performance test of 1 - 3 type piezoelectric composite material

The prepared l-3 type piezoelectric ceramics composite was tested using the Agllent E499lA RF impedance/material analyzer manufactured by Agilent. Compared to traditional network analyzers, the frequency impedance/material analyzer has a wide measurement range. The measurable frequency range is from 3MHz to 3gHz (measurement accuracy is 1 Mhz); the impedance is tested at 50 compared to the network analyzer. The measurement accuracy is high, when the test material impedance value deviates from 50. The measurement accuracy will be worse; the Agilent E499lA RF impedance/material analyzer can measure the impedance of non-50 devices.

It can be seen from the test results that the series and parallel resonant frequencies of the l-3 type Pzt disc piezoelectric ceramic are 45.968 MHz and 60.253 MHz; the center frequency is 53 MHz, and the electromechanical coherence factor k is 0.6842.Compared with single-phase piezoelectric ceramic PZT-SH, its electromechanical coincidence coefficient is increased by 33.3% compared to single phase pressure.The piezoelectric properties of the electric ceramics have been significantly improved.

 Using PZT--SH piezoelectric materials piezoelectric transducer that have been polarized, using the cutting and filling method, the PZT material is at its pole.The cross-sectional area of the piezoelectric ceramic column is square, the column width is 36.03 um, and the thickness d is A piezoelectric ceramic post with a period of 36.52 um, in which the slit width is 24.14 um. Finally obtained piezoelectric ceramic phase.The material volume fraction ear is 35.84% of the l-3 type piezoelectric composite material.

The prepared 1-3 type piezoelectric tube scanner is slowly solidified by a slow temperature and a vacuum-free condition, so that it is well bonded to the piezoelectric phase. The performance of the prepared l-3 type piezoelectric composite was tested by Agilent E499lA RF impedance/material analyzer. The series and parallel resonant frequencies of the piezoelectric composite were 45.968 MHz and 60.253 MHz, respectively. The center frequency is fc is about 53MHz, and the electromechanical coincidence coefficient k is 0.6842. Compared with the single-phase piezoelectric ceramic PZT--SH, the electromechanical coincidence coefficient is increased by 33.3% compared with the single-phase piezoelectric ceramic pressure. The electrical performance has been significantly improved.

Finally, WA Smith established model of the 1-3 composite material, it is concluded that the thickness mode electromechanical coincidence coefficient of the 1-3 type piezoelectric ultrasonic transducer is between 30% and 80% of the piezoelectric phase volume fraction. The trend of change is slow, and when the volume fraction varies between 60% and 80%, the electromechanical coincidence coefficient of the l-3 type piezoelectric composite is almost twice that of the single-phase piezoelectric ceramic; for the same polymer Type piezoelectric composites, as long as the volume fraction of the functional piezoelectric material generally PZT is the same, regardless of how the columns are arranged in the polymer, the cross-sectional shape of the column is relatively constant. And the dielectric constant of piezoelectric ceramic element increases with the increasing of the volume fraction of the piezoelectric ceramic phase, which increases substantially linearly; since the piezoelectric ceramic material generally has a higher density than the non-piezoelectric phase (generally a polymer).

The density of the material is so as the volume fraction of the piezoelectric material increases, the proportion of the non-piezoelectric phase material in the composite material will become smaller and smaller, thus forming the l-3 type piezoelectric composite material. Density will also increase substantially Trend; With the increase of volume fraction of piezoelectric phase materials, the sound velocity of l-3 type piezo acoustic piezoelectric sensor also increases basically; however, its growth trend is basically divided into three segments, of which the pressure is reduced with low volume fraction. When the volume fraction of the electric phase material increases, the speed of sound increases rapidly; when the volume fraction of the piezoelectric phase is between 30% and 80%,The speed of sound increases substantially linearly; when the volume fraction exceeds 80%, the growth trend begins to increase again.

The cause of this phenomenon, as the volume fraction increases, which needs to  overcome from larger mass loads. The speed of sound is also just beginning to increase but due to the action of the polymer, it then begins to fall and finally begins to increase. And the effect of the aspect ratio of the piezoelectric phase and the aspect ratio on the composite material of the l-3 composite is studied. The length-to-width ratio of the cross-section of the piezoelectric transducer oscillator is l type, that is, when the cross-section is square, The hydrostatic pressure constant and the hydrostatic pressure sensitivity value are ideal. In order to ensure a good thickness vibration mode of the l-3 type piezoelectric composite material, the interference of the vibration mode (such as the vibration mode) to the thickness vibration mode is suppressed as much as possible to ensure the directivity thereof. Its aspect ratio should be less than l type.