Design Manufacture And Characteristic Research Of Lead-Free Piezoelectric Sensor

Lead-free piezoelectric ceramics have good piezoelectric properties and environmentally friendly characteristics,which can be used to make environmentally friendly piezoelectric sensors.In this paper,the composition design,preparation process,performance test of lead-free piezoelectric ceramics and its application in piezoelectric acceleration sensors are studied.Lead-free piezoelectric acceleration sensors have the advantages of small size,light weight,high sensitivity,environmental friendliness,and easy installation.The performance of a piezoelectric accelerometer is closely related to the piezoelectric ceramic material used in its core varistor.Three kinds of lead-free piezoelectric ceramics（1-x）K_0.5Na_0.5NbO_3-xCaZrO₃（x=0.020,0.023,0.033,0.044）,（1-x）K_0.5Na_0.5NbO_3-xBaZrO₃（x=0.035,0.046,0.055,0.065）and Ba_0.85Ca_0.15Zr_0.1Ti_0.9O₃（sintering temperature is 1250°C,1270°C,1290°C）were prepared by traditional solid-phase sintering method,and were tested and analyzed.The results show that:（1）In the（1-x）K_0.5Na_0.5NbO_3-xCaZrO₃ lead-free piezoelectric ceramic system,when the CaZrO₃doping amount is x=0.033 and the sintering temperature is 1161°C,the comprehensive performance is the best,in which the piezoelectric constant d₃₃=114p C/N,the electromechanical coupling coefficient k_p=0.21,the resonance frequency f_r=295k Hz,the anti-resonance frequency f_a=300k Hz,and the frequency constant（N_p）is 2540Hz·m;（2）（1-x）K_0.5Na_0.5NbO_3-xBaZrO₃ lead-free piezoelectric ceramic system has good comprehensive performance when the doping amount is x=0.046 and the sintering temperature is 1158°C,in which the piezoelectric constant is d₃₃=141p C/N,the electromechanical coupling coefficient k_p=0.22,the resonance frequency f_r=333k Hz,the anti-resonance frequency f_a=340k Hz,and the frequency constant（N_p）is2867Hz·m;（3）By exploring the sintering temperature of(Ba_0.85Ca_0.15Zr_0.1Ti_0.9O₃),it is found that BCZT-based lead-free piezoelectric ceramics exhibit better comprehensive performance at a sintering temperature of 1270°C.Its piezoelectric constant is d₃₃=206p C/N,and the electromechanical coupling coefficient k_p=0.16.At this time,the resonance frequency f_r=319k Hz,the anti-resonance frequency f_a=322k Hz,and the frequency constant（N_p）is 2747Hz·m.The lead-free piezoelectric acceleration sensors are fabricated by using the above three piezoelectric materials as the pressure sensitive elements,and they are numbered 1,2 and 3 in sequence.The test results show that the charge sensitivity of these sensors is S₁=0.53p C/m·s^-2,S₂=0.72p C/m·s^-2,and S₃=1.03p C/m·s^-2,respectively.In addition,the maximum linear error of the temperature response isδ_t1=5.40%,δ_t2=5.88%,δ_t3=4.10%,and the maximum linear error of the acceleration response isδ_a1=5.36%,δ_a2=5.90%,δ_a3=4.17%,which are basically controlled within10%.Through long-term testing of the sensitivity of the sensor,it is found that the sensitivity of the three lead-free piezoelectric acceleration sensors has a small range,and has good long-term stability.Piezoelectric acceleration sensors can effectively protect the environment by using lead-free piezoelectric material components,providing important support for future sustainable development.