Fabrication And Performance Studies Of BCZT/epoxy Lead-free Piezoelectric Composites With Spiral Structure

Piezoelectric composites have been widely applied in medical testing,acoustic transducer,nondestructive testing and other areas because of the good properties of both the ceramics and the polymers they possess.In this paper,A novel BCZT ceramic/epoxy resin composite with spiral structure was fabricated by a roll forming-curling method,the composite was consist of spiral ceramic rings and epoxy resin.We talked about the effect of the sintering temperature,surface preparation,polarization process on the properties of the composites.The effect of the volume fraction of ceramics and aspect ratio Lw/Lt were also researched.We found the best way to fabricate the piezoelectric composites and got the best properties.The results show that we can get the composites with any volume fraction of the ceramic by the rolling-culling the film method.The sintering temperature is 1450°C.The polarization electric field is 2.1KV/mm,the polarization time is 15 min,and the polarization temperature is 30°C.The piezoelectric,dielectric and electromechanical coupling properties can be controlled by adjusting the volume fraction of the ceramics.A high electromechanical coupling property(Kt=47.6%)and the low acoustic impedance(Z=8 Mrayls)were obtained at 30% volume fraction of ceramic phase.Composite with a 20% volume fraction was found to possess the figure of merit(FOM)maximum value of 56.9×10-12m2/N.Meanwhile,the curie temperature was enhanced by the epoxy resin,and the stability of properties versus temperature was also improved.The electromechanical coupling property(Kt)can be also improved by reducing the aspect ratio Lw/Lt.The low acoustic impedance(Z)reduces with the decrease of the Lw/Lt.