Sodium Bismuth Titanate Lead-Free Piezoelectric Device’s Fabrication And Performance Optimization

The piezoelectric ceramic material is a very important high-tech material insociety today. But the composite materials of piezoelectric ceramic are mainlywith Pb. The composition of Pb would be caused pollution when it is sintering inhigh temperature and abandoned without effective treatment. The lead-freepiezoelectric ceramics such came into being as emerge as the times require,especially sodium bismuth titanate lead-free piezoelectric ceramics, with itsexcellent performance began a new chapter of lead-free piezoelectric ceramics.The production by the subject of sodium bismuth titanate lead-free piezoelectricceramics have high piezoelectric coefficient, and use in the self test function ofmicro piezoelectric pump. Lead-free piezoelectric vibrator piezoelectric pumpcan be used in medicine, biotechnology and other high-tech fields.Make the lead-free powder of Zrx(Bi0.5Na0.5)0.94Ba0.06Ti1-xO3by using thesol-gel method. Through the SEM and XRD, analyse the microstructure of thematerial, determine the particle size morphology, and surface activity.Make the BNT-BT powder by using the traditional solid-phase method.Through many experiments the optimum process parameters are as follows:milling time is15hours, the best of pre-sintering temperature is850℃, theoptimum sintering temperature is1180℃, keep the temperature for3hours, thepolarization field strength is2.6KV and the polarization time is15minutes.Make the BNT-BT powder by using the sol-gel process. It can be drawn theoptimum process parameters as follow by the X-ray diffraction, scanning electronmicroscope picture and the final performance test results: the temperature of sol-gel is40~60℃, the best of pre-sintering temperature is650℃, the optimumsintering temperature is1150°C, keep the temperature for3hours, thepolarization field strength is2.6KV and the polarization time is15minutes. Alsoit has the appropriate introduction of Zr elements for the performance improvement. After the performance test, it shows: when x=0.10, piezoelectricproperties have achieved the best, the piezoelectric coefficient has reached218PC/N.Synthesize ternary lead-free piezoelectric powder by the sol-gel of0.852(Na0.5Bi0.5)TiO3-0.028Ba(ZrxTi1-x)O3-0.12(K0.5Bi0.5)TiO3, and byintroducing Zr doping to improve its piezoelectric properties. The experimentalresults show that: when x=0.15, the lead-free piezoelectric vibrator is tripartite-tetragonal perovskite structure, the piezoelectric coefficients d33has reached225PC/N, electromechanical coupling factor Kp is38.7%, the mechanical qualityfactor Qmis137, dielectric loss tgδ and dielectric constant εr are0.038and727.The overall performances meet the requirements of the project and achieve thedesired vision.