Ultrasonic sensor, piezoelectric composite ceramic chip and preparation method of blank of piezoelectric composite ceramic chip

Abstract

The invention relates to a sensor, in particular to an ultrasonic sensor, a piezoelectric composite ceramic piece and a preparation method of a blank of the piezoelectric composite ceramic piece, and the preparation method comprises the following steps: S1, arranging two division bars on one surface of the piezoelectric ceramic piece at an interval; s2, the area between the two parting strips is filled with a polymer to form a polymer phase, and the polymer phase is flush with the tops of the parting strips; s3, another piezoelectric ceramic piece is attached to the top of the polymer phase, and the parting strip is located between the two corresponding adjacent piezoelectric ceramic pieces; and S4, superposing the piezoelectric ceramic pieces layer by layer to form a piezoelectric composite ceramic piece blank. According to the preparation method of the piezoelectric composite ceramic piece blank, the distance between the adjacent piezoelectric ceramic pieces is only controlled by the thickness of the parting strips and is not limited by the defects of a traditional cutting-pouring method, and the minimum thickness can be achieved. The number of bubbles in the piezoelectric composite ceramic piece blank is smaller, the manufactured piezoelectric composite ceramic piece blank is higher in quality, and the performance of an ultrasonic sensor product is better.

Description

technical field [0001] The invention relates to a sensor, in particular to an ultrasonic sensor, a piezoelectric composite ceramic sheet and a preparation method thereof. Background technique [0002] In the actual application scenarios of ultrasonic sensors with air / gas as the coupling medium, the high impedance difference between the sensor sensitive element and the measured medium is a key factor restricting the development of ultrasonic sensor technology. The acoustic impedance of gaseous media such as air, natural gas, and biogas is very small. For example, the acoustic impedance of air is only 420Rayl, while the acoustic impedance of conventional piezoelectric materials is as high as 30×10 6 -40×10 6 Rayl, such a high impedance difference reduces the ultrasonic energy entering the medium, which directly affects the performance of the sensor. [0003] From the current public reports, it is the most direct way to reduce the high impedance difference between the sensiti...

AI Technical Summary

Problems solved by technology

[0004] The traditional 2-2 type piezoelectric composite preparation method is generally the cutting-casting method, but limited by the thickness of the slicer blade, it is difficult to prepare a piezoelectric composite material with a sufficiently small thickness of the polymer phase.

Piezoelectric ceramics cut by a slicer still have edge chipping, which affects the performance of composite piezoelectric materials

And it will produce a large mechanical impact during the cutting process, so it cannot be used to make composite materials with thin piezoelectric phases

In the patent CN111848001A, the cutting-casting method is used to prepare the 2-2 type piezoelectric composite material, so the above-mentioned defects are unavoidable in the preparation process

Patent CN105702851B adopts centrifugal pouring method to prepare 2-2 piezoelectric composite materials. Although it can overcome the above shortcomings and make the polymer phase thin enough, it needs to strictly control the centrifuge speed and centrifugation time, and the process is relatively complicated.

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