The Time And Frequency Domain On Test Theory And Method Of Pzt Piezoelectric Ceramics Thick Film Using Ultrasound

In recent years, the piezoelectric ceramics material has been more and more important used in the industry, civil and military. And zirconium titanic acid lead piezoelectric ceramics aslo called (PZT), because of the outstanding electrical machinery performance, curie temperature and stabile piezoelectricity performance, it is more advantage than other types of piezoelectric ceramics. In produces and life application, it is getting more and more used. Now, comparing the PZT thick film with its thin film, PZT thick film has the bigger driving force and the more obvious piezoelectric effect, and the PZT piezoelectricity thick film material not only has the merit of block body material but also the membranous material, therefore in the preparation of piezoelectricity, ferroelectricity and pyroelectric component, the PZT thick film has widespread application.Ultrasonic measurement has high examination sensitivity, strong penetrability, the simple equipment and the inexpensive expense, and more importmantly, it does not have injury to the human body, so the ultrasonic measurement is becoming more and more important in life.When material thickness d is smaller than its longitudinal wave length ? , we call that this material is the thin layer material. If using conventional ultrasonic measurement, it is unable to separate its each echo signal, therefore we use frequency and time domain of low-frequency ultrasound measurement to characterize the thick film sample.In this paper, we first use the frequency domain of ultrasound measurement, and then infer the theoretical calculation formulation which this experiment needs, according to the computational method of the thin layer based on the substrate, we infer the computational method of the thin layer which does not include the substrate. According to the formulation, we can calculate the speed, the thickness and the attenuation of PZT piezoelectricity thick film .We also carry the analysis on the computed result.Then, we use another measurement called the time domain on low-frequency ultrasound measurement to characterize, this methond contains convolution and the reversion convolution. Firstly we have analyzed that in the water immersion coupling situation, we send ultrasound to incidence piezoelectric ceramics thick film, after the ultrasonic wave passes through the sample, we analyze the compsition of ultrasonic wave. Then we define the reference signal as theory transmission signal, comparise the theoretical calculation's transmission signal with the transmission signal by the experiment, estimate the the characteristic parameter of valuepiezoelectric ceramics thick film, and analyze the factor which can influence the parameter estimated value in the experiment.Because of the speed of convolution method in time domain is slow, we adopte another kind method to characterize. This is called reversion convolution method. In this method, we have defined the transmission recollection impact response function, and then we use it and the transmission signal from measurement to calculate the theory incident signal, Then we make theoretical incident signal by calculation comparise with the incident signal by experiment, and at last we estimate the characteristic parameter value of the sample.After comparise these two kinds of method, we discover that the reversion convolution method in time domain is ten times faster than usual convolution method. It is more efficiency in calculation.