A Vibration Sensor Based On Ferroelectric Ceramic Foam

With the advent of the new technological revolution,the world has begun to enter the era of information intelligence.The new generation of information technology such as IOT,artificial intelligence,and 5G has ushered in unprecedented development.As the sensing basis and data source of the new generation of information technology,sensor plays an important role in the information age.As one of the common sensors,acceleration vibration sensor is used to detect mechanical vibration.Accelerometer is mainly divided into three types,piezoelectric,capacitive and piezoresistive.Among them,piezoelectric accelerometr has high sensitivity,simple structure and best comprehensive performance,but the piezoelectric materials in the current piezoelectric accelerometer are mainly piezoelectric ceramics and thin films,with large elastic coefficient,which are hard and brittle,difficult to produce deformation and affect the sensitivity of the sensor.It is a reasonable and efficient method to develop ferroelectric ceramic nano structure ceramic polymer composite dispersed in polymer matrix.Due to its unique combination mode and different mass ratio or volume ratio,ferroelectric polymer composite has unique excellent performance.It not only has the high-voltage electrical performance of inorganic ferroelectric materials,but also has the advantages of mechanical flexibility and easy processing of polymer materials,which makes it have great application prospects in the field of accelerometer.In this subject,a niobium-doped lead zirconate titanate?PNZT?ferroelectric ceramic foam was prepared.Based on the PNZT ferroelectric ceramic foam,a piezoelectric accelerometer was designed.Its working principle was analyzed.Based on its theoretical model,and the production of PNZT ferroelectric ceramic foam accelerometer was realized,and finally its sensing performance was tested.First,the structure of the accelerometer of PNZT ferroelectric ceramic foam was designed.Its structure mainly includes four parts,which are three-dimensional interconnected PNZT ferroelectric ceramic foam,glass substrate,silver paste electrode and aluminum foil electrode.Then,the working principle of the accelerometer is analyzed to provide the basis for the next theoretical research.Finally,the theoretical model of the acceleration vibration sensor is established,and the theoretical model of the accelerometer under different excitation modes is analyzed.Then,PNZT ferroelectric ceramic foam was prepared by sol-gel method,and its microstructure was characterized.The X-ray diffraction?XRD?spectrum was used to investigate the annealing temperature of the PNZT ferroelectric ceramic foam.The results showed that the PNZT ferroelectric ceramic foam with an annealing temperature of 800?C had the best crystallization and almost no undesired Peaks.800?C was selected as the annealing temperature.It can be seen from the scanning electron microscope?SEM?photos that the PNZT ferroelectric ceramic foam is composed of interconnected uniform pores with an average pore size of about 100?m and the thickness of the PNZT ferroelectric ceramic foam skeleton is about 20?m.Based on the prepared PNZT ferroelectric ceramic foam,two PNZT ferroelectric ceramic foam polymers were prepared,namely polydimethylsiloxane?PDMS?-PNZT ferroelectric ceramic foam polymer material and polyvinylidene fluoride.Ethylene?PVDF?-PNZT ferroelectric ceramic foam polymers and their microstructures were characterized.The PNZT ferroelectric ceramic foam was placed in a completed mold,and then PDMS and PVDF solutions were added dropwise,so that the polymer solution was fully mixed with the PNZT ferroelectric ceramic foam,and finally heated and cured to obtain two flexible PNZT ferroelectric ceramic foams polymers.It can be seen from their SEM photos that the pores of the PNZT ferroelectric ceramic foam are filled with a polymer solution,and the PNZT ferroelectric ceramic foam is uniformly compounded with the polymer.Finally,the glass plate was used as the substrate,the silver paste and aluminum foil were the upper and lower electrodes respectively,and the piezoelectric ceramic foam and its polymer material were used as the conversion elements.The prepation of the PNZT ferroelectric ceramic foam accelerometer was completed,and its sensing performance is tested.The test results show that under the excitation of a sinusoidal signal with a frequency of 80Hz,the output voltage also increases as the excitation acceleration value increases.When the excitation acceleration is 4.26g,the output voltage amplitude is about 7.34?10^-4V.The sine waveform corresponding to the output voltage is the same as the waveform period of the input signal and has a good response relationship.At the same time,PNZT ferroelectric ceramic foam accelerometer has a good linear relationship between the acceleration and output voltage,and the linearity is high,the sensitivity can reach 0.4m V/g.