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Preparation Of NBT-KBT-BT Based Lead-free Ceramics And Its Piezoelectric,Luminescent Properties

Posted on:2021-05-18Degree:MasterType:Thesis
Country:ChinaCandidate:N JiaoFull Text:PDF
GTID:2491306503974839Subject:Materials Science and Engineering
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Piezoelectric ceramics are widely used in sensors,transducers,photocatalysis,fluorescence and other fields.The piezoelectric properties,fluorescence properties and bandgap of these ceramics can be tuned and controlled by designing their composition.Previous studies have shown that lead-based ceramics have better piezoelectric properties and higher temperature stability.However,lead is very harmful to the environment and human health.Lead-free piezoelectric materials have attracted more and more attention in recent years.Among many lead-free piezoelectric ceramics,(Na,Bi)TiO2(NBT)has high piezoelectric properties and compact structure.In this work,the piezoelectric properties,bandgap and fluorescence properties of(Na,Bi)TiO3(NBT)based ceramics were studied by doping with Ni2+,Sm3+,respectively.0.90Na0.5Bi0.5(Ti(1-x/0.90)Nix/0.90)O3-0.05K0.5Bi0.5TiO3-0.05BaTiO3(x=0~-0.03)and 0.90(Na0.5Bi0.5.x/0.90Smx/0.90)TiO3-0.05K0.5Bi0.5TiO3-0.05BaTiO3(x=0.00-0.015)were prepared by the traditional solid-state reaction method.They were characterized and studied systematically.In the second chapter,the narrow bandgap,high voltage electrical system of 0.90Na0.5Bi0.5(Ti(1-x/0.90)Nix/0.90)O3-0.05K0.5Bi0.5TiO3-0.05BaTiO3 was studied.The results show that the tetragonal phase P4bm and the rhombohedral phase R3c coexist regardless of Ni2+ doping level.With the increase of Ni2+ concentration,the volume fraction of tetragonal phase P4bm increased gradually.Because of the scaffold effect of Ni2+ ions,the bandgap decreases from 3.02 eV to 2.5 eV and the absorption of visible light was enhanced.When x=0.01,the piezoelectric properties reach the peak,d33=162 pCN-1,Pr=24.4 μC cm-2,εr=1119,tanδ=0.033,Eg=2.5 eV.In the third chapter,0.90(Na0.5Bi0.5-x/0.90Smx/0.90)TiO3-0.05K0.5Bi0.5TiO3-0.05BaTiO3 was synthesized and systematically characterized.The introduction of Sm3+makes the system emit 563 nm,597 nm and 645 nm fluorescence under 480 nm excitation light.With the increase of Sm3+ concentration,the fluorescence intensity increases gradually.SEM images show the grain size decreases with the increase of Sm3+concentration.When x=0.003,the piezoelectric properties meet the peak point,d33=193 pC N-1,Pr=32.5 μC cm-2r=964,tanδ=0.0279.
Keywords/Search Tags:lead-free piezoelectric ceramics, sodium bismuth titanate, piezoelectricity, bandgap, luminescence
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