fe-BCZTx ceramic samples has been lower than the room temperature.The ferroelectric properties of the doped ceramics are tested,and the results show that the residual polarization of the ceramics will decrease with the increase of Fe doping.2%Fe-BCZT50 ceramics have the smallest coercive field0.52k V/cm.?3?The effect of Fe doping on the energy storage performance of Fe-BCZTx ceramics was studied.The results show that the introduction of Fe ions will significantly change the shape of the hysteresis loop of BCZTx ceramics.With the increase of Fe content,the electric hysteresis loop of the ceramic sample gradually becomes narrower and thinner,and the area decreases accordingly,and the residual polarization intensity shows a significant decrease.Fe doping can improve the energy storage capacity of the BCZTx system ceramics.2%Fe-BCZTx ceramics have the best energy storage performance at room temperature.Fatigue tests on three sets of samples show that at room temperature 2%Fe-BCZTx ceramics have no significant changes in energy storage performance with the increase of the number of applied electric fields.The releasable energy densities of 2%Fe-BCZT44,2%Fe-BCZT50 and2%Fe-BCZT56 ceramics are respectively 0.191J/cm³,0.185J/cm³and 0.190J/cm³,and the energy storage efficiency exceeds 90%.1%Fe-BCZT50 ceramic has little change in energy storage density and energy storage efficiency in the temperature range of50?-150?,showing the best temperature stability of energy storage.